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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Generic hugetlb support.
4 * (C) Nadia Yvette Chambers, April 2004
5 */
6#include <linux/list.h>
7#include <linux/init.h>
8#include <linux/mm.h>
9#include <linux/seq_file.h>
10#include <linux/sysctl.h>
11#include <linux/highmem.h>
12#include <linux/mmu_notifier.h>
13#include <linux/nodemask.h>
14#include <linux/pagemap.h>
15#include <linux/mempolicy.h>
16#include <linux/compiler.h>
17#include <linux/cpuset.h>
18#include <linux/mutex.h>
19#include <linux/memblock.h>
20#include <linux/sysfs.h>
21#include <linux/slab.h>
22#include <linux/sched/mm.h>
23#include <linux/mmdebug.h>
24#include <linux/sched/signal.h>
25#include <linux/rmap.h>
26#include <linux/string_helpers.h>
27#include <linux/swap.h>
28#include <linux/swapops.h>
29#include <linux/jhash.h>
30#include <linux/numa.h>
31#include <linux/llist.h>
32#include <linux/cma.h>
33
34#include <asm/page.h>
35#include <asm/pgalloc.h>
36#include <asm/tlb.h>
37
38#include <linux/io.h>
39#include <linux/hugetlb.h>
40#include <linux/hugetlb_cgroup.h>
41#include <linux/node.h>
42#include <linux/userfaultfd_k.h>
43#include <linux/page_owner.h>
44#include "internal.h"
45
46int hugetlb_max_hstate __read_mostly;
47unsigned int default_hstate_idx;
48struct hstate hstates[HUGE_MAX_HSTATE];
49
50#ifdef CONFIG_CMA
51static struct cma *hugetlb_cma[MAX_NUMNODES];
52#endif
53static unsigned long hugetlb_cma_size __initdata;
54
55/*
56 * Minimum page order among possible hugepage sizes, set to a proper value
57 * at boot time.
58 */
59static unsigned int minimum_order __read_mostly = UINT_MAX;
60
61__initdata LIST_HEAD(huge_boot_pages);
62
63/* for command line parsing */
64static struct hstate * __initdata parsed_hstate;
65static unsigned long __initdata default_hstate_max_huge_pages;
66static bool __initdata parsed_valid_hugepagesz = true;
67static bool __initdata parsed_default_hugepagesz;
68
69/*
70 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
71 * free_huge_pages, and surplus_huge_pages.
72 */
73DEFINE_SPINLOCK(hugetlb_lock);
74
75/*
76 * Serializes faults on the same logical page. This is used to
77 * prevent spurious OOMs when the hugepage pool is fully utilized.
78 */
79static int num_fault_mutexes;
80struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
81
82/* Forward declaration */
83static int hugetlb_acct_memory(struct hstate *h, long delta);
84
85static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
86{
87 bool free = (spool->count == 0) && (spool->used_hpages == 0);
88
89 spin_unlock(&spool->lock);
90
91 /* If no pages are used, and no other handles to the subpool
92 * remain, give up any reservations based on minimum size and
93 * free the subpool */
94 if (free) {
95 if (spool->min_hpages != -1)
96 hugetlb_acct_memory(spool->hstate,
97 -spool->min_hpages);
98 kfree(spool);
99 }
100}
101
102struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
103 long min_hpages)
104{
105 struct hugepage_subpool *spool;
106
107 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
108 if (!spool)
109 return NULL;
110
111 spin_lock_init(&spool->lock);
112 spool->count = 1;
113 spool->max_hpages = max_hpages;
114 spool->hstate = h;
115 spool->min_hpages = min_hpages;
116
117 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
118 kfree(spool);
119 return NULL;
120 }
121 spool->rsv_hpages = min_hpages;
122
123 return spool;
124}
125
126void hugepage_put_subpool(struct hugepage_subpool *spool)
127{
128 spin_lock(&spool->lock);
129 BUG_ON(!spool->count);
130 spool->count--;
131 unlock_or_release_subpool(spool);
132}
133
134/*
135 * Subpool accounting for allocating and reserving pages.
136 * Return -ENOMEM if there are not enough resources to satisfy the
137 * request. Otherwise, return the number of pages by which the
138 * global pools must be adjusted (upward). The returned value may
139 * only be different than the passed value (delta) in the case where
140 * a subpool minimum size must be maintained.
141 */
142static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
143 long delta)
144{
145 long ret = delta;
146
147 if (!spool)
148 return ret;
149
150 spin_lock(&spool->lock);
151
152 if (spool->max_hpages != -1) { /* maximum size accounting */
153 if ((spool->used_hpages + delta) <= spool->max_hpages)
154 spool->used_hpages += delta;
155 else {
156 ret = -ENOMEM;
157 goto unlock_ret;
158 }
159 }
160
161 /* minimum size accounting */
162 if (spool->min_hpages != -1 && spool->rsv_hpages) {
163 if (delta > spool->rsv_hpages) {
164 /*
165 * Asking for more reserves than those already taken on
166 * behalf of subpool. Return difference.
167 */
168 ret = delta - spool->rsv_hpages;
169 spool->rsv_hpages = 0;
170 } else {
171 ret = 0; /* reserves already accounted for */
172 spool->rsv_hpages -= delta;
173 }
174 }
175
176unlock_ret:
177 spin_unlock(&spool->lock);
178 return ret;
179}
180
181/*
182 * Subpool accounting for freeing and unreserving pages.
183 * Return the number of global page reservations that must be dropped.
184 * The return value may only be different than the passed value (delta)
185 * in the case where a subpool minimum size must be maintained.
186 */
187static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
188 long delta)
189{
190 long ret = delta;
191
192 if (!spool)
193 return delta;
194
195 spin_lock(&spool->lock);
196
197 if (spool->max_hpages != -1) /* maximum size accounting */
198 spool->used_hpages -= delta;
199
200 /* minimum size accounting */
201 if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
202 if (spool->rsv_hpages + delta <= spool->min_hpages)
203 ret = 0;
204 else
205 ret = spool->rsv_hpages + delta - spool->min_hpages;
206
207 spool->rsv_hpages += delta;
208 if (spool->rsv_hpages > spool->min_hpages)
209 spool->rsv_hpages = spool->min_hpages;
210 }
211
212 /*
213 * If hugetlbfs_put_super couldn't free spool due to an outstanding
214 * quota reference, free it now.
215 */
216 unlock_or_release_subpool(spool);
217
218 return ret;
219}
220
221static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
222{
223 return HUGETLBFS_SB(inode->i_sb)->spool;
224}
225
226static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
227{
228 return subpool_inode(file_inode(vma->vm_file));
229}
230
231/* Helper that removes a struct file_region from the resv_map cache and returns
232 * it for use.
233 */
234static struct file_region *
235get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
236{
237 struct file_region *nrg = NULL;
238
239 VM_BUG_ON(resv->region_cache_count <= 0);
240
241 resv->region_cache_count--;
242 nrg = list_first_entry(&resv->region_cache, struct file_region, link);
243 VM_BUG_ON(!nrg);
244 list_del(&nrg->link);
245
246 nrg->from = from;
247 nrg->to = to;
248
249 return nrg;
250}
251
252static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg,
253 struct file_region *rg)
254{
255#ifdef CONFIG_CGROUP_HUGETLB
256 nrg->reservation_counter = rg->reservation_counter;
257 nrg->css = rg->css;
258 if (rg->css)
259 css_get(rg->css);
260#endif
261}
262
263/* Helper that records hugetlb_cgroup uncharge info. */
264static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
265 struct hstate *h,
266 struct resv_map *resv,
267 struct file_region *nrg)
268{
269#ifdef CONFIG_CGROUP_HUGETLB
270 if (h_cg) {
271 nrg->reservation_counter =
272 &h_cg->rsvd_hugepage[hstate_index(h)];
273 nrg->css = &h_cg->css;
274 if (!resv->pages_per_hpage)
275 resv->pages_per_hpage = pages_per_huge_page(h);
276 /* pages_per_hpage should be the same for all entries in
277 * a resv_map.
278 */
279 VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h));
280 } else {
281 nrg->reservation_counter = NULL;
282 nrg->css = NULL;
283 }
284#endif
285}
286
287static bool has_same_uncharge_info(struct file_region *rg,
288 struct file_region *org)
289{
290#ifdef CONFIG_CGROUP_HUGETLB
291 return rg && org &&
292 rg->reservation_counter == org->reservation_counter &&
293 rg->css == org->css;
294
295#else
296 return true;
297#endif
298}
299
300static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
301{
302 struct file_region *nrg = NULL, *prg = NULL;
303
304 prg = list_prev_entry(rg, link);
305 if (&prg->link != &resv->regions && prg->to == rg->from &&
306 has_same_uncharge_info(prg, rg)) {
307 prg->to = rg->to;
308
309 list_del(&rg->link);
310 kfree(rg);
311
312 coalesce_file_region(resv, prg);
313 return;
314 }
315
316 nrg = list_next_entry(rg, link);
317 if (&nrg->link != &resv->regions && nrg->from == rg->to &&
318 has_same_uncharge_info(nrg, rg)) {
319 nrg->from = rg->from;
320
321 list_del(&rg->link);
322 kfree(rg);
323
324 coalesce_file_region(resv, nrg);
325 return;
326 }
327}
328
329/* Must be called with resv->lock held. Calling this with count_only == true
330 * will count the number of pages to be added but will not modify the linked
331 * list. If regions_needed != NULL and count_only == true, then regions_needed
332 * will indicate the number of file_regions needed in the cache to carry out to
333 * add the regions for this range.
334 */
335static long add_reservation_in_range(struct resv_map *resv, long f, long t,
336 struct hugetlb_cgroup *h_cg,
337 struct hstate *h, long *regions_needed,
338 bool count_only)
339{
340 long add = 0;
341 struct list_head *head = &resv->regions;
342 long last_accounted_offset = f;
343 struct file_region *rg = NULL, *trg = NULL, *nrg = NULL;
344
345 if (regions_needed)
346 *regions_needed = 0;
347
348 /* In this loop, we essentially handle an entry for the range
349 * [last_accounted_offset, rg->from), at every iteration, with some
350 * bounds checking.
351 */
352 list_for_each_entry_safe(rg, trg, head, link) {
353 /* Skip irrelevant regions that start before our range. */
354 if (rg->from < f) {
355 /* If this region ends after the last accounted offset,
356 * then we need to update last_accounted_offset.
357 */
358 if (rg->to > last_accounted_offset)
359 last_accounted_offset = rg->to;
360 continue;
361 }
362
363 /* When we find a region that starts beyond our range, we've
364 * finished.
365 */
366 if (rg->from > t)
367 break;
368
369 /* Add an entry for last_accounted_offset -> rg->from, and
370 * update last_accounted_offset.
371 */
372 if (rg->from > last_accounted_offset) {
373 add += rg->from - last_accounted_offset;
374 if (!count_only) {
375 nrg = get_file_region_entry_from_cache(
376 resv, last_accounted_offset, rg->from);
377 record_hugetlb_cgroup_uncharge_info(h_cg, h,
378 resv, nrg);
379 list_add(&nrg->link, rg->link.prev);
380 coalesce_file_region(resv, nrg);
381 } else if (regions_needed)
382 *regions_needed += 1;
383 }
384
385 last_accounted_offset = rg->to;
386 }
387
388 /* Handle the case where our range extends beyond
389 * last_accounted_offset.
390 */
391 if (last_accounted_offset < t) {
392 add += t - last_accounted_offset;
393 if (!count_only) {
394 nrg = get_file_region_entry_from_cache(
395 resv, last_accounted_offset, t);
396 record_hugetlb_cgroup_uncharge_info(h_cg, h, resv, nrg);
397 list_add(&nrg->link, rg->link.prev);
398 coalesce_file_region(resv, nrg);
399 } else if (regions_needed)
400 *regions_needed += 1;
401 }
402
403 VM_BUG_ON(add < 0);
404 return add;
405}
406
407/* Must be called with resv->lock acquired. Will drop lock to allocate entries.
408 */
409static int allocate_file_region_entries(struct resv_map *resv,
410 int regions_needed)
411 __must_hold(&resv->lock)
412{
413 struct list_head allocated_regions;
414 int to_allocate = 0, i = 0;
415 struct file_region *trg = NULL, *rg = NULL;
416
417 VM_BUG_ON(regions_needed < 0);
418
419 INIT_LIST_HEAD(&allocated_regions);
420
421 /*
422 * Check for sufficient descriptors in the cache to accommodate
423 * the number of in progress add operations plus regions_needed.
424 *
425 * This is a while loop because when we drop the lock, some other call
426 * to region_add or region_del may have consumed some region_entries,
427 * so we keep looping here until we finally have enough entries for
428 * (adds_in_progress + regions_needed).
429 */
430 while (resv->region_cache_count <
431 (resv->adds_in_progress + regions_needed)) {
432 to_allocate = resv->adds_in_progress + regions_needed -
433 resv->region_cache_count;
434
435 /* At this point, we should have enough entries in the cache
436 * for all the existings adds_in_progress. We should only be
437 * needing to allocate for regions_needed.
438 */
439 VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress);
440
441 spin_unlock(&resv->lock);
442 for (i = 0; i < to_allocate; i++) {
443 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
444 if (!trg)
445 goto out_of_memory;
446 list_add(&trg->link, &allocated_regions);
447 }
448
449 spin_lock(&resv->lock);
450
451 list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
452 list_del(&rg->link);
453 list_add(&rg->link, &resv->region_cache);
454 resv->region_cache_count++;
455 }
456 }
457
458 return 0;
459
460out_of_memory:
461 list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
462 list_del(&rg->link);
463 kfree(rg);
464 }
465 return -ENOMEM;
466}
467
468/*
469 * Add the huge page range represented by [f, t) to the reserve
470 * map. Regions will be taken from the cache to fill in this range.
471 * Sufficient regions should exist in the cache due to the previous
472 * call to region_chg with the same range, but in some cases the cache will not
473 * have sufficient entries due to races with other code doing region_add or
474 * region_del. The extra needed entries will be allocated.
475 *
476 * regions_needed is the out value provided by a previous call to region_chg.
477 *
478 * Return the number of new huge pages added to the map. This number is greater
479 * than or equal to zero. If file_region entries needed to be allocated for
480 * this operation and we were not able to allocate, it returns -ENOMEM.
481 * region_add of regions of length 1 never allocate file_regions and cannot
482 * fail; region_chg will always allocate at least 1 entry and a region_add for
483 * 1 page will only require at most 1 entry.
484 */
485static long region_add(struct resv_map *resv, long f, long t,
486 long in_regions_needed, struct hstate *h,
487 struct hugetlb_cgroup *h_cg)
488{
489 long add = 0, actual_regions_needed = 0;
490
491 spin_lock(&resv->lock);
492retry:
493
494 /* Count how many regions are actually needed to execute this add. */
495 add_reservation_in_range(resv, f, t, NULL, NULL, &actual_regions_needed,
496 true);
497
498 /*
499 * Check for sufficient descriptors in the cache to accommodate
500 * this add operation. Note that actual_regions_needed may be greater
501 * than in_regions_needed, as the resv_map may have been modified since
502 * the region_chg call. In this case, we need to make sure that we
503 * allocate extra entries, such that we have enough for all the
504 * existing adds_in_progress, plus the excess needed for this
505 * operation.
506 */
507 if (actual_regions_needed > in_regions_needed &&
508 resv->region_cache_count <
509 resv->adds_in_progress +
510 (actual_regions_needed - in_regions_needed)) {
511 /* region_add operation of range 1 should never need to
512 * allocate file_region entries.
513 */
514 VM_BUG_ON(t - f <= 1);
515
516 if (allocate_file_region_entries(
517 resv, actual_regions_needed - in_regions_needed)) {
518 return -ENOMEM;
519 }
520
521 goto retry;
522 }
523
524 add = add_reservation_in_range(resv, f, t, h_cg, h, NULL, false);
525
526 resv->adds_in_progress -= in_regions_needed;
527
528 spin_unlock(&resv->lock);
529 VM_BUG_ON(add < 0);
530 return add;
531}
532
533/*
534 * Examine the existing reserve map and determine how many
535 * huge pages in the specified range [f, t) are NOT currently
536 * represented. This routine is called before a subsequent
537 * call to region_add that will actually modify the reserve
538 * map to add the specified range [f, t). region_chg does
539 * not change the number of huge pages represented by the
540 * map. A number of new file_region structures is added to the cache as a
541 * placeholder, for the subsequent region_add call to use. At least 1
542 * file_region structure is added.
543 *
544 * out_regions_needed is the number of regions added to the
545 * resv->adds_in_progress. This value needs to be provided to a follow up call
546 * to region_add or region_abort for proper accounting.
547 *
548 * Returns the number of huge pages that need to be added to the existing
549 * reservation map for the range [f, t). This number is greater or equal to
550 * zero. -ENOMEM is returned if a new file_region structure or cache entry
551 * is needed and can not be allocated.
552 */
553static long region_chg(struct resv_map *resv, long f, long t,
554 long *out_regions_needed)
555{
556 long chg = 0;
557
558 spin_lock(&resv->lock);
559
560 /* Count how many hugepages in this range are NOT respresented. */
561 chg = add_reservation_in_range(resv, f, t, NULL, NULL,
562 out_regions_needed, true);
563
564 if (*out_regions_needed == 0)
565 *out_regions_needed = 1;
566
567 if (allocate_file_region_entries(resv, *out_regions_needed))
568 return -ENOMEM;
569
570 resv->adds_in_progress += *out_regions_needed;
571
572 spin_unlock(&resv->lock);
573 return chg;
574}
575
576/*
577 * Abort the in progress add operation. The adds_in_progress field
578 * of the resv_map keeps track of the operations in progress between
579 * calls to region_chg and region_add. Operations are sometimes
580 * aborted after the call to region_chg. In such cases, region_abort
581 * is called to decrement the adds_in_progress counter. regions_needed
582 * is the value returned by the region_chg call, it is used to decrement
583 * the adds_in_progress counter.
584 *
585 * NOTE: The range arguments [f, t) are not needed or used in this
586 * routine. They are kept to make reading the calling code easier as
587 * arguments will match the associated region_chg call.
588 */
589static void region_abort(struct resv_map *resv, long f, long t,
590 long regions_needed)
591{
592 spin_lock(&resv->lock);
593 VM_BUG_ON(!resv->region_cache_count);
594 resv->adds_in_progress -= regions_needed;
595 spin_unlock(&resv->lock);
596}
597
598/*
599 * Delete the specified range [f, t) from the reserve map. If the
600 * t parameter is LONG_MAX, this indicates that ALL regions after f
601 * should be deleted. Locate the regions which intersect [f, t)
602 * and either trim, delete or split the existing regions.
603 *
604 * Returns the number of huge pages deleted from the reserve map.
605 * In the normal case, the return value is zero or more. In the
606 * case where a region must be split, a new region descriptor must
607 * be allocated. If the allocation fails, -ENOMEM will be returned.
608 * NOTE: If the parameter t == LONG_MAX, then we will never split
609 * a region and possibly return -ENOMEM. Callers specifying
610 * t == LONG_MAX do not need to check for -ENOMEM error.
611 */
612static long region_del(struct resv_map *resv, long f, long t)
613{
614 struct list_head *head = &resv->regions;
615 struct file_region *rg, *trg;
616 struct file_region *nrg = NULL;
617 long del = 0;
618
619retry:
620 spin_lock(&resv->lock);
621 list_for_each_entry_safe(rg, trg, head, link) {
622 /*
623 * Skip regions before the range to be deleted. file_region
624 * ranges are normally of the form [from, to). However, there
625 * may be a "placeholder" entry in the map which is of the form
626 * (from, to) with from == to. Check for placeholder entries
627 * at the beginning of the range to be deleted.
628 */
629 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
630 continue;
631
632 if (rg->from >= t)
633 break;
634
635 if (f > rg->from && t < rg->to) { /* Must split region */
636 /*
637 * Check for an entry in the cache before dropping
638 * lock and attempting allocation.
639 */
640 if (!nrg &&
641 resv->region_cache_count > resv->adds_in_progress) {
642 nrg = list_first_entry(&resv->region_cache,
643 struct file_region,
644 link);
645 list_del(&nrg->link);
646 resv->region_cache_count--;
647 }
648
649 if (!nrg) {
650 spin_unlock(&resv->lock);
651 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
652 if (!nrg)
653 return -ENOMEM;
654 goto retry;
655 }
656
657 del += t - f;
658
659 /* New entry for end of split region */
660 nrg->from = t;
661 nrg->to = rg->to;
662
663 copy_hugetlb_cgroup_uncharge_info(nrg, rg);
664
665 INIT_LIST_HEAD(&nrg->link);
666
667 /* Original entry is trimmed */
668 rg->to = f;
669
670 hugetlb_cgroup_uncharge_file_region(
671 resv, rg, nrg->to - nrg->from);
672
673 list_add(&nrg->link, &rg->link);
674 nrg = NULL;
675 break;
676 }
677
678 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
679 del += rg->to - rg->from;
680 hugetlb_cgroup_uncharge_file_region(resv, rg,
681 rg->to - rg->from);
682 list_del(&rg->link);
683 kfree(rg);
684 continue;
685 }
686
687 if (f <= rg->from) { /* Trim beginning of region */
688 del += t - rg->from;
689 rg->from = t;
690
691 hugetlb_cgroup_uncharge_file_region(resv, rg,
692 t - rg->from);
693 } else { /* Trim end of region */
694 del += rg->to - f;
695 rg->to = f;
696
697 hugetlb_cgroup_uncharge_file_region(resv, rg,
698 rg->to - f);
699 }
700 }
701
702 spin_unlock(&resv->lock);
703 kfree(nrg);
704 return del;
705}
706
707/*
708 * A rare out of memory error was encountered which prevented removal of
709 * the reserve map region for a page. The huge page itself was free'ed
710 * and removed from the page cache. This routine will adjust the subpool
711 * usage count, and the global reserve count if needed. By incrementing
712 * these counts, the reserve map entry which could not be deleted will
713 * appear as a "reserved" entry instead of simply dangling with incorrect
714 * counts.
715 */
716void hugetlb_fix_reserve_counts(struct inode *inode)
717{
718 struct hugepage_subpool *spool = subpool_inode(inode);
719 long rsv_adjust;
720
721 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
722 if (rsv_adjust) {
723 struct hstate *h = hstate_inode(inode);
724
725 hugetlb_acct_memory(h, 1);
726 }
727}
728
729/*
730 * Count and return the number of huge pages in the reserve map
731 * that intersect with the range [f, t).
732 */
733static long region_count(struct resv_map *resv, long f, long t)
734{
735 struct list_head *head = &resv->regions;
736 struct file_region *rg;
737 long chg = 0;
738
739 spin_lock(&resv->lock);
740 /* Locate each segment we overlap with, and count that overlap. */
741 list_for_each_entry(rg, head, link) {
742 long seg_from;
743 long seg_to;
744
745 if (rg->to <= f)
746 continue;
747 if (rg->from >= t)
748 break;
749
750 seg_from = max(rg->from, f);
751 seg_to = min(rg->to, t);
752
753 chg += seg_to - seg_from;
754 }
755 spin_unlock(&resv->lock);
756
757 return chg;
758}
759
760/*
761 * Convert the address within this vma to the page offset within
762 * the mapping, in pagecache page units; huge pages here.
