x86/speculation/mds: Fix documentation typo
[linux/fpc-iii.git] / mm / hugetlb.c
blob64a62584290c48b1e597c84fdeee95c290b894ea
1 /*
2 * Generic hugetlb support.
3 * (C) Nadia Yvette Chambers, April 2004
4 */
5 #include <linux/list.h>
6 #include <linux/init.h>
7 #include <linux/mm.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/mmdebug.h>
22 #include <linux/sched/signal.h>
23 #include <linux/rmap.h>
24 #include <linux/string_helpers.h>
25 #include <linux/swap.h>
26 #include <linux/swapops.h>
27 #include <linux/jhash.h>
29 #include <asm/page.h>
30 #include <asm/pgtable.h>
31 #include <asm/tlb.h>
33 #include <linux/io.h>
34 #include <linux/hugetlb.h>
35 #include <linux/hugetlb_cgroup.h>
36 #include <linux/node.h>
37 #include <linux/userfaultfd_k.h>
38 #include "internal.h"
40 int hugepages_treat_as_movable;
42 int hugetlb_max_hstate __read_mostly;
43 unsigned int default_hstate_idx;
44 struct hstate hstates[HUGE_MAX_HSTATE];
46 * Minimum page order among possible hugepage sizes, set to a proper value
47 * at boot time.
49 static unsigned int minimum_order __read_mostly = UINT_MAX;
51 __initdata LIST_HEAD(huge_boot_pages);
53 /* for command line parsing */
54 static struct hstate * __initdata parsed_hstate;
55 static unsigned long __initdata default_hstate_max_huge_pages;
56 static unsigned long __initdata default_hstate_size;
57 static bool __initdata parsed_valid_hugepagesz = true;
60 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
61 * free_huge_pages, and surplus_huge_pages.
63 DEFINE_SPINLOCK(hugetlb_lock);
66 * Serializes faults on the same logical page. This is used to
67 * prevent spurious OOMs when the hugepage pool is fully utilized.
69 static int num_fault_mutexes;
70 struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
72 /* Forward declaration */
73 static int hugetlb_acct_memory(struct hstate *h, long delta);
75 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
77 bool free = (spool->count == 0) && (spool->used_hpages == 0);
79 spin_unlock(&spool->lock);
81 /* If no pages are used, and no other handles to the subpool
82 * remain, give up any reservations mased on minimum size and
83 * free the subpool */
84 if (free) {
85 if (spool->min_hpages != -1)
86 hugetlb_acct_memory(spool->hstate,
87 -spool->min_hpages);
88 kfree(spool);
92 struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
93 long min_hpages)
95 struct hugepage_subpool *spool;
97 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
98 if (!spool)
99 return NULL;
101 spin_lock_init(&spool->lock);
102 spool->count = 1;
103 spool->max_hpages = max_hpages;
104 spool->hstate = h;
105 spool->min_hpages = min_hpages;
107 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
108 kfree(spool);
109 return NULL;
111 spool->rsv_hpages = min_hpages;
113 return spool;
116 void hugepage_put_subpool(struct hugepage_subpool *spool)
118 spin_lock(&spool->lock);
119 BUG_ON(!spool->count);
120 spool->count--;
121 unlock_or_release_subpool(spool);
125 * Subpool accounting for allocating and reserving pages.
126 * Return -ENOMEM if there are not enough resources to satisfy the
127 * the request. Otherwise, return the number of pages by which the
128 * global pools must be adjusted (upward). The returned value may
129 * only be different than the passed value (delta) in the case where
130 * a subpool minimum size must be manitained.
132 static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
133 long delta)
135 long ret = delta;
137 if (!spool)
138 return ret;
140 spin_lock(&spool->lock);
142 if (spool->max_hpages != -1) { /* maximum size accounting */
143 if ((spool->used_hpages + delta) <= spool->max_hpages)
144 spool->used_hpages += delta;
145 else {
146 ret = -ENOMEM;
147 goto unlock_ret;
151 /* minimum size accounting */
152 if (spool->min_hpages != -1 && spool->rsv_hpages) {
153 if (delta > spool->rsv_hpages) {
155 * Asking for more reserves than those already taken on
156 * behalf of subpool. Return difference.
158 ret = delta - spool->rsv_hpages;
159 spool->rsv_hpages = 0;
160 } else {
161 ret = 0; /* reserves already accounted for */
162 spool->rsv_hpages -= delta;
166 unlock_ret:
167 spin_unlock(&spool->lock);
168 return ret;
172 * Subpool accounting for freeing and unreserving pages.
173 * Return the number of global page reservations that must be dropped.
174 * The return value may only be different than the passed value (delta)
175 * in the case where a subpool minimum size must be maintained.
177 static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
178 long delta)
180 long ret = delta;
182 if (!spool)
183 return delta;
185 spin_lock(&spool->lock);
187 if (spool->max_hpages != -1) /* maximum size accounting */
188 spool->used_hpages -= delta;
190 /* minimum size accounting */
191 if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
192 if (spool->rsv_hpages + delta <= spool->min_hpages)
193 ret = 0;
194 else
195 ret = spool->rsv_hpages + delta - spool->min_hpages;
197 spool->rsv_hpages += delta;
198 if (spool->rsv_hpages > spool->min_hpages)
199 spool->rsv_hpages = spool->min_hpages;
203 * If hugetlbfs_put_super couldn't free spool due to an outstanding
204 * quota reference, free it now.
206 unlock_or_release_subpool(spool);
208 return ret;
211 static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
213 return HUGETLBFS_SB(inode->i_sb)->spool;
216 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
218 return subpool_inode(file_inode(vma->vm_file));
222 * Region tracking -- allows tracking of reservations and instantiated pages
223 * across the pages in a mapping.
225 * The region data structures are embedded into a resv_map and protected
226 * by a resv_map's lock. The set of regions within the resv_map represent
227 * reservations for huge pages, or huge pages that have already been
228 * instantiated within the map. The from and to elements are huge page
229 * indicies into the associated mapping. from indicates the starting index
230 * of the region. to represents the first index past the end of the region.
232 * For example, a file region structure with from == 0 and to == 4 represents
233 * four huge pages in a mapping. It is important to note that the to element
234 * represents the first element past the end of the region. This is used in
235 * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
237 * Interval notation of the form [from, to) will be used to indicate that
238 * the endpoint from is inclusive and to is exclusive.
240 struct file_region {
241 struct list_head link;
242 long from;
243 long to;
247 * Add the huge page range represented by [f, t) to the reserve
248 * map. In the normal case, existing regions will be expanded
249 * to accommodate the specified range. Sufficient regions should
250 * exist for expansion due to the previous call to region_chg
251 * with the same range. However, it is possible that region_del
252 * could have been called after region_chg and modifed the map
253 * in such a way that no region exists to be expanded. In this
254 * case, pull a region descriptor from the cache associated with
255 * the map and use that for the new range.
257 * Return the number of new huge pages added to the map. This
258 * number is greater than or equal to zero.
260 static long region_add(struct resv_map *resv, long f, long t)
262 struct list_head *head = &resv->regions;
263 struct file_region *rg, *nrg, *trg;
264 long add = 0;
266 spin_lock(&resv->lock);
267 /* Locate the region we are either in or before. */
268 list_for_each_entry(rg, head, link)
269 if (f <= rg->to)
270 break;
273 * If no region exists which can be expanded to include the
274 * specified range, the list must have been modified by an
275 * interleving call to region_del(). Pull a region descriptor
276 * from the cache and use it for this range.
278 if (&rg->link == head || t < rg->from) {
279 VM_BUG_ON(resv->region_cache_count <= 0);
281 resv->region_cache_count--;
282 nrg = list_first_entry(&resv->region_cache, struct file_region,
283 link);
284 list_del(&nrg->link);
286 nrg->from = f;
287 nrg->to = t;
288 list_add(&nrg->link, rg->link.prev);
290 add += t - f;
291 goto out_locked;
294 /* Round our left edge to the current segment if it encloses us. */
295 if (f > rg->from)
296 f = rg->from;
298 /* Check for and consume any regions we now overlap with. */
299 nrg = rg;
300 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
301 if (&rg->link == head)
302 break;
303 if (rg->from > t)
304 break;
306 /* If this area reaches higher then extend our area to
307 * include it completely. If this is not the first area
308 * which we intend to reuse, free it. */
309 if (rg->to > t)
310 t = rg->to;
311 if (rg != nrg) {
312 /* Decrement return value by the deleted range.
313 * Another range will span this area so that by
314 * end of routine add will be >= zero
316 add -= (rg->to - rg->from);
317 list_del(&rg->link);
318 kfree(rg);
322 add += (nrg->from - f); /* Added to beginning of region */
323 nrg->from = f;
324 add += t - nrg->to; /* Added to end of region */
325 nrg->to = t;
327 out_locked:
328 resv->adds_in_progress--;
329 spin_unlock(&resv->lock);
330 VM_BUG_ON(add < 0);
331 return add;
335 * Examine the existing reserve map and determine how many
336 * huge pages in the specified range [f, t) are NOT currently
337 * represented. This routine is called before a subsequent
338 * call to region_add that will actually modify the reserve
339 * map to add the specified range [f, t). region_chg does
340 * not change the number of huge pages represented by the
341 * map. However, if the existing regions in the map can not
342 * be expanded to represent the new range, a new file_region
343 * structure is added to the map as a placeholder. This is
344 * so that the subsequent region_add call will have all the
345 * regions it needs and will not fail.
347 * Upon entry, region_chg will also examine the cache of region descriptors
348 * associated with the map. If there are not enough descriptors cached, one
349 * will be allocated for the in progress add operation.
351 * Returns the number of huge pages that need to be added to the existing
352 * reservation map for the range [f, t). This number is greater or equal to
353 * zero. -ENOMEM is returned if a new file_region structure or cache entry
354 * is needed and can not be allocated.
356 static long region_chg(struct resv_map *resv, long f, long t)
358 struct list_head *head = &resv->regions;
359 struct file_region *rg, *nrg = NULL;
360 long chg = 0;
362 retry:
363 spin_lock(&resv->lock);
364 retry_locked:
365 resv->adds_in_progress++;
368 * Check for sufficient descriptors in the cache to accommodate
369 * the number of in progress add operations.
371 if (resv->adds_in_progress > resv->region_cache_count) {
372 struct file_region *trg;
374 VM_BUG_ON(resv->adds_in_progress - resv->region_cache_count > 1);
375 /* Must drop lock to allocate a new descriptor. */
376 resv->adds_in_progress--;
377 spin_unlock(&resv->lock);
379 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
380 if (!trg) {
381 kfree(nrg);
382 return -ENOMEM;
385 spin_lock(&resv->lock);
386 list_add(&trg->link, &resv->region_cache);
387 resv->region_cache_count++;
388 goto retry_locked;
391 /* Locate the region we are before or in. */
392 list_for_each_entry(rg, head, link)
393 if (f <= rg->to)
394 break;
396 /* If we are below the current region then a new region is required.
397 * Subtle, allocate a new region at the position but make it zero
398 * size such that we can guarantee to record the reservation. */
399 if (&rg->link == head || t < rg->from) {
400 if (!nrg) {
401 resv->adds_in_progress--;
402 spin_unlock(&resv->lock);
403 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
404 if (!nrg)
405 return -ENOMEM;
407 nrg->from = f;
408 nrg->to = f;
409 INIT_LIST_HEAD(&nrg->link);
410 goto retry;
413 list_add(&nrg->link, rg->link.prev);
414 chg = t - f;
415 goto out_nrg;
418 /* Round our left edge to the current segment if it encloses us. */
419 if (f > rg->from)
420 f = rg->from;
421 chg = t - f;
423 /* Check for and consume any regions we now overlap with. */
424 list_for_each_entry(rg, rg->link.prev, link) {
425 if (&rg->link == head)
426 break;
427 if (rg->from > t)
428 goto out;
430 /* We overlap with this area, if it extends further than
431 * us then we must extend ourselves. Account for its
432 * existing reservation. */
433 if (rg->to > t) {
434 chg += rg->to - t;
435 t = rg->to;
437 chg -= rg->to - rg->from;
440 out:
441 spin_unlock(&resv->lock);
442 /* We already know we raced and no longer need the new region */
443 kfree(nrg);
444 return chg;
445 out_nrg:
446 spin_unlock(&resv->lock);
447 return chg;
451 * Abort the in progress add operation. The adds_in_progress field
452 * of the resv_map keeps track of the operations in progress between
453 * calls to region_chg and region_add. Operations are sometimes
454 * aborted after the call to region_chg. In such cases, region_abort
455 * is called to decrement the adds_in_progress counter.
457 * NOTE: The range arguments [f, t) are not needed or used in this
458 * routine. They are kept to make reading the calling code easier as
459 * arguments will match the associated region_chg call.
461 static void region_abort(struct resv_map *resv, long f, long t)
463 spin_lock(&resv->lock);
464 VM_BUG_ON(!resv->region_cache_count);
465 resv->adds_in_progress--;
466 spin_unlock(&resv->lock);
470 * Delete the specified range [f, t) from the reserve map. If the
471 * t parameter is LONG_MAX, this indicates that ALL regions after f
472 * should be deleted. Locate the regions which intersect [f, t)
473 * and either trim, delete or split the existing regions.
475 * Returns the number of huge pages deleted from the reserve map.
476 * In the normal case, the return value is zero or more. In the
477 * case where a region must be split, a new region descriptor must
478 * be allocated. If the allocation fails, -ENOMEM will be returned.
479 * NOTE: If the parameter t == LONG_MAX, then we will never split
480 * a region and possibly return -ENOMEM. Callers specifying
481 * t == LONG_MAX do not need to check for -ENOMEM error.
483 static long region_del(struct resv_map *resv, long f, long t)
485 struct list_head *head = &resv->regions;
486 struct file_region *rg, *trg;
487 struct file_region *nrg = NULL;
488 long del = 0;
490 retry:
491 spin_lock(&resv->lock);
492 list_for_each_entry_safe(rg, trg, head, link) {
494 * Skip regions before the range to be deleted. file_region
495 * ranges are normally of the form [from, to). However, there
496 * may be a "placeholder" entry in the map which is of the form
497 * (from, to) with from == to. Check for placeholder entries
498 * at the beginning of the range to be deleted.
500 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
501 continue;
503 if (rg->from >= t)
504 break;
506 if (f > rg->from && t < rg->to) { /* Must split region */
508 * Check for an entry in the cache before dropping
509 * lock and attempting allocation.
511 if (!nrg &&
512 resv->region_cache_count > resv->adds_in_progress) {
513 nrg = list_first_entry(&resv->region_cache,
514 struct file_region,
515 link);
516 list_del(&nrg->link);
517 resv->region_cache_count--;
520 if (!nrg) {
521 spin_unlock(&resv->lock);
522 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
523 if (!nrg)
524 return -ENOMEM;
525 goto retry;
528 del += t - f;
530 /* New entry for end of split region */
531 nrg->from = t;
532 nrg->to = rg->to;
533 INIT_LIST_HEAD(&nrg->link);
535 /* Original entry is trimmed */
536 rg->to = f;
538 list_add(&nrg->link, &rg->link);
539 nrg = NULL;
540 break;
543 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
544 del += rg->to - rg->from;
545 list_del(&rg->link);
546 kfree(rg);
547 continue;
550 if (f <= rg->from) { /* Trim beginning of region */
551 del += t - rg->from;
552 rg->from = t;
553 } else { /* Trim end of region */
554 del += rg->to - f;
555 rg->to = f;
559 spin_unlock(&resv->lock);
560 kfree(nrg);
561 return del;
565 * A rare out of memory error was encountered which prevented removal of
566 * the reserve map region for a page. The huge page itself was free'ed
567 * and removed from the page cache. This routine will adjust the subpool
568 * usage count, and the global reserve count if needed. By incrementing
569 * these counts, the reserve map entry which could not be deleted will
570 * appear as a "reserved" entry instead of simply dangling with incorrect
571 * counts.
573 void hugetlb_fix_reserve_counts(struct inode *inode)
575 struct hugepage_subpool *spool = subpool_inode(inode);
576 long rsv_adjust;
578 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
579 if (rsv_adjust) {
580 struct hstate *h = hstate_inode(inode);
582 hugetlb_acct_memory(h, 1);
587 * Count and return the number of huge pages in the reserve map
588 * that intersect with the range [f, t).
590 static long region_count(struct resv_map *resv, long f, long t)
592 struct list_head *head = &resv->regions;
593 struct file_region *rg;
594 long chg = 0;
596 spin_lock(&resv->lock);
597 /* Locate each segment we overlap with, and count that overlap. */
598 list_for_each_entry(rg, head, link) {
599 long seg_from;
600 long seg_to;
602 if (rg->to <= f)
603 continue;
604 if (rg->from >= t)
605 break;
607 seg_from = max(rg->from, f);
608 seg_to = min(rg->to, t);
610 chg += seg_to - seg_from;
612 spin_unlock(&resv->lock);
614 return chg;
618 * Convert the address within this vma to the page offset within
619 * the mapping, in pagecache page units; huge pages here.
621 static pgoff_t vma_hugecache_offset(struct hstate *h,
622 struct vm_area_struct *vma, unsigned long address)
624 return ((address - vma->vm_start) >> huge_page_shift(h)) +
625 (vma->vm_pgoff >> huge_page_order(h));
628 pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
629 unsigned long address)
631 return vma_hugecache_offset(hstate_vma(vma), vma, address);
633 EXPORT_SYMBOL_GPL(linear_hugepage_index);
636 * Return the size of the pages allocated when backing a VMA. In the majority
637 * cases this will be same size as used by the page table entries.