763 */
764static pgoff_t vma_hugecache_offset(struct hstate *h,
765 struct vm_area_struct *vma, unsigned long address)
766{
767 return ((address - vma->vm_start) >> huge_page_shift(h)) +
768 (vma->vm_pgoff >> huge_page_order(h));
769}
770
771pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
772 unsigned long address)
773{
774 return vma_hugecache_offset(hstate_vma(vma), vma, address);
775}
776EXPORT_SYMBOL_GPL(linear_hugepage_index);
777
778/*
779 * Return the size of the pages allocated when backing a VMA. In the majority
780 * cases this will be same size as used by the page table entries.
781 */
782unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
783{
784 if (vma->vm_ops && vma->vm_ops->pagesize)
785 return vma->vm_ops->pagesize(vma);
786 return PAGE_SIZE;
787}
788EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
789
790/*
791 * Return the page size being used by the MMU to back a VMA. In the majority
792 * of cases, the page size used by the kernel matches the MMU size. On
793 * architectures where it differs, an architecture-specific 'strong'
794 * version of this symbol is required.
795 */
796__weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
797{
798 return vma_kernel_pagesize(vma);
799}
800
801/*
802 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
803 * bits of the reservation map pointer, which are always clear due to
804 * alignment.
805 */
806#define HPAGE_RESV_OWNER (1UL << 0)
807#define HPAGE_RESV_UNMAPPED (1UL << 1)
808#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
809
810/*
811 * These helpers are used to track how many pages are reserved for
812 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
813 * is guaranteed to have their future faults succeed.
814 *
815 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
816 * the reserve counters are updated with the hugetlb_lock held. It is safe
817 * to reset the VMA at fork() time as it is not in use yet and there is no
818 * chance of the global counters getting corrupted as a result of the values.
819 *
820 * The private mapping reservation is represented in a subtly different
821 * manner to a shared mapping. A shared mapping has a region map associated
822 * with the underlying file, this region map represents the backing file
823 * pages which have ever had a reservation assigned which this persists even
824 * after the page is instantiated. A private mapping has a region map
825 * associated with the original mmap which is attached to all VMAs which
826 * reference it, this region map represents those offsets which have consumed
827 * reservation ie. where pages have been instantiated.
828 */
829static unsigned long get_vma_private_data(struct vm_area_struct *vma)
830{
831 return (unsigned long)vma->vm_private_data;
832}
833
834static void set_vma_private_data(struct vm_area_struct *vma,
835 unsigned long value)
836{
837 vma->vm_private_data = (void *)value;
838}
839
840static void
841resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map,
842 struct hugetlb_cgroup *h_cg,
843 struct hstate *h)
844{
845#ifdef CONFIG_CGROUP_HUGETLB
846 if (!h_cg || !h) {
847 resv_map->reservation_counter = NULL;
848 resv_map->pages_per_hpage = 0;
849 resv_map->css = NULL;
850 } else {
851 resv_map->reservation_counter =
852 &h_cg->rsvd_hugepage[hstate_index(h)];
853 resv_map->pages_per_hpage = pages_per_huge_page(h);
854 resv_map->css = &h_cg->css;
855 }
856#endif
857}
858
859struct resv_map *resv_map_alloc(void)
860{
861 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
862 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
863
864 if (!resv_map || !rg) {
865 kfree(resv_map);
866 kfree(rg);
867 return NULL;
868 }
869
870 kref_init(&resv_map->refs);
871 spin_lock_init(&resv_map->lock);
872 INIT_LIST_HEAD(&resv_map->regions);
873
874 resv_map->adds_in_progress = 0;
875 /*
876 * Initialize these to 0. On shared mappings, 0's here indicate these
877 * fields don't do cgroup accounting. On private mappings, these will be
878 * re-initialized to the proper values, to indicate that hugetlb cgroup
879 * reservations are to be un-charged from here.
880 */
881 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL);
882
883 INIT_LIST_HEAD(&resv_map->region_cache);
884 list_add(&rg->link, &resv_map->region_cache);
885 resv_map->region_cache_count = 1;
886
887 return resv_map;
888}
889
890void resv_map_release(struct kref *ref)
891{
892 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
893 struct list_head *head = &resv_map->region_cache;
894 struct file_region *rg, *trg;
895
896 /* Clear out any active regions before we release the map. */
897 region_del(resv_map, 0, LONG_MAX);
898
899 /* ... and any entries left in the cache */
900 list_for_each_entry_safe(rg, trg, head, link) {
901 list_del(&rg->link);
902 kfree(rg);
903 }
904
905 VM_BUG_ON(resv_map->adds_in_progress);
906
907 kfree(resv_map);
908}
909
910static inline struct resv_map *inode_resv_map(struct inode *inode)
911{
912 /*
913 * At inode evict time, i_mapping may not point to the original
914 * address space within the inode. This original address space
915 * contains the pointer to the resv_map. So, always use the
916 * address space embedded within the inode.
917 * The VERY common case is inode->mapping == &inode->i_data but,
918 * this may not be true for device special inodes.
919 */
920 return (struct resv_map *)(&inode->i_data)->private_data;
921}
922
923static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
924{
925 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
926 if (vma->vm_flags & VM_MAYSHARE) {
927 struct address_space *mapping = vma->vm_file->f_mapping;
928 struct inode *inode = mapping->host;
929
930 return inode_resv_map(inode);
931
932 } else {
933 return (struct resv_map *)(get_vma_private_data(vma) &
934 ~HPAGE_RESV_MASK);
935 }
936}
937
938static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
939{
940 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
941 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
942
943 set_vma_private_data(vma, (get_vma_private_data(vma) &
944 HPAGE_RESV_MASK) | (unsigned long)map);
945}
946
947static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
948{
949 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
950 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
951
952 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
953}
954
955static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
956{
957 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
958
959 return (get_vma_private_data(vma) & flag) != 0;
960}
961
962/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
963void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
964{
965 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
966 if (!(vma->vm_flags & VM_MAYSHARE))
967 vma->vm_private_data = (void *)0;
968}
969
970/* Returns true if the VMA has associated reserve pages */
971static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
972{
973 if (vma->vm_flags & VM_NORESERVE) {
974 /*
975 * This address is already reserved by other process(chg == 0),
976 * so, we should decrement reserved count. Without decrementing,
977 * reserve count remains after releasing inode, because this
978 * allocated page will go into page cache and is regarded as
979 * coming from reserved pool in releasing step. Currently, we
980 * don't have any other solution to deal with this situation
981 * properly, so add work-around here.
982 */
983 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
984 return true;
985 else
986 return false;
987 }
988
989 /* Shared mappings always use reserves */
990 if (vma->vm_flags & VM_MAYSHARE) {
991 /*
992 * We know VM_NORESERVE is not set. Therefore, there SHOULD
993 * be a region map for all pages. The only situation where
994 * there is no region map is if a hole was punched via
995 * fallocate. In this case, there really are no reserves to
996 * use. This situation is indicated if chg != 0.
997 */
998 if (chg)
999 return false;
1000 else
1001 return true;
1002 }
1003
1004 /*
1005 * Only the process that called mmap() has reserves for
1006 * private mappings.
1007 */
1008 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1009 /*
1010 * Like the shared case above, a hole punch or truncate
1011 * could have been performed on the private mapping.
1012 * Examine the value of chg to determine if reserves
1013 * actually exist or were previously consumed.
1014 * Very Subtle - The value of chg comes from a previous
1015 * call to vma_needs_reserves(). The reserve map for
1016 * private mappings has different (opposite) semantics
1017 * than that of shared mappings. vma_needs_reserves()
1018 * has already taken this difference in semantics into
1019 * account. Therefore, the meaning of chg is the same
1020 * as in the shared case above. Code could easily be
1021 * combined, but keeping it separate draws attention to
1022 * subtle differences.
1023 */
1024 if (chg)
1025 return false;
1026 else
1027 return true;
1028 }
1029
1030 return false;
1031}
1032
1033static void enqueue_huge_page(struct hstate *h, struct page *page)
1034{
1035 int nid = page_to_nid(page);
1036 list_move(&page->lru, &h->hugepage_freelists[nid]);
1037 h->free_huge_pages++;
1038 h->free_huge_pages_node[nid]++;
1039}
1040
1041static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
1042{
1043 struct page *page;
1044 bool nocma = !!(current->flags & PF_MEMALLOC_NOCMA);
1045
1046 list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
1047 if (nocma && is_migrate_cma_page(page))
1048 continue;
1049
1050 if (!PageHWPoison(page))
1051 break;
1052 }
1053
1054 /*
1055 * if 'non-isolated free hugepage' not found on the list,
1056 * the allocation fails.
1057 */
1058 if (&h->hugepage_freelists[nid] == &page->lru)
1059 return NULL;
1060 list_move(&page->lru, &h->hugepage_activelist);
1061 set_page_refcounted(page);
1062 h->free_huge_pages--;
1063 h->free_huge_pages_node[nid]--;
1064 return page;
1065}
1066
1067static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
1068 nodemask_t *nmask)
1069{
1070 unsigned int cpuset_mems_cookie;
1071 struct zonelist *zonelist;
1072 struct zone *zone;
1073 struct zoneref *z;
1074 int node = NUMA_NO_NODE;
1075
1076 zonelist = node_zonelist(nid, gfp_mask);
1077
1078retry_cpuset:
1079 cpuset_mems_cookie = read_mems_allowed_begin();
1080 for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) {
1081 struct page *page;
1082
1083 if (!cpuset_zone_allowed(zone, gfp_mask))
1084 continue;
1085 /*
1086 * no need to ask again on the same node. Pool is node rather than
1087 * zone aware
1088 */
1089 if (zone_to_nid(zone) == node)
1090 continue;
1091 node = zone_to_nid(zone);
1092
1093 page = dequeue_huge_page_node_exact(h, node);
1094 if (page)
1095 return page;
1096 }
1097 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
1098 goto retry_cpuset;
1099
1100 return NULL;
1101}
1102
1103static struct page *dequeue_huge_page_vma(struct hstate *h,
1104 struct vm_area_struct *vma,
1105 unsigned long address, int avoid_reserve,
1106 long chg)
1107{
1108 struct page *page;
1109 struct mempolicy *mpol;
1110 gfp_t gfp_mask;
1111 nodemask_t *nodemask;
1112 int nid;
1113
1114 /*
1115 * A child process with MAP_PRIVATE mappings created by their parent
1116 * have no page reserves. This check ensures that reservations are
1117 * not "stolen". The child may still get SIGKILLed
1118 */
1119 if (!vma_has_reserves(vma, chg) &&
1120 h->free_huge_pages - h->resv_huge_pages == 0)
1121 goto err;
1122
1123 /* If reserves cannot be used, ensure enough pages are in the pool */
1124 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
1125 goto err;
1126
1127 gfp_mask = htlb_alloc_mask(h);
1128 nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1129 page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask);
1130 if (page && !avoid_reserve && vma_has_reserves(vma, chg)) {
1131 SetPagePrivate(page);
1132 h->resv_huge_pages--;
1133 }
1134
1135 mpol_cond_put(mpol);
1136 return page;
1137
1138err:
1139 return NULL;
1140}
1141
1142/*
1143 * common helper functions for hstate_next_node_to_{alloc|free}.
1144 * We may have allocated or freed a huge page based on a different
1145 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1146 * be outside of *nodes_allowed. Ensure that we use an allowed
1147 * node for alloc or free.
1148 */
1149static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
1150{
1151 nid = next_node_in(nid, *nodes_allowed);
1152 VM_BUG_ON(nid >= MAX_NUMNODES);
1153
1154 return nid;
1155}
1156
1157static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
1158{
1159 if (!node_isset(nid, *nodes_allowed))
1160 nid = next_node_allowed(nid, nodes_allowed);
1161 return nid;
1162}
1163
1164/*
1165 * returns the previously saved node ["this node"] from which to
1166 * allocate a persistent huge page for the pool and advance the
1167 * next node from which to allocate, handling wrap at end of node
1168 * mask.
1169 */
1170static int hstate_next_node_to_alloc(struct hstate *h,
1171 nodemask_t *nodes_allowed)
1172{
1173 int nid;
1174
1175 VM_BUG_ON(!nodes_allowed);
1176
1177 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
1178 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
1179
1180 return nid;
1181}
1182
1183/*
1184 * helper for free_pool_huge_page() - return the previously saved
1185 * node ["this node"] from which to free a huge page. Advance the
1186 * next node id whether or not we find a free huge page to free so
1187 * that the next attempt to free addresses the next node.
1188 */
1189static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
1190{
1191 int nid;
1192
1193 VM_BUG_ON(!nodes_allowed);
1194
1195 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
1196 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
1197
1198 return nid;
1199}
1200
1201#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1202 for (nr_nodes = nodes_weight(*mask); \
1203 nr_nodes > 0 && \
1204 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1205 nr_nodes--)
1206
1207#define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1208 for (nr_nodes = nodes_weight(*mask); \
1209 nr_nodes > 0 && \
1210 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1211 nr_nodes--)
1212
1213#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1214static void destroy_compound_gigantic_page(struct page *page,
1215 unsigned int order)
1216{
1217 int i;
1218 int nr_pages = 1 << order;
1219 struct page *p = page + 1;
1220
1221 atomic_set(compound_mapcount_ptr(page), 0);
1222 if (hpage_pincount_available(page))
1223 atomic_set(compound_pincount_ptr(page), 0);
1224
1225 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1226 clear_compound_head(p);
1227 set_page_refcounted(p);
1228 }
1229
1230 set_compound_order(page, 0);
1231 __ClearPageHead(page);
1232}
1233
1234static void free_gigantic_page(struct page *page, unsigned int order)
1235{
1236 /*
1237 * If the page isn't allocated using the cma allocator,
1238 * cma_release() returns false.
1239 */
1240#ifdef CONFIG_CMA
1241 if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order))
1242 return;
1243#endif
1244
1245 free_contig_range(page_to_pfn(page), 1 << order);
1246}
1247
1248#ifdef CONFIG_CONTIG_ALLOC
1249static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1250 int nid, nodemask_t *nodemask)
1251{
1252 unsigned long nr_pages = 1UL << huge_page_order(h);
1253 if (nid == NUMA_NO_NODE)
1254 nid = numa_mem_id();
1255
1256#ifdef CONFIG_CMA
1257 {
1258 struct page *page;
1259 int node;
1260
1261 if (hugetlb_cma[nid]) {
1262 page = cma_alloc(hugetlb_cma[nid], nr_pages,
1263 huge_page_order(h), true);
1264 if (page)
1265 return page;
1266 }
1267
1268 if (!(gfp_mask & __GFP_THISNODE)) {
1269 for_each_node_mask(node, *nodemask) {
1270 if (node == nid || !hugetlb_cma[node])
1271 continue;
1272
1273 page = cma_alloc(hugetlb_cma[node], nr_pages,
1274 huge_page_order(h), true);
1275 if (page)
1276 return page;
1277 }
1278 }
1279 }
1280#endif
1281
1282 return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1283}
1284
1285static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1286static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1287#else /* !CONFIG_CONTIG_ALLOC */
1288static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1289 int nid, nodemask_t *nodemask)
1290{
1291 return NULL;
1292}
1293#endif /* CONFIG_CONTIG_ALLOC */
1294
1295#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1296static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1297 int nid, nodemask_t *nodemask)
1298{
1299 return NULL;
1300}
1301static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1302static inline void destroy_compound_gigantic_page(struct page *page,
1303 unsigned int order) { }
1304#endif
1305
1306static void update_and_free_page(struct hstate *h, struct page *page)
1307{
1308 int i;
1309
1310 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1311 return;
1312
1313 h->nr_huge_pages--;
1314 h->nr_huge_pages_node[page_to_nid(page)]--;
1315 for (i = 0; i < pages_per_huge_page(h); i++) {
1316 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
1317 1 << PG_referenced | 1 << PG_dirty |
1318 1 << PG_active | 1 << PG_private |
1319 1 << PG_writeback);
1320 }
1321 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1322 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
1323 set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
1324 set_page_refcounted(page);
1325 if (hstate_is_gigantic(h)) {
1326 /*
1327 * Temporarily drop the hugetlb_lock, because
1328 * we might block in free_gigantic_page().
1329 */
1330 spin_unlock(&hugetlb_lock);
1331 destroy_compound_gigantic_page(page, huge_page_order(h));
1332 free_gigantic_page(page, huge_page_order(h));
1333 spin_lock(&hugetlb_lock);
1334 } else {
1335 __free_pages(page, huge_page_order(h));
1336 }
1337}
1338
1339struct hstate *size_to_hstate(unsigned long size)
1340{
1341 struct hstate *h;
1342
1343 for_each_hstate(h) {
1344 if (huge_page_size(h) == size)
1345 return h;
1346 }
1347 return NULL;
1348}
1349
1350/*
1351 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1352 * to hstate->hugepage_activelist.)
1353 *
1354 * This function can be called for tail pages, but never returns true for them.
1355 */
1356bool page_huge_active(struct page *page)
1357{
1358 VM_BUG_ON_PAGE(!PageHuge(page), page);
1359 return PageHead(page) && PagePrivate(&page[1]);
1360}
1361
1362/* never called for tail page */
1363static void set_page_huge_active(struct page *page)
1364{
1365 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1366 SetPagePrivate(&page[1]);
1367}
1368
1369static void clear_page_huge_active(struct page *page)
1370{
1371 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1372 ClearPagePrivate(&page[1]);
1373}
1374
1375/*
1376 * Internal hugetlb specific page flag. Do not use outside of the hugetlb
1377 * code
1378 */
1379static inline bool PageHugeTemporary(struct page *page)
1380{
1381 if (!PageHuge(page))
1382 return false;
1383
1384 return (unsigned long)page[2].mapping == -1U;
1385}
1386
1387static inline void SetPageHugeTemporary(struct page *page)
1388{
1389 page[2].mapping = (void *)-1U;
1390}
1391
1392static inline void ClearPageHugeTemporary(struct page *page)
1393{
1394 page[2].mapping = NULL;
1395}
1396
1397static void __free_huge_page(struct page *page)
1398{
1399 /*
1400 * Can't pass hstate in here because it is called from the
1401 * compound page destructor.
1402 */
1403 struct hstate *h = page_hstate(page);
1404 int nid = page_to_nid(page);
1405 struct hugepage_subpool *spool =
1406 (struct hugepage_subpool *)page_private(page);
1407 bool restore_reserve;
1408
1409 VM_BUG_ON_PAGE(page_count(page), page);
1410 VM_BUG_ON_PAGE(page_mapcount(page), page);
1411
1412 set_page_private(page, 0);
1413 page->mapping = NULL;
1414 restore_reserve = PagePrivate(page);
1415 ClearPagePrivate(page);
1416
1417 /*
1418 * If PagePrivate() was set on page, page allocation consumed a
1419 * reservation. If the page was associated with a subpool, there
1420 * would have been a page reserved in the subpool before allocation
1421 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1422 * reservtion, do not call hugepage_subpool_put_pages() as this will
1423 * remove the reserved page from the subpool.
1424 */
1425 if (!restore_reserve) {
1426 /*
1427 * A return code of zero implies that the subpool will be
1428 * under its minimum size if the reservation is not restored
1429 * after page is free. Therefore, force restore_reserve
1430 * operation.
1431 */
1432 if (hugepage_subpool_put_pages(spool, 1) == 0)
1433 restore_reserve = true;
1434 }
1435
1436 spin_lock(&hugetlb_lock);
1437 clear_page_huge_active(page);
1438 hugetlb_cgroup_uncharge_page(hstate_index(h),
1439 pages_per_huge_page(h), page);
1440 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
1441 pages_per_huge_page(h), page);
1442 if (restore_reserve)
1443 h->resv_huge_pages++;
1444
1445 if (PageHugeTemporary(page)) {
1446 list_del(&page->lru);
1447 ClearPageHugeTemporary(page);
1448 update_and_free_page(h, page);
1449 } else if (h->surplus_huge_pages_node[nid]) {
1450 /* remove the page from active list */
1451 list_del(&page->lru);
1452 update_and_free_page(h, page);
1453 h->surplus_huge_pages--;
1454 h->surplus_huge_pages_node[nid]--;
1455 } else {
1456 arch_clear_hugepage_flags(page);
1457 enqueue_huge_page(h, page);
1458 }
1459 spin_unlock(&hugetlb_lock);
1460}
1461
1462/*
1463 * As free_huge_page() can be called from a non-task context, we have
1464 * to defer the actual freeing in a workqueue to prevent potential
1465 * hugetlb_lock deadlock.
1466 *
1467 * free_hpage_workfn() locklessly retrieves the linked list of pages to
1468 * be freed and frees them one-by-one. As the page->mapping pointer is
1469 * going to be cleared in __free_huge_page() anyway, it is reused as the
1470 * llist_node structure of a lockless linked list of huge pages to be freed.
1471 */
1472static LLIST_HEAD(hpage_freelist);
1473
1474static void free_hpage_workfn(struct work_struct *work)
1475{
1476 struct llist_node *node;
1477 struct page *page;
1478
1479 node = llist_del_all(&hpage_freelist);
1480
1481 while (node) {
1482 page = container_of((struct address_space **)node,
1483 struct page, mapping);
1484 node = node->next;
1485 __free_huge_page(page);
1486 }
1487}
1488static DECLARE_WORK(free_hpage_work, free_hpage_workfn);
1489
1490void free_huge_page(struct page *page)
1491{
1492 /*
1493 * Defer freeing if in non-task context to avoid hugetlb_lock deadlock.
1494 */
1495 if (!in_task()) {
1496 /*
1497 * Only call schedule_work() if hpage_freelist is previously
1498 * empty. Otherwise, schedule_work() had been called but the
1499 * workfn hasn't retrieved the list yet.
1500 */
1501 if (llist_add((struct llist_node *)&page->mapping,
1502 &hpage_freelist))
1503 schedule_work(&free_hpage_work);
1504 return;
1505 }
1506
1507 __free_huge_page(page);
1508}
1509
1510static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1511{
1512 INIT_LIST_HEAD(&page->lru);
1513 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1514 spin_lock(&hugetlb_lock);
1515 set_hugetlb_cgroup(page, NULL);
1516 set_hugetlb_cgroup_rsvd(page, NULL);
1517 h->nr_huge_pages++;
1518 h->nr_huge_pages_node[nid]++;
1519 spin_unlock(&hugetlb_lock);
1520}
1521
1522static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1523{
1524 int i;
1525 int nr_pages = 1 << order;
1526 struct page *p = page + 1;
1527
1528 /* we rely on prep_new_huge_page to set the destructor */
1529 set_compound_order(page, order);
1530 __ClearPageReserved(page);
1531 __SetPageHead(page);
1532 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1533 /*
1534 * For gigantic hugepages allocated through bootmem at
1535 * boot, it's safer to be consistent with the not-gigantic
1536 * hugepages and clear the PG_reserved bit from all tail pages
1537 * too. Otherwise drivers using get_user_pages() to access tail
1538 * pages may get the reference counting wrong if they see
1539 * PG_reserved set on a tail page (despite the head page not
1540 * having PG_reserved set). Enforcing this consistency between
1541 * head and tail pages allows drivers to optimize away a check
1542 * on the head page when they need know if put_page() is needed
1543 * after get_user_pages().
1544 */
1545 __ClearPageReserved(p);
1546 set_page_count(p, 0);
1547 set_compound_head(p, page);
1548 }
1549 atomic_set(compound_mapcount_ptr(page), -1);
1550
1551 if (hpage_pincount_available(page))
1552 atomic_set(compound_pincount_ptr(page), 0);
1553}
1554
1555/*
1556 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1557 * transparent huge pages. See the PageTransHuge() documentation for more
1558 * details.
1559 */
1560int PageHuge(struct page *page)
1561{
1562 if (!PageCompound(page))
1563 return 0;
1564
1565 page = compound_head(page);
1566 return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1567}
1568EXPORT_SYMBOL_GPL(PageHuge);
1569
1570/*
1571 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1572 * normal or transparent huge pages.
1573 */
1574int PageHeadHuge(struct page *page_head)
1575{
1576 if (!PageHead(page_head))
1577 return 0;
1578
1579 return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
1580}
1581
1582/*
1583 * Find address_space associated with hugetlbfs page.
1584 * Upon entry page is locked and page 'was' mapped although mapped state
1585 * could change. If necessary, use anon_vma to find vma and associated
1586 * address space. The returned mapping may be stale, but it can not be
1587 * invalid as page lock (which is held) is required to destroy mapping.
1588 */
1589static struct address_space *_get_hugetlb_page_mapping(struct page *hpage)
1590{
1591 struct anon_vma *anon_vma;
1592 pgoff_t pgoff_start, pgoff_end;
1593 struct anon_vma_chain *avc;
1594 struct address_space *mapping = page_mapping(hpage);
1595
1596 /* Simple file based mapping */
1597 if (mapping)
1598 return mapping;
1599
1600 /*
1601 * Even anonymous hugetlbfs mappings are associated with an
1602 * underlying hugetlbfs file (see hugetlb_file_setup in mmap
1603 * code). Find a vma associated with the anonymous vma, and
1604 * use the file pointer to get address_space.
1605 */
1606 anon_vma = page_lock_anon_vma_read(hpage);
1607 if (!anon_vma)
1608 return mapping; /* NULL */
1609
1610 /* Use first found vma */
1611 pgoff_start = page_to_pgoff(hpage);
1612 pgoff_end = pgoff_start + pages_per_huge_page(page_hstate(hpage)) - 1;
1613 anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root,
1614 pgoff_start, pgoff_end) {
1615 struct vm_area_struct *vma = avc->vma;
1616
1617 mapping = vma->vm_file->f_mapping;
1618 break;
1619 }
1620
1621 anon_vma_unlock_read(anon_vma);
1622 return mapping;
1623}
1624
1625/*
1626 * Find and lock address space (mapping) in write mode.
1627 *
1628 * Upon entry, the page is locked which allows us to find the mapping
1629 * even in the case of an anon page. However, locking order dictates
1630 * the i_mmap_rwsem be acquired BEFORE the page lock. This is hugetlbfs
1631 * specific. So, we first try to lock the sema while still holding the
1632 * page lock. If this works, great! If not, then we need to drop the
1633 * page lock and then acquire i_mmap_rwsem and reacquire page lock. Of
1634 * course, need to revalidate state along the way.
1635 */
1636struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
1637{
1638 struct address_space *mapping, *mapping2;
1639
1640 mapping = _get_hugetlb_page_mapping(hpage);
1641retry:
1642 if (!mapping)
1643 return mapping;
1644
1645 /*
1646 * If no contention, take lock and return
1647 */
1648 if (i_mmap_trylock_write(mapping))
1649 return mapping;
1650
1651 /*
1652 * Must drop page lock and wait on mapping sema.
1653 * Note: Once page lock is dropped, mapping could become invalid.
1654 * As a hack, increase map count until we lock page again.
1655 */
1656 atomic_inc(&hpage->_mapcount);
1657 unlock_page(hpage);
1658 i_mmap_lock_write(mapping);
1659 lock_page(hpage);
1660 atomic_add_negative(-1, &hpage->_mapcount);
1661
1662 /* verify page is still mapped */
1663 if (!page_mapped(hpage)) {
1664 i_mmap_unlock_write(mapping);
1665 return NULL;
1666 }
1667
1668 /*
1669 * Get address space again and verify it is the same one
1670 * we locked. If not, drop lock and retry.
1671 */
1672 mapping2 = _get_hugetlb_page_mapping(hpage);
1673 if (mapping2 != mapping) {
1674 i_mmap_unlock_write(mapping);
1675 mapping = mapping2;
1676 goto retry;
1677 }
1678
1679 return mapping;
1680}
1681
1682pgoff_t __basepage_index(struct page *page)
1683{
1684 struct page *page_head = compound_head(page);
1685 pgoff_t index = page_index(page_head);
1686 unsigned long compound_idx;
1687
1688 if (!PageHuge(page_head))
1689 return page_index(page);
1690
1691 if (compound_order(page_head) >= MAX_ORDER)
1692 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
1693 else
1694 compound_idx = page - page_head;
1695
1696 return (index << compound_order(page_head)) + compound_idx;
1697}
1698
1699static struct page *alloc_buddy_huge_page(struct hstate *h,
1700 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1701 nodemask_t *node_alloc_noretry)
1702{
1703 int order = huge_page_order(h);
1704 struct page *page;
1705 bool alloc_try_hard = true;
1706
1707 /*
1708 * By default we always try hard to allocate the page with
1709 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1710 * a loop (to adjust global huge page counts) and previous allocation
1711 * failed, do not continue to try hard on the same node. Use the
1712 * node_alloc_noretry bitmap to manage this state information.
1713 */
1714 if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry))
1715 alloc_try_hard = false;
1716 gfp_mask |= __GFP_COMP|__GFP_NOWARN;
1717 if (alloc_try_hard)
1718 gfp_mask |= __GFP_RETRY_MAYFAIL;
1719 if (nid == NUMA_NO_NODE)
1720 nid = numa_mem_id();
1721 page = __alloc_pages_nodemask(gfp_mask, order, nid, nmask);
1722 if (page)
1723 __count_vm_event(HTLB_BUDDY_PGALLOC);
1724 else
1725 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1726
1727 /*
1728 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1729 * indicates an overall state change. Clear bit so that we resume
1730 * normal 'try hard' allocations.
1731 */
1732 if (node_alloc_noretry && page && !alloc_try_hard)
1733 node_clear(nid, *node_alloc_noretry);
1734
1735 /*
1736 * If we tried hard to get a page but failed, set bit so that
1737 * subsequent attempts will not try as hard until there is an
1738 * overall state change.
1739 */
1740 if (node_alloc_noretry && !page && alloc_try_hard)
1741 node_set(nid, *node_alloc_noretry);
1742
1743 return page;
1744}
1745
1746/*
1747 * Common helper to allocate a fresh hugetlb page. All specific allocators
1748 * should use this function to get new hugetlb pages
1749 */
1750static struct page *alloc_fresh_huge_page(struct hstate *h,
1751 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1752 nodemask_t *node_alloc_noretry)
1753{
1754 struct page *page;
1755
1756 if (hstate_is_gigantic(h))
1757 page = alloc_gigantic_page(h, gfp_mask, nid, nmask);
1758 else
1759 page = alloc_buddy_huge_page(h, gfp_mask,
1760 nid, nmask, node_alloc_noretry);
1761 if (!page)
1762 return NULL;
1763
1764 if (hstate_is_gigantic(h))
1765 prep_compound_gigantic_page(page, huge_page_order(h));
1766 prep_new_huge_page(h, page, page_to_nid(page));
1767
1768 return page;
1769}
1770
1771/*
1772 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1773 * manner.
1774 */
1775static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1776 nodemask_t *node_alloc_noretry)
1777{
1778 struct page *page;
1779 int nr_nodes, node;
1780 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1781
1782 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1783 page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
1784 node_alloc_noretry);
1785 if (page)
1786 break;
1787 }
1788
1789 if (!page)
1790 return 0;
1791
1792 put_page(page); /* free it into the hugepage allocator */
1793
1794 return 1;
1795}
1796
1797/*
1798 * Free huge page from pool from next node to free.
1799 * Attempt to keep persistent huge pages more or less
1800 * balanced over allowed nodes.
1801 * Called with hugetlb_lock locked.
1802 */
1803static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1804 bool acct_surplus)
1805{
1806 int nr_nodes, node;
1807 int ret = 0;
1808
1809 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1810 /*
1811 * If we're returning unused surplus pages, only examine
1812 * nodes with surplus pages.
1813 */
1814 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1815 !list_empty(&h->hugepage_freelists[node])) {
1816 struct page *page =
1817 list_entry(h->hugepage_freelists[node].next,
1818 struct page, lru);
1819 list_del(&page->lru);
1820 h->free_huge_pages--;
1821 h->free_huge_pages_node[node]--;
1822 if (acct_surplus) {
1823 h->surplus_huge_pages--;
1824 h->surplus_huge_pages_node[node]--;
1825 }
1826 update_and_free_page(h, page);
1827 ret = 1;
1828 break;
1829 }
1830 }
1831
1832 return ret;
1833}
1834
1835/*
1836 * Dissolve a given free hugepage into free buddy pages. This function does
1837 * nothing for in-use hugepages and non-hugepages.
1838 * This function returns values like below:
1839 *
1840 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1841 * (allocated or reserved.)
1842 * 0: successfully dissolved free hugepages or the page is not a
1843 * hugepage (considered as already dissolved)
1844 */
1845int dissolve_free_huge_page(struct page *page)
1846{
1847 int rc = -EBUSY;
1848
1849 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1850 if (!PageHuge(page))
1851 return 0;
1852
1853 spin_lock(&hugetlb_lock);
1854 if (!PageHuge(page)) {
1855 rc = 0;
1856 goto out;
1857 }
1858
1859 if (!page_count(page)) {
1860 struct page *head = compound_head(page);
1861 struct hstate *h = page_hstate(head);
1862 int nid = page_to_nid(head);
1863 if (h->free_huge_pages - h->resv_huge_pages == 0)
1864 goto out;
1865 /*
1866 * Move PageHWPoison flag from head page to the raw error page,
1867 * which makes any subpages rather than the error page reusable.
1868 */
1869 if (PageHWPoison(head) && page != head) {
1870 SetPageHWPoison(page);
1871 ClearPageHWPoison(head);
1872 }
1873 list_del(&head->lru);
1874 h->free_huge_pages--;
1875 h->free_huge_pages_node[nid]--;
1876 h->max_huge_pages--;
1877 update_and_free_page(h, head);
1878 rc = 0;
1879 }
1880out:
1881 spin_unlock(&hugetlb_lock);
1882 return rc;
1883}
1884
1885/*
1886 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1887 * make specified memory blocks removable from the system.
1888 * Note that this will dissolve a free gigantic hugepage completely, if any
1889 * part of it lies within the given range.
1890 * Also note that if dissolve_free_huge_page() returns with an error, all
1891 * free hugepages that were dissolved before that error are lost.
1892 */
1893int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1894{
1895 unsigned long pfn;
1896 struct page *page;
1897 int rc = 0;
1898
1899 if (!hugepages_supported())
1900 return rc;
1901
1902 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
1903 page = pfn_to_page(pfn);
1904 rc = dissolve_free_huge_page(page);
1905 if (rc)
1906 break;
1907 }
1908
1909 return rc;
1910}
1911
1912/*
1913 * Allocates a fresh surplus page from the page allocator.
1914 */
1915static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
1916 int nid, nodemask_t *nmask)
1917{
1918 struct page *page = NULL;
1919
1920 if (hstate_is_gigantic(h))
1921 return NULL;
1922
1923 spin_lock(&hugetlb_lock);
1924 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
1925 goto out_unlock;
1926 spin_unlock(&hugetlb_lock);
1927
1928 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1929 if (!page)
1930 return NULL;
1931
1932 spin_lock(&hugetlb_lock);
1933 /*
1934 * We could have raced with the pool size change.
1935 * Double check that and simply deallocate the new page
1936 * if we would end up overcommiting the surpluses. Abuse
1937 * temporary page to workaround the nasty free_huge_page
1938 * codeflow
1939 */
1940 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1941 SetPageHugeTemporary(page);
1942 spin_unlock(&hugetlb_lock);
1943 put_page(page);
1944 return NULL;
1945 } else {
1946 h->surplus_huge_pages++;
1947 h->surplus_huge_pages_node[page_to_nid(page)]++;
1948 }
1949
1950out_unlock:
1951 spin_unlock(&hugetlb_lock);
1952
1953 return page;
1954}
1955
1956static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
1957 int nid, nodemask_t *nmask)
1958{
1959 struct page *page;
1960
1961 if (hstate_is_gigantic(h))
1962 return NULL;
1963
1964 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1965 if (!page)
1966 return NULL;
1967
1968 /*
1969 * We do not account these pages as surplus because they are only
1970 * temporary and will be released properly on the last reference
1971 */
1972 SetPageHugeTemporary(page);
1973
1974 return page;
1975}
1976
1977/*
1978 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1979 */
1980static
1981struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
1982 struct vm_area_struct *vma, unsigned long addr)
1983{
1984 struct page *page;
1985 struct mempolicy *mpol;
1986 gfp_t gfp_mask = htlb_alloc_mask(h);
1987 int nid;
1988 nodemask_t *nodemask;
1989
1990 nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
1991 page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
1992 mpol_cond_put(mpol);
1993
1994 return page;
1995}
1996
1997/* page migration callback function */
1998struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
1999 nodemask_t *nmask, gfp_t gfp_mask)
2000{
2001 spin_lock(&hugetlb_lock);
2002 if (h->free_huge_pages - h->resv_huge_pages > 0) {
2003 struct page *page;
2004
2005 page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
2006 if (page) {
2007 spin_unlock(&hugetlb_lock);
2008 return page;
2009 }
2010 }
2011 spin_unlock(&hugetlb_lock);
2012
2013 return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
2014}
2015
2016/* mempolicy aware migration callback */
2017struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
2018 unsigned long address)
2019{
2020 struct mempolicy *mpol;
2021 nodemask_t *nodemask;
2022 struct page *page;
2023 gfp_t gfp_mask;
2024 int node;
2025
2026 gfp_mask = htlb_alloc_mask(h);
2027 node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
2028 page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask);
2029 mpol_cond_put(mpol);
2030
2031 return page;
2032}
2033
2034/*
2035 * Increase the hugetlb pool such that it can accommodate a reservation
2036 * of size 'delta'.
2037 */
2038static int gather_surplus_pages(struct hstate *h, int delta)
2039 __must_hold(&hugetlb_lock)
2040{
2041 struct list_head surplus_list;
2042 struct page *page, *tmp;
2043 int ret, i;
2044 int needed, allocated;
2045 bool alloc_ok = true;
2046
2047 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
2048 if (needed <= 0) {
2049 h->resv_huge_pages += delta;
2050 return 0;
2051 }
2052
2053 allocated = 0;
2054 INIT_LIST_HEAD(&surplus_list);
2055
2056 ret = -ENOMEM;
2057retry:
2058 spin_unlock(&hugetlb_lock);
2059 for (i = 0; i < needed; i++) {
2060 page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
2061 NUMA_NO_NODE, NULL);
2062 if (!page) {
2063 alloc_ok = false;
2064 break;
2065 }
2066 list_add(&page->lru, &surplus_list);
2067 cond_resched();
2068 }
2069 allocated += i;
2070
2071 /*
2072 * After retaking hugetlb_lock, we need to recalculate 'needed'
2073 * because either resv_huge_pages or free_huge_pages may have changed.
2074 */
2075 spin_lock(&hugetlb_lock);
2076 needed = (h->resv_huge_pages + delta) -
2077 (h->free_huge_pages + allocated);
2078 if (needed > 0) {
2079 if (alloc_ok)
2080 goto retry;
2081 /*
2082 * We were not able to allocate enough pages to
2083 * satisfy the entire reservation so we free what
2084 * we've allocated so far.
2085 */
2086 goto free;
2087 }
2088 /*
2089 * The surplus_list now contains _at_least_ the number of extra pages
2090 * needed to accommodate the reservation. Add the appropriate number
2091 * of pages to the hugetlb pool and free the extras back to the buddy
2092 * allocator. Commit the entire reservation here to prevent another
2093 * process from stealing the pages as they are added to the pool but
2094 * before they are reserved.
2095 */
2096 needed += allocated;
2097 h->resv_huge_pages += delta;
2098 ret = 0;
2099
2100 /* Free the needed pages to the hugetlb pool */
2101 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
2102 if ((--needed) < 0)
2103 break;
2104 /*
2105 * This page is now managed by the hugetlb allocator and has
2106 * no users -- drop the buddy allocator's reference.
2107 */
2108 put_page_testzero(page);
2109 VM_BUG_ON_PAGE(page_count(page), page);
2110 enqueue_huge_page(h, page);
2111 }
2112free:
2113 spin_unlock(&hugetlb_lock);
2114
2115 /* Free unnecessary surplus pages to the buddy allocator */
2116 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
2117 put_page(page);
2118 spin_lock(&hugetlb_lock);
2119
2120 return ret;
2121}
2122
2123/*
2124 * This routine has two main purposes:
2125 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2126 * in unused_resv_pages. This corresponds to the prior adjustments made
2127 * to the associated reservation map.
2128 * 2) Free any unused surplus pages that may have been allocated to satisfy
2129 * the reservation. As many as unused_resv_pages may be freed.
2130 *
2131 * Called with hugetlb_lock held. However, the lock could be dropped (and
2132 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
2133 * we must make sure nobody else can claim pages we are in the process of
2134 * freeing. Do this by ensuring resv_huge_page always is greater than the
2135 * number of huge pages we plan to free when dropping the lock.
2136 */
2137static void return_unused_surplus_pages(struct hstate *h,
2138 unsigned long unused_resv_pages)
2139{
2140 unsigned long nr_pages;
2141
2142 /* Cannot return gigantic pages currently */
2143 if (hstate_is_gigantic(h))
2144 goto out;
2145
2146 /*
2147 * Part (or even all) of the reservation could have been backed
2148 * by pre-allocated pages. Only free surplus pages.
2149 */
2150 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2151
2152 /*
2153 * We want to release as many surplus pages as possible, spread
2154 * evenly across all nodes with memory. Iterate across these nodes
2155 * until we can no longer free unreserved surplus pages. This occurs
2156 * when the nodes with surplus pages have no free pages.
2157 * free_pool_huge_page() will balance the freed pages across the
2158 * on-line nodes with memory and will handle the hstate accounting.
2159 *
2160 * Note that we decrement resv_huge_pages as we free the pages. If
2161 * we drop the lock, resv_huge_pages will still be sufficiently large
2162 * to cover subsequent pages we may free.
2163 */
2164 while (nr_pages--) {
2165 h->resv_huge_pages--;
2166 unused_resv_pages--;
2167 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
2168 goto out;
2169 cond_resched_lock(&hugetlb_lock);
2170 }
2171
2172out:
2173 /* Fully uncommit the reservation */
2174 h->resv_huge_pages -= unused_resv_pages;
2175}
2176
2177
2178/*
2179 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2180 * are used by the huge page allocation routines to manage reservations.
2181 *
2182 * vma_needs_reservation is called to determine if the huge page at addr
2183 * within the vma has an associated reservation. If a reservation is
2184 * needed, the value 1 is returned. The caller is then responsible for
2185 * managing the global reservation and subpool usage counts. After
2186 * the huge page has been allocated, vma_commit_reservation is called
2187 * to add the page to the reservation map. If the page allocation fails,
2188 * the reservation must be ended instead of committed. vma_end_reservation
2189 * is called in such cases.
2190 *
2191 * In the normal case, vma_commit_reservation returns the same value
2192 * as the preceding vma_needs_reservation call. The only time this
2193 * is not the case is if a reserve map was changed between calls. It
2194 * is the responsibility of the caller to notice the difference and
2195 * take appropriate action.
2196 *
2197 * vma_add_reservation is used in error paths where a reservation must
2198 * be restored when a newly allocated huge page must be freed. It is
2199 * to be called after calling vma_needs_reservation to determine if a
2200 * reservation exists.
2201 */
2202enum vma_resv_mode {
2203 VMA_NEEDS_RESV,
2204 VMA_COMMIT_RESV,
2205 VMA_END_RESV,
2206 VMA_ADD_RESV,
2207};
2208static long __vma_reservation_common(struct hstate *h,
2209 struct vm_area_struct *vma, unsigned long addr,
2210 enum vma_resv_mode mode)
2211{
2212 struct resv_map *resv;
2213 pgoff_t idx;
2214 long ret;
2215 long dummy_out_regions_needed;
2216
2217 resv = vma_resv_map(vma);
2218 if (!resv)
2219 return 1;
2220
2221 idx = vma_hugecache_offset(h, vma, addr);
2222 switch (mode) {
2223 case VMA_NEEDS_RESV:
2224 ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed);
2225 /* We assume that vma_reservation_* routines always operate on
2226 * 1 page, and that adding to resv map a 1 page entry can only
2227 * ever require 1 region.
2228 */
2229 VM_BUG_ON(dummy_out_regions_needed != 1);
2230 break;
2231 case VMA_COMMIT_RESV:
2232 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2233 /* region_add calls of range 1 should never fail. */
2234 VM_BUG_ON(ret < 0);
2235 break;
2236 case VMA_END_RESV:
2237 region_abort(resv, idx, idx + 1, 1);
2238 ret = 0;
2239 break;
2240 case VMA_ADD_RESV:
2241 if (vma->vm_flags & VM_MAYSHARE) {
2242 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2243 /* region_add calls of range 1 should never fail. */
2244 VM_BUG_ON(ret < 0);
2245 } else {
2246 region_abort(resv, idx, idx + 1, 1);
2247 ret = region_del(resv, idx, idx + 1);
2248 }
2249 break;
2250 default:
2251 BUG();
2252 }
2253
2254 if (vma->vm_flags & VM_MAYSHARE)
2255 return ret;
2256 else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) {
2257 /*
2258 * In most cases, reserves always exist for private mappings.
2259 * However, a file associated with mapping could have been
2260 * hole punched or truncated after reserves were consumed.
2261 * As subsequent fault on such a range will not use reserves.
2262 * Subtle - The reserve map for private mappings has the
2263 * opposite meaning than that of shared mappings. If NO
2264 * entry is in the reserve map, it means a reservation exists.
2265 * If an entry exists in the reserve map, it means the
2266 * reservation has already been consumed. As a result, the
2267 * return value of this routine is the opposite of the
2268 * value returned from reserve map manipulation routines above.
2269 */
2270 if (ret)
2271 return 0;
2272 else
2273 return 1;
2274 }
2275 else
2276 return ret < 0 ? ret : 0;
2277}
2278
2279static long vma_needs_reservation(struct hstate *h,
2280 struct vm_area_struct *vma, unsigned long addr)
2281{
2282 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2283}
2284
2285static long vma_commit_reservation(struct hstate *h,
2286 struct vm_area_struct *vma, unsigned long addr)
2287{
2288 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
2289}
2290
2291static void vma_end_reservation(struct hstate *h,
2292 struct vm_area_struct *vma, unsigned long addr)
2293{
2294 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2295}
2296
2297static long vma_add_reservation(struct hstate *h,
2298 struct vm_area_struct *vma, unsigned long addr)
2299{
2300 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
2301}
2302
2303/*
2304 * This routine is called to restore a reservation on error paths. In the
2305 * specific error paths, a huge page was allocated (via alloc_huge_page)
2306 * and is about to be freed. If a reservation for the page existed,
2307 * alloc_huge_page would have consumed the reservation and set PagePrivate
2308 * in the newly allocated page. When the page is freed via free_huge_page,
2309 * the global reservation count will be incremented if PagePrivate is set.