639 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
641 struct hstate *hstate;
643 if (!is_vm_hugetlb_page(vma))
644 return PAGE_SIZE;
646 hstate = hstate_vma(vma);
648 return 1UL << huge_page_shift(hstate);
650 EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
653 * Return the page size being used by the MMU to back a VMA. In the majority
654 * of cases, the page size used by the kernel matches the MMU size. On
655 * architectures where it differs, an architecture-specific version of this
656 * function is required.
658 #ifndef vma_mmu_pagesize
659 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
661 return vma_kernel_pagesize(vma);
663 #endif
666 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
667 * bits of the reservation map pointer, which are always clear due to
668 * alignment.
670 #define HPAGE_RESV_OWNER (1UL << 0)
671 #define HPAGE_RESV_UNMAPPED (1UL << 1)
672 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
675 * These helpers are used to track how many pages are reserved for
676 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
677 * is guaranteed to have their future faults succeed.
679 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
680 * the reserve counters are updated with the hugetlb_lock held. It is safe
681 * to reset the VMA at fork() time as it is not in use yet and there is no
682 * chance of the global counters getting corrupted as a result of the values.
684 * The private mapping reservation is represented in a subtly different
685 * manner to a shared mapping. A shared mapping has a region map associated
686 * with the underlying file, this region map represents the backing file
687 * pages which have ever had a reservation assigned which this persists even
688 * after the page is instantiated. A private mapping has a region map
689 * associated with the original mmap which is attached to all VMAs which
690 * reference it, this region map represents those offsets which have consumed
691 * reservation ie. where pages have been instantiated.
693 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
695 return (unsigned long)vma->vm_private_data;
698 static void set_vma_private_data(struct vm_area_struct *vma,
699 unsigned long value)
701 vma->vm_private_data = (void *)value;
704 struct resv_map *resv_map_alloc(void)
706 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
707 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
709 if (!resv_map || !rg) {
710 kfree(resv_map);
711 kfree(rg);
712 return NULL;
715 kref_init(&resv_map->refs);
716 spin_lock_init(&resv_map->lock);
717 INIT_LIST_HEAD(&resv_map->regions);
719 resv_map->adds_in_progress = 0;
721 INIT_LIST_HEAD(&resv_map->region_cache);
722 list_add(&rg->link, &resv_map->region_cache);
723 resv_map->region_cache_count = 1;
725 return resv_map;
728 void resv_map_release(struct kref *ref)
730 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
731 struct list_head *head = &resv_map->region_cache;
732 struct file_region *rg, *trg;
734 /* Clear out any active regions before we release the map. */
735 region_del(resv_map, 0, LONG_MAX);
737 /* ... and any entries left in the cache */
738 list_for_each_entry_safe(rg, trg, head, link) {
739 list_del(&rg->link);
740 kfree(rg);
743 VM_BUG_ON(resv_map->adds_in_progress);
745 kfree(resv_map);
748 static inline struct resv_map *inode_resv_map(struct inode *inode)
750 return inode->i_mapping->private_data;
753 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
755 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
756 if (vma->vm_flags & VM_MAYSHARE) {
757 struct address_space *mapping = vma->vm_file->f_mapping;
758 struct inode *inode = mapping->host;
760 return inode_resv_map(inode);
762 } else {
763 return (struct resv_map *)(get_vma_private_data(vma) &
764 ~HPAGE_RESV_MASK);
768 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
770 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
771 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
773 set_vma_private_data(vma, (get_vma_private_data(vma) &
774 HPAGE_RESV_MASK) | (unsigned long)map);
777 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
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) | flags);
785 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
787 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
789 return (get_vma_private_data(vma) & flag) != 0;
792 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
793 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
795 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
796 if (!(vma->vm_flags & VM_MAYSHARE))
797 vma->vm_private_data = (void *)0;
800 /* Returns true if the VMA has associated reserve pages */
801 static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
803 if (vma->vm_flags & VM_NORESERVE) {
805 * This address is already reserved by other process(chg == 0),
806 * so, we should decrement reserved count. Without decrementing,
807 * reserve count remains after releasing inode, because this
808 * allocated page will go into page cache and is regarded as
809 * coming from reserved pool in releasing step. Currently, we
810 * don't have any other solution to deal with this situation
811 * properly, so add work-around here.
813 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
814 return true;
815 else
816 return false;
819 /* Shared mappings always use reserves */
820 if (vma->vm_flags & VM_MAYSHARE) {
822 * We know VM_NORESERVE is not set. Therefore, there SHOULD
823 * be a region map for all pages. The only situation where
824 * there is no region map is if a hole was punched via
825 * fallocate. In this case, there really are no reverves to
826 * use. This situation is indicated if chg != 0.
828 if (chg)
829 return false;
830 else
831 return true;
835 * Only the process that called mmap() has reserves for
836 * private mappings.
838 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
840 * Like the shared case above, a hole punch or truncate
841 * could have been performed on the private mapping.
842 * Examine the value of chg to determine if reserves
843 * actually exist or were previously consumed.
844 * Very Subtle - The value of chg comes from a previous
845 * call to vma_needs_reserves(). The reserve map for
846 * private mappings has different (opposite) semantics
847 * than that of shared mappings. vma_needs_reserves()
848 * has already taken this difference in semantics into
849 * account. Therefore, the meaning of chg is the same
850 * as in the shared case above. Code could easily be
851 * combined, but keeping it separate draws attention to
852 * subtle differences.
854 if (chg)
855 return false;
856 else
857 return true;
860 return false;
863 static void enqueue_huge_page(struct hstate *h, struct page *page)
865 int nid = page_to_nid(page);
866 list_move(&page->lru, &h->hugepage_freelists[nid]);
867 h->free_huge_pages++;
868 h->free_huge_pages_node[nid]++;
871 static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
873 struct page *page;
875 list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
876 if (!PageHWPoison(page))
877 break;
879 * if 'non-isolated free hugepage' not found on the list,
880 * the allocation fails.
882 if (&h->hugepage_freelists[nid] == &page->lru)
883 return NULL;
884 list_move(&page->lru, &h->hugepage_activelist);
885 set_page_refcounted(page);
886 h->free_huge_pages--;
887 h->free_huge_pages_node[nid]--;
888 return page;
891 static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
892 nodemask_t *nmask)
894 unsigned int cpuset_mems_cookie;
895 struct zonelist *zonelist;
896 struct zone *zone;
897 struct zoneref *z;
898 int node = -1;
900 zonelist = node_zonelist(nid, gfp_mask);
902 retry_cpuset:
903 cpuset_mems_cookie = read_mems_allowed_begin();
904 for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) {
905 struct page *page;
907 if (!cpuset_zone_allowed(zone, gfp_mask))
908 continue;
910 * no need to ask again on the same node. Pool is node rather than
911 * zone aware
913 if (zone_to_nid(zone) == node)
914 continue;
915 node = zone_to_nid(zone);
917 page = dequeue_huge_page_node_exact(h, node);
918 if (page)
919 return page;
921 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
922 goto retry_cpuset;
924 return NULL;
927 /* Movability of hugepages depends on migration support. */
928 static inline gfp_t htlb_alloc_mask(struct hstate *h)
930 if (hugepages_treat_as_movable || hugepage_migration_supported(h))
931 return GFP_HIGHUSER_MOVABLE;
932 else
933 return GFP_HIGHUSER;
936 static struct page *dequeue_huge_page_vma(struct hstate *h,
937 struct vm_area_struct *vma,
938 unsigned long address, int avoid_reserve,
939 long chg)
941 struct page *page;
942 struct mempolicy *mpol;
943 gfp_t gfp_mask;
944 nodemask_t *nodemask;
945 int nid;
948 * A child process with MAP_PRIVATE mappings created by their parent
949 * have no page reserves. This check ensures that reservations are
950 * not "stolen". The child may still get SIGKILLed
952 if (!vma_has_reserves(vma, chg) &&
953 h->free_huge_pages - h->resv_huge_pages == 0)
954 goto err;
956 /* If reserves cannot be used, ensure enough pages are in the pool */
957 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
958 goto err;
960 gfp_mask = htlb_alloc_mask(h);
961 nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
962 page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask);
963 if (page && !avoid_reserve && vma_has_reserves(vma, chg)) {
964 SetPagePrivate(page);
965 h->resv_huge_pages--;
968 mpol_cond_put(mpol);
969 return page;
971 err:
972 return NULL;
976 * common helper functions for hstate_next_node_to_{alloc|free}.
977 * We may have allocated or freed a huge page based on a different
978 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
979 * be outside of *nodes_allowed. Ensure that we use an allowed
980 * node for alloc or free.
982 static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
984 nid = next_node_in(nid, *nodes_allowed);
985 VM_BUG_ON(nid >= MAX_NUMNODES);
987 return nid;
990 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
992 if (!node_isset(nid, *nodes_allowed))
993 nid = next_node_allowed(nid, nodes_allowed);
994 return nid;
998 * returns the previously saved node ["this node"] from which to
999 * allocate a persistent huge page for the pool and advance the
1000 * next node from which to allocate, handling wrap at end of node
1001 * mask.
1003 static int hstate_next_node_to_alloc(struct hstate *h,
1004 nodemask_t *nodes_allowed)
1006 int nid;
1008 VM_BUG_ON(!nodes_allowed);
1010 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
1011 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
1013 return nid;
1017 * helper for free_pool_huge_page() - return the previously saved
1018 * node ["this node"] from which to free a huge page. Advance the
1019 * next node id whether or not we find a free huge page to free so
1020 * that the next attempt to free addresses the next node.
1022 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
1024 int nid;
1026 VM_BUG_ON(!nodes_allowed);
1028 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
1029 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
1031 return nid;
1034 #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1035 for (nr_nodes = nodes_weight(*mask); \
1036 nr_nodes > 0 && \
1037 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1038 nr_nodes--)
1040 #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1041 for (nr_nodes = nodes_weight(*mask); \
1042 nr_nodes > 0 && \
1043 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1044 nr_nodes--)
1046 #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1047 static void destroy_compound_gigantic_page(struct page *page,
1048 unsigned int order)
1050 int i;
1051 int nr_pages = 1 << order;
1052 struct page *p = page + 1;
1054 atomic_set(compound_mapcount_ptr(page), 0);
1055 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1056 clear_compound_head(p);
1057 set_page_refcounted(p);
1060 set_compound_order(page, 0);
1061 __ClearPageHead(page);
1064 static void free_gigantic_page(struct page *page, unsigned int order)
1066 free_contig_range(page_to_pfn(page), 1 << order);
1069 static int __alloc_gigantic_page(unsigned long start_pfn,
1070 unsigned long nr_pages, gfp_t gfp_mask)
1072 unsigned long end_pfn = start_pfn + nr_pages;
1073 return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
1074 gfp_mask);
1077 static bool pfn_range_valid_gigantic(struct zone *z,
1078 unsigned long start_pfn, unsigned long nr_pages)
1080 unsigned long i, end_pfn = start_pfn + nr_pages;
1081 struct page *page;
1083 for (i = start_pfn; i < end_pfn; i++) {
1084 if (!pfn_valid(i))
1085 return false;
1087 page = pfn_to_page(i);
1089 if (page_zone(page) != z)
1090 return false;
1092 if (PageReserved(page))
1093 return false;
1095 if (page_count(page) > 0)
1096 return false;
1098 if (PageHuge(page))
1099 return false;
1102 return true;
1105 static bool zone_spans_last_pfn(const struct zone *zone,
1106 unsigned long start_pfn, unsigned long nr_pages)
1108 unsigned long last_pfn = start_pfn + nr_pages - 1;
1109 return zone_spans_pfn(zone, last_pfn);
1112 static struct page *alloc_gigantic_page(int nid, struct hstate *h)
1114 unsigned int order = huge_page_order(h);
1115 unsigned long nr_pages = 1 << order;
1116 unsigned long ret, pfn, flags;
1117 struct zonelist *zonelist;
1118 struct zone *zone;
1119 struct zoneref *z;
1120 gfp_t gfp_mask;
1122 gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1123 zonelist = node_zonelist(nid, gfp_mask);
1124 for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), NULL) {
1125 spin_lock_irqsave(&zone->lock, flags);
1127 pfn = ALIGN(zone->zone_start_pfn, nr_pages);
1128 while (zone_spans_last_pfn(zone, pfn, nr_pages)) {
1129 if (pfn_range_valid_gigantic(zone, pfn, nr_pages)) {
1131 * We release the zone lock here because
1132 * alloc_contig_range() will also lock the zone
1133 * at some point. If there's an allocation
1134 * spinning on this lock, it may win the race
1135 * and cause alloc_contig_range() to fail...
1137 spin_unlock_irqrestore(&zone->lock, flags);
1138 ret = __alloc_gigantic_page(pfn, nr_pages, gfp_mask);
1139 if (!ret)
1140 return pfn_to_page(pfn);
1141 spin_lock_irqsave(&zone->lock, flags);
1143 pfn += nr_pages;
1146 spin_unlock_irqrestore(&zone->lock, flags);
1149 return NULL;
1152 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1153 static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1155 static struct page *alloc_fresh_gigantic_page_node(struct hstate *h, int nid)
1157 struct page *page;
1159 page = alloc_gigantic_page(nid, h);
1160 if (page) {
1161 prep_compound_gigantic_page(page, huge_page_order(h));
1162 prep_new_huge_page(h, page, nid);
1165 return page;
1168 static int alloc_fresh_gigantic_page(struct hstate *h,
1169 nodemask_t *nodes_allowed)
1171 struct page *page = NULL;
1172 int nr_nodes, node;
1174 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1175 page = alloc_fresh_gigantic_page_node(h, node);
1176 if (page)
1177 return 1;
1180 return 0;
1183 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1184 static inline bool gigantic_page_supported(void) { return false; }
1185 static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1186 static inline void destroy_compound_gigantic_page(struct page *page,
1187 unsigned int order) { }
1188 static inline int alloc_fresh_gigantic_page(struct hstate *h,
1189 nodemask_t *nodes_allowed) { return 0; }
1190 #endif
1192 static void update_and_free_page(struct hstate *h, struct page *page)
1194 int i;
1196 if (hstate_is_gigantic(h) && !gigantic_page_supported())
1197 return;
1199 h->nr_huge_pages--;
1200 h->nr_huge_pages_node[page_to_nid(page)]--;
1201 for (i = 0; i < pages_per_huge_page(h); i++) {
1202 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
1203 1 << PG_referenced | 1 << PG_dirty |
1204 1 << PG_active | 1 << PG_private |
1205 1 << PG_writeback);
1207 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1208 set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
1209 set_page_refcounted(page);
1210 if (hstate_is_gigantic(h)) {
1211 destroy_compound_gigantic_page(page, huge_page_order(h));
1212 free_gigantic_page(page, huge_page_order(h));
1213 } else {
1214 __free_pages(page, huge_page_order(h));
1218 struct hstate *size_to_hstate(unsigned long size)
1220 struct hstate *h;
1222 for_each_hstate(h) {
1223 if (huge_page_size(h) == size)
1224 return h;
1226 return NULL;
1230 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1231 * to hstate->hugepage_activelist.)
1233 * This function can be called for tail pages, but never returns true for them.
1235 bool page_huge_active(struct page *page)
1237 VM_BUG_ON_PAGE(!PageHuge(page), page);
1238 return PageHead(page) && PagePrivate(&page[1]);
1241 /* never called for tail page */
1242 static void set_page_huge_active(struct page *page)
1244 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1245 SetPagePrivate(&page[1]);
1248 static void clear_page_huge_active(struct page *page)
1250 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1251 ClearPagePrivate(&page[1]);
1254 void free_huge_page(struct page *page)
1257 * Can't pass hstate in here because it is called from the
1258 * compound page destructor.
1260 struct hstate *h = page_hstate(page);
1261 int nid = page_to_nid(page);
1262 struct hugepage_subpool *spool =
1263 (struct hugepage_subpool *)page_private(page);
1264 bool restore_reserve;
1266 set_page_private(page, 0);
1267 page->mapping = NULL;
1268 VM_BUG_ON_PAGE(page_count(page), page);
1269 VM_BUG_ON_PAGE(page_mapcount(page), page);
1270 restore_reserve = PagePrivate(page);
1271 ClearPagePrivate(page);
1274 * A return code of zero implies that the subpool will be under its
1275 * minimum size if the reservation is not restored after page is free.
1276 * Therefore, force restore_reserve operation.