2310 * However, free_huge_page can not adjust the reserve map. Adjust the
2311 * reserve map here to be consistent with global reserve count adjustments
2312 * to be made by free_huge_page.
2313 */
2314static void restore_reserve_on_error(struct hstate *h,
2315 struct vm_area_struct *vma, unsigned long address,
2316 struct page *page)
2317{
2318 if (unlikely(PagePrivate(page))) {
2319 long rc = vma_needs_reservation(h, vma, address);
2320
2321 if (unlikely(rc < 0)) {
2322 /*
2323 * Rare out of memory condition in reserve map
2324 * manipulation. Clear PagePrivate so that
2325 * global reserve count will not be incremented
2326 * by free_huge_page. This will make it appear
2327 * as though the reservation for this page was
2328 * consumed. This may prevent the task from
2329 * faulting in the page at a later time. This
2330 * is better than inconsistent global huge page
2331 * accounting of reserve counts.
2332 */
2333 ClearPagePrivate(page);
2334 } else if (rc) {
2335 rc = vma_add_reservation(h, vma, address);
2336 if (unlikely(rc < 0))
2337 /*
2338 * See above comment about rare out of
2339 * memory condition.
2340 */
2341 ClearPagePrivate(page);
2342 } else
2343 vma_end_reservation(h, vma, address);
2344 }
2345}
2346
2347struct page *alloc_huge_page(struct vm_area_struct *vma,
2348 unsigned long addr, int avoid_reserve)
2349{
2350 struct hugepage_subpool *spool = subpool_vma(vma);
2351 struct hstate *h = hstate_vma(vma);
2352 struct page *page;
2353 long map_chg, map_commit;
2354 long gbl_chg;
2355 int ret, idx;
2356 struct hugetlb_cgroup *h_cg;
2357 bool deferred_reserve;
2358
2359 idx = hstate_index(h);
2360 /*
2361 * Examine the region/reserve map to determine if the process
2362 * has a reservation for the page to be allocated. A return
2363 * code of zero indicates a reservation exists (no change).
2364 */
2365 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
2366 if (map_chg < 0)
2367 return ERR_PTR(-ENOMEM);
2368
2369 /*
2370 * Processes that did not create the mapping will have no
2371 * reserves as indicated by the region/reserve map. Check
2372 * that the allocation will not exceed the subpool limit.
2373 * Allocations for MAP_NORESERVE mappings also need to be
2374 * checked against any subpool limit.
2375 */
2376 if (map_chg || avoid_reserve) {
2377 gbl_chg = hugepage_subpool_get_pages(spool, 1);
2378 if (gbl_chg < 0) {
2379 vma_end_reservation(h, vma, addr);
2380 return ERR_PTR(-ENOSPC);
2381 }
2382
2383 /*
2384 * Even though there was no reservation in the region/reserve
2385 * map, there could be reservations associated with the
2386 * subpool that can be used. This would be indicated if the
2387 * return value of hugepage_subpool_get_pages() is zero.
2388 * However, if avoid_reserve is specified we still avoid even
2389 * the subpool reservations.
2390 */
2391 if (avoid_reserve)
2392 gbl_chg = 1;
2393 }
2394
2395 /* If this allocation is not consuming a reservation, charge it now.
2396 */
2397 deferred_reserve = map_chg || avoid_reserve || !vma_resv_map(vma);
2398 if (deferred_reserve) {
2399 ret = hugetlb_cgroup_charge_cgroup_rsvd(
2400 idx, pages_per_huge_page(h), &h_cg);
2401 if (ret)
2402 goto out_subpool_put;
2403 }
2404
2405 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2406 if (ret)
2407 goto out_uncharge_cgroup_reservation;
2408
2409 spin_lock(&hugetlb_lock);
2410 /*
2411 * glb_chg is passed to indicate whether or not a page must be taken
2412 * from the global free pool (global change). gbl_chg == 0 indicates
2413 * a reservation exists for the allocation.
2414 */
2415 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
2416 if (!page) {
2417 spin_unlock(&hugetlb_lock);
2418 page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2419 if (!page)
2420 goto out_uncharge_cgroup;
2421 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
2422 SetPagePrivate(page);
2423 h->resv_huge_pages--;
2424 }
2425 spin_lock(&hugetlb_lock);
2426 list_move(&page->lru, &h->hugepage_activelist);
2427 /* Fall through */
2428 }
2429 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2430 /* If allocation is not consuming a reservation, also store the
2431 * hugetlb_cgroup pointer on the page.
2432 */
2433 if (deferred_reserve) {
2434 hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h),
2435 h_cg, page);
2436 }
2437
2438 spin_unlock(&hugetlb_lock);
2439
2440 set_page_private(page, (unsigned long)spool);
2441
2442 map_commit = vma_commit_reservation(h, vma, addr);
2443 if (unlikely(map_chg > map_commit)) {
2444 /*
2445 * The page was added to the reservation map between
2446 * vma_needs_reservation and vma_commit_reservation.
2447 * This indicates a race with hugetlb_reserve_pages.
2448 * Adjust for the subpool count incremented above AND
2449 * in hugetlb_reserve_pages for the same page. Also,
2450 * the reservation count added in hugetlb_reserve_pages
2451 * no longer applies.
2452 */
2453 long rsv_adjust;
2454
2455 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
2456 hugetlb_acct_memory(h, -rsv_adjust);
2457 }
2458 return page;
2459
2460out_uncharge_cgroup:
2461 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2462out_uncharge_cgroup_reservation:
2463 if (deferred_reserve)
2464 hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
2465 h_cg);
2466out_subpool_put:
2467 if (map_chg || avoid_reserve)
2468 hugepage_subpool_put_pages(spool, 1);
2469 vma_end_reservation(h, vma, addr);
2470 return ERR_PTR(-ENOSPC);
2471}
2472
2473int alloc_bootmem_huge_page(struct hstate *h)
2474 __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
2475int __alloc_bootmem_huge_page(struct hstate *h)
2476{
2477 struct huge_bootmem_page *m;
2478 int nr_nodes, node;
2479
2480 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2481 void *addr;
2482
2483 addr = memblock_alloc_try_nid_raw(
2484 huge_page_size(h), huge_page_size(h),
2485 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2486 if (addr) {
2487 /*
2488 * Use the beginning of the huge page to store the
2489 * huge_bootmem_page struct (until gather_bootmem
2490 * puts them into the mem_map).
2491 */
2492 m = addr;
2493 goto found;
2494 }
2495 }
2496 return 0;
2497
2498found:
2499 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2500 /* Put them into a private list first because mem_map is not up yet */
2501 INIT_LIST_HEAD(&m->list);
2502 list_add(&m->list, &huge_boot_pages);
2503 m->hstate = h;
2504 return 1;
2505}
2506
2507static void __init prep_compound_huge_page(struct page *page,
2508 unsigned int order)
2509{
2510 if (unlikely(order > (MAX_ORDER - 1)))
2511 prep_compound_gigantic_page(page, order);
2512 else
2513 prep_compound_page(page, order);
2514}
2515
2516/* Put bootmem huge pages into the standard lists after mem_map is up */
2517static void __init gather_bootmem_prealloc(void)
2518{
2519 struct huge_bootmem_page *m;
2520
2521 list_for_each_entry(m, &huge_boot_pages, list) {
2522 struct page *page = virt_to_page(m);
2523 struct hstate *h = m->hstate;
2524
2525 WARN_ON(page_count(page) != 1);
2526 prep_compound_huge_page(page, h->order);
2527 WARN_ON(PageReserved(page));
2528 prep_new_huge_page(h, page, page_to_nid(page));
2529 put_page(page); /* free it into the hugepage allocator */
2530
2531 /*
2532 * If we had gigantic hugepages allocated at boot time, we need
2533 * to restore the 'stolen' pages to totalram_pages in order to
2534 * fix confusing memory reports from free(1) and another
2535 * side-effects, like CommitLimit going negative.
2536 */
2537 if (hstate_is_gigantic(h))
2538 adjust_managed_page_count(page, 1 << h->order);
2539 cond_resched();
2540 }
2541}
2542
2543static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
2544{
2545 unsigned long i;
2546 nodemask_t *node_alloc_noretry;
2547
2548 if (!hstate_is_gigantic(h)) {
2549 /*
2550 * Bit mask controlling how hard we retry per-node allocations.
2551 * Ignore errors as lower level routines can deal with
2552 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2553 * time, we are likely in bigger trouble.
2554 */
2555 node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry),
2556 GFP_KERNEL);
2557 } else {
2558 /* allocations done at boot time */
2559 node_alloc_noretry = NULL;
2560 }
2561
2562 /* bit mask controlling how hard we retry per-node allocations */
2563 if (node_alloc_noretry)
2564 nodes_clear(*node_alloc_noretry);
2565
2566 for (i = 0; i < h->max_huge_pages; ++i) {
2567 if (hstate_is_gigantic(h)) {
2568 if (hugetlb_cma_size) {
2569 pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
2570 break;
2571 }
2572 if (!alloc_bootmem_huge_page(h))
2573 break;
2574 } else if (!alloc_pool_huge_page(h,
2575 &node_states[N_MEMORY],
2576 node_alloc_noretry))
2577 break;
2578 cond_resched();
2579 }
2580 if (i < h->max_huge_pages) {
2581 char buf[32];
2582
2583 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2584 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2585 h->max_huge_pages, buf, i);
2586 h->max_huge_pages = i;
2587 }
2588
2589 kfree(node_alloc_noretry);
2590}
2591
2592static void __init hugetlb_init_hstates(void)
2593{
2594 struct hstate *h;
2595
2596 for_each_hstate(h) {
2597 if (minimum_order > huge_page_order(h))
2598 minimum_order = huge_page_order(h);
2599
2600 /* oversize hugepages were init'ed in early boot */
2601 if (!hstate_is_gigantic(h))
2602 hugetlb_hstate_alloc_pages(h);
2603 }
2604 VM_BUG_ON(minimum_order == UINT_MAX);
2605}
2606
2607static void __init report_hugepages(void)
2608{
2609 struct hstate *h;
2610
2611 for_each_hstate(h) {
2612 char buf[32];
2613
2614 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2615 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2616 buf, h->free_huge_pages);
2617 }
2618}
2619
2620#ifdef CONFIG_HIGHMEM
2621static void try_to_free_low(struct hstate *h, unsigned long count,
2622 nodemask_t *nodes_allowed)
2623{
2624 int i;
2625
2626 if (hstate_is_gigantic(h))
2627 return;
2628
2629 for_each_node_mask(i, *nodes_allowed) {
2630 struct page *page, *next;
2631 struct list_head *freel = &h->hugepage_freelists[i];
2632 list_for_each_entry_safe(page, next, freel, lru) {
2633 if (count >= h->nr_huge_pages)
2634 return;
2635 if (PageHighMem(page))
2636 continue;
2637 list_del(&page->lru);
2638 update_and_free_page(h, page);
2639 h->free_huge_pages--;
2640 h->free_huge_pages_node[page_to_nid(page)]--;
2641 }
2642 }
2643}
2644#else
2645static inline void try_to_free_low(struct hstate *h, unsigned long count,
2646 nodemask_t *nodes_allowed)
2647{
2648}
2649#endif
2650
2651/*
2652 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2653 * balanced by operating on them in a round-robin fashion.
2654 * Returns 1 if an adjustment was made.
2655 */
2656static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
2657 int delta)
2658{
2659 int nr_nodes, node;
2660
2661 VM_BUG_ON(delta != -1 && delta != 1);
2662
2663 if (delta < 0) {
2664 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2665 if (h->surplus_huge_pages_node[node])
2666 goto found;
2667 }
2668 } else {
2669 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2670 if (h->surplus_huge_pages_node[node] <
2671 h->nr_huge_pages_node[node])
2672 goto found;
2673 }
2674 }
2675 return 0;
2676
2677found:
2678 h->surplus_huge_pages += delta;
2679 h->surplus_huge_pages_node[node] += delta;
2680 return 1;
2681}
2682
2683#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2684static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2685 nodemask_t *nodes_allowed)
2686{
2687 unsigned long min_count, ret;
2688 NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL);
2689
2690 /*
2691 * Bit mask controlling how hard we retry per-node allocations.
2692 * If we can not allocate the bit mask, do not attempt to allocate
2693 * the requested huge pages.
2694 */
2695 if (node_alloc_noretry)
2696 nodes_clear(*node_alloc_noretry);
2697 else
2698 return -ENOMEM;
2699
2700 spin_lock(&hugetlb_lock);
2701
2702 /*
2703 * Check for a node specific request.
2704 * Changing node specific huge page count may require a corresponding
2705 * change to the global count. In any case, the passed node mask
2706 * (nodes_allowed) will restrict alloc/free to the specified node.
2707 */
2708 if (nid != NUMA_NO_NODE) {
2709 unsigned long old_count = count;
2710
2711 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
2712 /*
2713 * User may have specified a large count value which caused the
2714 * above calculation to overflow. In this case, they wanted
2715 * to allocate as many huge pages as possible. Set count to
2716 * largest possible value to align with their intention.
2717 */
2718 if (count < old_count)
2719 count = ULONG_MAX;
2720 }
2721
2722 /*
2723 * Gigantic pages runtime allocation depend on the capability for large
2724 * page range allocation.
2725 * If the system does not provide this feature, return an error when
2726 * the user tries to allocate gigantic pages but let the user free the
2727 * boottime allocated gigantic pages.
2728 */
2729 if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
2730 if (count > persistent_huge_pages(h)) {
2731 spin_unlock(&hugetlb_lock);
2732 NODEMASK_FREE(node_alloc_noretry);
2733 return -EINVAL;
2734 }
2735 /* Fall through to decrease pool */
2736 }
2737
2738 /*
2739 * Increase the pool size
2740 * First take pages out of surplus state. Then make up the
2741 * remaining difference by allocating fresh huge pages.
2742 *
2743 * We might race with alloc_surplus_huge_page() here and be unable
2744 * to convert a surplus huge page to a normal huge page. That is
2745 * not critical, though, it just means the overall size of the
2746 * pool might be one hugepage larger than it needs to be, but
2747 * within all the constraints specified by the sysctls.
2748 */
2749 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2750 if (!adjust_pool_surplus(h, nodes_allowed, -1))
2751 break;
2752 }
2753
2754 while (count > persistent_huge_pages(h)) {
2755 /*
2756 * If this allocation races such that we no longer need the
2757 * page, free_huge_page will handle it by freeing the page
2758 * and reducing the surplus.
2759 */
2760 spin_unlock(&hugetlb_lock);
2761
2762 /* yield cpu to avoid soft lockup */
2763 cond_resched();
2764
2765 ret = alloc_pool_huge_page(h, nodes_allowed,
2766 node_alloc_noretry);
2767 spin_lock(&hugetlb_lock);
2768 if (!ret)
2769 goto out;
2770
2771 /* Bail for signals. Probably ctrl-c from user */
2772 if (signal_pending(current))
2773 goto out;
2774 }
2775
2776 /*
2777 * Decrease the pool size
2778 * First return free pages to the buddy allocator (being careful
2779 * to keep enough around to satisfy reservations). Then place
2780 * pages into surplus state as needed so the pool will shrink
2781 * to the desired size as pages become free.
2782 *
2783 * By placing pages into the surplus state independent of the
2784 * overcommit value, we are allowing the surplus pool size to
2785 * exceed overcommit. There are few sane options here. Since
2786 * alloc_surplus_huge_page() is checking the global counter,
2787 * though, we'll note that we're not allowed to exceed surplus
2788 * and won't grow the pool anywhere else. Not until one of the
2789 * sysctls are changed, or the surplus pages go out of use.
2790 */
2791 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2792 min_count = max(count, min_count);
2793 try_to_free_low(h, min_count, nodes_allowed);
2794 while (min_count < persistent_huge_pages(h)) {
2795 if (!free_pool_huge_page(h, nodes_allowed, 0))
2796 break;
2797 cond_resched_lock(&hugetlb_lock);
2798 }
2799 while (count < persistent_huge_pages(h)) {
2800 if (!adjust_pool_surplus(h, nodes_allowed, 1))
2801 break;
2802 }
2803out:
2804 h->max_huge_pages = persistent_huge_pages(h);
2805 spin_unlock(&hugetlb_lock);
2806
2807 NODEMASK_FREE(node_alloc_noretry);
2808
2809 return 0;
2810}
2811
2812#define HSTATE_ATTR_RO(_name) \
2813 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2814
2815#define HSTATE_ATTR(_name) \
2816 static struct kobj_attribute _name##_attr = \
2817 __ATTR(_name, 0644, _name##_show, _name##_store)
2818
2819static struct kobject *hugepages_kobj;
2820static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2821
2822static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
2823
2824static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2825{
2826 int i;
2827
2828 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2829 if (hstate_kobjs[i] == kobj) {
2830 if (nidp)
2831 *nidp = NUMA_NO_NODE;
2832 return &hstates[i];
2833 }
2834
2835 return kobj_to_node_hstate(kobj, nidp);
2836}
2837
2838static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2839 struct kobj_attribute *attr, char *buf)
2840{
2841 struct hstate *h;
2842 unsigned long nr_huge_pages;
2843 int nid;
2844
2845 h = kobj_to_hstate(kobj, &nid);
2846 if (nid == NUMA_NO_NODE)
2847 nr_huge_pages = h->nr_huge_pages;
2848 else
2849 nr_huge_pages = h->nr_huge_pages_node[nid];
2850
2851 return sprintf(buf, "%lu\n", nr_huge_pages);
2852}
2853
2854static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
2855 struct hstate *h, int nid,
2856 unsigned long count, size_t len)
2857{
2858 int err;
2859 nodemask_t nodes_allowed, *n_mask;
2860
2861 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
2862 return -EINVAL;
2863
2864 if (nid == NUMA_NO_NODE) {
2865 /*
2866 * global hstate attribute
2867 */
2868 if (!(obey_mempolicy &&
2869 init_nodemask_of_mempolicy(&nodes_allowed)))
2870 n_mask = &node_states[N_MEMORY];
2871 else
2872 n_mask = &nodes_allowed;
2873 } else {
2874 /*
2875 * Node specific request. count adjustment happens in
2876 * set_max_huge_pages() after acquiring hugetlb_lock.
2877 */
2878 init_nodemask_of_node(&nodes_allowed, nid);
2879 n_mask = &nodes_allowed;
2880 }
2881
2882 err = set_max_huge_pages(h, count, nid, n_mask);
2883
2884 return err ? err : len;
2885}
2886
2887static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
2888 struct kobject *kobj, const char *buf,
2889 size_t len)
2890{
2891 struct hstate *h;
2892 unsigned long count;
2893 int nid;
2894 int err;
2895
2896 err = kstrtoul(buf, 10, &count);
2897 if (err)
2898 return err;
2899
2900 h = kobj_to_hstate(kobj, &nid);
2901 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
2902}
2903
2904static ssize_t nr_hugepages_show(struct kobject *kobj,
2905 struct kobj_attribute *attr, char *buf)
2906{
2907 return nr_hugepages_show_common(kobj, attr, buf);
2908}
2909
2910static ssize_t nr_hugepages_store(struct kobject *kobj,
2911 struct kobj_attribute *attr, const char *buf, size_t len)
2912{
2913 return nr_hugepages_store_common(false, kobj, buf, len);
2914}
2915HSTATE_ATTR(nr_hugepages);
2916
2917#ifdef CONFIG_NUMA
2918
2919/*
2920 * hstate attribute for optionally mempolicy-based constraint on persistent
2921 * huge page alloc/free.
2922 */
2923static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
2924 struct kobj_attribute *attr, char *buf)
2925{
2926 return nr_hugepages_show_common(kobj, attr, buf);
2927}
2928
2929static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
2930 struct kobj_attribute *attr, const char *buf, size_t len)
2931{
2932 return nr_hugepages_store_common(true, kobj, buf, len);
2933}
2934HSTATE_ATTR(nr_hugepages_mempolicy);
2935#endif
2936
2937
2938static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
2939 struct kobj_attribute *attr, char *buf)
2940{
2941 struct hstate *h = kobj_to_hstate(kobj, NULL);
2942 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
2943}
2944
2945static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
2946 struct kobj_attribute *attr, const char *buf, size_t count)
2947{
2948 int err;
2949 unsigned long input;
2950 struct hstate *h = kobj_to_hstate(kobj, NULL);
2951
2952 if (hstate_is_gigantic(h))
2953 return -EINVAL;
2954
2955 err = kstrtoul(buf, 10, &input);
2956 if (err)
2957 return err;
2958
2959 spin_lock(&hugetlb_lock);
2960 h->nr_overcommit_huge_pages = input;
2961 spin_unlock(&hugetlb_lock);
2962
2963 return count;
2964}
2965HSTATE_ATTR(nr_overcommit_hugepages);
2966
2967static ssize_t free_hugepages_show(struct kobject *kobj,
2968 struct kobj_attribute *attr, char *buf)
2969{
2970 struct hstate *h;
2971 unsigned long free_huge_pages;
2972 int nid;
2973
2974 h = kobj_to_hstate(kobj, &nid);
2975 if (nid == NUMA_NO_NODE)
2976 free_huge_pages = h->free_huge_pages;
2977 else
2978 free_huge_pages = h->free_huge_pages_node[nid];
2979
2980 return sprintf(buf, "%lu\n", free_huge_pages);
2981}
2982HSTATE_ATTR_RO(free_hugepages);
2983
2984static ssize_t resv_hugepages_show(struct kobject *kobj,
2985 struct kobj_attribute *attr, char *buf)
2986{
2987 struct hstate *h = kobj_to_hstate(kobj, NULL);
2988 return sprintf(buf, "%lu\n", h->resv_huge_pages);
2989}
2990HSTATE_ATTR_RO(resv_hugepages);
2991
2992static ssize_t surplus_hugepages_show(struct kobject *kobj,
2993 struct kobj_attribute *attr, char *buf)
2994{
2995 struct hstate *h;
2996 unsigned long surplus_huge_pages;
2997 int nid;
2998
2999 h = kobj_to_hstate(kobj, &nid);
3000 if (nid == NUMA_NO_NODE)
3001 surplus_huge_pages = h->surplus_huge_pages;
3002 else
3003 surplus_huge_pages = h->surplus_huge_pages_node[nid];
3004
3005 return sprintf(buf, "%lu\n", surplus_huge_pages);
3006}
3007HSTATE_ATTR_RO(surplus_hugepages);
3008
3009static struct attribute *hstate_attrs[] = {
3010 &nr_hugepages_attr.attr,
3011 &nr_overcommit_hugepages_attr.attr,
3012 &free_hugepages_attr.attr,
3013 &resv_hugepages_attr.attr,
3014 &surplus_hugepages_attr.attr,
3015#ifdef CONFIG_NUMA
3016 &nr_hugepages_mempolicy_attr.attr,
3017#endif
3018 NULL,
3019};
3020
3021static const struct attribute_group hstate_attr_group = {
3022 .attrs = hstate_attrs,
3023};
3024
3025static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
3026 struct kobject **hstate_kobjs,
3027 const struct attribute_group *hstate_attr_group)
3028{
3029 int retval;
3030 int hi = hstate_index(h);
3031
3032 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
3033 if (!hstate_kobjs[hi])
3034 return -ENOMEM;
3035
3036 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
3037 if (retval)
3038 kobject_put(hstate_kobjs[hi]);
3039
3040 return retval;
3041}
3042
3043static void __init hugetlb_sysfs_init(void)
3044{
3045 struct hstate *h;
3046 int err;
3047
3048 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
3049 if (!hugepages_kobj)
3050 return;
3051
3052 for_each_hstate(h) {
3053 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
3054 hstate_kobjs, &hstate_attr_group);
3055 if (err)
3056 pr_err("HugeTLB: Unable to add hstate %s", h->name);
3057 }
3058}
3059
3060#ifdef CONFIG_NUMA
3061
3062/*
3063 * node_hstate/s - associate per node hstate attributes, via their kobjects,
3064 * with node devices in node_devices[] using a parallel array. The array
3065 * index of a node device or _hstate == node id.
3066 * This is here to avoid any static dependency of the node device driver, in
3067 * the base kernel, on the hugetlb module.
3068 */
3069struct node_hstate {
3070 struct kobject *hugepages_kobj;
3071 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
3072};
3073static struct node_hstate node_hstates[MAX_NUMNODES];
3074
3075/*
3076 * A subset of global hstate attributes for node devices
3077 */
3078static struct attribute *per_node_hstate_attrs[] = {
3079 &nr_hugepages_attr.attr,
3080 &free_hugepages_attr.attr,
3081 &surplus_hugepages_attr.attr,
3082 NULL,
3083};
3084
3085static const struct attribute_group per_node_hstate_attr_group = {
3086 .attrs = per_node_hstate_attrs,
3087};
3088
3089/*
3090 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3091 * Returns node id via non-NULL nidp.
3092 */
3093static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3094{
3095 int nid;
3096
3097 for (nid = 0; nid < nr_node_ids; nid++) {
3098 struct node_hstate *nhs = &node_hstates[nid];
3099 int i;
3100 for (i = 0; i < HUGE_MAX_HSTATE; i++)
3101 if (nhs->hstate_kobjs[i] == kobj) {
3102 if (nidp)
3103 *nidp = nid;
3104 return &hstates[i];
3105 }
3106 }
3107
3108 BUG();
3109 return NULL;
3110}
3111
3112/*
3113 * Unregister hstate attributes from a single node device.
3114 * No-op if no hstate attributes attached.
3115 */
3116static void hugetlb_unregister_node(struct node *node)
3117{
3118 struct hstate *h;
3119 struct node_hstate *nhs = &node_hstates[node->dev.id];
3120
3121 if (!nhs->hugepages_kobj)
3122 return; /* no hstate attributes */
3123
3124 for_each_hstate(h) {
3125 int idx = hstate_index(h);
3126 if (nhs->hstate_kobjs[idx]) {
3127 kobject_put(nhs->hstate_kobjs[idx]);
3128 nhs->hstate_kobjs[idx] = NULL;
3129 }
3130 }
3131
3132 kobject_put(nhs->hugepages_kobj);
3133 nhs->hugepages_kobj = NULL;
3134}
3135
3136
3137/*
3138 * Register hstate attributes for a single node device.
3139 * No-op if attributes already registered.
3140 */
3141static void hugetlb_register_node(struct node *node)
3142{
3143 struct hstate *h;
3144 struct node_hstate *nhs = &node_hstates[node->dev.id];
3145 int err;
3146
3147 if (nhs->hugepages_kobj)
3148 return; /* already allocated */
3149
3150 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
3151 &node->dev.kobj);
3152 if (!nhs->hugepages_kobj)
3153 return;
3154
3155 for_each_hstate(h) {
3156 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
3157 nhs->hstate_kobjs,
3158 &per_node_hstate_attr_group);
3159 if (err) {
3160 pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3161 h->name, node->dev.id);
3162 hugetlb_unregister_node(node);
3163 break;
3164 }
3165 }
3166}
3167
3168/*
3169 * hugetlb init time: register hstate attributes for all registered node
3170 * devices of nodes that have memory. All on-line nodes should have
3171 * registered their associated device by this time.
3172 */
3173static void __init hugetlb_register_all_nodes(void)
3174{
3175 int nid;
3176
3177 for_each_node_state(nid, N_MEMORY) {
3178 struct node *node = node_devices[nid];
3179 if (node->dev.id == nid)
3180 hugetlb_register_node(node);
3181 }
3182
3183 /*
3184 * Let the node device driver know we're here so it can
3185 * [un]register hstate attributes on node hotplug.
3186 */
3187 register_hugetlbfs_with_node(hugetlb_register_node,
3188 hugetlb_unregister_node);
3189}
3190#else /* !CONFIG_NUMA */
3191
3192static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3193{
3194 BUG();
3195 if (nidp)
3196 *nidp = -1;
3197 return NULL;
3198}
3199
3200static void hugetlb_register_all_nodes(void) { }
3201
3202#endif
3203
3204static int __init hugetlb_init(void)
3205{
3206 int i;
3207
3208 if (!hugepages_supported()) {
3209 if (hugetlb_max_hstate || default_hstate_max_huge_pages)
3210 pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
3211 return 0;
3212 }
3213
3214 /*
3215 * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some
3216 * architectures depend on setup being done here.
3217 */
3218 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
3219 if (!parsed_default_hugepagesz) {
3220 /*
3221 * If we did not parse a default huge page size, set
3222 * default_hstate_idx to HPAGE_SIZE hstate. And, if the
3223 * number of huge pages for this default size was implicitly
3224 * specified, set that here as well.
3225 * Note that the implicit setting will overwrite an explicit
3226 * setting. A warning will be printed in this case.
3227 */
3228 default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE));
3229 if (default_hstate_max_huge_pages) {
3230 if (default_hstate.max_huge_pages) {
3231 char buf[32];
3232
3233 string_get_size(huge_page_size(&default_hstate),
3234 1, STRING_UNITS_2, buf, 32);
3235 pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
3236 default_hstate.max_huge_pages, buf);
3237 pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
3238 default_hstate_max_huge_pages);
3239 }
3240 default_hstate.max_huge_pages =
3241 default_hstate_max_huge_pages;
3242 }
3243 }
3244
3245 hugetlb_cma_check();
3246 hugetlb_init_hstates();
3247 gather_bootmem_prealloc();
3248 report_hugepages();
3249
3250 hugetlb_sysfs_init();
3251 hugetlb_register_all_nodes();
3252 hugetlb_cgroup_file_init();
3253
3254#ifdef CONFIG_SMP
3255 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
3256#else
3257 num_fault_mutexes = 1;
3258#endif
3259 hugetlb_fault_mutex_table =
3260 kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
3261 GFP_KERNEL);
3262 BUG_ON(!hugetlb_fault_mutex_table);
3263
3264 for (i = 0; i < num_fault_mutexes; i++)
3265 mutex_init(&hugetlb_fault_mutex_table[i]);
3266 return 0;
3267}
3268subsys_initcall(hugetlb_init);
3269
3270/* Overwritten by architectures with more huge page sizes */
3271bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
3272{
3273 return size == HPAGE_SIZE;
3274}
3275
3276void __init hugetlb_add_hstate(unsigned int order)
3277{
3278 struct hstate *h;
3279 unsigned long i;
3280
3281 if (size_to_hstate(PAGE_SIZE << order)) {
3282 return;
3283 }
3284 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
3285 BUG_ON(order == 0);
3286 h = &hstates[hugetlb_max_hstate++];
3287 h->order = order;
3288 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
3289 h->nr_huge_pages = 0;
3290 h->free_huge_pages = 0;
3291 for (i = 0; i < MAX_NUMNODES; ++i)
3292 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
3293 INIT_LIST_HEAD(&h->hugepage_activelist);
3294 h->next_nid_to_alloc = first_memory_node;
3295 h->next_nid_to_free = first_memory_node;
3296 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
3297 huge_page_size(h)/1024);
3298
3299 parsed_hstate = h;
3300}
3301
3302/*
3303 * hugepages command line processing
3304 * hugepages normally follows a valid hugepagsz or default_hugepagsz
3305 * specification. If not, ignore the hugepages value. hugepages can also
3306 * be the first huge page command line option in which case it implicitly
3307 * specifies the number of huge pages for the default size.
3308 */
3309static int __init hugepages_setup(char *s)
3310{
3311 unsigned long *mhp;
3312 static unsigned long *last_mhp;
3313
3314 if (!parsed_valid_hugepagesz) {
3315 pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
3316 parsed_valid_hugepagesz = true;
3317 return 0;
3318 }
3319
3320 /*
3321 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
3322 * yet, so this hugepages= parameter goes to the "default hstate".
3323 * Otherwise, it goes with the previously parsed hugepagesz or
3324 * default_hugepagesz.
3325 */
3326 else if (!hugetlb_max_hstate)
3327 mhp = &default_hstate_max_huge_pages;
3328 else
3329 mhp = &parsed_hstate->max_huge_pages;
3330
3331 if (mhp == last_mhp) {
3332 pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
3333 return 0;
3334 }
3335
3336 if (sscanf(s, "%lu", mhp) <= 0)
3337 *mhp = 0;
3338
3339 /*
3340 * Global state is always initialized later in hugetlb_init.
3341 * But we need to allocate >= MAX_ORDER hstates here early to still
3342 * use the bootmem allocator.
3343 */
3344 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
3345 hugetlb_hstate_alloc_pages(parsed_hstate);
3346
3347 last_mhp = mhp;
3348
3349 return 1;
3350}
3351__setup("hugepages=", hugepages_setup);
3352
3353/*
3354 * hugepagesz command line processing
3355 * A specific huge page size can only be specified once with hugepagesz.
3356 * hugepagesz is followed by hugepages on the command line. The global
3357 * variable 'parsed_valid_hugepagesz' is used to determine if prior
3358 * hugepagesz argument was valid.
3359 */
3360static int __init hugepagesz_setup(char *s)
3361{
3362 unsigned long size;
3363 struct hstate *h;
3364
3365 parsed_valid_hugepagesz = false;
3366 size = (unsigned long)memparse(s, NULL);
3367
3368 if (!arch_hugetlb_valid_size(size)) {
3369 pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
3370 return 0;
3371 }
3372
3373 h = size_to_hstate(size);
3374 if (h) {
3375 /*
3376 * hstate for this size already exists. This is normally
3377 * an error, but is allowed if the existing hstate is the
3378 * default hstate. More specifically, it is only allowed if
3379 * the number of huge pages for the default hstate was not
3380 * previously specified.
3381 */
3382 if (!parsed_default_hugepagesz || h != &default_hstate ||
3383 default_hstate.max_huge_pages) {
3384 pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s);
3385 return 0;
3386 }
3387
3388 /*
3389 * No need to call hugetlb_add_hstate() as hstate already
3390 * exists. But, do set parsed_hstate so that a following
3391 * hugepages= parameter will be applied to this hstate.
3392 */
3393 parsed_hstate = h;
3394 parsed_valid_hugepagesz = true;
3395 return 1;
3396 }
3397
3398 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3399 parsed_valid_hugepagesz = true;
3400 return 1;
3401}
3402__setup("hugepagesz=", hugepagesz_setup);
3403
3404/*
3405 * default_hugepagesz command line input
3406 * Only one instance of default_hugepagesz allowed on command line.
3407 */
3408static int __init default_hugepagesz_setup(char *s)
3409{
3410 unsigned long size;
3411
3412 parsed_valid_hugepagesz = false;
3413 if (parsed_default_hugepagesz) {
3414 pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
3415 return 0;
3416 }
3417
3418 size = (unsigned long)memparse(s, NULL);
3419
3420 if (!arch_hugetlb_valid_size(size)) {
3421 pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
3422 return 0;
3423 }
3424
3425 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3426 parsed_valid_hugepagesz = true;
3427 parsed_default_hugepagesz = true;
3428 default_hstate_idx = hstate_index(size_to_hstate(size));
3429
3430 /*
3431 * The number of default huge pages (for this size) could have been
3432 * specified as the first hugetlb parameter: hugepages=X. If so,
3433 * then default_hstate_max_huge_pages is set. If the default huge
3434 * page size is gigantic (>= MAX_ORDER), then the pages must be
3435 * allocated here from bootmem allocator.
3436 */
3437 if (default_hstate_max_huge_pages) {
3438 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
3439 if (hstate_is_gigantic(&default_hstate))
3440 hugetlb_hstate_alloc_pages(&default_hstate);
3441 default_hstate_max_huge_pages = 0;
3442 }
3443
3444 return 1;
3445}
3446__setup("default_hugepagesz=", default_hugepagesz_setup);
3447
3448static unsigned int allowed_mems_nr(struct hstate *h)
3449{
3450 int node;
3451 unsigned int nr = 0;
3452 nodemask_t *mpol_allowed;
3453 unsigned int *array = h->free_huge_pages_node;
3454 gfp_t gfp_mask = htlb_alloc_mask(h);
3455
3456 mpol_allowed = policy_nodemask_current(gfp_mask);
3457
3458 for_each_node_mask(node, cpuset_current_mems_allowed) {
3459 if (!mpol_allowed ||
3460 (mpol_allowed && node_isset(node, *mpol_allowed)))
3461 nr += array[node];
3462 }
3463
3464 return nr;
3465}
3466
3467#ifdef CONFIG_SYSCTL
3468static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
3469 void *buffer, size_t *length,
3470 loff_t *ppos, unsigned long *out)
3471{
3472 struct ctl_table dup_table;
3473
3474 /*
3475 * In order to avoid races with __do_proc_doulongvec_minmax(), we
3476 * can duplicate the @table and alter the duplicate of it.
3477 */
3478 dup_table = *table;
3479 dup_table.data = out;
3480
3481 return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
3482}
3483
3484static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
3485 struct ctl_table *table, int write,
3486 void *buffer, size_t *length, loff_t *ppos)
3487{
3488 struct hstate *h = &default_hstate;
3489 unsigned long tmp = h->max_huge_pages;
3490 int ret;
3491
3492 if (!hugepages_supported())
3493 return -EOPNOTSUPP;
3494
3495 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3496 &tmp);
3497 if (ret)
3498 goto out;
3499
3500 if (write)
3501 ret = __nr_hugepages_store_common(obey_mempolicy, h,
3502 NUMA_NO_NODE, tmp, *length);
3503out:
3504 return ret;
3505}
3506
3507int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3508 void *buffer, size_t *length, loff_t *ppos)
3509{
3510
3511 return hugetlb_sysctl_handler_common(false, table, write,
3512 buffer, length, ppos);
3513}
3514
3515#ifdef CONFIG_NUMA
3516int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
3517 void *buffer, size_t *length, loff_t *ppos)
3518{
3519 return hugetlb_sysctl_handler_common(true, table, write,
3520 buffer, length, ppos);
3521}
3522#endif /* CONFIG_NUMA */
3523
3524int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3525 void *buffer, size_t *length, loff_t *ppos)
3526{
3527 struct hstate *h = &default_hstate;
3528 unsigned long tmp;
3529 int ret;
3530
3531 if (!hugepages_supported())
3532 return -EOPNOTSUPP;
3533
3534 tmp = h->nr_overcommit_huge_pages;
3535
3536 if (write && hstate_is_gigantic(h))
3537 return -EINVAL;
3538
3539 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3540 &tmp);
3541 if (ret)
3542 goto out;
3543
3544 if (write) {
3545 spin_lock(&hugetlb_lock);
3546 h->nr_overcommit_huge_pages = tmp;
3547 spin_unlock(&hugetlb_lock);
3548 }
3549out:
3550 return ret;
3551}
3552
3553#endif /* CONFIG_SYSCTL */
3554
3555void hugetlb_report_meminfo(struct seq_file *m)
3556{
3557 struct hstate *h;
3558 unsigned long total = 0;
3559
3560 if (!hugepages_supported())
3561 return;
3562
3563 for_each_hstate(h) {
3564 unsigned long count = h->nr_huge_pages;
3565
3566 total += (PAGE_SIZE << huge_page_order(h)) * count;
3567
3568 if (h == &default_hstate)
3569 seq_printf(m,
3570 "HugePages_Total: %5lu\n"
3571 "HugePages_Free: %5lu\n"
3572 "HugePages_Rsvd: %5lu\n"
3573 "HugePages_Surp: %5lu\n"
3574 "Hugepagesize: %8lu kB\n",
3575 count,
3576 h->free_huge_pages,
3577 h->resv_huge_pages,
3578 h->surplus_huge_pages,
3579 (PAGE_SIZE << huge_page_order(h)) / 1024);
3580 }
3581
3582 seq_printf(m, "Hugetlb: %8lu kB\n", total / 1024);
3583}
3584
3585int hugetlb_report_node_meminfo(int nid, char *buf)
3586{
3587 struct hstate *h = &default_hstate;
3588 if (!hugepages_supported())
3589 return 0;
3590 return sprintf(buf,
3591 "Node %d HugePages_Total: %5u\n"
3592 "Node %d HugePages_Free: %5u\n"
3593 "Node %d HugePages_Surp: %5u\n",
3594 nid, h->nr_huge_pages_node[nid],
3595 nid, h->free_huge_pages_node[nid],
3596 nid, h->surplus_huge_pages_node[nid]);
3597}
3598
3599void hugetlb_show_meminfo(void)
3600{
3601 struct hstate *h;
3602 int nid;
3603
3604 if (!hugepages_supported())
3605 return;
3606
3607 for_each_node_state(nid, N_MEMORY)
3608 for_each_hstate(h)
3609 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3610 nid,
3611 h->nr_huge_pages_node[nid],
3612 h->free_huge_pages_node[nid],
3613 h->surplus_huge_pages_node[nid],
3614 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
3615}
3616
3617void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
3618{
3619 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
3620 atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
3621}
3622
3623/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3624unsigned long hugetlb_total_pages(void)
3625{
3626 struct hstate *h;
3627 unsigned long nr_total_pages = 0;
3628
3629 for_each_hstate(h)
3630 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
3631 return nr_total_pages;
3632}
3633
3634static int hugetlb_acct_memory(struct hstate *h, long delta)
3635{
3636 int ret = -ENOMEM;
3637
3638 spin_lock(&hugetlb_lock);
3639 /*
3640 * When cpuset is configured, it breaks the strict hugetlb page
3641 * reservation as the accounting is done on a global variable. Such
3642 * reservation is completely rubbish in the presence of cpuset because
3643 * the reservation is not checked against page availability for the
3644 * current cpuset. Application can still potentially OOM'ed by kernel
3645 * with lack of free htlb page in cpuset that the task is in.
3646 * Attempt to enforce strict accounting with cpuset is almost
3647 * impossible (or too ugly) because cpuset is too fluid that
3648 * task or memory node can be dynamically moved between cpusets.
3649 *
3650 * The change of semantics for shared hugetlb mapping with cpuset is
3651 * undesirable. However, in order to preserve some of the semantics,
3652 * we fall back to check against current free page availability as
3653 * a best attempt and hopefully to minimize the impact of changing
3654 * semantics that cpuset has.
3655 *
3656 * Apart from cpuset, we also have memory policy mechanism that
3657 * also determines from which node the kernel will allocate memory
3658 * in a NUMA system. So similar to cpuset, we also should consider
3659 * the memory policy of the current task. Similar to the description
3660 * above.
3661 */
3662 if (delta > 0) {
3663 if (gather_surplus_pages(h, delta) < 0)
3664 goto out;
3665
3666 if (delta > allowed_mems_nr(h)) {
3667 return_unused_surplus_pages(h, delta);
3668 goto out;
3669 }
3670 }
3671
3672 ret = 0;
3673 if (delta < 0)
3674 return_unused_surplus_pages(h, (unsigned long) -delta);
3675
3676out:
3677 spin_unlock(&hugetlb_lock);
3678 return ret;
3679}
3680
3681static void hugetlb_vm_op_open(struct vm_area_struct *vma)
3682{
3683 struct resv_map *resv = vma_resv_map(vma);
3684
3685 /*
3686 * This new VMA should share its siblings reservation map if present.
3687 * The VMA will only ever have a valid reservation map pointer where
3688 * it is being copied for another still existing VMA. As that VMA
3689 * has a reference to the reservation map it cannot disappear until
3690 * after this open call completes. It is therefore safe to take a
3691 * new reference here without additional locking.
3692 */
3693 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3694 kref_get(&resv->refs);
3695}
3696
3697static void hugetlb_vm_op_close(struct vm_area_struct *vma)
3698{
3699 struct hstate *h = hstate_vma(vma);
3700 struct resv_map *resv = vma_resv_map(vma);
3701 struct hugepage_subpool *spool = subpool_vma(vma);
3702 unsigned long reserve, start, end;
3703 long gbl_reserve;
3704
3705 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3706 return;
3707
3708 start = vma_hugecache_offset(h, vma, vma->vm_start);
3709 end = vma_hugecache_offset(h, vma, vma->vm_end);
3710
3711 reserve = (end - start) - region_count(resv, start, end);
3712 hugetlb_cgroup_uncharge_counter(resv, start, end);
3713 if (reserve) {
3714 /*
3715 * Decrement reserve counts. The global reserve count may be
3716 * adjusted if the subpool has a minimum size.
3717 */
3718 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
3719 hugetlb_acct_memory(h, -gbl_reserve);
3720 }
3721
3722 kref_put(&resv->refs, resv_map_release);
3723}
3724
3725static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
3726{
3727 if (addr & ~(huge_page_mask(hstate_vma(vma))))
3728 return -EINVAL;
3729 return 0;
3730}
3731
3732static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
3733{
3734 struct hstate *hstate = hstate_vma(vma);
3735
3736 return 1UL << huge_page_shift(hstate);
3737}
3738
3739/*
3740 * We cannot handle pagefaults against hugetlb pages at all. They cause
3741 * handle_mm_fault() to try to instantiate regular-sized pages in the
3742 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3743 * this far.
3744 */
3745static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
3746{
3747 BUG();
3748 return 0;
3749}
3750
3751/*
3752 * When a new function is introduced to vm_operations_struct and added
3753 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
3754 * This is because under System V memory model, mappings created via
3755 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
3756 * their original vm_ops are overwritten with shm_vm_ops.