1278 if (hugepage_subpool_put_pages(spool, 1) == 0)
1279 restore_reserve = true;
1281 spin_lock(&hugetlb_lock);
1282 clear_page_huge_active(page);
1283 hugetlb_cgroup_uncharge_page(hstate_index(h),
1284 pages_per_huge_page(h), page);
1285 if (restore_reserve)
1286 h->resv_huge_pages++;
1288 if (h->surplus_huge_pages_node[nid]) {
1289 /* remove the page from active list */
1290 list_del(&page->lru);
1291 update_and_free_page(h, page);
1292 h->surplus_huge_pages--;
1293 h->surplus_huge_pages_node[nid]--;
1294 } else {
1295 arch_clear_hugepage_flags(page);
1296 enqueue_huge_page(h, page);
1298 spin_unlock(&hugetlb_lock);
1301 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1303 INIT_LIST_HEAD(&page->lru);
1304 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1305 spin_lock(&hugetlb_lock);
1306 set_hugetlb_cgroup(page, NULL);
1307 h->nr_huge_pages++;
1308 h->nr_huge_pages_node[nid]++;
1309 spin_unlock(&hugetlb_lock);
1310 put_page(page); /* free it into the hugepage allocator */
1313 static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1315 int i;
1316 int nr_pages = 1 << order;
1317 struct page *p = page + 1;
1319 /* we rely on prep_new_huge_page to set the destructor */
1320 set_compound_order(page, order);
1321 __ClearPageReserved(page);
1322 __SetPageHead(page);
1323 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1325 * For gigantic hugepages allocated through bootmem at
1326 * boot, it's safer to be consistent with the not-gigantic
1327 * hugepages and clear the PG_reserved bit from all tail pages
1328 * too. Otherwse drivers using get_user_pages() to access tail
1329 * pages may get the reference counting wrong if they see
1330 * PG_reserved set on a tail page (despite the head page not
1331 * having PG_reserved set). Enforcing this consistency between
1332 * head and tail pages allows drivers to optimize away a check
1333 * on the head page when they need know if put_page() is needed
1334 * after get_user_pages().
1336 __ClearPageReserved(p);
1337 set_page_count(p, 0);
1338 set_compound_head(p, page);
1340 atomic_set(compound_mapcount_ptr(page), -1);
1344 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1345 * transparent huge pages. See the PageTransHuge() documentation for more
1346 * details.
1348 int PageHuge(struct page *page)
1350 if (!PageCompound(page))
1351 return 0;
1353 page = compound_head(page);
1354 return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1356 EXPORT_SYMBOL_GPL(PageHuge);
1359 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1360 * normal or transparent huge pages.
1362 int PageHeadHuge(struct page *page_head)
1364 if (!PageHead(page_head))
1365 return 0;
1367 return get_compound_page_dtor(page_head) == free_huge_page;
1370 pgoff_t __basepage_index(struct page *page)
1372 struct page *page_head = compound_head(page);
1373 pgoff_t index = page_index(page_head);
1374 unsigned long compound_idx;
1376 if (!PageHuge(page_head))
1377 return page_index(page);
1379 if (compound_order(page_head) >= MAX_ORDER)
1380 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
1381 else
1382 compound_idx = page - page_head;
1384 return (index << compound_order(page_head)) + compound_idx;
1387 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
1389 struct page *page;
1391 page = __alloc_pages_node(nid,
1392 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
1393 __GFP_RETRY_MAYFAIL|__GFP_NOWARN,
1394 huge_page_order(h));
1395 if (page) {
1396 prep_new_huge_page(h, page, nid);
1399 return page;
1402 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
1404 struct page *page;
1405 int nr_nodes, node;
1406 int ret = 0;
1408 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1409 page = alloc_fresh_huge_page_node(h, node);
1410 if (page) {
1411 ret = 1;
1412 break;
1416 if (ret)
1417 count_vm_event(HTLB_BUDDY_PGALLOC);
1418 else
1419 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1421 return ret;
1425 * Free huge page from pool from next node to free.
1426 * Attempt to keep persistent huge pages more or less
1427 * balanced over allowed nodes.
1428 * Called with hugetlb_lock locked.
1430 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1431 bool acct_surplus)
1433 int nr_nodes, node;
1434 int ret = 0;
1436 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1438 * If we're returning unused surplus pages, only examine
1439 * nodes with surplus pages.
1441 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1442 !list_empty(&h->hugepage_freelists[node])) {
1443 struct page *page =
1444 list_entry(h->hugepage_freelists[node].next,
1445 struct page, lru);
1446 list_del(&page->lru);
1447 h->free_huge_pages--;
1448 h->free_huge_pages_node[node]--;
1449 if (acct_surplus) {
1450 h->surplus_huge_pages--;
1451 h->surplus_huge_pages_node[node]--;
1453 update_and_free_page(h, page);
1454 ret = 1;
1455 break;
1459 return ret;
1463 * Dissolve a given free hugepage into free buddy pages. This function does
1464 * nothing for in-use (including surplus) hugepages. Returns -EBUSY if the
1465 * number of free hugepages would be reduced below the number of reserved
1466 * hugepages.
1468 int dissolve_free_huge_page(struct page *page)
1470 int rc = 0;
1472 spin_lock(&hugetlb_lock);
1473 if (PageHuge(page) && !page_count(page)) {
1474 struct page *head = compound_head(page);
1475 struct hstate *h = page_hstate(head);
1476 int nid = page_to_nid(head);
1477 if (h->free_huge_pages - h->resv_huge_pages == 0) {
1478 rc = -EBUSY;
1479 goto out;
1482 * Move PageHWPoison flag from head page to the raw error page,
1483 * which makes any subpages rather than the error page reusable.
1485 if (PageHWPoison(head) && page != head) {
1486 SetPageHWPoison(page);
1487 ClearPageHWPoison(head);
1489 list_del(&head->lru);
1490 h->free_huge_pages--;
1491 h->free_huge_pages_node[nid]--;
1492 h->max_huge_pages--;
1493 update_and_free_page(h, head);
1495 out:
1496 spin_unlock(&hugetlb_lock);
1497 return rc;
1501 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1502 * make specified memory blocks removable from the system.
1503 * Note that this will dissolve a free gigantic hugepage completely, if any
1504 * part of it lies within the given range.
1505 * Also note that if dissolve_free_huge_page() returns with an error, all
1506 * free hugepages that were dissolved before that error are lost.
1508 int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1510 unsigned long pfn;
1511 struct page *page;
1512 int rc = 0;
1514 if (!hugepages_supported())
1515 return rc;
1517 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
1518 page = pfn_to_page(pfn);
1519 if (PageHuge(page) && !page_count(page)) {
1520 rc = dissolve_free_huge_page(page);
1521 if (rc)
1522 break;
1526 return rc;
1529 static struct page *__hugetlb_alloc_buddy_huge_page(struct hstate *h,
1530 gfp_t gfp_mask, int nid, nodemask_t *nmask)
1532 int order = huge_page_order(h);
1534 gfp_mask |= __GFP_COMP|__GFP_RETRY_MAYFAIL|__GFP_NOWARN;
1535 if (nid == NUMA_NO_NODE)
1536 nid = numa_mem_id();
1537 return __alloc_pages_nodemask(gfp_mask, order, nid, nmask);
1540 static struct page *__alloc_buddy_huge_page(struct hstate *h, gfp_t gfp_mask,
1541 int nid, nodemask_t *nmask)
1543 struct page *page;
1544 unsigned int r_nid;
1546 if (hstate_is_gigantic(h))
1547 return NULL;
1550 * Assume we will successfully allocate the surplus page to
1551 * prevent racing processes from causing the surplus to exceed
1552 * overcommit
1554 * This however introduces a different race, where a process B
1555 * tries to grow the static hugepage pool while alloc_pages() is
1556 * called by process A. B will only examine the per-node
1557 * counters in determining if surplus huge pages can be
1558 * converted to normal huge pages in adjust_pool_surplus(). A
1559 * won't be able to increment the per-node counter, until the
1560 * lock is dropped by B, but B doesn't drop hugetlb_lock until
1561 * no more huge pages can be converted from surplus to normal
1562 * state (and doesn't try to convert again). Thus, we have a
1563 * case where a surplus huge page exists, the pool is grown, and
1564 * the surplus huge page still exists after, even though it
1565 * should just have been converted to a normal huge page. This
1566 * does not leak memory, though, as the hugepage will be freed
1567 * once it is out of use. It also does not allow the counters to
1568 * go out of whack in adjust_pool_surplus() as we don't modify
1569 * the node values until we've gotten the hugepage and only the
1570 * per-node value is checked there.
1572 spin_lock(&hugetlb_lock);
1573 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1574 spin_unlock(&hugetlb_lock);
1575 return NULL;
1576 } else {
1577 h->nr_huge_pages++;
1578 h->surplus_huge_pages++;
1580 spin_unlock(&hugetlb_lock);
1582 page = __hugetlb_alloc_buddy_huge_page(h, gfp_mask, nid, nmask);
1584 spin_lock(&hugetlb_lock);
1585 if (page) {
1586 INIT_LIST_HEAD(&page->lru);
1587 r_nid = page_to_nid(page);
1588 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1589 set_hugetlb_cgroup(page, NULL);
1591 * We incremented the global counters already
1593 h->nr_huge_pages_node[r_nid]++;
1594 h->surplus_huge_pages_node[r_nid]++;
1595 __count_vm_event(HTLB_BUDDY_PGALLOC);
1596 } else {
1597 h->nr_huge_pages--;
1598 h->surplus_huge_pages--;
1599 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1601 spin_unlock(&hugetlb_lock);
1603 return page;
1607 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1609 static
1610 struct page *__alloc_buddy_huge_page_with_mpol(struct hstate *h,
1611 struct vm_area_struct *vma, unsigned long addr)
1613 struct page *page;
1614 struct mempolicy *mpol;
1615 gfp_t gfp_mask = htlb_alloc_mask(h);
1616 int nid;
1617 nodemask_t *nodemask;
1619 nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
1620 page = __alloc_buddy_huge_page(h, gfp_mask, nid, nodemask);
1621 mpol_cond_put(mpol);
1623 return page;
1627 * This allocation function is useful in the context where vma is irrelevant.
1628 * E.g. soft-offlining uses this function because it only cares physical
1629 * address of error page.
1631 struct page *alloc_huge_page_node(struct hstate *h, int nid)
1633 gfp_t gfp_mask = htlb_alloc_mask(h);
1634 struct page *page = NULL;
1636 if (nid != NUMA_NO_NODE)
1637 gfp_mask |= __GFP_THISNODE;
1639 spin_lock(&hugetlb_lock);
1640 if (h->free_huge_pages - h->resv_huge_pages > 0)
1641 page = dequeue_huge_page_nodemask(h, gfp_mask, nid, NULL);
1642 spin_unlock(&hugetlb_lock);
1644 if (!page)
1645 page = __alloc_buddy_huge_page(h, gfp_mask, nid, NULL);
1647 return page;
1651 struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
1652 nodemask_t *nmask)
1654 gfp_t gfp_mask = htlb_alloc_mask(h);
1656 spin_lock(&hugetlb_lock);
1657 if (h->free_huge_pages - h->resv_huge_pages > 0) {
1658 struct page *page;
1660 page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
1661 if (page) {
1662 spin_unlock(&hugetlb_lock);
1663 return page;
1666 spin_unlock(&hugetlb_lock);
1668 /* No reservations, try to overcommit */
1670 return __alloc_buddy_huge_page(h, gfp_mask, preferred_nid, nmask);
1674 * Increase the hugetlb pool such that it can accommodate a reservation
1675 * of size 'delta'.
1677 static int gather_surplus_pages(struct hstate *h, int delta)
1679 struct list_head surplus_list;
1680 struct page *page, *tmp;
1681 int ret, i;
1682 int needed, allocated;
1683 bool alloc_ok = true;
1685 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1686 if (needed <= 0) {
1687 h->resv_huge_pages += delta;
1688 return 0;
1691 allocated = 0;
1692 INIT_LIST_HEAD(&surplus_list);
1694 ret = -ENOMEM;
1695 retry:
1696 spin_unlock(&hugetlb_lock);
1697 for (i = 0; i < needed; i++) {
1698 page = __alloc_buddy_huge_page(h, htlb_alloc_mask(h),
1699 NUMA_NO_NODE, NULL);
1700 if (!page) {
1701 alloc_ok = false;
1702 break;
1704 list_add(&page->lru, &surplus_list);
1705 cond_resched();
1707 allocated += i;
1710 * After retaking hugetlb_lock, we need to recalculate 'needed'
1711 * because either resv_huge_pages or free_huge_pages may have changed.
1713 spin_lock(&hugetlb_lock);
1714 needed = (h->resv_huge_pages + delta) -
1715 (h->free_huge_pages + allocated);
1716 if (needed > 0) {
1717 if (alloc_ok)
1718 goto retry;
1720 * We were not able to allocate enough pages to
1721 * satisfy the entire reservation so we free what
1722 * we've allocated so far.
1724 goto free;
1727 * The surplus_list now contains _at_least_ the number of extra pages
1728 * needed to accommodate the reservation. Add the appropriate number
1729 * of pages to the hugetlb pool and free the extras back to the buddy
1730 * allocator. Commit the entire reservation here to prevent another
1731 * process from stealing the pages as they are added to the pool but
1732 * before they are reserved.
1734 needed += allocated;
1735 h->resv_huge_pages += delta;
1736 ret = 0;
1738 /* Free the needed pages to the hugetlb pool */
1739 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1740 if ((--needed) < 0)
1741 break;
1743 * This page is now managed by the hugetlb allocator and has
1744 * no users -- drop the buddy allocator's reference.
1746 put_page_testzero(page);
1747 VM_BUG_ON_PAGE(page_count(page), page);
1748 enqueue_huge_page(h, page);
1750 free:
1751 spin_unlock(&hugetlb_lock);
1753 /* Free unnecessary surplus pages to the buddy allocator */
1754 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
1755 put_page(page);
1756 spin_lock(&hugetlb_lock);
1758 return ret;
1762 * This routine has two main purposes:
1763 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
1764 * in unused_resv_pages. This corresponds to the prior adjustments made
1765 * to the associated reservation map.
1766 * 2) Free any unused surplus pages that may have been allocated to satisfy
1767 * the reservation. As many as unused_resv_pages may be freed.
1769 * Called with hugetlb_lock held. However, the lock could be dropped (and
1770 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
1771 * we must make sure nobody else can claim pages we are in the process of
1772 * freeing. Do this by ensuring resv_huge_page always is greater than the
1773 * number of huge pages we plan to free when dropping the lock.
1775 static void return_unused_surplus_pages(struct hstate *h,
1776 unsigned long unused_resv_pages)
1778 unsigned long nr_pages;
1780 /* Cannot return gigantic pages currently */
1781 if (hstate_is_gigantic(h))
1782 goto out;
1785 * Part (or even all) of the reservation could have been backed
1786 * by pre-allocated pages. Only free surplus pages.
1788 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1791 * We want to release as many surplus pages as possible, spread
1792 * evenly across all nodes with memory. Iterate across these nodes
1793 * until we can no longer free unreserved surplus pages. This occurs
1794 * when the nodes with surplus pages have no free pages.
1795 * free_pool_huge_page() will balance the the freed pages across the
1796 * on-line nodes with memory and will handle the hstate accounting.
1798 * Note that we decrement resv_huge_pages as we free the pages. If
1799 * we drop the lock, resv_huge_pages will still be sufficiently large
1800 * to cover subsequent pages we may free.
1802 while (nr_pages--) {
1803 h->resv_huge_pages--;
1804 unused_resv_pages--;
1805 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1806 goto out;
1807 cond_resched_lock(&hugetlb_lock);
1810 out:
1811 /* Fully uncommit the reservation */
1812 h->resv_huge_pages -= unused_resv_pages;
1817 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1818 * are used by the huge page allocation routines to manage reservations.
1820 * vma_needs_reservation is called to determine if the huge page at addr
1821 * within the vma has an associated reservation. If a reservation is
1822 * needed, the value 1 is returned. The caller is then responsible for
1823 * managing the global reservation and subpool usage counts. After
1824 * the huge page has been allocated, vma_commit_reservation is called
1825 * to add the page to the reservation map. If the page allocation fails,
1826 * the reservation must be ended instead of committed. vma_end_reservation
1827 * is called in such cases.
1829 * In the normal case, vma_commit_reservation returns the same value
1830 * as the preceding vma_needs_reservation call. The only time this
1831 * is not the case is if a reserve map was changed between calls. It
1832 * is the responsibility of the caller to notice the difference and
1833 * take appropriate action.
1835 * vma_add_reservation is used in error paths where a reservation must
1836 * be restored when a newly allocated huge page must be freed. It is
1837 * to be called after calling vma_needs_reservation to determine if a
1838 * reservation exists.
1840 enum vma_resv_mode {
1841 VMA_NEEDS_RESV,
1842 VMA_COMMIT_RESV,
1843 VMA_END_RESV,
1844 VMA_ADD_RESV,
1846 static long __vma_reservation_common(struct hstate *h,
1847 struct vm_area_struct *vma, unsigned long addr,
1848 enum vma_resv_mode mode)
1850 struct resv_map *resv;
1851 pgoff_t idx;
1852 long ret;
1854 resv = vma_resv_map(vma);
1855 if (!resv)
1856 return 1;
1858 idx = vma_hugecache_offset(h, vma, addr);
1859 switch (mode) {
1860 case VMA_NEEDS_RESV:
1861 ret = region_chg(resv, idx, idx + 1);
1862 break;
1863 case VMA_COMMIT_RESV:
1864 ret = region_add(resv, idx, idx + 1);
1865 break;
1866 case VMA_END_RESV:
1867 region_abort(resv, idx, idx + 1);
1868 ret = 0;
1869 break;
1870 case VMA_ADD_RESV:
1871 if (vma->vm_flags & VM_MAYSHARE)
1872 ret = region_add(resv, idx, idx + 1);
1873 else {
1874 region_abort(resv, idx, idx + 1);
1875 ret = region_del(resv, idx, idx + 1);
1877 break;
1878 default:
1879 BUG();
1882 if (vma->vm_flags & VM_MAYSHARE)
1883 return ret;
1884 else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) {
1886 * In most cases, reserves always exist for private mappings.
1887 * However, a file associated with mapping could have been
1888 * hole punched or truncated after reserves were consumed.
1889 * As subsequent fault on such a range will not use reserves.
1890 * Subtle - The reserve map for private mappings has the
1891 * opposite meaning than that of shared mappings. If NO
1892 * entry is in the reserve map, it means a reservation exists.
1893 * If an entry exists in the reserve map, it means the
1894 * reservation has already been consumed. As a result, the
1895 * return value of this routine is the opposite of the
1896 * value returned from reserve map manipulation routines above.
1898 if (ret)
1899 return 0;
1900 else
1901 return 1;
1903 else
1904 return ret < 0 ? ret : 0;
1907 static long vma_needs_reservation(struct hstate *h,
1908 struct vm_area_struct *vma, unsigned long addr)
1910 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
1913 static long vma_commit_reservation(struct hstate *h,
1914 struct vm_area_struct *vma, unsigned long addr)
1916 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
1919 static void vma_end_reservation(struct hstate *h,
1920 struct vm_area_struct *vma, unsigned long addr)
1922 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
1925 static long vma_add_reservation(struct hstate *h,
1926 struct vm_area_struct *vma, unsigned long addr)
1928 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
1932 * This routine is called to restore a reservation on error paths. In the
1933 * specific error paths, a huge page was allocated (via alloc_huge_page)
1934 * and is about to be freed. If a reservation for the page existed,
1935 * alloc_huge_page would have consumed the reservation and set PagePrivate
1936 * in the newly allocated page. When the page is freed via free_huge_page,
1937 * the global reservation count will be incremented if PagePrivate is set.
1938 * However, free_huge_page can not adjust the reserve map. Adjust the
1939 * reserve map here to be consistent with global reserve count adjustments
1940 * to be made by free_huge_page.
1942 static void restore_reserve_on_error(struct hstate *h,
1943 struct vm_area_struct *vma, unsigned long address,
1944 struct page *page)
1946 if (unlikely(PagePrivate(page))) {
1947 long rc = vma_needs_reservation(h, vma, address);
1949 if (unlikely(rc < 0)) {
1951 * Rare out of memory condition in reserve map
1952 * manipulation. Clear PagePrivate so that
1953 * global reserve count will not be incremented
1954 * by free_huge_page. This will make it appear
1955 * as though the reservation for this page was
1956 * consumed. This may prevent the task from
1957 * faulting in the page at a later time. This
1958 * is better than inconsistent global huge page
1959 * accounting of reserve counts.
1961 ClearPagePrivate(page);
1962 } else if (rc) {
1963 rc = vma_add_reservation(h, vma, address);
1964 if (unlikely(rc < 0))
1966 * See above comment about rare out of
1967 * memory condition.
1969 ClearPagePrivate(page);
1970 } else
1971 vma_end_reservation(h, vma, address);
1975 struct page *alloc_huge_page(struct vm_area_struct *vma,
1976 unsigned long addr, int avoid_reserve)
1978 struct hugepage_subpool *spool = subpool_vma(vma);
1979 struct hstate *h = hstate_vma(vma);
1980 struct page *page;
1981 long map_chg, map_commit;
1982 long gbl_chg;
1983 int ret, idx;
1984 struct hugetlb_cgroup *h_cg;
1986 idx = hstate_index(h);
1988 * Examine the region/reserve map to determine if the process
1989 * has a reservation for the page to be allocated. A return
1990 * code of zero indicates a reservation exists (no change).
1992 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
1993 if (map_chg < 0)
1994 return ERR_PTR(-ENOMEM);
1997 * Processes that did not create the mapping will have no
1998 * reserves as indicated by the region/reserve map. Check
1999 * that the allocation will not exceed the subpool limit.
2000 * Allocations for MAP_NORESERVE mappings also need to be
2001 * checked against any subpool limit.
2003 if (map_chg || avoid_reserve) {
2004 gbl_chg = hugepage_subpool_get_pages(spool, 1);
2005 if (gbl_chg < 0) {
2006 vma_end_reservation(h, vma, addr);
2007 return ERR_PTR(-ENOSPC);
2011 * Even though there was no reservation in the region/reserve
2012 * map, there could be reservations associated with the
2013 * subpool that can be used. This would be indicated if the
2014 * return value of hugepage_subpool_get_pages() is zero.
2015 * However, if avoid_reserve is specified we still avoid even
2016 * the subpool reservations.
2018 if (avoid_reserve)
2019 gbl_chg = 1;
2022 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2023 if (ret)
2024 goto out_subpool_put;
2026 spin_lock(&hugetlb_lock);
2028 * glb_chg is passed to indicate whether or not a page must be taken
2029 * from the global free pool (global change). gbl_chg == 0 indicates
2030 * a reservation exists for the allocation.
2032 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
2033 if (!page) {
2034 spin_unlock(&hugetlb_lock);
2035 page = __alloc_buddy_huge_page_with_mpol(h, vma, addr);
2036 if (!page)
2037 goto out_uncharge_cgroup;
2038 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
2039 SetPagePrivate(page);
2040 h->resv_huge_pages--;
2042 spin_lock(&hugetlb_lock);
2043 list_move(&page->lru, &h->hugepage_activelist);
2044 /* Fall through */
2046 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2047 spin_unlock(&hugetlb_lock);
2049 set_page_private(page, (unsigned long)spool);
2051 map_commit = vma_commit_reservation(h, vma, addr);
2052 if (unlikely(map_chg > map_commit)) {
2054 * The page was added to the reservation map between
2055 * vma_needs_reservation and vma_commit_reservation.
2056 * This indicates a race with hugetlb_reserve_pages.
2057 * Adjust for the subpool count incremented above AND
2058 * in hugetlb_reserve_pages for the same page. Also,
2059 * the reservation count added in hugetlb_reserve_pages
2060 * no longer applies.
2062 long rsv_adjust;
2064 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
2065 hugetlb_acct_memory(h, -rsv_adjust);
2067 return page;
2069 out_uncharge_cgroup:
2070 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2071 out_subpool_put:
2072 if (map_chg || avoid_reserve)
2073 hugepage_subpool_put_pages(spool, 1);
2074 vma_end_reservation(h, vma, addr);
2075 return ERR_PTR(-ENOSPC);
2079 * alloc_huge_page()'s wrapper which simply returns the page if allocation
2080 * succeeds, otherwise NULL. This function is called from new_vma_page(),
2081 * where no ERR_VALUE is expected to be returned.
2083 struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
2084 unsigned long addr, int avoid_reserve)
2086 struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
2087 if (IS_ERR(page))
2088 page = NULL;
2089 return page;
2092 int alloc_bootmem_huge_page(struct hstate *h)
2093 __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
2094 int __alloc_bootmem_huge_page(struct hstate *h)
2096 struct huge_bootmem_page *m;
2097 int nr_nodes, node;
2099 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2100 void *addr;
2102 addr = memblock_virt_alloc_try_nid_nopanic(
2103 huge_page_size(h), huge_page_size(h),
2104 0, BOOTMEM_ALLOC_ACCESSIBLE, node);
2105 if (addr) {
2107 * Use the beginning of the huge page to store the
2108 * huge_bootmem_page struct (until gather_bootmem
2109 * puts them into the mem_map).
2111 m = addr;
2112 goto found;
2115 return 0;
2117 found:
2118 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2119 /* Put them into a private list first because mem_map is not up yet */
2120 list_add(&m->list, &huge_boot_pages);
2121 m->hstate = h;
2122 return 1;
2125 static void __init prep_compound_huge_page(struct page *page,
2126 unsigned int order)
2128 if (unlikely(order > (MAX_ORDER - 1)))
2129 prep_compound_gigantic_page(page, order);
2130 else
2131 prep_compound_page(page, order);
2134 /* Put bootmem huge pages into the standard lists after mem_map is up */
2135 static void __init gather_bootmem_prealloc(void)
2137 struct huge_bootmem_page *m;
2139 list_for_each_entry(m, &huge_boot_pages, list) {
2140 struct hstate *h = m->hstate;
2141 struct page *page;
2143 #ifdef CONFIG_HIGHMEM
2144 page = pfn_to_page(m->phys >> PAGE_SHIFT);
2145 memblock_free_late(__pa(m),
2146 sizeof(struct huge_bootmem_page));
2147 #else
2148 page = virt_to_page(m);
2149 #endif
2150 WARN_ON(page_count(page) != 1);
2151 prep_compound_huge_page(page, h->order);
2152 WARN_ON(PageReserved(page));
2153 prep_new_huge_page(h, page, page_to_nid(page));
2155 * If we had gigantic hugepages allocated at boot time, we need
2156 * to restore the 'stolen' pages to totalram_pages in order to
2157 * fix confusing memory reports from free(1) and another
2158 * side-effects, like CommitLimit going negative.
2160 if (hstate_is_gigantic(h))
2161 adjust_managed_page_count(page, 1 << h->order);
2162 cond_resched();
2166 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
2168 unsigned long i;
2170 for (i = 0; i < h->max_huge_pages; ++i) {
2171 if (hstate_is_gigantic(h)) {
2172 if (!alloc_bootmem_huge_page(h))
2173 break;
2174 } else if (!alloc_fresh_huge_page(h,
2175 &node_states[N_MEMORY]))
2176 break;
2177 cond_resched();
2179 if (i < h->max_huge_pages) {
2180 char buf[32];
2182 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2183 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2184 h->max_huge_pages, buf, i);
2185 h->max_huge_pages = i;
2189 static void __init hugetlb_init_hstates(void)
2191 struct hstate *h;
2193 for_each_hstate(h) {
2194 if (minimum_order > huge_page_order(h))
2195 minimum_order = huge_page_order(h);
2197 /* oversize hugepages were init'ed in early boot */
2198 if (!hstate_is_gigantic(h))
2199 hugetlb_hstate_alloc_pages(h);
2201 VM_BUG_ON(minimum_order == UINT_MAX);
2204 static void __init report_hugepages(void)
2206 struct hstate *h;
2208 for_each_hstate(h) {
2209 char buf[32];
2211 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2212 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2213 buf, h->free_huge_pages);
2217 #ifdef CONFIG_HIGHMEM
2218 static void try_to_free_low(struct hstate *h, unsigned long count,
2219 nodemask_t *nodes_allowed)
2221 int i;
2223 if (hstate_is_gigantic(h))
2224 return;
2226 for_each_node_mask(i, *nodes_allowed) {
2227 struct page *page, *next;
2228 struct list_head *freel = &h->hugepage_freelists[i];
2229 list_for_each_entry_safe(page, next, freel, lru) {
2230 if (count >= h->nr_huge_pages)
2231 return;
2232 if (PageHighMem(page))
2233 continue;
2234 list_del(&page->lru);
2235 update_and_free_page(h, page);
2236 h->free_huge_pages--;
2237 h->free_huge_pages_node[page_to_nid(page)]--;
2241 #else
2242 static inline void try_to_free_low(struct hstate *h, unsigned long count,
2243 nodemask_t *nodes_allowed)
2246 #endif
2249 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2250 * balanced by operating on them in a round-robin fashion.
2251 * Returns 1 if an adjustment was made.
2253 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
2254 int delta)
2256 int nr_nodes, node;
2258 VM_BUG_ON(delta != -1 && delta != 1);
2260 if (delta < 0) {
2261 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2262 if (h->surplus_huge_pages_node[node])
2263 goto found;
2265 } else {
2266 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2267 if (h->surplus_huge_pages_node[node] <
2268 h->nr_huge_pages_node[node])
2269 goto found;
2272 return 0;
2274 found:
2275 h->surplus_huge_pages += delta;
2276 h->surplus_huge_pages_node[node] += delta;
2277 return 1;
2280 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2281 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
2282 nodemask_t *nodes_allowed)
2284 unsigned long min_count, ret;
2286 if (hstate_is_gigantic(h) && !gigantic_page_supported())
2287 return h->max_huge_pages;
2290 * Increase the pool size
2291 * First take pages out of surplus state. Then make up the
2292 * remaining difference by allocating fresh huge pages.
2294 * We might race with __alloc_buddy_huge_page() here and be unable
2295 * to convert a surplus huge page to a normal huge page. That is
2296 * not critical, though, it just means the overall size of the
2297 * pool might be one hugepage larger than it needs to be, but
2298 * within all the constraints specified by the sysctls.
2300 spin_lock(&hugetlb_lock);
2301 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2302 if (!adjust_pool_surplus(h, nodes_allowed, -1))
2303 break;
2306 while (count > persistent_huge_pages(h)) {
2308 * If this allocation races such that we no longer need the
2309 * page, free_huge_page will handle it by freeing the page
2310 * and reducing the surplus.
2312 spin_unlock(&hugetlb_lock);
2314 /* yield cpu to avoid soft lockup */
2315 cond_resched();
2317 if (hstate_is_gigantic(h))
2318 ret = alloc_fresh_gigantic_page(h, nodes_allowed);
2319 else
2320 ret = alloc_fresh_huge_page(h, nodes_allowed);
2321 spin_lock(&hugetlb_lock);
2322 if (!ret)
2323 goto out;
2325 /* Bail for signals. Probably ctrl-c from user */
2326 if (signal_pending(current))
2327 goto out;
2331 * Decrease the pool size
2332 * First return free pages to the buddy allocator (being careful
2333 * to keep enough around to satisfy reservations). Then place
2334 * pages into surplus state as needed so the pool will shrink
2335 * to the desired size as pages become free.
2337 * By placing pages into the surplus state independent of the
2338 * overcommit value, we are allowing the surplus pool size to
2339 * exceed overcommit. There are few sane options here. Since
2340 * __alloc_buddy_huge_page() is checking the global counter,
2341 * though, we'll note that we're not allowed to exceed surplus
2342 * and won't grow the pool anywhere else. Not until one of the
2343 * sysctls are changed, or the surplus pages go out of use.
2345 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2346 min_count = max(count, min_count);
2347 try_to_free_low(h, min_count, nodes_allowed);
2348 while (min_count < persistent_huge_pages(h)) {
2349 if (!free_pool_huge_page(h, nodes_allowed, 0))
2350 break;
2351 cond_resched_lock(&hugetlb_lock);
2353 while (count < persistent_huge_pages(h)) {
2354 if (!adjust_pool_surplus(h, nodes_allowed, 1))
2355 break;
2357 out:
2358 ret = persistent_huge_pages(h);
2359 spin_unlock(&hugetlb_lock);
2360 return ret;
2363 #define HSTATE_ATTR_RO(_name) \
2364 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2366 #define HSTATE_ATTR(_name) \
2367 static struct kobj_attribute _name##_attr = \
2368 __ATTR(_name, 0644, _name##_show, _name##_store)
2370 static struct kobject *hugepages_kobj;
2371 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2373 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
2375 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2377 int i;
2379 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2380 if (hstate_kobjs[i] == kobj) {
2381 if (nidp)
2382 *nidp = NUMA_NO_NODE;
2383 return &hstates[i];
2386 return kobj_to_node_hstate(kobj, nidp);
2389 static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2390 struct kobj_attribute *attr, char *buf)
2392 struct hstate *h;
2393 unsigned long nr_huge_pages;
2394 int nid;
2396 h = kobj_to_hstate(kobj, &nid);
2397 if (nid == NUMA_NO_NODE)
2398 nr_huge_pages = h->nr_huge_pages;
2399 else
2400 nr_huge_pages = h->nr_huge_pages_node[nid];
2402 return sprintf(buf, "%lu\n", nr_huge_pages);
2405 static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
2406 struct hstate *h, int nid,
2407 unsigned long count, size_t len)
2409 int err;
2410 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
2412 if (hstate_is_gigantic(h) && !gigantic_page_supported()) {
2413 err = -EINVAL;
2414 goto out;
2417 if (nid == NUMA_NO_NODE) {
2419 * global hstate attribute
2421 if (!(obey_mempolicy &&
2422 init_nodemask_of_mempolicy(nodes_allowed))) {
2423 NODEMASK_FREE(nodes_allowed);
2424 nodes_allowed = &node_states[N_MEMORY];
2426 } else if (nodes_allowed) {
2428 * per node hstate attribute: adjust count to global,
2429 * but restrict alloc/free to the specified node.
2431 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
2432 init_nodemask_of_node(nodes_allowed, nid);
2433 } else
2434 nodes_allowed = &node_states[N_MEMORY];
2436 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
2438 if (nodes_allowed != &node_states[N_MEMORY])
2439 NODEMASK_FREE(nodes_allowed);
2441 return len;
2442 out:
2443 NODEMASK_FREE(nodes_allowed);
2444 return err;
2447 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
2448 struct kobject *kobj, const char *buf,
2449 size_t len)
2451 struct hstate *h;
2452 unsigned long count;
2453 int nid;
2454 int err;
2456 err = kstrtoul(buf, 10, &count);
2457 if (err)
2458 return err;
2460 h = kobj_to_hstate(kobj, &nid);
2461 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
2464 static ssize_t nr_hugepages_show(struct kobject *kobj,
2465 struct kobj_attribute *attr, char *buf)
2467 return nr_hugepages_show_common(kobj, attr, buf);
2470 static ssize_t nr_hugepages_store(struct kobject *kobj,
2471 struct kobj_attribute *attr, const char *buf, size_t len)
2473 return nr_hugepages_store_common(false, kobj, buf, len);
2475 HSTATE_ATTR(nr_hugepages);
2477 #ifdef CONFIG_NUMA
2480 * hstate attribute for optionally mempolicy-based constraint on persistent
2481 * huge page alloc/free.