3757 */
3758const struct vm_operations_struct hugetlb_vm_ops = {
3759 .fault = hugetlb_vm_op_fault,
3760 .open = hugetlb_vm_op_open,
3761 .close = hugetlb_vm_op_close,
3762 .split = hugetlb_vm_op_split,
3763 .pagesize = hugetlb_vm_op_pagesize,
3764};
3765
3766static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
3767 int writable)
3768{
3769 pte_t entry;
3770
3771 if (writable) {
3772 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
3773 vma->vm_page_prot)));
3774 } else {
3775 entry = huge_pte_wrprotect(mk_huge_pte(page,
3776 vma->vm_page_prot));
3777 }
3778 entry = pte_mkyoung(entry);
3779 entry = pte_mkhuge(entry);
3780 entry = arch_make_huge_pte(entry, vma, page, writable);
3781
3782 return entry;
3783}
3784
3785static void set_huge_ptep_writable(struct vm_area_struct *vma,
3786 unsigned long address, pte_t *ptep)
3787{
3788 pte_t entry;
3789
3790 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3791 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3792 update_mmu_cache(vma, address, ptep);
3793}
3794
3795bool is_hugetlb_entry_migration(pte_t pte)
3796{
3797 swp_entry_t swp;
3798
3799 if (huge_pte_none(pte) || pte_present(pte))
3800 return false;
3801 swp = pte_to_swp_entry(pte);
3802 if (non_swap_entry(swp) && is_migration_entry(swp))
3803 return true;
3804 else
3805 return false;
3806}
3807
3808static int is_hugetlb_entry_hwpoisoned(pte_t pte)
3809{
3810 swp_entry_t swp;
3811
3812 if (huge_pte_none(pte) || pte_present(pte))
3813 return 0;
3814 swp = pte_to_swp_entry(pte);
3815 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
3816 return 1;
3817 else
3818 return 0;
3819}
3820
3821int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
3822 struct vm_area_struct *vma)
3823{
3824 pte_t *src_pte, *dst_pte, entry, dst_entry;
3825 struct page *ptepage;
3826 unsigned long addr;
3827 int cow;
3828 struct hstate *h = hstate_vma(vma);
3829 unsigned long sz = huge_page_size(h);
3830 struct address_space *mapping = vma->vm_file->f_mapping;
3831 struct mmu_notifier_range range;
3832 int ret = 0;
3833
3834 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
3835
3836 if (cow) {
3837 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
3838 vma->vm_start,
3839 vma->vm_end);
3840 mmu_notifier_invalidate_range_start(&range);
3841 } else {
3842 /*
3843 * For shared mappings i_mmap_rwsem must be held to call
3844 * huge_pte_alloc, otherwise the returned ptep could go
3845 * away if part of a shared pmd and another thread calls
3846 * huge_pmd_unshare.
3847 */
3848 i_mmap_lock_read(mapping);
3849 }
3850
3851 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3852 spinlock_t *src_ptl, *dst_ptl;
3853 src_pte = huge_pte_offset(src, addr, sz);
3854 if (!src_pte)
3855 continue;
3856 dst_pte = huge_pte_alloc(dst, addr, sz);
3857 if (!dst_pte) {
3858 ret = -ENOMEM;
3859 break;
3860 }
3861
3862 /*
3863 * If the pagetables are shared don't copy or take references.
3864 * dst_pte == src_pte is the common case of src/dest sharing.
3865 *
3866 * However, src could have 'unshared' and dst shares with
3867 * another vma. If dst_pte !none, this implies sharing.
3868 * Check here before taking page table lock, and once again
3869 * after taking the lock below.
3870 */
3871 dst_entry = huge_ptep_get(dst_pte);
3872 if ((dst_pte == src_pte) || !huge_pte_none(dst_entry))
3873 continue;
3874
3875 dst_ptl = huge_pte_lock(h, dst, dst_pte);
3876 src_ptl = huge_pte_lockptr(h, src, src_pte);
3877 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
3878 entry = huge_ptep_get(src_pte);
3879 dst_entry = huge_ptep_get(dst_pte);
3880 if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) {
3881 /*
3882 * Skip if src entry none. Also, skip in the
3883 * unlikely case dst entry !none as this implies
3884 * sharing with another vma.
3885 */
3886 ;
3887 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
3888 is_hugetlb_entry_hwpoisoned(entry))) {
3889 swp_entry_t swp_entry = pte_to_swp_entry(entry);
3890
3891 if (is_write_migration_entry(swp_entry) && cow) {
3892 /*
3893 * COW mappings require pages in both
3894 * parent and child to be set to read.
3895 */
3896 make_migration_entry_read(&swp_entry);
3897 entry = swp_entry_to_pte(swp_entry);
3898 set_huge_swap_pte_at(src, addr, src_pte,
3899 entry, sz);
3900 }
3901 set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
3902 } else {
3903 if (cow) {
3904 /*
3905 * No need to notify as we are downgrading page
3906 * table protection not changing it to point
3907 * to a new page.
3908 *
3909 * See Documentation/vm/mmu_notifier.rst
3910 */
3911 huge_ptep_set_wrprotect(src, addr, src_pte);
3912 }
3913 entry = huge_ptep_get(src_pte);
3914 ptepage = pte_page(entry);
3915 get_page(ptepage);
3916 page_dup_rmap(ptepage, true);
3917 set_huge_pte_at(dst, addr, dst_pte, entry);
3918 hugetlb_count_add(pages_per_huge_page(h), dst);
3919 }
3920 spin_unlock(src_ptl);
3921 spin_unlock(dst_ptl);
3922 }
3923
3924 if (cow)
3925 mmu_notifier_invalidate_range_end(&range);
3926 else
3927 i_mmap_unlock_read(mapping);
3928
3929 return ret;
3930}
3931
3932void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
3933 unsigned long start, unsigned long end,
3934 struct page *ref_page)
3935{
3936 struct mm_struct *mm = vma->vm_mm;
3937 unsigned long address;
3938 pte_t *ptep;
3939 pte_t pte;
3940 spinlock_t *ptl;
3941 struct page *page;
3942 struct hstate *h = hstate_vma(vma);
3943 unsigned long sz = huge_page_size(h);
3944 struct mmu_notifier_range range;
3945
3946 WARN_ON(!is_vm_hugetlb_page(vma));
3947 BUG_ON(start & ~huge_page_mask(h));
3948 BUG_ON(end & ~huge_page_mask(h));
3949
3950 /*
3951 * This is a hugetlb vma, all the pte entries should point
3952 * to huge page.
3953 */
3954 tlb_change_page_size(tlb, sz);
3955 tlb_start_vma(tlb, vma);
3956
3957 /*
3958 * If sharing possible, alert mmu notifiers of worst case.
3959 */
3960 mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
3961 end);
3962 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
3963 mmu_notifier_invalidate_range_start(&range);
3964 address = start;
3965 for (; address < end; address += sz) {
3966 ptep = huge_pte_offset(mm, address, sz);
3967 if (!ptep)
3968 continue;
3969
3970 ptl = huge_pte_lock(h, mm, ptep);
3971 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
3972 spin_unlock(ptl);
3973 /*
3974 * We just unmapped a page of PMDs by clearing a PUD.
3975 * The caller's TLB flush range should cover this area.
3976 */
3977 continue;
3978 }
3979
3980 pte = huge_ptep_get(ptep);
3981 if (huge_pte_none(pte)) {
3982 spin_unlock(ptl);
3983 continue;
3984 }
3985
3986 /*
3987 * Migrating hugepage or HWPoisoned hugepage is already
3988 * unmapped and its refcount is dropped, so just clear pte here.
3989 */
3990 if (unlikely(!pte_present(pte))) {
3991 huge_pte_clear(mm, address, ptep, sz);
3992 spin_unlock(ptl);
3993 continue;
3994 }
3995
3996 page = pte_page(pte);
3997 /*
3998 * If a reference page is supplied, it is because a specific
3999 * page is being unmapped, not a range. Ensure the page we
4000 * are about to unmap is the actual page of interest.
4001 */
4002 if (ref_page) {
4003 if (page != ref_page) {
4004 spin_unlock(ptl);
4005 continue;
4006 }
4007 /*
4008 * Mark the VMA as having unmapped its page so that
4009 * future faults in this VMA will fail rather than
4010 * looking like data was lost
4011 */
4012 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
4013 }
4014
4015 pte = huge_ptep_get_and_clear(mm, address, ptep);
4016 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
4017 if (huge_pte_dirty(pte))
4018 set_page_dirty(page);
4019
4020 hugetlb_count_sub(pages_per_huge_page(h), mm);
4021 page_remove_rmap(page, true);
4022
4023 spin_unlock(ptl);
4024 tlb_remove_page_size(tlb, page, huge_page_size(h));
4025 /*
4026 * Bail out after unmapping reference page if supplied
4027 */
4028 if (ref_page)
4029 break;
4030 }
4031 mmu_notifier_invalidate_range_end(&range);
4032 tlb_end_vma(tlb, vma);
4033}
4034
4035void __unmap_hugepage_range_final(struct mmu_gather *tlb,
4036 struct vm_area_struct *vma, unsigned long start,
4037 unsigned long end, struct page *ref_page)
4038{
4039 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
4040
4041 /*
4042 * Clear this flag so that x86's huge_pmd_share page_table_shareable
4043 * test will fail on a vma being torn down, and not grab a page table
4044 * on its way out. We're lucky that the flag has such an appropriate
4045 * name, and can in fact be safely cleared here. We could clear it
4046 * before the __unmap_hugepage_range above, but all that's necessary
4047 * is to clear it before releasing the i_mmap_rwsem. This works
4048 * because in the context this is called, the VMA is about to be
4049 * destroyed and the i_mmap_rwsem is held.
4050 */
4051 vma->vm_flags &= ~VM_MAYSHARE;
4052}
4053
4054void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
4055 unsigned long end, struct page *ref_page)
4056{
4057 struct mm_struct *mm;
4058 struct mmu_gather tlb;
4059 unsigned long tlb_start = start;
4060 unsigned long tlb_end = end;
4061
4062 /*
4063 * If shared PMDs were possibly used within this vma range, adjust
4064 * start/end for worst case tlb flushing.
4065 * Note that we can not be sure if PMDs are shared until we try to
4066 * unmap pages. However, we want to make sure TLB flushing covers
4067 * the largest possible range.
4068 */
4069 adjust_range_if_pmd_sharing_possible(vma, &tlb_start, &tlb_end);
4070
4071 mm = vma->vm_mm;
4072
4073 tlb_gather_mmu(&tlb, mm, tlb_start, tlb_end);
4074 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
4075 tlb_finish_mmu(&tlb, tlb_start, tlb_end);
4076}
4077
4078/*
4079 * This is called when the original mapper is failing to COW a MAP_PRIVATE
4080 * mappping it owns the reserve page for. The intention is to unmap the page
4081 * from other VMAs and let the children be SIGKILLed if they are faulting the
4082 * same region.
4083 */
4084static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
4085 struct page *page, unsigned long address)
4086{
4087 struct hstate *h = hstate_vma(vma);
4088 struct vm_area_struct *iter_vma;
4089 struct address_space *mapping;
4090 pgoff_t pgoff;
4091
4092 /*
4093 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
4094 * from page cache lookup which is in HPAGE_SIZE units.
4095 */
4096 address = address & huge_page_mask(h);
4097 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
4098 vma->vm_pgoff;
4099 mapping = vma->vm_file->f_mapping;
4100
4101 /*
4102 * Take the mapping lock for the duration of the table walk. As
4103 * this mapping should be shared between all the VMAs,
4104 * __unmap_hugepage_range() is called as the lock is already held
4105 */
4106 i_mmap_lock_write(mapping);
4107 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
4108 /* Do not unmap the current VMA */
4109 if (iter_vma == vma)
4110 continue;
4111
4112 /*
4113 * Shared VMAs have their own reserves and do not affect
4114 * MAP_PRIVATE accounting but it is possible that a shared
4115 * VMA is using the same page so check and skip such VMAs.
4116 */
4117 if (iter_vma->vm_flags & VM_MAYSHARE)
4118 continue;
4119
4120 /*
4121 * Unmap the page from other VMAs without their own reserves.
4122 * They get marked to be SIGKILLed if they fault in these
4123 * areas. This is because a future no-page fault on this VMA
4124 * could insert a zeroed page instead of the data existing
4125 * from the time of fork. This would look like data corruption
4126 */
4127 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
4128 unmap_hugepage_range(iter_vma, address,
4129 address + huge_page_size(h), page);
4130 }
4131 i_mmap_unlock_write(mapping);
4132}
4133
4134/*
4135 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4136 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
4137 * cannot race with other handlers or page migration.
4138 * Keep the pte_same checks anyway to make transition from the mutex easier.
4139 */
4140static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
4141 unsigned long address, pte_t *ptep,
4142 struct page *pagecache_page, spinlock_t *ptl)
4143{
4144 pte_t pte;
4145 struct hstate *h = hstate_vma(vma);
4146 struct page *old_page, *new_page;
4147 int outside_reserve = 0;
4148 vm_fault_t ret = 0;
4149 unsigned long haddr = address & huge_page_mask(h);
4150 struct mmu_notifier_range range;
4151
4152 pte = huge_ptep_get(ptep);
4153 old_page = pte_page(pte);
4154
4155retry_avoidcopy:
4156 /* If no-one else is actually using this page, avoid the copy
4157 * and just make the page writable */
4158 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
4159 page_move_anon_rmap(old_page, vma);
4160 set_huge_ptep_writable(vma, haddr, ptep);
4161 return 0;
4162 }
4163
4164 /*
4165 * If the process that created a MAP_PRIVATE mapping is about to
4166 * perform a COW due to a shared page count, attempt to satisfy
4167 * the allocation without using the existing reserves. The pagecache
4168 * page is used to determine if the reserve at this address was
4169 * consumed or not. If reserves were used, a partial faulted mapping
4170 * at the time of fork() could consume its reserves on COW instead
4171 * of the full address range.
4172 */
4173 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
4174 old_page != pagecache_page)
4175 outside_reserve = 1;
4176
4177 get_page(old_page);
4178
4179 /*
4180 * Drop page table lock as buddy allocator may be called. It will
4181 * be acquired again before returning to the caller, as expected.
4182 */
4183 spin_unlock(ptl);
4184 new_page = alloc_huge_page(vma, haddr, outside_reserve);
4185
4186 if (IS_ERR(new_page)) {
4187 /*
4188 * If a process owning a MAP_PRIVATE mapping fails to COW,
4189 * it is due to references held by a child and an insufficient
4190 * huge page pool. To guarantee the original mappers
4191 * reliability, unmap the page from child processes. The child
4192 * may get SIGKILLed if it later faults.
4193 */
4194 if (outside_reserve) {
4195 put_page(old_page);
4196 BUG_ON(huge_pte_none(pte));
4197 unmap_ref_private(mm, vma, old_page, haddr);
4198 BUG_ON(huge_pte_none(pte));
4199 spin_lock(ptl);
4200 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4201 if (likely(ptep &&
4202 pte_same(huge_ptep_get(ptep), pte)))
4203 goto retry_avoidcopy;
4204 /*
4205 * race occurs while re-acquiring page table
4206 * lock, and our job is done.
4207 */
4208 return 0;
4209 }
4210
4211 ret = vmf_error(PTR_ERR(new_page));
4212 goto out_release_old;
4213 }
4214
4215 /*
4216 * When the original hugepage is shared one, it does not have
4217 * anon_vma prepared.
4218 */
4219 if (unlikely(anon_vma_prepare(vma))) {
4220 ret = VM_FAULT_OOM;
4221 goto out_release_all;
4222 }
4223
4224 copy_user_huge_page(new_page, old_page, address, vma,
4225 pages_per_huge_page(h));
4226 __SetPageUptodate(new_page);
4227
4228 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
4229 haddr + huge_page_size(h));
4230 mmu_notifier_invalidate_range_start(&range);
4231
4232 /*
4233 * Retake the page table lock to check for racing updates
4234 * before the page tables are altered
4235 */
4236 spin_lock(ptl);
4237 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4238 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
4239 ClearPagePrivate(new_page);
4240
4241 /* Break COW */
4242 huge_ptep_clear_flush(vma, haddr, ptep);
4243 mmu_notifier_invalidate_range(mm, range.start, range.end);
4244 set_huge_pte_at(mm, haddr, ptep,
4245 make_huge_pte(vma, new_page, 1));
4246 page_remove_rmap(old_page, true);
4247 hugepage_add_new_anon_rmap(new_page, vma, haddr);
4248 set_page_huge_active(new_page);
4249 /* Make the old page be freed below */
4250 new_page = old_page;
4251 }
4252 spin_unlock(ptl);
4253 mmu_notifier_invalidate_range_end(&range);
4254out_release_all:
4255 restore_reserve_on_error(h, vma, haddr, new_page);
4256 put_page(new_page);
4257out_release_old:
4258 put_page(old_page);
4259
4260 spin_lock(ptl); /* Caller expects lock to be held */
4261 return ret;
4262}
4263
4264/* Return the pagecache page at a given address within a VMA */
4265static struct page *hugetlbfs_pagecache_page(struct hstate *h,
4266 struct vm_area_struct *vma, unsigned long address)
4267{
4268 struct address_space *mapping;
4269 pgoff_t idx;
4270
4271 mapping = vma->vm_file->f_mapping;
4272 idx = vma_hugecache_offset(h, vma, address);
4273
4274 return find_lock_page(mapping, idx);
4275}
4276
4277/*
4278 * Return whether there is a pagecache page to back given address within VMA.
4279 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
4280 */
4281static bool hugetlbfs_pagecache_present(struct hstate *h,
4282 struct vm_area_struct *vma, unsigned long address)
4283{
4284 struct address_space *mapping;
4285 pgoff_t idx;
4286 struct page *page;
4287
4288 mapping = vma->vm_file->f_mapping;
4289 idx = vma_hugecache_offset(h, vma, address);
4290
4291 page = find_get_page(mapping, idx);
4292 if (page)
4293 put_page(page);
4294 return page != NULL;
4295}
4296
4297int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
4298 pgoff_t idx)
4299{
4300 struct inode *inode = mapping->host;
4301 struct hstate *h = hstate_inode(inode);
4302 int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
4303
4304 if (err)
4305 return err;
4306 ClearPagePrivate(page);
4307
4308 /*
4309 * set page dirty so that it will not be removed from cache/file
4310 * by non-hugetlbfs specific code paths.
4311 */
4312 set_page_dirty(page);
4313
4314 spin_lock(&inode->i_lock);
4315 inode->i_blocks += blocks_per_huge_page(h);
4316 spin_unlock(&inode->i_lock);
4317 return 0;
4318}
4319
4320static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
4321 struct vm_area_struct *vma,
4322 struct address_space *mapping, pgoff_t idx,
4323 unsigned long address, pte_t *ptep, unsigned int flags)
4324{
4325 struct hstate *h = hstate_vma(vma);
4326 vm_fault_t ret = VM_FAULT_SIGBUS;
4327 int anon_rmap = 0;
4328 unsigned long size;
4329 struct page *page;
4330 pte_t new_pte;
4331 spinlock_t *ptl;
4332 unsigned long haddr = address & huge_page_mask(h);
4333 bool new_page = false;
4334
4335 /*
4336 * Currently, we are forced to kill the process in the event the
4337 * original mapper has unmapped pages from the child due to a failed
4338 * COW. Warn that such a situation has occurred as it may not be obvious
4339 */
4340 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
4341 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4342 current->pid);
4343 return ret;
4344 }
4345
4346 /*
4347 * We can not race with truncation due to holding i_mmap_rwsem.
4348 * i_size is modified when holding i_mmap_rwsem, so check here
4349 * once for faults beyond end of file.
4350 */
4351 size = i_size_read(mapping->host) >> huge_page_shift(h);
4352 if (idx >= size)
4353 goto out;
4354
4355retry:
4356 page = find_lock_page(mapping, idx);
4357 if (!page) {
4358 /*
4359 * Check for page in userfault range
4360 */
4361 if (userfaultfd_missing(vma)) {
4362 u32 hash;
4363 struct vm_fault vmf = {
4364 .vma = vma,
4365 .address = haddr,
4366 .flags = flags,
4367 /*
4368 * Hard to debug if it ends up being
4369 * used by a callee that assumes
4370 * something about the other
4371 * uninitialized fields... same as in
4372 * memory.c
4373 */
4374 };
4375
4376 /*
4377 * hugetlb_fault_mutex and i_mmap_rwsem must be
4378 * dropped before handling userfault. Reacquire
4379 * after handling fault to make calling code simpler.
4380 */
4381 hash = hugetlb_fault_mutex_hash(mapping, idx);
4382 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4383 i_mmap_unlock_read(mapping);
4384 ret = handle_userfault(&vmf, VM_UFFD_MISSING);
4385 i_mmap_lock_read(mapping);
4386 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4387 goto out;
4388 }
4389
4390 page = alloc_huge_page(vma, haddr, 0);
4391 if (IS_ERR(page)) {
4392 /*
4393 * Returning error will result in faulting task being
4394 * sent SIGBUS. The hugetlb fault mutex prevents two
4395 * tasks from racing to fault in the same page which
4396 * could result in false unable to allocate errors.
4397 * Page migration does not take the fault mutex, but
4398 * does a clear then write of pte's under page table
4399 * lock. Page fault code could race with migration,
4400 * notice the clear pte and try to allocate a page
4401 * here. Before returning error, get ptl and make
4402 * sure there really is no pte entry.
4403 */
4404 ptl = huge_pte_lock(h, mm, ptep);
4405 if (!huge_pte_none(huge_ptep_get(ptep))) {
4406 ret = 0;
4407 spin_unlock(ptl);
4408 goto out;
4409 }
4410 spin_unlock(ptl);
4411 ret = vmf_error(PTR_ERR(page));
4412 goto out;
4413 }
4414 clear_huge_page(page, address, pages_per_huge_page(h));
4415 __SetPageUptodate(page);
4416 new_page = true;
4417
4418 if (vma->vm_flags & VM_MAYSHARE) {
4419 int err = huge_add_to_page_cache(page, mapping, idx);
4420 if (err) {
4421 put_page(page);
4422 if (err == -EEXIST)
4423 goto retry;
4424 goto out;
4425 }
4426 } else {
4427 lock_page(page);
4428 if (unlikely(anon_vma_prepare(vma))) {
4429 ret = VM_FAULT_OOM;
4430 goto backout_unlocked;
4431 }
4432 anon_rmap = 1;
4433 }
4434 } else {
4435 /*
4436 * If memory error occurs between mmap() and fault, some process
4437 * don't have hwpoisoned swap entry for errored virtual address.
4438 * So we need to block hugepage fault by PG_hwpoison bit check.
4439 */
4440 if (unlikely(PageHWPoison(page))) {
4441 ret = VM_FAULT_HWPOISON |
4442 VM_FAULT_SET_HINDEX(hstate_index(h));
4443 goto backout_unlocked;
4444 }
4445 }
4446
4447 /*
4448 * If we are going to COW a private mapping later, we examine the
4449 * pending reservations for this page now. This will ensure that
4450 * any allocations necessary to record that reservation occur outside
4451 * the spinlock.
4452 */
4453 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4454 if (vma_needs_reservation(h, vma, haddr) < 0) {
4455 ret = VM_FAULT_OOM;
4456 goto backout_unlocked;
4457 }
4458 /* Just decrements count, does not deallocate */
4459 vma_end_reservation(h, vma, haddr);
4460 }
4461
4462 ptl = huge_pte_lock(h, mm, ptep);
4463 ret = 0;
4464 if (!huge_pte_none(huge_ptep_get(ptep)))
4465 goto backout;
4466
4467 if (anon_rmap) {
4468 ClearPagePrivate(page);
4469 hugepage_add_new_anon_rmap(page, vma, haddr);
4470 } else
4471 page_dup_rmap(page, true);
4472 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
4473 && (vma->vm_flags & VM_SHARED)));
4474 set_huge_pte_at(mm, haddr, ptep, new_pte);
4475
4476 hugetlb_count_add(pages_per_huge_page(h), mm);
4477 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4478 /* Optimization, do the COW without a second fault */
4479 ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
4480 }
4481
4482 spin_unlock(ptl);
4483
4484 /*
4485 * Only make newly allocated pages active. Existing pages found
4486 * in the pagecache could be !page_huge_active() if they have been
4487 * isolated for migration.