2483 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
2484 struct kobj_attribute *attr, char *buf)
2486 return nr_hugepages_show_common(kobj, attr, buf);
2489 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
2490 struct kobj_attribute *attr, const char *buf, size_t len)
2492 return nr_hugepages_store_common(true, kobj, buf, len);
2494 HSTATE_ATTR(nr_hugepages_mempolicy);
2495 #endif
2498 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
2499 struct kobj_attribute *attr, char *buf)
2501 struct hstate *h = kobj_to_hstate(kobj, NULL);
2502 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
2505 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
2506 struct kobj_attribute *attr, const char *buf, size_t count)
2508 int err;
2509 unsigned long input;
2510 struct hstate *h = kobj_to_hstate(kobj, NULL);
2512 if (hstate_is_gigantic(h))
2513 return -EINVAL;
2515 err = kstrtoul(buf, 10, &input);
2516 if (err)
2517 return err;
2519 spin_lock(&hugetlb_lock);
2520 h->nr_overcommit_huge_pages = input;
2521 spin_unlock(&hugetlb_lock);
2523 return count;
2525 HSTATE_ATTR(nr_overcommit_hugepages);
2527 static ssize_t free_hugepages_show(struct kobject *kobj,
2528 struct kobj_attribute *attr, char *buf)
2530 struct hstate *h;
2531 unsigned long free_huge_pages;
2532 int nid;
2534 h = kobj_to_hstate(kobj, &nid);
2535 if (nid == NUMA_NO_NODE)
2536 free_huge_pages = h->free_huge_pages;
2537 else
2538 free_huge_pages = h->free_huge_pages_node[nid];
2540 return sprintf(buf, "%lu\n", free_huge_pages);
2542 HSTATE_ATTR_RO(free_hugepages);
2544 static ssize_t resv_hugepages_show(struct kobject *kobj,
2545 struct kobj_attribute *attr, char *buf)
2547 struct hstate *h = kobj_to_hstate(kobj, NULL);
2548 return sprintf(buf, "%lu\n", h->resv_huge_pages);
2550 HSTATE_ATTR_RO(resv_hugepages);
2552 static ssize_t surplus_hugepages_show(struct kobject *kobj,
2553 struct kobj_attribute *attr, char *buf)
2555 struct hstate *h;
2556 unsigned long surplus_huge_pages;
2557 int nid;
2559 h = kobj_to_hstate(kobj, &nid);
2560 if (nid == NUMA_NO_NODE)
2561 surplus_huge_pages = h->surplus_huge_pages;
2562 else
2563 surplus_huge_pages = h->surplus_huge_pages_node[nid];
2565 return sprintf(buf, "%lu\n", surplus_huge_pages);
2567 HSTATE_ATTR_RO(surplus_hugepages);
2569 static struct attribute *hstate_attrs[] = {
2570 &nr_hugepages_attr.attr,
2571 &nr_overcommit_hugepages_attr.attr,
2572 &free_hugepages_attr.attr,
2573 &resv_hugepages_attr.attr,
2574 &surplus_hugepages_attr.attr,
2575 #ifdef CONFIG_NUMA
2576 &nr_hugepages_mempolicy_attr.attr,
2577 #endif
2578 NULL,
2581 static const struct attribute_group hstate_attr_group = {
2582 .attrs = hstate_attrs,
2585 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
2586 struct kobject **hstate_kobjs,
2587 const struct attribute_group *hstate_attr_group)
2589 int retval;
2590 int hi = hstate_index(h);
2592 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
2593 if (!hstate_kobjs[hi])
2594 return -ENOMEM;
2596 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
2597 if (retval)
2598 kobject_put(hstate_kobjs[hi]);
2600 return retval;
2603 static void __init hugetlb_sysfs_init(void)
2605 struct hstate *h;
2606 int err;
2608 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
2609 if (!hugepages_kobj)
2610 return;
2612 for_each_hstate(h) {
2613 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
2614 hstate_kobjs, &hstate_attr_group);
2615 if (err)
2616 pr_err("Hugetlb: Unable to add hstate %s", h->name);
2620 #ifdef CONFIG_NUMA
2623 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2624 * with node devices in node_devices[] using a parallel array. The array
2625 * index of a node device or _hstate == node id.
2626 * This is here to avoid any static dependency of the node device driver, in
2627 * the base kernel, on the hugetlb module.
2629 struct node_hstate {
2630 struct kobject *hugepages_kobj;
2631 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2633 static struct node_hstate node_hstates[MAX_NUMNODES];
2636 * A subset of global hstate attributes for node devices
2638 static struct attribute *per_node_hstate_attrs[] = {
2639 &nr_hugepages_attr.attr,
2640 &free_hugepages_attr.attr,
2641 &surplus_hugepages_attr.attr,
2642 NULL,
2645 static const struct attribute_group per_node_hstate_attr_group = {
2646 .attrs = per_node_hstate_attrs,
2650 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2651 * Returns node id via non-NULL nidp.
2653 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
2655 int nid;
2657 for (nid = 0; nid < nr_node_ids; nid++) {
2658 struct node_hstate *nhs = &node_hstates[nid];
2659 int i;
2660 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2661 if (nhs->hstate_kobjs[i] == kobj) {
2662 if (nidp)
2663 *nidp = nid;
2664 return &hstates[i];
2668 BUG();
2669 return NULL;
2673 * Unregister hstate attributes from a single node device.
2674 * No-op if no hstate attributes attached.
2676 static void hugetlb_unregister_node(struct node *node)
2678 struct hstate *h;
2679 struct node_hstate *nhs = &node_hstates[node->dev.id];
2681 if (!nhs->hugepages_kobj)
2682 return; /* no hstate attributes */
2684 for_each_hstate(h) {
2685 int idx = hstate_index(h);
2686 if (nhs->hstate_kobjs[idx]) {
2687 kobject_put(nhs->hstate_kobjs[idx]);
2688 nhs->hstate_kobjs[idx] = NULL;
2692 kobject_put(nhs->hugepages_kobj);
2693 nhs->hugepages_kobj = NULL;
2698 * Register hstate attributes for a single node device.
2699 * No-op if attributes already registered.
2701 static void hugetlb_register_node(struct node *node)
2703 struct hstate *h;
2704 struct node_hstate *nhs = &node_hstates[node->dev.id];
2705 int err;
2707 if (nhs->hugepages_kobj)
2708 return; /* already allocated */
2710 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
2711 &node->dev.kobj);
2712 if (!nhs->hugepages_kobj)
2713 return;
2715 for_each_hstate(h) {
2716 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
2717 nhs->hstate_kobjs,
2718 &per_node_hstate_attr_group);
2719 if (err) {
2720 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
2721 h->name, node->dev.id);
2722 hugetlb_unregister_node(node);
2723 break;
2729 * hugetlb init time: register hstate attributes for all registered node
2730 * devices of nodes that have memory. All on-line nodes should have
2731 * registered their associated device by this time.
2733 static void __init hugetlb_register_all_nodes(void)
2735 int nid;
2737 for_each_node_state(nid, N_MEMORY) {
2738 struct node *node = node_devices[nid];
2739 if (node->dev.id == nid)
2740 hugetlb_register_node(node);
2744 * Let the node device driver know we're here so it can
2745 * [un]register hstate attributes on node hotplug.
2747 register_hugetlbfs_with_node(hugetlb_register_node,
2748 hugetlb_unregister_node);
2750 #else /* !CONFIG_NUMA */
2752 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
2754 BUG();
2755 if (nidp)
2756 *nidp = -1;
2757 return NULL;
2760 static void hugetlb_register_all_nodes(void) { }
2762 #endif
2764 static int __init hugetlb_init(void)
2766 int i;
2768 if (!hugepages_supported())
2769 return 0;
2771 if (!size_to_hstate(default_hstate_size)) {
2772 if (default_hstate_size != 0) {
2773 pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n",
2774 default_hstate_size, HPAGE_SIZE);
2777 default_hstate_size = HPAGE_SIZE;
2778 if (!size_to_hstate(default_hstate_size))
2779 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
2781 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
2782 if (default_hstate_max_huge_pages) {
2783 if (!default_hstate.max_huge_pages)
2784 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
2787 hugetlb_init_hstates();
2788 gather_bootmem_prealloc();
2789 report_hugepages();
2791 hugetlb_sysfs_init();
2792 hugetlb_register_all_nodes();
2793 hugetlb_cgroup_file_init();
2795 #ifdef CONFIG_SMP
2796 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
2797 #else
2798 num_fault_mutexes = 1;
2799 #endif
2800 hugetlb_fault_mutex_table =
2801 kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
2802 BUG_ON(!hugetlb_fault_mutex_table);
2804 for (i = 0; i < num_fault_mutexes; i++)
2805 mutex_init(&hugetlb_fault_mutex_table[i]);
2806 return 0;
2808 subsys_initcall(hugetlb_init);
2810 /* Should be called on processing a hugepagesz=... option */
2811 void __init hugetlb_bad_size(void)
2813 parsed_valid_hugepagesz = false;
2816 void __init hugetlb_add_hstate(unsigned int order)
2818 struct hstate *h;
2819 unsigned long i;
2821 if (size_to_hstate(PAGE_SIZE << order)) {
2822 pr_warn("hugepagesz= specified twice, ignoring\n");
2823 return;
2825 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2826 BUG_ON(order == 0);
2827 h = &hstates[hugetlb_max_hstate++];
2828 h->order = order;
2829 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2830 h->nr_huge_pages = 0;
2831 h->free_huge_pages = 0;
2832 for (i = 0; i < MAX_NUMNODES; ++i)
2833 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2834 INIT_LIST_HEAD(&h->hugepage_activelist);
2835 h->next_nid_to_alloc = first_memory_node;
2836 h->next_nid_to_free = first_memory_node;
2837 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
2838 huge_page_size(h)/1024);
2840 parsed_hstate = h;
2843 static int __init hugetlb_nrpages_setup(char *s)
2845 unsigned long *mhp;
2846 static unsigned long *last_mhp;
2848 if (!parsed_valid_hugepagesz) {
2849 pr_warn("hugepages = %s preceded by "
2850 "an unsupported hugepagesz, ignoring\n", s);
2851 parsed_valid_hugepagesz = true;
2852 return 1;
2855 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2856 * so this hugepages= parameter goes to the "default hstate".
2858 else if (!hugetlb_max_hstate)
2859 mhp = &default_hstate_max_huge_pages;
2860 else
2861 mhp = &parsed_hstate->max_huge_pages;
2863 if (mhp == last_mhp) {
2864 pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
2865 return 1;
2868 if (sscanf(s, "%lu", mhp) <= 0)
2869 *mhp = 0;
2872 * Global state is always initialized later in hugetlb_init.
2873 * But we need to allocate >= MAX_ORDER hstates here early to still
2874 * use the bootmem allocator.
2876 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2877 hugetlb_hstate_alloc_pages(parsed_hstate);
2879 last_mhp = mhp;
2881 return 1;
2883 __setup("hugepages=", hugetlb_nrpages_setup);
2885 static int __init hugetlb_default_setup(char *s)
2887 default_hstate_size = memparse(s, &s);
2888 return 1;
2890 __setup("default_hugepagesz=", hugetlb_default_setup);
2892 static unsigned int cpuset_mems_nr(unsigned int *array)
2894 int node;
2895 unsigned int nr = 0;
2897 for_each_node_mask(node, cpuset_current_mems_allowed)
2898 nr += array[node];
2900 return nr;
2903 #ifdef CONFIG_SYSCTL
2904 static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
2905 struct ctl_table *table, int write,
2906 void __user *buffer, size_t *length, loff_t *ppos)
2908 struct hstate *h = &default_hstate;
2909 unsigned long tmp = h->max_huge_pages;
2910 int ret;
2912 if (!hugepages_supported())
2913 return -EOPNOTSUPP;
2915 table->data = &tmp;
2916 table->maxlen = sizeof(unsigned long);
2917 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2918 if (ret)
2919 goto out;
2921 if (write)
2922 ret = __nr_hugepages_store_common(obey_mempolicy, h,
2923 NUMA_NO_NODE, tmp, *length);
2924 out:
2925 return ret;
2928 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
2929 void __user *buffer, size_t *length, loff_t *ppos)
2932 return hugetlb_sysctl_handler_common(false, table, write,
2933 buffer, length, ppos);
2936 #ifdef CONFIG_NUMA
2937 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
2938 void __user *buffer, size_t *length, loff_t *ppos)
2940 return hugetlb_sysctl_handler_common(true, table, write,
2941 buffer, length, ppos);
2943 #endif /* CONFIG_NUMA */
2945 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2946 void __user *buffer,
2947 size_t *length, loff_t *ppos)
2949 struct hstate *h = &default_hstate;
2950 unsigned long tmp;
2951 int ret;
2953 if (!hugepages_supported())
2954 return -EOPNOTSUPP;
2956 tmp = h->nr_overcommit_huge_pages;
2958 if (write && hstate_is_gigantic(h))
2959 return -EINVAL;
2961 table->data = &tmp;
2962 table->maxlen = sizeof(unsigned long);
2963 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2964 if (ret)
2965 goto out;
2967 if (write) {
2968 spin_lock(&hugetlb_lock);
2969 h->nr_overcommit_huge_pages = tmp;
2970 spin_unlock(&hugetlb_lock);
2972 out:
2973 return ret;
2976 #endif /* CONFIG_SYSCTL */
2978 void hugetlb_report_meminfo(struct seq_file *m)
2980 struct hstate *h = &default_hstate;
2981 if (!hugepages_supported())
2982 return;
2983 seq_printf(m,
2984 "HugePages_Total: %5lu\n"
2985 "HugePages_Free: %5lu\n"
2986 "HugePages_Rsvd: %5lu\n"
2987 "HugePages_Surp: %5lu\n"
2988 "Hugepagesize: %8lu kB\n",
2989 h->nr_huge_pages,
2990 h->free_huge_pages,
2991 h->resv_huge_pages,
2992 h->surplus_huge_pages,
2993 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2996 int hugetlb_report_node_meminfo(int nid, char *buf)
2998 struct hstate *h = &default_hstate;
2999 if (!hugepages_supported())
3000 return 0;
3001 return sprintf(buf,
3002 "Node %d HugePages_Total: %5u\n"
3003 "Node %d HugePages_Free: %5u\n"
3004 "Node %d HugePages_Surp: %5u\n",
3005 nid, h->nr_huge_pages_node[nid],
3006 nid, h->free_huge_pages_node[nid],
3007 nid, h->surplus_huge_pages_node[nid]);
3010 void hugetlb_show_meminfo(void)
3012 struct hstate *h;
3013 int nid;
3015 if (!hugepages_supported())
3016 return;
3018 for_each_node_state(nid, N_MEMORY)
3019 for_each_hstate(h)
3020 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3021 nid,
3022 h->nr_huge_pages_node[nid],
3023 h->free_huge_pages_node[nid],
3024 h->surplus_huge_pages_node[nid],
3025 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
3028 void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
3030 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
3031 atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
3034 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3035 unsigned long hugetlb_total_pages(void)
3037 struct hstate *h;
3038 unsigned long nr_total_pages = 0;
3040 for_each_hstate(h)
3041 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
3042 return nr_total_pages;
3045 static int hugetlb_acct_memory(struct hstate *h, long delta)
3047 int ret = -ENOMEM;
3049 spin_lock(&hugetlb_lock);
3051 * When cpuset is configured, it breaks the strict hugetlb page
3052 * reservation as the accounting is done on a global variable. Such
3053 * reservation is completely rubbish in the presence of cpuset because
3054 * the reservation is not checked against page availability for the
3055 * current cpuset. Application can still potentially OOM'ed by kernel
3056 * with lack of free htlb page in cpuset that the task is in.
3057 * Attempt to enforce strict accounting with cpuset is almost
3058 * impossible (or too ugly) because cpuset is too fluid that
3059 * task or memory node can be dynamically moved between cpusets.
3061 * The change of semantics for shared hugetlb mapping with cpuset is
3062 * undesirable. However, in order to preserve some of the semantics,
3063 * we fall back to check against current free page availability as
3064 * a best attempt and hopefully to minimize the impact of changing
3065 * semantics that cpuset has.
3067 if (delta > 0) {
3068 if (gather_surplus_pages(h, delta) < 0)
3069 goto out;
3071 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
3072 return_unused_surplus_pages(h, delta);
3073 goto out;
3077 ret = 0;
3078 if (delta < 0)
3079 return_unused_surplus_pages(h, (unsigned long) -delta);
3081 out:
3082 spin_unlock(&hugetlb_lock);
3083 return ret;
3086 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
3088 struct resv_map *resv = vma_resv_map(vma);
3091 * This new VMA should share its siblings reservation map if present.
3092 * The VMA will only ever have a valid reservation map pointer where
3093 * it is being copied for another still existing VMA. As that VMA
3094 * has a reference to the reservation map it cannot disappear until
3095 * after this open call completes. It is therefore safe to take a
3096 * new reference here without additional locking.
3098 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3099 kref_get(&resv->refs);
3102 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
3104 struct hstate *h = hstate_vma(vma);
3105 struct resv_map *resv = vma_resv_map(vma);
3106 struct hugepage_subpool *spool = subpool_vma(vma);
3107 unsigned long reserve, start, end;
3108 long gbl_reserve;
3110 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3111 return;
3113 start = vma_hugecache_offset(h, vma, vma->vm_start);
3114 end = vma_hugecache_offset(h, vma, vma->vm_end);
3116 reserve = (end - start) - region_count(resv, start, end);
3118 kref_put(&resv->refs, resv_map_release);
3120 if (reserve) {
3122 * Decrement reserve counts. The global reserve count may be
3123 * adjusted if the subpool has a minimum size.
3125 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
3126 hugetlb_acct_memory(h, -gbl_reserve);
3130 static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
3132 if (addr & ~(huge_page_mask(hstate_vma(vma))))
3133 return -EINVAL;
3134 return 0;
3138 * We cannot handle pagefaults against hugetlb pages at all. They cause
3139 * handle_mm_fault() to try to instantiate regular-sized pages in the
3140 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3141 * this far.
3143 static int hugetlb_vm_op_fault(struct vm_fault *vmf)
3145 BUG();
3146 return 0;
3149 const struct vm_operations_struct hugetlb_vm_ops = {
3150 .fault = hugetlb_vm_op_fault,
3151 .open = hugetlb_vm_op_open,
3152 .close = hugetlb_vm_op_close,
3153 .split = hugetlb_vm_op_split,
3156 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
3157 int writable)
3159 pte_t entry;
3161 if (writable) {
3162 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
3163 vma->vm_page_prot)));
3164 } else {
3165 entry = huge_pte_wrprotect(mk_huge_pte(page,
3166 vma->vm_page_prot));
3168 entry = pte_mkyoung(entry);
3169 entry = pte_mkhuge(entry);
3170 entry = arch_make_huge_pte(entry, vma, page, writable);
3172 return entry;
3175 static void set_huge_ptep_writable(struct vm_area_struct *vma,
3176 unsigned long address, pte_t *ptep)
3178 pte_t entry;
3180 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3181 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3182 update_mmu_cache(vma, address, ptep);
3185 bool is_hugetlb_entry_migration(pte_t pte)
3187 swp_entry_t swp;
3189 if (huge_pte_none(pte) || pte_present(pte))
3190 return false;
3191 swp = pte_to_swp_entry(pte);
3192 if (non_swap_entry(swp) && is_migration_entry(swp))
3193 return true;
3194 else
3195 return false;
3198 static int is_hugetlb_entry_hwpoisoned(pte_t pte)
3200 swp_entry_t swp;
3202 if (huge_pte_none(pte) || pte_present(pte))
3203 return 0;
3204 swp = pte_to_swp_entry(pte);
3205 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
3206 return 1;
3207 else
3208 return 0;
3211 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
3212 struct vm_area_struct *vma)
3214 pte_t *src_pte, *dst_pte, entry, dst_entry;
3215 struct page *ptepage;
3216 unsigned long addr;
3217 int cow;
3218 struct hstate *h = hstate_vma(vma);
3219 unsigned long sz = huge_page_size(h);
3220 unsigned long mmun_start; /* For mmu_notifiers */
3221 unsigned long mmun_end; /* For mmu_notifiers */
3222 int ret = 0;
3224 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
3226 mmun_start = vma->vm_start;
3227 mmun_end = vma->vm_end;
3228 if (cow)
3229 mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);
3231 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3232 spinlock_t *src_ptl, *dst_ptl;
3233 src_pte = huge_pte_offset(src, addr, sz);
3234 if (!src_pte)
3235 continue;
3236 dst_pte = huge_pte_alloc(dst, addr, sz);
3237 if (!dst_pte) {
3238 ret = -ENOMEM;
3239 break;
3243 * If the pagetables are shared don't copy or take references.
3244 * dst_pte == src_pte is the common case of src/dest sharing.
3246 * However, src could have 'unshared' and dst shares with
3247 * another vma. If dst_pte !none, this implies sharing.
3248 * Check here before taking page table lock, and once again
3249 * after taking the lock below.
3251 dst_entry = huge_ptep_get(dst_pte);
3252 if ((dst_pte == src_pte) || !huge_pte_none(dst_entry))
3253 continue;
3255 dst_ptl = huge_pte_lock(h, dst, dst_pte);
3256 src_ptl = huge_pte_lockptr(h, src, src_pte);
3257 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
3258 entry = huge_ptep_get(src_pte);
3259 dst_entry = huge_ptep_get(dst_pte);
3260 if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) {
3262 * Skip if src entry none. Also, skip in the
3263 * unlikely case dst entry !none as this implies
3264 * sharing with another vma.
3267 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
3268 is_hugetlb_entry_hwpoisoned(entry))) {
3269 swp_entry_t swp_entry = pte_to_swp_entry(entry);
3271 if (is_write_migration_entry(swp_entry) && cow) {
3273 * COW mappings require pages in both
3274 * parent and child to be set to read.
3276 make_migration_entry_read(&swp_entry);
3277 entry = swp_entry_to_pte(swp_entry);
3278 set_huge_swap_pte_at(src, addr, src_pte,
3279 entry, sz);
3281 set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
3282 } else {
3283 if (cow) {
3284 huge_ptep_set_wrprotect(src, addr, src_pte);
3285 mmu_notifier_invalidate_range(src, mmun_start,
3286 mmun_end);
3288 entry = huge_ptep_get(src_pte);
3289 ptepage = pte_page(entry);
3290 get_page(ptepage);
3291 page_dup_rmap(ptepage, true);
3292 set_huge_pte_at(dst, addr, dst_pte, entry);
3293 hugetlb_count_add(pages_per_huge_page(h), dst);
3295 spin_unlock(src_ptl);
3296 spin_unlock(dst_ptl);
3299 if (cow)
3300 mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);
3302 return ret;
3305 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
3306 unsigned long start, unsigned long end,
3307 struct page *ref_page)
3309 struct mm_struct *mm = vma->vm_mm;
3310 unsigned long address;
3311 pte_t *ptep;
3312 pte_t pte;
3313 spinlock_t *ptl;
3314 struct page *page;
3315 struct hstate *h = hstate_vma(vma);
3316 unsigned long sz = huge_page_size(h);
3317 const unsigned long mmun_start = start; /* For mmu_notifiers */
3318 const unsigned long mmun_end = end; /* For mmu_notifiers */
3320 WARN_ON(!is_vm_hugetlb_page(vma));
3321 BUG_ON(start & ~huge_page_mask(h));
3322 BUG_ON(end & ~huge_page_mask(h));
3325 * This is a hugetlb vma, all the pte entries should point
3326 * to huge page.
3328 tlb_remove_check_page_size_change(tlb, sz);
3329 tlb_start_vma(tlb, vma);
3330 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3331 address = start;
3332 for (; address < end; address += sz) {
3333 ptep = huge_pte_offset(mm, address, sz);
3334 if (!ptep)
3335 continue;
3337 ptl = huge_pte_lock(h, mm, ptep);
3338 if (huge_pmd_unshare(mm, &address, ptep)) {
3339 spin_unlock(ptl);
3340 continue;
3343 pte = huge_ptep_get(ptep);
3344 if (huge_pte_none(pte)) {
3345 spin_unlock(ptl);
3346 continue;
3350 * Migrating hugepage or HWPoisoned hugepage is already
3351 * unmapped and its refcount is dropped, so just clear pte here.
3353 if (unlikely(!pte_present(pte))) {
3354 huge_pte_clear(mm, address, ptep, sz);
3355 spin_unlock(ptl);
3356 continue;
3359 page = pte_page(pte);
3361 * If a reference page is supplied, it is because a specific
3362 * page is being unmapped, not a range. Ensure the page we
3363 * are about to unmap is the actual page of interest.
3365 if (ref_page) {
3366 if (page != ref_page) {
3367 spin_unlock(ptl);
3368 continue;
3371 * Mark the VMA as having unmapped its page so that
3372 * future faults in this VMA will fail rather than
3373 * looking like data was lost
3375 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
3378 pte = huge_ptep_get_and_clear(mm, address, ptep);
3379 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
3380 if (huge_pte_dirty(pte))
3381 set_page_dirty(page);
3383 hugetlb_count_sub(pages_per_huge_page(h), mm);
3384 page_remove_rmap(page, true);
3386 spin_unlock(ptl);
3387 tlb_remove_page_size(tlb, page, huge_page_size(h));
3389 * Bail out after unmapping reference page if supplied
3391 if (ref_page)
3392 break;
3394 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3395 tlb_end_vma(tlb, vma);
3398 void __unmap_hugepage_range_final(struct mmu_gather *tlb,
3399 struct vm_area_struct *vma, unsigned long start,
3400 unsigned long end, struct page *ref_page)
3402 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
3405 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3406 * test will fail on a vma being torn down, and not grab a page table
3407 * on its way out. We're lucky that the flag has such an appropriate
3408 * name, and can in fact be safely cleared here. We could clear it
3409 * before the __unmap_hugepage_range above, but all that's necessary
3410 * is to clear it before releasing the i_mmap_rwsem. This works
3411 * because in the context this is called, the VMA is about to be
3412 * destroyed and the i_mmap_rwsem is held.
3414 vma->vm_flags &= ~VM_MAYSHARE;
3417 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
3418 unsigned long end, struct page *ref_page)
3420 struct mm_struct *mm;
3421 struct mmu_gather tlb;
3423 mm = vma->vm_mm;
3425 tlb_gather_mmu(&tlb, mm, start, end);
3426 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
3427 tlb_finish_mmu(&tlb, start, end);
3431 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3432 * mappping it owns the reserve page for. The intention is to unmap the page
3433 * from other VMAs and let the children be SIGKILLed if they are faulting the
3434 * same region.
3436 static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
3437 struct page *page, unsigned long address)
3439 struct hstate *h = hstate_vma(vma);
3440 struct vm_area_struct *iter_vma;
3441 struct address_space *mapping;
3442 pgoff_t pgoff;
3445 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3446 * from page cache lookup which is in HPAGE_SIZE units.
3448 address = address & huge_page_mask(h);
3449 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
3450 vma->vm_pgoff;
3451 mapping = vma->vm_file->f_mapping;
3454 * Take the mapping lock for the duration of the table walk. As
3455 * this mapping should be shared between all the VMAs,
3456 * __unmap_hugepage_range() is called as the lock is already held
3458 i_mmap_lock_write(mapping);
3459 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
3460 /* Do not unmap the current VMA */
3461 if (iter_vma == vma)
3462 continue;
3465 * Shared VMAs have their own reserves and do not affect
3466 * MAP_PRIVATE accounting but it is possible that a shared
3467 * VMA is using the same page so check and skip such VMAs.
3469 if (iter_vma->vm_flags & VM_MAYSHARE)
3470 continue;
3473 * Unmap the page from other VMAs without their own reserves.
3474 * They get marked to be SIGKILLed if they fault in these
3475 * areas. This is because a future no-page fault on this VMA
3476 * could insert a zeroed page instead of the data existing
3477 * from the time of fork. This would look like data corruption
3479 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
3480 unmap_hugepage_range(iter_vma, address,
3481 address + huge_page_size(h), page);
3483 i_mmap_unlock_write(mapping);
3487 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3488 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3489 * cannot race with other handlers or page migration.
3490 * Keep the pte_same checks anyway to make transition from the mutex easier.
3492 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
3493 unsigned long address, pte_t *ptep,
3494 struct page *pagecache_page, spinlock_t *ptl)
3496 pte_t pte;
3497 struct hstate *h = hstate_vma(vma);
3498 struct page *old_page, *new_page;
3499 int ret = 0, outside_reserve = 0;
3500 unsigned long mmun_start; /* For mmu_notifiers */
3501 unsigned long mmun_end; /* For mmu_notifiers */
3503 pte = huge_ptep_get(ptep);
3504 old_page = pte_page(pte);
3506 retry_avoidcopy:
3507 /* If no-one else is actually using this page, avoid the copy
3508 * and just make the page writable */
3509 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
3510 page_move_anon_rmap(old_page, vma);
3511 set_huge_ptep_writable(vma, address, ptep);
3512 return 0;
3516 * If the process that created a MAP_PRIVATE mapping is about to
3517 * perform a COW due to a shared page count, attempt to satisfy
3518 * the allocation without using the existing reserves. The pagecache
3519 * page is used to determine if the reserve at this address was
3520 * consumed or not. If reserves were used, a partial faulted mapping
3521 * at the time of fork() could consume its reserves on COW instead
3522 * of the full address range.
3524 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
3525 old_page != pagecache_page)
3526 outside_reserve = 1;
3528 get_page(old_page);
3531 * Drop page table lock as buddy allocator may be called. It will
3532 * be acquired again before returning to the caller, as expected.
3534 spin_unlock(ptl);
3535 new_page = alloc_huge_page(vma, address, outside_reserve);
3537 if (IS_ERR(new_page)) {
3539 * If a process owning a MAP_PRIVATE mapping fails to COW,
3540 * it is due to references held by a child and an insufficient
3541 * huge page pool. To guarantee the original mappers
3542 * reliability, unmap the page from child processes. The child
3543 * may get SIGKILLed if it later faults.
3545 if (outside_reserve) {
3546 put_page(old_page);
3547 BUG_ON(huge_pte_none(pte));
3548 unmap_ref_private(mm, vma, old_page, address);
3549 BUG_ON(huge_pte_none(pte));
3550 spin_lock(ptl);
3551 ptep = huge_pte_offset(mm, address & huge_page_mask(h),
3552 huge_page_size(h));
3553 if (likely(ptep &&
3554 pte_same(huge_ptep_get(ptep), pte)))
3555 goto retry_avoidcopy;
3557 * race occurs while re-acquiring page table
3558 * lock, and our job is done.
3560 return 0;
3563 ret = (PTR_ERR(new_page) == -ENOMEM) ?
3564 VM_FAULT_OOM : VM_FAULT_SIGBUS;
3565 goto out_release_old;
3569 * When the original hugepage is shared one, it does not have
3570 * anon_vma prepared.
3572 if (unlikely(anon_vma_prepare(vma))) {
3573 ret = VM_FAULT_OOM;
3574 goto out_release_all;
3577 copy_user_huge_page(new_page, old_page, address, vma,
3578 pages_per_huge_page(h));
3579 __SetPageUptodate(new_page);
3581 mmun_start = address & huge_page_mask(h);
3582 mmun_end = mmun_start + huge_page_size(h);
3583 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3586 * Retake the page table lock to check for racing updates
3587 * before the page tables are altered
3589 spin_lock(ptl);
3590 ptep = huge_pte_offset(mm, address & huge_page_mask(h),
3591 huge_page_size(h));
3592 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
3593 ClearPagePrivate(new_page);
3595 /* Break COW */
3596 huge_ptep_clear_flush(vma, address, ptep);
3597 mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
3598 set_huge_pte_at(mm, address, ptep,
3599 make_huge_pte(vma, new_page, 1));
3600 page_remove_rmap(old_page, true);
3601 hugepage_add_new_anon_rmap(new_page, vma, address);
3602 set_page_huge_active(new_page);
3603 /* Make the old page be freed below */
3604 new_page = old_page;
3606 spin_unlock(ptl);
3607 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3608 out_release_all:
3609 restore_reserve_on_error(h, vma, address, new_page);
3610 put_page(new_page);
3611 out_release_old:
3612 put_page(old_page);
3614 spin_lock(ptl); /* Caller expects lock to be held */
3615 return ret;
3618 /* Return the pagecache page at a given address within a VMA */
3619 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
3620 struct vm_area_struct *vma, unsigned long address)
3622 struct address_space *mapping;
3623 pgoff_t idx;
3625 mapping = vma->vm_file->f_mapping;
3626 idx = vma_hugecache_offset(h, vma, address);
3628 return find_lock_page(mapping, idx);
3632 * Return whether there is a pagecache page to back given address within VMA.
3633 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
3635 static bool hugetlbfs_pagecache_present(struct hstate *h,
3636 struct vm_area_struct *vma, unsigned long address)
3638 struct address_space *mapping;
3639 pgoff_t idx;
3640 struct page *page;
3642 mapping = vma->vm_file->f_mapping;
3643 idx = vma_hugecache_offset(h, vma, address);
3645 page = find_get_page(mapping, idx);
3646 if (page)
3647 put_page(page);
3648 return page != NULL;
3651 int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
3652 pgoff_t idx)
3654 struct inode *inode = mapping->host;
3655 struct hstate *h = hstate_inode(inode);
3656 int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
3658 if (err)
3659 return err;
3660 ClearPagePrivate(page);
3663 * set page dirty so that it will not be removed from cache/file
3664 * by non-hugetlbfs specific code paths.
3666 set_page_dirty(page);
3668 spin_lock(&inode->i_lock);
3669 inode->i_blocks += blocks_per_huge_page(h);
3670 spin_unlock(&inode->i_lock);
3671 return 0;
3674 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
3675 struct address_space *mapping, pgoff_t idx,
3676 unsigned long address, pte_t *ptep, unsigned int flags)
3678 struct hstate *h = hstate_vma(vma);
3679 int ret = VM_FAULT_SIGBUS;
3680 int anon_rmap = 0;
3681 unsigned long size;
3682 struct page *page;
3683 pte_t new_pte;
3684 spinlock_t *ptl;
3685 bool new_page = false;
3688 * Currently, we are forced to kill the process in the event the
3689 * original mapper has unmapped pages from the child due to a failed
3690 * COW. Warn that such a situation has occurred as it may not be obvious
3692 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
3693 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
3694 current->pid);
3695 return ret;
3699 * Use page lock to guard against racing truncation
3700 * before we get page_table_lock.