4488 */
4489 if (new_page)
4490 set_page_huge_active(page);
4491
4492 unlock_page(page);
4493out:
4494 return ret;
4495
4496backout:
4497 spin_unlock(ptl);
4498backout_unlocked:
4499 unlock_page(page);
4500 restore_reserve_on_error(h, vma, haddr, page);
4501 put_page(page);
4502 goto out;
4503}
4504
4505#ifdef CONFIG_SMP
4506u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4507{
4508 unsigned long key[2];
4509 u32 hash;
4510
4511 key[0] = (unsigned long) mapping;
4512 key[1] = idx;
4513
4514 hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
4515
4516 return hash & (num_fault_mutexes - 1);
4517}
4518#else
4519/*
4520 * For uniprocesor systems we always use a single mutex, so just
4521 * return 0 and avoid the hashing overhead.
4522 */
4523u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4524{
4525 return 0;
4526}
4527#endif
4528
4529vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
4530 unsigned long address, unsigned int flags)
4531{
4532 pte_t *ptep, entry;
4533 spinlock_t *ptl;
4534 vm_fault_t ret;
4535 u32 hash;
4536 pgoff_t idx;
4537 struct page *page = NULL;
4538 struct page *pagecache_page = NULL;
4539 struct hstate *h = hstate_vma(vma);
4540 struct address_space *mapping;
4541 int need_wait_lock = 0;
4542 unsigned long haddr = address & huge_page_mask(h);
4543
4544 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4545 if (ptep) {
4546 /*
4547 * Since we hold no locks, ptep could be stale. That is
4548 * OK as we are only making decisions based on content and
4549 * not actually modifying content here.
4550 */
4551 entry = huge_ptep_get(ptep);
4552 if (unlikely(is_hugetlb_entry_migration(entry))) {
4553 migration_entry_wait_huge(vma, mm, ptep);
4554 return 0;
4555 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
4556 return VM_FAULT_HWPOISON_LARGE |
4557 VM_FAULT_SET_HINDEX(hstate_index(h));
4558 }
4559
4560 /*
4561 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4562 * until finished with ptep. This serves two purposes:
4563 * 1) It prevents huge_pmd_unshare from being called elsewhere
4564 * and making the ptep no longer valid.
4565 * 2) It synchronizes us with i_size modifications during truncation.
4566 *
4567 * ptep could have already be assigned via huge_pte_offset. That
4568 * is OK, as huge_pte_alloc will return the same value unless
4569 * something has changed.
4570 */
4571 mapping = vma->vm_file->f_mapping;
4572 i_mmap_lock_read(mapping);
4573 ptep = huge_pte_alloc(mm, haddr, huge_page_size(h));
4574 if (!ptep) {
4575 i_mmap_unlock_read(mapping);
4576 return VM_FAULT_OOM;
4577 }
4578
4579 /*
4580 * Serialize hugepage allocation and instantiation, so that we don't
4581 * get spurious allocation failures if two CPUs race to instantiate
4582 * the same page in the page cache.
4583 */
4584 idx = vma_hugecache_offset(h, vma, haddr);
4585 hash = hugetlb_fault_mutex_hash(mapping, idx);
4586 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4587
4588 entry = huge_ptep_get(ptep);
4589 if (huge_pte_none(entry)) {
4590 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
4591 goto out_mutex;
4592 }
4593
4594 ret = 0;
4595
4596 /*
4597 * entry could be a migration/hwpoison entry at this point, so this
4598 * check prevents the kernel from going below assuming that we have
4599 * an active hugepage in pagecache. This goto expects the 2nd page
4600 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
4601 * properly handle it.
4602 */
4603 if (!pte_present(entry))
4604 goto out_mutex;
4605
4606 /*
4607 * If we are going to COW the mapping later, we examine the pending
4608 * reservations for this page now. This will ensure that any
4609 * allocations necessary to record that reservation occur outside the
4610 * spinlock. For private mappings, we also lookup the pagecache
4611 * page now as it is used to determine if a reservation has been
4612 * consumed.
4613 */
4614 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
4615 if (vma_needs_reservation(h, vma, haddr) < 0) {
4616 ret = VM_FAULT_OOM;
4617 goto out_mutex;
4618 }
4619 /* Just decrements count, does not deallocate */
4620 vma_end_reservation(h, vma, haddr);
4621
4622 if (!(vma->vm_flags & VM_MAYSHARE))
4623 pagecache_page = hugetlbfs_pagecache_page(h,
4624 vma, haddr);
4625 }
4626
4627 ptl = huge_pte_lock(h, mm, ptep);
4628
4629 /* Check for a racing update before calling hugetlb_cow */
4630 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
4631 goto out_ptl;
4632
4633 /*
4634 * hugetlb_cow() requires page locks of pte_page(entry) and
4635 * pagecache_page, so here we need take the former one
4636 * when page != pagecache_page or !pagecache_page.
4637 */
4638 page = pte_page(entry);
4639 if (page != pagecache_page)
4640 if (!trylock_page(page)) {
4641 need_wait_lock = 1;
4642 goto out_ptl;
4643 }
4644
4645 get_page(page);
4646
4647 if (flags & FAULT_FLAG_WRITE) {
4648 if (!huge_pte_write(entry)) {
4649 ret = hugetlb_cow(mm, vma, address, ptep,
4650 pagecache_page, ptl);
4651 goto out_put_page;
4652 }
4653 entry = huge_pte_mkdirty(entry);
4654 }
4655 entry = pte_mkyoung(entry);
4656 if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
4657 flags & FAULT_FLAG_WRITE))
4658 update_mmu_cache(vma, haddr, ptep);
4659out_put_page:
4660 if (page != pagecache_page)
4661 unlock_page(page);
4662 put_page(page);
4663out_ptl:
4664 spin_unlock(ptl);
4665
4666 if (pagecache_page) {
4667 unlock_page(pagecache_page);
4668 put_page(pagecache_page);
4669 }
4670out_mutex:
4671 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4672 i_mmap_unlock_read(mapping);
4673 /*
4674 * Generally it's safe to hold refcount during waiting page lock. But
4675 * here we just wait to defer the next page fault to avoid busy loop and
4676 * the page is not used after unlocked before returning from the current
4677 * page fault. So we are safe from accessing freed page, even if we wait
4678 * here without taking refcount.
4679 */
4680 if (need_wait_lock)
4681 wait_on_page_locked(page);
4682 return ret;
4683}
4684
4685/*
4686 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
4687 * modifications for huge pages.
4688 */
4689int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
4690 pte_t *dst_pte,
4691 struct vm_area_struct *dst_vma,
4692 unsigned long dst_addr,
4693 unsigned long src_addr,
4694 struct page **pagep)
4695{
4696 struct address_space *mapping;
4697 pgoff_t idx;
4698 unsigned long size;
4699 int vm_shared = dst_vma->vm_flags & VM_SHARED;
4700 struct hstate *h = hstate_vma(dst_vma);
4701 pte_t _dst_pte;
4702 spinlock_t *ptl;
4703 int ret;
4704 struct page *page;
4705
4706 if (!*pagep) {
4707 ret = -ENOMEM;
4708 page = alloc_huge_page(dst_vma, dst_addr, 0);
4709 if (IS_ERR(page))
4710 goto out;
4711
4712 ret = copy_huge_page_from_user(page,
4713 (const void __user *) src_addr,
4714 pages_per_huge_page(h), false);
4715
4716 /* fallback to copy_from_user outside mmap_lock */
4717 if (unlikely(ret)) {
4718 ret = -ENOENT;
4719 *pagep = page;
4720 /* don't free the page */
4721 goto out;
4722 }
4723 } else {
4724 page = *pagep;
4725 *pagep = NULL;
4726 }
4727
4728 /*
4729 * The memory barrier inside __SetPageUptodate makes sure that
4730 * preceding stores to the page contents become visible before
4731 * the set_pte_at() write.
4732 */
4733 __SetPageUptodate(page);
4734
4735 mapping = dst_vma->vm_file->f_mapping;
4736 idx = vma_hugecache_offset(h, dst_vma, dst_addr);
4737
4738 /*
4739 * If shared, add to page cache
4740 */
4741 if (vm_shared) {
4742 size = i_size_read(mapping->host) >> huge_page_shift(h);
4743 ret = -EFAULT;
4744 if (idx >= size)
4745 goto out_release_nounlock;
4746
4747 /*
4748 * Serialization between remove_inode_hugepages() and
4749 * huge_add_to_page_cache() below happens through the
4750 * hugetlb_fault_mutex_table that here must be hold by
4751 * the caller.
4752 */
4753 ret = huge_add_to_page_cache(page, mapping, idx);
4754 if (ret)
4755 goto out_release_nounlock;
4756 }
4757
4758 ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
4759 spin_lock(ptl);
4760
4761 /*
4762 * Recheck the i_size after holding PT lock to make sure not
4763 * to leave any page mapped (as page_mapped()) beyond the end
4764 * of the i_size (remove_inode_hugepages() is strict about
4765 * enforcing that). If we bail out here, we'll also leave a
4766 * page in the radix tree in the vm_shared case beyond the end
4767 * of the i_size, but remove_inode_hugepages() will take care
4768 * of it as soon as we drop the hugetlb_fault_mutex_table.
4769 */
4770 size = i_size_read(mapping->host) >> huge_page_shift(h);
4771 ret = -EFAULT;
4772 if (idx >= size)
4773 goto out_release_unlock;
4774
4775 ret = -EEXIST;
4776 if (!huge_pte_none(huge_ptep_get(dst_pte)))
4777 goto out_release_unlock;
4778
4779 if (vm_shared) {
4780 page_dup_rmap(page, true);
4781 } else {
4782 ClearPagePrivate(page);
4783 hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
4784 }
4785
4786 _dst_pte = make_huge_pte(dst_vma, page, dst_vma->vm_flags & VM_WRITE);
4787 if (dst_vma->vm_flags & VM_WRITE)
4788 _dst_pte = huge_pte_mkdirty(_dst_pte);
4789 _dst_pte = pte_mkyoung(_dst_pte);
4790
4791 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
4792
4793 (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
4794 dst_vma->vm_flags & VM_WRITE);
4795 hugetlb_count_add(pages_per_huge_page(h), dst_mm);
4796
4797 /* No need to invalidate - it was non-present before */
4798 update_mmu_cache(dst_vma, dst_addr, dst_pte);
4799
4800 spin_unlock(ptl);
4801 set_page_huge_active(page);
4802 if (vm_shared)
4803 unlock_page(page);
4804 ret = 0;
4805out:
4806 return ret;
4807out_release_unlock:
4808 spin_unlock(ptl);
4809 if (vm_shared)
4810 unlock_page(page);
4811out_release_nounlock:
4812 put_page(page);
4813 goto out;
4814}
4815
4816long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
4817 struct page **pages, struct vm_area_struct **vmas,
4818 unsigned long *position, unsigned long *nr_pages,
4819 long i, unsigned int flags, int *locked)
4820{
4821 unsigned long pfn_offset;
4822 unsigned long vaddr = *position;
4823 unsigned long remainder = *nr_pages;
4824 struct hstate *h = hstate_vma(vma);
4825 int err = -EFAULT;
4826
4827 while (vaddr < vma->vm_end && remainder) {
4828 pte_t *pte;
4829 spinlock_t *ptl = NULL;
4830 int absent;
4831 struct page *page;
4832
4833 /*
4834 * If we have a pending SIGKILL, don't keep faulting pages and
4835 * potentially allocating memory.
4836 */
4837 if (fatal_signal_pending(current)) {
4838 remainder = 0;
4839 break;
4840 }
4841
4842 /*
4843 * Some archs (sparc64, sh*) have multiple pte_ts to
4844 * each hugepage. We have to make sure we get the
4845 * first, for the page indexing below to work.
4846 *
4847 * Note that page table lock is not held when pte is null.
4848 */
4849 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
4850 huge_page_size(h));
4851 if (pte)
4852 ptl = huge_pte_lock(h, mm, pte);
4853 absent = !pte || huge_pte_none(huge_ptep_get(pte));
4854
4855 /*
4856 * When coredumping, it suits get_dump_page if we just return
4857 * an error where there's an empty slot with no huge pagecache
4858 * to back it. This way, we avoid allocating a hugepage, and
4859 * the sparse dumpfile avoids allocating disk blocks, but its
4860 * huge holes still show up with zeroes where they need to be.
4861 */
4862 if (absent && (flags & FOLL_DUMP) &&
4863 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4864 if (pte)
4865 spin_unlock(ptl);
4866 remainder = 0;
4867 break;
4868 }
4869
4870 /*
4871 * We need call hugetlb_fault for both hugepages under migration
4872 * (in which case hugetlb_fault waits for the migration,) and
4873 * hwpoisoned hugepages (in which case we need to prevent the
4874 * caller from accessing to them.) In order to do this, we use
4875 * here is_swap_pte instead of is_hugetlb_entry_migration and
4876 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4877 * both cases, and because we can't follow correct pages
4878 * directly from any kind of swap entries.
4879 */
4880 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
4881 ((flags & FOLL_WRITE) &&
4882 !huge_pte_write(huge_ptep_get(pte)))) {
4883 vm_fault_t ret;
4884 unsigned int fault_flags = 0;
4885
4886 if (pte)
4887 spin_unlock(ptl);
4888 if (flags & FOLL_WRITE)
4889 fault_flags |= FAULT_FLAG_WRITE;
4890 if (locked)
4891 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
4892 FAULT_FLAG_KILLABLE;
4893 if (flags & FOLL_NOWAIT)
4894 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
4895 FAULT_FLAG_RETRY_NOWAIT;
4896 if (flags & FOLL_TRIED) {
4897 /*
4898 * Note: FAULT_FLAG_ALLOW_RETRY and
4899 * FAULT_FLAG_TRIED can co-exist
4900 */
4901 fault_flags |= FAULT_FLAG_TRIED;
4902 }
4903 ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
4904 if (ret & VM_FAULT_ERROR) {
4905 err = vm_fault_to_errno(ret, flags);
4906 remainder = 0;
4907 break;
4908 }
4909 if (ret & VM_FAULT_RETRY) {
4910 if (locked &&
4911 !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
4912 *locked = 0;
4913 *nr_pages = 0;
4914 /*
4915 * VM_FAULT_RETRY must not return an
4916 * error, it will return zero
4917 * instead.
4918 *
4919 * No need to update "position" as the
4920 * caller will not check it after
4921 * *nr_pages is set to 0.
4922 */
4923 return i;
4924 }
4925 continue;
4926 }
4927
4928 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4929 page = pte_page(huge_ptep_get(pte));
4930
4931 /*
4932 * If subpage information not requested, update counters
4933 * and skip the same_page loop below.
4934 */
4935 if (!pages && !vmas && !pfn_offset &&
4936 (vaddr + huge_page_size(h) < vma->vm_end) &&
4937 (remainder >= pages_per_huge_page(h))) {
4938 vaddr += huge_page_size(h);
4939 remainder -= pages_per_huge_page(h);
4940 i += pages_per_huge_page(h);
4941 spin_unlock(ptl);
4942 continue;
4943 }
4944
4945same_page:
4946 if (pages) {
4947 pages[i] = mem_map_offset(page, pfn_offset);
4948 /*
4949 * try_grab_page() should always succeed here, because:
4950 * a) we hold the ptl lock, and b) we've just checked
4951 * that the huge page is present in the page tables. If
4952 * the huge page is present, then the tail pages must
4953 * also be present. The ptl prevents the head page and
4954 * tail pages from being rearranged in any way. So this
4955 * page must be available at this point, unless the page
4956 * refcount overflowed:
4957 */
4958 if (WARN_ON_ONCE(!try_grab_page(pages[i], flags))) {
4959 spin_unlock(ptl);
4960 remainder = 0;
4961 err = -ENOMEM;
4962 break;
4963 }
4964 }
4965
4966 if (vmas)
4967 vmas[i] = vma;
4968
4969 vaddr += PAGE_SIZE;
4970 ++pfn_offset;
4971 --remainder;
4972 ++i;
4973 if (vaddr < vma->vm_end && remainder &&
4974 pfn_offset < pages_per_huge_page(h)) {
4975 /*
4976 * We use pfn_offset to avoid touching the pageframes
4977 * of this compound page.
4978 */
4979 goto same_page;
4980 }
4981 spin_unlock(ptl);
4982 }
4983 *nr_pages = remainder;
4984 /*
4985 * setting position is actually required only if remainder is
4986 * not zero but it's faster not to add a "if (remainder)"
4987 * branch.
4988 */
4989 *position = vaddr;
4990
4991 return i ? i : err;
4992}
4993
4994#ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4995/*
4996 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4997 * implement this.
4998 */
4999#define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
5000#endif
5001
5002unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
5003 unsigned long address, unsigned long end, pgprot_t newprot)
5004{
5005 struct mm_struct *mm = vma->vm_mm;
5006 unsigned long start = address;
5007 pte_t *ptep;
5008 pte_t pte;
5009 struct hstate *h = hstate_vma(vma);
5010 unsigned long pages = 0;
5011 bool shared_pmd = false;
5012 struct mmu_notifier_range range;
5013
5014 /*
5015 * In the case of shared PMDs, the area to flush could be beyond
5016 * start/end. Set range.start/range.end to cover the maximum possible
5017 * range if PMD sharing is possible.
5018 */
5019 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
5020 0, vma, mm, start, end);
5021 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5022
5023 BUG_ON(address >= end);
5024 flush_cache_range(vma, range.start, range.end);
5025
5026 mmu_notifier_invalidate_range_start(&range);
5027 i_mmap_lock_write(vma->vm_file->f_mapping);
5028 for (; address < end; address += huge_page_size(h)) {
5029 spinlock_t *ptl;
5030 ptep = huge_pte_offset(mm, address, huge_page_size(h));
5031 if (!ptep)
5032 continue;
5033 ptl = huge_pte_lock(h, mm, ptep);
5034 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
5035 pages++;
5036 spin_unlock(ptl);
5037 shared_pmd = true;
5038 continue;
5039 }
5040 pte = huge_ptep_get(ptep);
5041 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
5042 spin_unlock(ptl);
5043 continue;
5044 }
5045 if (unlikely(is_hugetlb_entry_migration(pte))) {
5046 swp_entry_t entry = pte_to_swp_entry(pte);
5047
5048 if (is_write_migration_entry(entry)) {
5049 pte_t newpte;
5050
5051 make_migration_entry_read(&entry);
5052 newpte = swp_entry_to_pte(entry);
5053 set_huge_swap_pte_at(mm, address, ptep,
5054 newpte, huge_page_size(h));
5055 pages++;
5056 }
5057 spin_unlock(ptl);
5058 continue;
5059 }
5060 if (!huge_pte_none(pte)) {
5061 pte_t old_pte;
5062
5063 old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
5064 pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
5065 pte = arch_make_huge_pte(pte, vma, NULL, 0);
5066 huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
5067 pages++;
5068 }
5069 spin_unlock(ptl);
5070 }
5071 /*
5072 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
5073 * may have cleared our pud entry and done put_page on the page table:
5074 * once we release i_mmap_rwsem, another task can do the final put_page
5075 * and that page table be reused and filled with junk. If we actually
5076 * did unshare a page of pmds, flush the range corresponding to the pud.
5077 */
5078 if (shared_pmd)
5079 flush_hugetlb_tlb_range(vma, range.start, range.end);
5080 else
5081 flush_hugetlb_tlb_range(vma, start, end);
5082 /*
5083 * No need to call mmu_notifier_invalidate_range() we are downgrading
5084 * page table protection not changing it to point to a new page.
5085 *
5086 * See Documentation/vm/mmu_notifier.rst
5087 */
5088 i_mmap_unlock_write(vma->vm_file->f_mapping);
5089 mmu_notifier_invalidate_range_end(&range);
5090
5091 return pages << h->order;
5092}
5093
5094int hugetlb_reserve_pages(struct inode *inode,
5095 long from, long to,
5096 struct vm_area_struct *vma,
5097 vm_flags_t vm_flags)
5098{
5099 long ret, chg, add = -1;
5100 struct hstate *h = hstate_inode(inode);
5101 struct hugepage_subpool *spool = subpool_inode(inode);
5102 struct resv_map *resv_map;
5103 struct hugetlb_cgroup *h_cg = NULL;
5104 long gbl_reserve, regions_needed = 0;
5105
5106 /* This should never happen */
5107 if (from > to) {
5108 VM_WARN(1, "%s called with a negative range\n", __func__);
5109 return -EINVAL;
5110 }
5111
5112 /*
5113 * Only apply hugepage reservation if asked. At fault time, an
5114 * attempt will be made for VM_NORESERVE to allocate a page
5115 * without using reserves
5116 */
5117 if (vm_flags & VM_NORESERVE)
5118 return 0;
5119
5120 /*
5121 * Shared mappings base their reservation on the number of pages that
5122 * are already allocated on behalf of the file. Private mappings need
5123 * to reserve the full area even if read-only as mprotect() may be
5124 * called to make the mapping read-write. Assume !vma is a shm mapping
5125 */
5126 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5127 /*
5128 * resv_map can not be NULL as hugetlb_reserve_pages is only
5129 * called for inodes for which resv_maps were created (see
5130 * hugetlbfs_get_inode).
5131 */
5132 resv_map = inode_resv_map(inode);
5133
5134 chg = region_chg(resv_map, from, to, ®ions_needed);
5135
5136 } else {
5137 /* Private mapping. */
5138 resv_map = resv_map_alloc();
5139 if (!resv_map)
5140 return -ENOMEM;
5141
5142 chg = to - from;
5143
5144 set_vma_resv_map(vma, resv_map);
5145 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
5146 }
5147
5148 if (chg < 0) {
5149 ret = chg;
5150 goto out_err;
5151 }
5152
5153 ret = hugetlb_cgroup_charge_cgroup_rsvd(
5154 hstate_index(h), chg * pages_per_huge_page(h), &h_cg);
5155
5156 if (ret < 0) {
5157 ret = -ENOMEM;
5158 goto out_err;
5159 }
5160
5161 if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) {
5162 /* For private mappings, the hugetlb_cgroup uncharge info hangs
5163 * of the resv_map.
5164 */
5165 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
5166 }
5167
5168 /*
5169 * There must be enough pages in the subpool for the mapping. If
5170 * the subpool has a minimum size, there may be some global
5171 * reservations already in place (gbl_reserve).
5172 */
5173 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
5174 if (gbl_reserve < 0) {
5175 ret = -ENOSPC;
5176 goto out_uncharge_cgroup;
5177 }
5178
5179 /*
5180 * Check enough hugepages are available for the reservation.
5181 * Hand the pages back to the subpool if there are not
5182 */
5183 ret = hugetlb_acct_memory(h, gbl_reserve);
5184 if (ret < 0) {
5185 goto out_put_pages;
5186 }
5187
5188 /*
5189 * Account for the reservations made. Shared mappings record regions
5190 * that have reservations as they are shared by multiple VMAs.