3702 retry:
3703 page = find_lock_page(mapping, idx);
3704 if (!page) {
3705 size = i_size_read(mapping->host) >> huge_page_shift(h);
3706 if (idx >= size)
3707 goto out;
3710 * Check for page in userfault range
3712 if (userfaultfd_missing(vma)) {
3713 u32 hash;
3714 struct vm_fault vmf = {
3715 .vma = vma,
3716 .address = address,
3717 .flags = flags,
3719 * Hard to debug if it ends up being
3720 * used by a callee that assumes
3721 * something about the other
3722 * uninitialized fields... same as in
3723 * memory.c
3728 * hugetlb_fault_mutex must be dropped before
3729 * handling userfault. Reacquire after handling
3730 * fault to make calling code simpler.
3732 hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping,
3733 idx, address);
3734 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
3735 ret = handle_userfault(&vmf, VM_UFFD_MISSING);
3736 mutex_lock(&hugetlb_fault_mutex_table[hash]);
3737 goto out;
3740 page = alloc_huge_page(vma, address, 0);
3741 if (IS_ERR(page)) {
3742 ret = PTR_ERR(page);
3743 if (ret == -ENOMEM)
3744 ret = VM_FAULT_OOM;
3745 else
3746 ret = VM_FAULT_SIGBUS;
3747 goto out;
3749 clear_huge_page(page, address, pages_per_huge_page(h));
3750 __SetPageUptodate(page);
3751 new_page = true;
3753 if (vma->vm_flags & VM_MAYSHARE) {
3754 int err = huge_add_to_page_cache(page, mapping, idx);
3755 if (err) {
3756 put_page(page);
3757 if (err == -EEXIST)
3758 goto retry;
3759 goto out;
3761 } else {
3762 lock_page(page);
3763 if (unlikely(anon_vma_prepare(vma))) {
3764 ret = VM_FAULT_OOM;
3765 goto backout_unlocked;
3767 anon_rmap = 1;
3769 } else {
3771 * If memory error occurs between mmap() and fault, some process
3772 * don't have hwpoisoned swap entry for errored virtual address.
3773 * So we need to block hugepage fault by PG_hwpoison bit check.
3775 if (unlikely(PageHWPoison(page))) {
3776 ret = VM_FAULT_HWPOISON |
3777 VM_FAULT_SET_HINDEX(hstate_index(h));
3778 goto backout_unlocked;
3783 * If we are going to COW a private mapping later, we examine the
3784 * pending reservations for this page now. This will ensure that
3785 * any allocations necessary to record that reservation occur outside
3786 * the spinlock.
3788 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3789 if (vma_needs_reservation(h, vma, address) < 0) {
3790 ret = VM_FAULT_OOM;
3791 goto backout_unlocked;
3793 /* Just decrements count, does not deallocate */
3794 vma_end_reservation(h, vma, address);
3797 ptl = huge_pte_lock(h, mm, ptep);
3798 size = i_size_read(mapping->host) >> huge_page_shift(h);
3799 if (idx >= size)
3800 goto backout;
3802 ret = 0;
3803 if (!huge_pte_none(huge_ptep_get(ptep)))
3804 goto backout;
3806 if (anon_rmap) {
3807 ClearPagePrivate(page);
3808 hugepage_add_new_anon_rmap(page, vma, address);
3809 } else
3810 page_dup_rmap(page, true);
3811 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
3812 && (vma->vm_flags & VM_SHARED)));
3813 set_huge_pte_at(mm, address, ptep, new_pte);
3815 hugetlb_count_add(pages_per_huge_page(h), mm);
3816 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3817 /* Optimization, do the COW without a second fault */
3818 ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
3821 spin_unlock(ptl);
3824 * Only make newly allocated pages active. Existing pages found
3825 * in the pagecache could be !page_huge_active() if they have been
3826 * isolated for migration.
3828 if (new_page)
3829 set_page_huge_active(page);
3831 unlock_page(page);
3832 out:
3833 return ret;
3835 backout:
3836 spin_unlock(ptl);
3837 backout_unlocked:
3838 unlock_page(page);
3839 restore_reserve_on_error(h, vma, address, page);
3840 put_page(page);
3841 goto out;
3844 #ifdef CONFIG_SMP
3845 u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3846 struct vm_area_struct *vma,
3847 struct address_space *mapping,
3848 pgoff_t idx, unsigned long address)
3850 unsigned long key[2];
3851 u32 hash;
3853 if (vma->vm_flags & VM_SHARED) {
3854 key[0] = (unsigned long) mapping;
3855 key[1] = idx;
3856 } else {
3857 key[0] = (unsigned long) mm;
3858 key[1] = address >> huge_page_shift(h);
3861 hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0);
3863 return hash & (num_fault_mutexes - 1);
3865 #else
3867 * For uniprocesor systems we always use a single mutex, so just
3868 * return 0 and avoid the hashing overhead.
3870 u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3871 struct vm_area_struct *vma,
3872 struct address_space *mapping,
3873 pgoff_t idx, unsigned long address)
3875 return 0;
3877 #endif
3879 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3880 unsigned long address, unsigned int flags)
3882 pte_t *ptep, entry;
3883 spinlock_t *ptl;
3884 int ret;
3885 u32 hash;
3886 pgoff_t idx;
3887 struct page *page = NULL;
3888 struct page *pagecache_page = NULL;
3889 struct hstate *h = hstate_vma(vma);
3890 struct address_space *mapping;
3891 int need_wait_lock = 0;
3893 address &= huge_page_mask(h);
3895 ptep = huge_pte_offset(mm, address, huge_page_size(h));
3896 if (ptep) {
3897 entry = huge_ptep_get(ptep);
3898 if (unlikely(is_hugetlb_entry_migration(entry))) {
3899 migration_entry_wait_huge(vma, mm, ptep);
3900 return 0;
3901 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
3902 return VM_FAULT_HWPOISON_LARGE |
3903 VM_FAULT_SET_HINDEX(hstate_index(h));
3904 } else {
3905 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
3906 if (!ptep)
3907 return VM_FAULT_OOM;
3910 mapping = vma->vm_file->f_mapping;
3911 idx = vma_hugecache_offset(h, vma, address);
3914 * Serialize hugepage allocation and instantiation, so that we don't
3915 * get spurious allocation failures if two CPUs race to instantiate
3916 * the same page in the page cache.
3918 hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping, idx, address);
3919 mutex_lock(&hugetlb_fault_mutex_table[hash]);
3921 entry = huge_ptep_get(ptep);
3922 if (huge_pte_none(entry)) {
3923 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3924 goto out_mutex;
3927 ret = 0;
3930 * entry could be a migration/hwpoison entry at this point, so this
3931 * check prevents the kernel from going below assuming that we have
3932 * a active hugepage in pagecache. This goto expects the 2nd page fault,
3933 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
3934 * handle it.
3936 if (!pte_present(entry))
3937 goto out_mutex;
3940 * If we are going to COW the mapping later, we examine the pending
3941 * reservations for this page now. This will ensure that any
3942 * allocations necessary to record that reservation occur outside the
3943 * spinlock. For private mappings, we also lookup the pagecache
3944 * page now as it is used to determine if a reservation has been
3945 * consumed.
3947 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3948 if (vma_needs_reservation(h, vma, address) < 0) {
3949 ret = VM_FAULT_OOM;
3950 goto out_mutex;
3952 /* Just decrements count, does not deallocate */
3953 vma_end_reservation(h, vma, address);
3955 if (!(vma->vm_flags & VM_MAYSHARE))
3956 pagecache_page = hugetlbfs_pagecache_page(h,
3957 vma, address);
3960 ptl = huge_pte_lock(h, mm, ptep);
3962 /* Check for a racing update before calling hugetlb_cow */
3963 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
3964 goto out_ptl;
3967 * hugetlb_cow() requires page locks of pte_page(entry) and
3968 * pagecache_page, so here we need take the former one
3969 * when page != pagecache_page or !pagecache_page.
3971 page = pte_page(entry);
3972 if (page != pagecache_page)
3973 if (!trylock_page(page)) {
3974 need_wait_lock = 1;
3975 goto out_ptl;
3978 get_page(page);
3980 if (flags & FAULT_FLAG_WRITE) {
3981 if (!huge_pte_write(entry)) {
3982 ret = hugetlb_cow(mm, vma, address, ptep,
3983 pagecache_page, ptl);
3984 goto out_put_page;
3986 entry = huge_pte_mkdirty(entry);
3988 entry = pte_mkyoung(entry);
3989 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
3990 flags & FAULT_FLAG_WRITE))
3991 update_mmu_cache(vma, address, ptep);
3992 out_put_page:
3993 if (page != pagecache_page)
3994 unlock_page(page);
3995 put_page(page);
3996 out_ptl:
3997 spin_unlock(ptl);
3999 if (pagecache_page) {
4000 unlock_page(pagecache_page);
4001 put_page(pagecache_page);
4003 out_mutex:
4004 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4006 * Generally it's safe to hold refcount during waiting page lock. But
4007 * here we just wait to defer the next page fault to avoid busy loop and
4008 * the page is not used after unlocked before returning from the current
4009 * page fault. So we are safe from accessing freed page, even if we wait
4010 * here without taking refcount.
4012 if (need_wait_lock)
4013 wait_on_page_locked(page);
4014 return ret;
4018 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4019 * modifications for huge pages.
4021 int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
4022 pte_t *dst_pte,
4023 struct vm_area_struct *dst_vma,
4024 unsigned long dst_addr,
4025 unsigned long src_addr,
4026 struct page **pagep)
4028 struct address_space *mapping;
4029 pgoff_t idx;
4030 unsigned long size;
4031 int vm_shared = dst_vma->vm_flags & VM_SHARED;
4032 struct hstate *h = hstate_vma(dst_vma);
4033 pte_t _dst_pte;
4034 spinlock_t *ptl;
4035 int ret;
4036 struct page *page;
4038 if (!*pagep) {
4039 ret = -ENOMEM;
4040 page = alloc_huge_page(dst_vma, dst_addr, 0);
4041 if (IS_ERR(page))
4042 goto out;
4044 ret = copy_huge_page_from_user(page,
4045 (const void __user *) src_addr,
4046 pages_per_huge_page(h), false);
4048 /* fallback to copy_from_user outside mmap_sem */
4049 if (unlikely(ret)) {
4050 ret = -ENOENT;
4051 *pagep = page;
4052 /* don't free the page */
4053 goto out;
4055 } else {
4056 page = *pagep;
4057 *pagep = NULL;
4061 * The memory barrier inside __SetPageUptodate makes sure that
4062 * preceding stores to the page contents become visible before
4063 * the set_pte_at() write.
4065 __SetPageUptodate(page);
4067 mapping = dst_vma->vm_file->f_mapping;
4068 idx = vma_hugecache_offset(h, dst_vma, dst_addr);
4071 * If shared, add to page cache
4073 if (vm_shared) {
4074 size = i_size_read(mapping->host) >> huge_page_shift(h);
4075 ret = -EFAULT;
4076 if (idx >= size)
4077 goto out_release_nounlock;
4080 * Serialization between remove_inode_hugepages() and
4081 * huge_add_to_page_cache() below happens through the
4082 * hugetlb_fault_mutex_table that here must be hold by
4083 * the caller.
4085 ret = huge_add_to_page_cache(page, mapping, idx);
4086 if (ret)
4087 goto out_release_nounlock;
4090 ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
4091 spin_lock(ptl);
4094 * Recheck the i_size after holding PT lock to make sure not
4095 * to leave any page mapped (as page_mapped()) beyond the end
4096 * of the i_size (remove_inode_hugepages() is strict about
4097 * enforcing that). If we bail out here, we'll also leave a
4098 * page in the radix tree in the vm_shared case beyond the end
4099 * of the i_size, but remove_inode_hugepages() will take care
4100 * of it as soon as we drop the hugetlb_fault_mutex_table.
4102 size = i_size_read(mapping->host) >> huge_page_shift(h);
4103 ret = -EFAULT;
4104 if (idx >= size)
4105 goto out_release_unlock;
4107 ret = -EEXIST;
4108 if (!huge_pte_none(huge_ptep_get(dst_pte)))
4109 goto out_release_unlock;
4111 if (vm_shared) {
4112 page_dup_rmap(page, true);
4113 } else {
4114 ClearPagePrivate(page);
4115 hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
4118 _dst_pte = make_huge_pte(dst_vma, page, dst_vma->vm_flags & VM_WRITE);
4119 if (dst_vma->vm_flags & VM_WRITE)
4120 _dst_pte = huge_pte_mkdirty(_dst_pte);
4121 _dst_pte = pte_mkyoung(_dst_pte);
4123 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
4125 (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
4126 dst_vma->vm_flags & VM_WRITE);
4127 hugetlb_count_add(pages_per_huge_page(h), dst_mm);
4129 /* No need to invalidate - it was non-present before */
4130 update_mmu_cache(dst_vma, dst_addr, dst_pte);
4132 spin_unlock(ptl);
4133 set_page_huge_active(page);
4134 if (vm_shared)
4135 unlock_page(page);
4136 ret = 0;
4137 out:
4138 return ret;
4139 out_release_unlock:
4140 spin_unlock(ptl);
4141 if (vm_shared)
4142 unlock_page(page);
4143 out_release_nounlock:
4144 put_page(page);
4145 goto out;
4148 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
4149 struct page **pages, struct vm_area_struct **vmas,
4150 unsigned long *position, unsigned long *nr_pages,
4151 long i, unsigned int flags, int *nonblocking)
4153 unsigned long pfn_offset;
4154 unsigned long vaddr = *position;
4155 unsigned long remainder = *nr_pages;
4156 struct hstate *h = hstate_vma(vma);
4157 int err = -EFAULT;
4159 while (vaddr < vma->vm_end && remainder) {
4160 pte_t *pte;
4161 spinlock_t *ptl = NULL;
4162 int absent;
4163 struct page *page;
4166 * If we have a pending SIGKILL, don't keep faulting pages and
4167 * potentially allocating memory.
4169 if (unlikely(fatal_signal_pending(current))) {
4170 remainder = 0;
4171 break;
4175 * Some archs (sparc64, sh*) have multiple pte_ts to
4176 * each hugepage. We have to make sure we get the
4177 * first, for the page indexing below to work.
4179 * Note that page table lock is not held when pte is null.
4181 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
4182 huge_page_size(h));
4183 if (pte)
4184 ptl = huge_pte_lock(h, mm, pte);
4185 absent = !pte || huge_pte_none(huge_ptep_get(pte));
4188 * When coredumping, it suits get_dump_page if we just return
4189 * an error where there's an empty slot with no huge pagecache
4190 * to back it. This way, we avoid allocating a hugepage, and
4191 * the sparse dumpfile avoids allocating disk blocks, but its
4192 * huge holes still show up with zeroes where they need to be.
4194 if (absent && (flags & FOLL_DUMP) &&
4195 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4196 if (pte)
4197 spin_unlock(ptl);
4198 remainder = 0;
4199 break;
4203 * We need call hugetlb_fault for both hugepages under migration
4204 * (in which case hugetlb_fault waits for the migration,) and
4205 * hwpoisoned hugepages (in which case we need to prevent the
4206 * caller from accessing to them.) In order to do this, we use
4207 * here is_swap_pte instead of is_hugetlb_entry_migration and
4208 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4209 * both cases, and because we can't follow correct pages
4210 * directly from any kind of swap entries.
4212 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
4213 ((flags & FOLL_WRITE) &&
4214 !huge_pte_write(huge_ptep_get(pte)))) {
4215 int ret;
4216 unsigned int fault_flags = 0;
4218 if (pte)
4219 spin_unlock(ptl);
4220 if (flags & FOLL_WRITE)
4221 fault_flags |= FAULT_FLAG_WRITE;
4222 if (nonblocking)
4223 fault_flags |= FAULT_FLAG_ALLOW_RETRY;
4224 if (flags & FOLL_NOWAIT)
4225 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
4226 FAULT_FLAG_RETRY_NOWAIT;
4227 if (flags & FOLL_TRIED) {
4228 VM_WARN_ON_ONCE(fault_flags &
4229 FAULT_FLAG_ALLOW_RETRY);
4230 fault_flags |= FAULT_FLAG_TRIED;
4232 ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
4233 if (ret & VM_FAULT_ERROR) {
4234 err = vm_fault_to_errno(ret, flags);
4235 remainder = 0;
4236 break;
4238 if (ret & VM_FAULT_RETRY) {
4239 if (nonblocking)
4240 *nonblocking = 0;
4241 *nr_pages = 0;
4243 * VM_FAULT_RETRY must not return an
4244 * error, it will return zero
4245 * instead.
4247 * No need to update "position" as the
4248 * caller will not check it after
4249 * *nr_pages is set to 0.
4251 return i;
4253 continue;
4256 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4257 page = pte_page(huge_ptep_get(pte));
4260 * Instead of doing 'try_get_page()' below in the same_page
4261 * loop, just check the count once here.
4263 if (unlikely(page_count(page) <= 0)) {
4264 if (pages) {
4265 spin_unlock(ptl);
4266 remainder = 0;
4267 err = -ENOMEM;
4268 break;
4271 same_page:
4272 if (pages) {
4273 pages[i] = mem_map_offset(page, pfn_offset);
4274 get_page(pages[i]);
4277 if (vmas)
4278 vmas[i] = vma;
4280 vaddr += PAGE_SIZE;
4281 ++pfn_offset;
4282 --remainder;
4283 ++i;
4284 if (vaddr < vma->vm_end && remainder &&
4285 pfn_offset < pages_per_huge_page(h)) {
4287 * We use pfn_offset to avoid touching the pageframes
4288 * of this compound page.
4290 goto same_page;
4292 spin_unlock(ptl);
4294 *nr_pages = remainder;
4296 * setting position is actually required only if remainder is
4297 * not zero but it's faster not to add a "if (remainder)"
4298 * branch.
4300 *position = vaddr;
4302 return i ? i : err;
4305 #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4307 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4308 * implement this.
4310 #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
4311 #endif
4313 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
4314 unsigned long address, unsigned long end, pgprot_t newprot)
4316 struct mm_struct *mm = vma->vm_mm;
4317 unsigned long start = address;
4318 pte_t *ptep;
4319 pte_t pte;
4320 struct hstate *h = hstate_vma(vma);
4321 unsigned long pages = 0;
4323 BUG_ON(address >= end);
4324 flush_cache_range(vma, address, end);
4326 mmu_notifier_invalidate_range_start(mm, start, end);
4327 i_mmap_lock_write(vma->vm_file->f_mapping);
4328 for (; address < end; address += huge_page_size(h)) {
4329 spinlock_t *ptl;
4330 ptep = huge_pte_offset(mm, address, huge_page_size(h));
4331 if (!ptep)
4332 continue;
4333 ptl = huge_pte_lock(h, mm, ptep);
4334 if (huge_pmd_unshare(mm, &address, ptep)) {
4335 pages++;
4336 spin_unlock(ptl);
4337 continue;
4339 pte = huge_ptep_get(ptep);
4340 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
4341 spin_unlock(ptl);
4342 continue;
4344 if (unlikely(is_hugetlb_entry_migration(pte))) {
4345 swp_entry_t entry = pte_to_swp_entry(pte);
4347 if (is_write_migration_entry(entry)) {
4348 pte_t newpte;
4350 make_migration_entry_read(&entry);
4351 newpte = swp_entry_to_pte(entry);
4352 set_huge_swap_pte_at(mm, address, ptep,
4353 newpte, huge_page_size(h));
4354 pages++;
4356 spin_unlock(ptl);
4357 continue;
4359 if (!huge_pte_none(pte)) {
4360 pte = huge_ptep_get_and_clear(mm, address, ptep);
4361 pte = pte_mkhuge(huge_pte_modify(pte, newprot));
4362 pte = arch_make_huge_pte(pte, vma, NULL, 0);
4363 set_huge_pte_at(mm, address, ptep, pte);
4364 pages++;
4366 spin_unlock(ptl);
4369 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4370 * may have cleared our pud entry and done put_page on the page table:
4371 * once we release i_mmap_rwsem, another task can do the final put_page
4372 * and that page table be reused and filled with junk.
4374 flush_hugetlb_tlb_range(vma, start, end);
4375 mmu_notifier_invalidate_range(mm, start, end);
4376 i_mmap_unlock_write(vma->vm_file->f_mapping);
4377 mmu_notifier_invalidate_range_end(mm, start, end);
4379 return pages << h->order;
4382 int hugetlb_reserve_pages(struct inode *inode,
4383 long from, long to,
4384 struct vm_area_struct *vma,
4385 vm_flags_t vm_flags)
4387 long ret, chg;
4388 struct hstate *h = hstate_inode(inode);
4389 struct hugepage_subpool *spool = subpool_inode(inode);
4390 struct resv_map *resv_map;
4391 long gbl_reserve;
4393 /* This should never happen */
4394 if (from > to) {
4395 VM_WARN(1, "%s called with a negative range\n", __func__);
4396 return -EINVAL;
4400 * Only apply hugepage reservation if asked. At fault time, an
4401 * attempt will be made for VM_NORESERVE to allocate a page
4402 * without using reserves
4404 if (vm_flags & VM_NORESERVE)
4405 return 0;
4408 * Shared mappings base their reservation on the number of pages that
4409 * are already allocated on behalf of the file. Private mappings need
4410 * to reserve the full area even if read-only as mprotect() may be
4411 * called to make the mapping read-write. Assume !vma is a shm mapping
4413 if (!vma || vma->vm_flags & VM_MAYSHARE) {
4414 resv_map = inode_resv_map(inode);
4416 chg = region_chg(resv_map, from, to);
4418 } else {
4419 resv_map = resv_map_alloc();
4420 if (!resv_map)
4421 return -ENOMEM;
4423 chg = to - from;
4425 set_vma_resv_map(vma, resv_map);
4426 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
4429 if (chg < 0) {
4430 ret = chg;
4431 goto out_err;
4435 * There must be enough pages in the subpool for the mapping. If
4436 * the subpool has a minimum size, there may be some global
4437 * reservations already in place (gbl_reserve).
4439 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
4440 if (gbl_reserve < 0) {
4441 ret = -ENOSPC;
4442 goto out_err;
4446 * Check enough hugepages are available for the reservation.
4447 * Hand the pages back to the subpool if there are not
4449 ret = hugetlb_acct_memory(h, gbl_reserve);
4450 if (ret < 0) {
4451 /* put back original number of pages, chg */
4452 (void)hugepage_subpool_put_pages(spool, chg);
4453 goto out_err;
4457 * Account for the reservations made. Shared mappings record regions
4458 * that have reservations as they are shared by multiple VMAs.
4459 * When the last VMA disappears, the region map says how much
4460 * the reservation was and the page cache tells how much of
4461 * the reservation was consumed. Private mappings are per-VMA and
4462 * only the consumed reservations are tracked. When the VMA
4463 * disappears, the original reservation is the VMA size and the
4464 * consumed reservations are stored in the map. Hence, nothing
4465 * else has to be done for private mappings here
4467 if (!vma || vma->vm_flags & VM_MAYSHARE) {
4468 long add = region_add(resv_map, from, to);
4470 if (unlikely(chg > add)) {
4472 * pages in this range were added to the reserve
4473 * map between region_chg and region_add. This
4474 * indicates a race with alloc_huge_page. Adjust
4475 * the subpool and reserve counts modified above
4476 * based on the difference.
4478 long rsv_adjust;
4480 rsv_adjust = hugepage_subpool_put_pages(spool,
4481 chg - add);
4482 hugetlb_acct_memory(h, -rsv_adjust);
4485 return 0;
4486 out_err:
4487 if (!vma || vma->vm_flags & VM_MAYSHARE)
4488 /* Don't call region_abort if region_chg failed */
4489 if (chg >= 0)
4490 region_abort(resv_map, from, to);
4491 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
4492 kref_put(&resv_map->refs, resv_map_release);
4493 return ret;
4496 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
4497 long freed)
4499 struct hstate *h = hstate_inode(inode);
4500 struct resv_map *resv_map = inode_resv_map(inode);
4501 long chg = 0;
4502 struct hugepage_subpool *spool = subpool_inode(inode);
4503 long gbl_reserve;
4505 if (resv_map) {
4506 chg = region_del(resv_map, start, end);
4508 * region_del() can fail in the rare case where a region
4509 * must be split and another region descriptor can not be
4510 * allocated. If end == LONG_MAX, it will not fail.
4512 if (chg < 0)
4513 return chg;
4516 spin_lock(&inode->i_lock);
4517 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
4518 spin_unlock(&inode->i_lock);
4521 * If the subpool has a minimum size, the number of global
4522 * reservations to be released may be adjusted.
4524 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
4525 hugetlb_acct_memory(h, -gbl_reserve);
4527 return 0;
4530 #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
4531 static unsigned long page_table_shareable(struct vm_area_struct *svma,
4532 struct vm_area_struct *vma,
4533 unsigned long addr, pgoff_t idx)
4535 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
4536 svma->vm_start;
4537 unsigned long sbase = saddr & PUD_MASK;
4538 unsigned long s_end = sbase + PUD_SIZE;
4540 /* Allow segments to share if only one is marked locked */
4541 unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
4542 unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
4545 * match the virtual addresses, permission and the alignment of the
4546 * page table page.
4548 if (pmd_index(addr) != pmd_index(saddr) ||
4549 vm_flags != svm_flags ||
4550 sbase < svma->vm_start || svma->vm_end < s_end)
4551 return 0;
4553 return saddr;
4556 static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
4558 unsigned long base = addr & PUD_MASK;
4559 unsigned long end = base + PUD_SIZE;
4562 * check on proper vm_flags and page table alignment
4564 if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
4565 return true;
4566 return false;
4570 * Determine if start,end range within vma could be mapped by shared pmd.
4571 * If yes, adjust start and end to cover range associated with possible
4572 * shared pmd mappings.
4574 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
4575 unsigned long *start, unsigned long *end)
4577 unsigned long check_addr = *start;
4579 if (!(vma->vm_flags & VM_MAYSHARE))
4580 return;
4582 for (check_addr = *start; check_addr < *end; check_addr += PUD_SIZE) {
4583 unsigned long a_start = check_addr & PUD_MASK;
4584 unsigned long a_end = a_start + PUD_SIZE;
4587 * If sharing is possible, adjust start/end if necessary.
4589 if (range_in_vma(vma, a_start, a_end)) {
4590 if (a_start < *start)
4591 *start = a_start;
4592 if (a_end > *end)
4593 *end = a_end;
4599 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
4600 * and returns the corresponding pte. While this is not necessary for the
4601 * !shared pmd case because we can allocate the pmd later as well, it makes the
4602 * code much cleaner. pmd allocation is essential for the shared case because
4603 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4604 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
4605 * bad pmd for sharing.
4607 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
4609 struct vm_area_struct *vma = find_vma(mm, addr);
4610 struct address_space *mapping = vma->vm_file->f_mapping;
4611 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
4612 vma->vm_pgoff;
4613 struct vm_area_struct *svma;
4614 unsigned long saddr;
4615 pte_t *spte = NULL;
4616 pte_t *pte;
4617 spinlock_t *ptl;
4619 if (!vma_shareable(vma, addr))
4620 return (pte_t *)pmd_alloc(mm, pud, addr);
4622 i_mmap_lock_write(mapping);
4623 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
4624 if (svma == vma)
4625 continue;
4627 saddr = page_table_shareable(svma, vma, addr, idx);
4628 if (saddr) {
4629 spte = huge_pte_offset(svma->vm_mm, saddr,
4630 vma_mmu_pagesize(svma));
4631 if (spte) {
4632 get_page(virt_to_page(spte));
4633 break;
4638 if (!spte)
4639 goto out;
4641 ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
4642 if (pud_none(*pud)) {
4643 pud_populate(mm, pud,
4644 (pmd_t *)((unsigned long)spte & PAGE_MASK));
4645 mm_inc_nr_pmds(mm);
4646 } else {
4647 put_page(virt_to_page(spte));
4649 spin_unlock(ptl);
4650 out:
4651 pte = (pte_t *)pmd_alloc(mm, pud, addr);
4652 i_mmap_unlock_write(mapping);
4653 return pte;
4657 * unmap huge page backed by shared pte.
4659 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
4660 * indicated by page_count > 1, unmap is achieved by clearing pud and
4661 * decrementing the ref count. If count == 1, the pte page is not shared.
4663 * called with page table lock held.
4665 * returns: 1 successfully unmapped a shared pte page
4666 * 0 the underlying pte page is not shared, or it is the last user
4668 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
4670 pgd_t *pgd = pgd_offset(mm, *addr);
4671 p4d_t *p4d = p4d_offset(pgd, *addr);
4672 pud_t *pud = pud_offset(p4d, *addr);
4674 BUG_ON(page_count(virt_to_page(ptep)) == 0);
4675 if (page_count(virt_to_page(ptep)) == 1)
4676 return 0;
4678 pud_clear(pud);
4679 put_page(virt_to_page(ptep));
4680 mm_dec_nr_pmds(mm);
4681 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
4682 return 1;
4684 #define want_pmd_share() (1)
4685 #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4686 pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
4688 return NULL;
4691 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
4693 return 0;
4696 void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
4697 unsigned long *start, unsigned long *end)
4700 #define want_pmd_share() (0)
4701 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4703 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
4704 pte_t *huge_pte_alloc(struct mm_struct *mm,
4705 unsigned long addr, unsigned long sz)
4707 pgd_t *pgd;
4708 p4d_t *p4d;
4709 pud_t *pud;
4710 pte_t *pte = NULL;
4712 pgd = pgd_offset(mm, addr);
4713 p4d = p4d_alloc(mm, pgd, addr);
4714 if (!p4d)
4715 return NULL;
4716 pud = pud_alloc(mm, p4d, addr);
4717 if (pud) {
4718 if (sz == PUD_SIZE) {
4719 pte = (pte_t *)pud;
4720 } else {
4721 BUG_ON(sz != PMD_SIZE);
4722 if (want_pmd_share() && pud_none(*pud))
4723 pte = huge_pmd_share(mm, addr, pud);
4724 else
4725 pte = (pte_t *)pmd_alloc(mm, pud, addr);
4728 BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
4730 return pte;
4734 * huge_pte_offset() - Walk the page table to resolve the hugepage
4735 * entry at address @addr
4737 * Return: Pointer to page table or swap entry (PUD or PMD) for
4738 * address @addr, or NULL if a p*d_none() entry is encountered and the
4739 * size @sz doesn't match the hugepage size at this level of the page
4740 * table.
4742 pte_t *huge_pte_offset(struct mm_struct *mm,
4743 unsigned long addr, unsigned long sz)
4745 pgd_t *pgd;
4746 p4d_t *p4d;
4747 pud_t *pud;
4748 pmd_t *pmd;
4750 pgd = pgd_offset(mm, addr);
4751 if (!pgd_present(*pgd))
4752 return NULL;
4753 p4d = p4d_offset(pgd, addr);
4754 if (!p4d_present(*p4d))
4755 return NULL;
4757 pud = pud_offset(p4d, addr);
4758 if (sz != PUD_SIZE && pud_none(*pud))
4759 return NULL;
4760 /* hugepage or swap? */
4761 if (pud_huge(*pud) || !pud_present(*pud))
4762 return (pte_t *)pud;
4764 pmd = pmd_offset(pud, addr);
4765 if (sz != PMD_SIZE && pmd_none(*pmd))
4766 return NULL;
4767 /* hugepage or swap? */
4768 if (pmd_huge(*pmd) || !pmd_present(*pmd))
4769 return (pte_t *)pmd;
4771 return NULL;
4774 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
4777 * These functions are overwritable if your architecture needs its own
4778 * behavior.
4780 struct page * __weak
4781 follow_huge_addr(struct mm_struct *mm, unsigned long address,
4782 int write)
4784 return ERR_PTR(-EINVAL);
4787 struct page * __weak
4788 follow_huge_pd(struct vm_area_struct *vma,
4789 unsigned long address, hugepd_t hpd, int flags, int pdshift)
4791 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
4792 return NULL;
4795 struct page * __weak
4796 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
4797 pmd_t *pmd, int flags)
4799 struct page *page = NULL;
4800 spinlock_t *ptl;
4801 pte_t pte;
4802 retry:
4803 ptl = pmd_lockptr(mm, pmd);
4804 spin_lock(ptl);
4806 * make sure that the address range covered by this pmd is not
4807 * unmapped from other threads.
4809 if (!pmd_huge(*pmd))
4810 goto out;
4811 pte = huge_ptep_get((pte_t *)pmd);
4812 if (pte_present(pte)) {
4813 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
4814 if (flags & FOLL_GET)
4815 get_page(page);
4816 } else {
4817 if (is_hugetlb_entry_migration(pte)) {
4818 spin_unlock(ptl);
4819 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
4820 goto retry;
4823 * hwpoisoned entry is treated as no_page_table in
4824 * follow_page_mask().
4827 out:
4828 spin_unlock(ptl);
4829 return page;
4832 struct page * __weak
4833 follow_huge_pud(struct mm_struct *mm, unsigned long address,
4834 pud_t *pud, int flags)
4836 if (flags & FOLL_GET)
4837 return NULL;
4839 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
4842 struct page * __weak
4843 follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
4845 if (flags & FOLL_GET)
4846 return NULL;
4848 return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
4851 bool isolate_huge_page(struct page *page, struct list_head *list)
4853 bool ret = true;
4855 VM_BUG_ON_PAGE(!PageHead(page), page);
4856 spin_lock(&hugetlb_lock);
4857 if (!page_huge_active(page) || !get_page_unless_zero(page)) {
4858 ret = false;
4859 goto unlock;
4861 clear_page_huge_active(page);
4862 list_move_tail(&page->lru, list);
4863 unlock:
4864 spin_unlock(&hugetlb_lock);
4865 return ret;
4868 void putback_active_hugepage(struct page *page)
4870 VM_BUG_ON_PAGE(!PageHead(page), page);
4871 spin_lock(&hugetlb_lock);
4872 set_page_huge_active(page);
4873 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
4874 spin_unlock(&hugetlb_lock);
4875 put_page(page);