5191 * When the last VMA disappears, the region map says how much
5192 * the reservation was and the page cache tells how much of
5193 * the reservation was consumed. Private mappings are per-VMA and
5194 * only the consumed reservations are tracked. When the VMA
5195 * disappears, the original reservation is the VMA size and the
5196 * consumed reservations are stored in the map. Hence, nothing
5197 * else has to be done for private mappings here
5198 */
5199 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5200 add = region_add(resv_map, from, to, regions_needed, h, h_cg);
5201
5202 if (unlikely(add < 0)) {
5203 hugetlb_acct_memory(h, -gbl_reserve);
5204 goto out_put_pages;
5205 } else if (unlikely(chg > add)) {
5206 /*
5207 * pages in this range were added to the reserve
5208 * map between region_chg and region_add. This
5209 * indicates a race with alloc_huge_page. Adjust
5210 * the subpool and reserve counts modified above
5211 * based on the difference.
5212 */
5213 long rsv_adjust;
5214
5215 hugetlb_cgroup_uncharge_cgroup_rsvd(
5216 hstate_index(h),
5217 (chg - add) * pages_per_huge_page(h), h_cg);
5218
5219 rsv_adjust = hugepage_subpool_put_pages(spool,
5220 chg - add);
5221 hugetlb_acct_memory(h, -rsv_adjust);
5222 }
5223 }
5224 return 0;
5225out_put_pages:
5226 /* put back original number of pages, chg */
5227 (void)hugepage_subpool_put_pages(spool, chg);
5228out_uncharge_cgroup:
5229 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
5230 chg * pages_per_huge_page(h), h_cg);
5231out_err:
5232 if (!vma || vma->vm_flags & VM_MAYSHARE)
5233 /* Only call region_abort if the region_chg succeeded but the
5234 * region_add failed or didn't run.
5235 */
5236 if (chg >= 0 && add < 0)
5237 region_abort(resv_map, from, to, regions_needed);
5238 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
5239 kref_put(&resv_map->refs, resv_map_release);
5240 return ret;
5241}
5242
5243long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
5244 long freed)
5245{
5246 struct hstate *h = hstate_inode(inode);
5247 struct resv_map *resv_map = inode_resv_map(inode);
5248 long chg = 0;
5249 struct hugepage_subpool *spool = subpool_inode(inode);
5250 long gbl_reserve;
5251
5252 /*
5253 * Since this routine can be called in the evict inode path for all
5254 * hugetlbfs inodes, resv_map could be NULL.
5255 */
5256 if (resv_map) {
5257 chg = region_del(resv_map, start, end);
5258 /*
5259 * region_del() can fail in the rare case where a region
5260 * must be split and another region descriptor can not be
5261 * allocated. If end == LONG_MAX, it will not fail.
5262 */
5263 if (chg < 0)
5264 return chg;
5265 }
5266
5267 spin_lock(&inode->i_lock);
5268 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
5269 spin_unlock(&inode->i_lock);
5270
5271 /*
5272 * If the subpool has a minimum size, the number of global
5273 * reservations to be released may be adjusted.
5274 */
5275 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
5276 hugetlb_acct_memory(h, -gbl_reserve);
5277
5278 return 0;
5279}
5280
5281#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
5282static unsigned long page_table_shareable(struct vm_area_struct *svma,
5283 struct vm_area_struct *vma,
5284 unsigned long addr, pgoff_t idx)
5285{
5286 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
5287 svma->vm_start;
5288 unsigned long sbase = saddr & PUD_MASK;
5289 unsigned long s_end = sbase + PUD_SIZE;
5290
5291 /* Allow segments to share if only one is marked locked */
5292 unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
5293 unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
5294
5295 /*
5296 * match the virtual addresses, permission and the alignment of the
5297 * page table page.
5298 */
5299 if (pmd_index(addr) != pmd_index(saddr) ||
5300 vm_flags != svm_flags ||
5301 sbase < svma->vm_start || svma->vm_end < s_end)
5302 return 0;
5303
5304 return saddr;
5305}
5306
5307static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
5308{
5309 unsigned long base = addr & PUD_MASK;
5310 unsigned long end = base + PUD_SIZE;
5311
5312 /*
5313 * check on proper vm_flags and page table alignment
5314 */
5315 if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
5316 return true;
5317 return false;
5318}
5319
5320/*
5321 * Determine if start,end range within vma could be mapped by shared pmd.
5322 * If yes, adjust start and end to cover range associated with possible
5323 * shared pmd mappings.
5324 */
5325void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5326 unsigned long *start, unsigned long *end)
5327{
5328 unsigned long a_start, a_end;
5329
5330 if (!(vma->vm_flags & VM_MAYSHARE))
5331 return;
5332
5333 /* Extend the range to be PUD aligned for a worst case scenario */
5334 a_start = ALIGN_DOWN(*start, PUD_SIZE);
5335 a_end = ALIGN(*end, PUD_SIZE);
5336
5337 /*
5338 * Intersect the range with the vma range, since pmd sharing won't be
5339 * across vma after all
5340 */
5341 *start = max(vma->vm_start, a_start);
5342 *end = min(vma->vm_end, a_end);
5343}
5344
5345/*
5346 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
5347 * and returns the corresponding pte. While this is not necessary for the
5348 * !shared pmd case because we can allocate the pmd later as well, it makes the
5349 * code much cleaner.
5350 *
5351 * This routine must be called with i_mmap_rwsem held in at least read mode.
5352 * For hugetlbfs, this prevents removal of any page table entries associated
5353 * with the address space. This is important as we are setting up sharing
5354 * based on existing page table entries (mappings).
5355 */
5356pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
5357{
5358 struct vm_area_struct *vma = find_vma(mm, addr);
5359 struct address_space *mapping = vma->vm_file->f_mapping;
5360 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
5361 vma->vm_pgoff;
5362 struct vm_area_struct *svma;
5363 unsigned long saddr;
5364 pte_t *spte = NULL;
5365 pte_t *pte;
5366 spinlock_t *ptl;
5367
5368 if (!vma_shareable(vma, addr))
5369 return (pte_t *)pmd_alloc(mm, pud, addr);
5370
5371 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
5372 if (svma == vma)
5373 continue;
5374
5375 saddr = page_table_shareable(svma, vma, addr, idx);
5376 if (saddr) {
5377 spte = huge_pte_offset(svma->vm_mm, saddr,
5378 vma_mmu_pagesize(svma));
5379 if (spte) {
5380 get_page(virt_to_page(spte));
5381 break;
5382 }
5383 }
5384 }
5385
5386 if (!spte)
5387 goto out;
5388
5389 ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
5390 if (pud_none(*pud)) {
5391 pud_populate(mm, pud,
5392 (pmd_t *)((unsigned long)spte & PAGE_MASK));
5393 mm_inc_nr_pmds(mm);
5394 } else {
5395 put_page(virt_to_page(spte));
5396 }
5397 spin_unlock(ptl);
5398out:
5399 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5400 return pte;
5401}
5402
5403/*
5404 * unmap huge page backed by shared pte.
5405 *
5406 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
5407 * indicated by page_count > 1, unmap is achieved by clearing pud and
5408 * decrementing the ref count. If count == 1, the pte page is not shared.
5409 *
5410 * Called with page table lock held and i_mmap_rwsem held in write mode.
5411 *
5412 * returns: 1 successfully unmapped a shared pte page
5413 * 0 the underlying pte page is not shared, or it is the last user
5414 */
5415int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5416 unsigned long *addr, pte_t *ptep)
5417{
5418 pgd_t *pgd = pgd_offset(mm, *addr);
5419 p4d_t *p4d = p4d_offset(pgd, *addr);
5420 pud_t *pud = pud_offset(p4d, *addr);
5421
5422 i_mmap_assert_write_locked(vma->vm_file->f_mapping);
5423 BUG_ON(page_count(virt_to_page(ptep)) == 0);
5424 if (page_count(virt_to_page(ptep)) == 1)
5425 return 0;
5426
5427 pud_clear(pud);
5428 put_page(virt_to_page(ptep));
5429 mm_dec_nr_pmds(mm);
5430 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
5431 return 1;
5432}
5433#define want_pmd_share() (1)
5434#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5435pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
5436{
5437 return NULL;
5438}
5439
5440int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5441 unsigned long *addr, pte_t *ptep)
5442{
5443 return 0;
5444}
5445
5446void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5447 unsigned long *start, unsigned long *end)
5448{
5449}
5450#define want_pmd_share() (0)
5451#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5452
5453#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
5454pte_t *huge_pte_alloc(struct mm_struct *mm,
5455 unsigned long addr, unsigned long sz)
5456{
5457 pgd_t *pgd;
5458 p4d_t *p4d;
5459 pud_t *pud;
5460 pte_t *pte = NULL;
5461
5462 pgd = pgd_offset(mm, addr);
5463 p4d = p4d_alloc(mm, pgd, addr);
5464 if (!p4d)
5465 return NULL;
5466 pud = pud_alloc(mm, p4d, addr);
5467 if (pud) {
5468 if (sz == PUD_SIZE) {
5469 pte = (pte_t *)pud;
5470 } else {
5471 BUG_ON(sz != PMD_SIZE);
5472 if (want_pmd_share() && pud_none(*pud))
5473 pte = huge_pmd_share(mm, addr, pud);
5474 else
5475 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5476 }
5477 }
5478 BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
5479
5480 return pte;
5481}
5482
5483/*
5484 * huge_pte_offset() - Walk the page table to resolve the hugepage
5485 * entry at address @addr
5486 *
5487 * Return: Pointer to page table entry (PUD or PMD) for
5488 * address @addr, or NULL if a !p*d_present() entry is encountered and the
5489 * size @sz doesn't match the hugepage size at this level of the page
5490 * table.
5491 */
5492pte_t *huge_pte_offset(struct mm_struct *mm,
5493 unsigned long addr, unsigned long sz)
5494{
5495 pgd_t *pgd;
5496 p4d_t *p4d;
5497 pud_t *pud;
5498 pmd_t *pmd;
5499
5500 pgd = pgd_offset(mm, addr);
5501 if (!pgd_present(*pgd))
5502 return NULL;
5503 p4d = p4d_offset(pgd, addr);
5504 if (!p4d_present(*p4d))
5505 return NULL;
5506
5507 pud = pud_offset(p4d, addr);
5508 if (sz == PUD_SIZE)
5509 /* must be pud huge, non-present or none */
5510 return (pte_t *)pud;
5511 if (!pud_present(*pud))
5512 return NULL;
5513 /* must have a valid entry and size to go further */
5514
5515 pmd = pmd_offset(pud, addr);
5516 /* must be pmd huge, non-present or none */
5517 return (pte_t *)pmd;
5518}
5519
5520#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
5521
5522/*
5523 * These functions are overwritable if your architecture needs its own
5524 * behavior.
5525 */
5526struct page * __weak
5527follow_huge_addr(struct mm_struct *mm, unsigned long address,
5528 int write)
5529{
5530 return ERR_PTR(-EINVAL);
5531}
5532
5533struct page * __weak
5534follow_huge_pd(struct vm_area_struct *vma,
5535 unsigned long address, hugepd_t hpd, int flags, int pdshift)
5536{
5537 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
5538 return NULL;
5539}
5540
5541struct page * __weak
5542follow_huge_pmd(struct mm_struct *mm, unsigned long address,
5543 pmd_t *pmd, int flags)
5544{
5545 struct page *page = NULL;
5546 spinlock_t *ptl;
5547 pte_t pte;
5548
5549 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
5550 if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
5551 (FOLL_PIN | FOLL_GET)))
5552 return NULL;
5553
5554retry:
5555 ptl = pmd_lockptr(mm, pmd);
5556 spin_lock(ptl);
5557 /*
5558 * make sure that the address range covered by this pmd is not
5559 * unmapped from other threads.
5560 */
5561 if (!pmd_huge(*pmd))
5562 goto out;
5563 pte = huge_ptep_get((pte_t *)pmd);
5564 if (pte_present(pte)) {
5565 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
5566 /*
5567 * try_grab_page() should always succeed here, because: a) we
5568 * hold the pmd (ptl) lock, and b) we've just checked that the
5569 * huge pmd (head) page is present in the page tables. The ptl
5570 * prevents the head page and tail pages from being rearranged
5571 * in any way. So this page must be available at this point,
5572 * unless the page refcount overflowed:
5573 */
5574 if (WARN_ON_ONCE(!try_grab_page(page, flags))) {
5575 page = NULL;
5576 goto out;
5577 }
5578 } else {
5579 if (is_hugetlb_entry_migration(pte)) {
5580 spin_unlock(ptl);
5581 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
5582 goto retry;
5583 }
5584 /*
5585 * hwpoisoned entry is treated as no_page_table in
5586 * follow_page_mask().
5587 */
5588 }
5589out:
5590 spin_unlock(ptl);
5591 return page;
5592}
5593
5594struct page * __weak
5595follow_huge_pud(struct mm_struct *mm, unsigned long address,
5596 pud_t *pud, int flags)
5597{
5598 if (flags & (FOLL_GET | FOLL_PIN))
5599 return NULL;
5600
5601 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
5602}
5603
5604struct page * __weak
5605follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
5606{
5607 if (flags & (FOLL_GET | FOLL_PIN))
5608 return NULL;
5609
5610 return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
5611}
5612
5613bool isolate_huge_page(struct page *page, struct list_head *list)
5614{
5615 bool ret = true;
5616
5617 VM_BUG_ON_PAGE(!PageHead(page), page);
5618 spin_lock(&hugetlb_lock);
5619 if (!page_huge_active(page) || !get_page_unless_zero(page)) {
5620 ret = false;
5621 goto unlock;
5622 }
5623 clear_page_huge_active(page);
5624 list_move_tail(&page->lru, list);
5625unlock:
5626 spin_unlock(&hugetlb_lock);
5627 return ret;
5628}
5629
5630void putback_active_hugepage(struct page *page)
5631{
5632 VM_BUG_ON_PAGE(!PageHead(page), page);
5633 spin_lock(&hugetlb_lock);
5634 set_page_huge_active(page);
5635 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
5636 spin_unlock(&hugetlb_lock);
5637 put_page(page);
5638}
5639
5640void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
5641{
5642 struct hstate *h = page_hstate(oldpage);
5643
5644 hugetlb_cgroup_migrate(oldpage, newpage);
5645 set_page_owner_migrate_reason(newpage, reason);
5646
5647 /*
5648 * transfer temporary state of the new huge page. This is
5649 * reverse to other transitions because the newpage is going to
5650 * be final while the old one will be freed so it takes over
5651 * the temporary status.
5652 *
5653 * Also note that we have to transfer the per-node surplus state
5654 * here as well otherwise the global surplus count will not match
5655 * the per-node's.
5656 */
5657 if (PageHugeTemporary(newpage)) {
5658 int old_nid = page_to_nid(oldpage);
5659 int new_nid = page_to_nid(newpage);
5660
5661 SetPageHugeTemporary(oldpage);
5662 ClearPageHugeTemporary(newpage);
5663
5664 spin_lock(&hugetlb_lock);
5665 if (h->surplus_huge_pages_node[old_nid]) {
5666 h->surplus_huge_pages_node[old_nid]--;
5667 h->surplus_huge_pages_node[new_nid]++;
5668 }
5669 spin_unlock(&hugetlb_lock);
5670 }
5671}
5672
5673#ifdef CONFIG_CMA
5674static bool cma_reserve_called __initdata;
5675
5676static int __init cmdline_parse_hugetlb_cma(char *p)
5677{
5678 hugetlb_cma_size = memparse(p, &p);
5679 return 0;
5680}
5681
5682early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
5683
5684void __init hugetlb_cma_reserve(int order)
5685{
5686 unsigned long size, reserved, per_node;
5687 int nid;
5688
5689 cma_reserve_called = true;
5690
5691 if (!hugetlb_cma_size)
5692 return;
5693
5694 if (hugetlb_cma_size < (PAGE_SIZE << order)) {
5695 pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
5696 (PAGE_SIZE << order) / SZ_1M);
5697 return;
5698 }
5699
5700 /*
5701 * If 3 GB area is requested on a machine with 4 numa nodes,
5702 * let's allocate 1 GB on first three nodes and ignore the last one.
5703 */
5704 per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
5705 pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
5706 hugetlb_cma_size / SZ_1M, per_node / SZ_1M);
5707
5708 reserved = 0;
5709 for_each_node_state(nid, N_ONLINE) {
5710 int res;
5711 char name[20];
5712
5713 size = min(per_node, hugetlb_cma_size - reserved);
5714 size = round_up(size, PAGE_SIZE << order);
5715
5716 snprintf(name, 20, "hugetlb%d", nid);
5717 res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order,
5718 0, false, name,
5719 &hugetlb_cma[nid], nid);
5720 if (res) {
5721 pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
5722 res, nid);
5723 continue;
5724 }
5725
5726 reserved += size;
5727 pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
5728 size / SZ_1M, nid);
5729
5730 if (reserved >= hugetlb_cma_size)
5731 break;
5732 }
5733}
5734
5735void __init hugetlb_cma_check(void)
5736{
5737 if (!hugetlb_cma_size || cma_reserve_called)
5738 return;
5739
5740 pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
5741}
5742
5743#endif /* CONFIG_CMA */
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/module.h>
8#include <linux/mm.h>
9#include <linux/seq_file.h>
10#include <linux/sysctl.h>
11#include <linux/highmem.h>
12#include <linux/mmu_notifier.h>
13#include <linux/nodemask.h>
14#include <linux/pagemap.h>
15#include <linux/mempolicy.h>
16#include <linux/compiler.h>
17#include <linux/cpuset.h>
18#include <linux/mutex.h>
19#include <linux/bootmem.h>
20#include <linux/sysfs.h>
21#include <linux/slab.h>
22#include <linux/rmap.h>
23#include <linux/swap.h>
24#include <linux/swapops.h>
25#include <linux/page-isolation.h>
26#include <linux/jhash.h>
27
28#include <asm/page.h>
29#include <asm/pgtable.h>
30#include <asm/tlb.h>
31
32#include <linux/io.h>
33#include <linux/hugetlb.h>
34#include <linux/hugetlb_cgroup.h>
35#include <linux/node.h>
36#include "internal.h"
37
38const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
39unsigned long hugepages_treat_as_movable;
40
41int hugetlb_max_hstate __read_mostly;
42unsigned int default_hstate_idx;
43struct hstate hstates[HUGE_MAX_HSTATE];
44
45__initdata LIST_HEAD(huge_boot_pages);
46
47/* for command line parsing */
48static struct hstate * __initdata parsed_hstate;
49static unsigned long __initdata default_hstate_max_huge_pages;
50static unsigned long __initdata default_hstate_size;
51
52/*
53 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
54 * free_huge_pages, and surplus_huge_pages.
55 */
56DEFINE_SPINLOCK(hugetlb_lock);
57
58/*
59 * Serializes faults on the same logical page. This is used to
60 * prevent spurious OOMs when the hugepage pool is fully utilized.
61 */
62static int num_fault_mutexes;
63static struct mutex *htlb_fault_mutex_table ____cacheline_aligned_in_smp;
64
65static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
66{
67 bool free = (spool->count == 0) && (spool->used_hpages == 0);
68
69 spin_unlock(&spool->lock);
70
71 /* If no pages are used, and no other handles to the subpool
72 * remain, free the subpool the subpool remain */
73 if (free)
74 kfree(spool);
75}
76
77struct hugepage_subpool *hugepage_new_subpool(long nr_blocks)
78{
79 struct hugepage_subpool *spool;
80
81 spool = kmalloc(sizeof(*spool), GFP_KERNEL);
82 if (!spool)
83 return NULL;
84
85 spin_lock_init(&spool->lock);
86 spool->count = 1;
87 spool->max_hpages = nr_blocks;
88 spool->used_hpages = 0;
89
90 return spool;
91}
92
93void hugepage_put_subpool(struct hugepage_subpool *spool)
94{
95 spin_lock(&spool->lock);
96 BUG_ON(!spool->count);
97 spool->count--;
98 unlock_or_release_subpool(spool);
99}
100
101static int hugepage_subpool_get_pages(struct hugepage_subpool *spool,
102 long delta)
103{
104 int ret = 0;
105
106 if (!spool)
107 return 0;
108
109 spin_lock(&spool->lock);
110 if ((spool->used_hpages + delta) <= spool->max_hpages) {
111 spool->used_hpages += delta;
112 } else {
113 ret = -ENOMEM;
114 }
115 spin_unlock(&spool->lock);
116
117 return ret;
118}
119
120static void hugepage_subpool_put_pages(struct hugepage_subpool *spool,
121 long delta)
122{
123 if (!spool)
124 return;
125
126 spin_lock(&spool->lock);
127 spool->used_hpages -= delta;
128 /* If hugetlbfs_put_super couldn't free spool due to
129 * an outstanding quota reference, free it now. */
130 unlock_or_release_subpool(spool);
131}
132
133static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
134{
135 return HUGETLBFS_SB(inode->i_sb)->spool;
136}
137
138static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
139{
140 return subpool_inode(file_inode(vma->vm_file));
141}
142
143/*
144 * Region tracking -- allows tracking of reservations and instantiated pages
145 * across the pages in a mapping.
146 *
147 * The region data structures are embedded into a resv_map and
148 * protected by a resv_map's lock
149 */
150struct file_region {
151 struct list_head link;
152 long from;
153 long to;
154};
155
156static long region_add(struct resv_map *resv, long f, long t)
157{
158 struct list_head *head = &resv->regions;
159 struct file_region *rg, *nrg, *trg;
160
161 spin_lock(&resv->lock);
162 /* Locate the region we are either in or before. */
163 list_for_each_entry(rg, head, link)
164 if (f <= rg->to)
165 break;
166
167 /* Round our left edge to the current segment if it encloses us. */
168 if (f > rg->from)
169 f = rg->from;
170
171 /* Check for and consume any regions we now overlap with. */
172 nrg = rg;
173 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
174 if (&rg->link == head)
175 break;
176 if (rg->from > t)
177 break;
178
179 /* If this area reaches higher then extend our area to
180 * include it completely. If this is not the first area
181 * which we intend to reuse, free it. */
182 if (rg->to > t)
183 t = rg->to;
184 if (rg != nrg) {
185 list_del(&rg->link);
186 kfree(rg);
187 }
188 }
189 nrg->from = f;
190 nrg->to = t;
191 spin_unlock(&resv->lock);
192 return 0;
193}
194
195static long region_chg(struct resv_map *resv, long f, long t)
196{
197 struct list_head *head = &resv->regions;
198 struct file_region *rg, *nrg = NULL;
199 long chg = 0;
200
201retry:
202 spin_lock(&resv->lock);
203 /* Locate the region we are before or in. */
204 list_for_each_entry(rg, head, link)
205 if (f <= rg->to)
206 break;
207
208 /* If we are below the current region then a new region is required.
209 * Subtle, allocate a new region at the position but make it zero
210 * size such that we can guarantee to record the reservation. */
211 if (&rg->link == head || t < rg->from) {
212 if (!nrg) {
213 spin_unlock(&resv->lock);
214 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
215 if (!nrg)
216 return -ENOMEM;
217
218 nrg->from = f;
219 nrg->to = f;
220 INIT_LIST_HEAD(&nrg->link);
221 goto retry;
222 }
223
224 list_add(&nrg->link, rg->link.prev);
225 chg = t - f;
226 goto out_nrg;
227 }
228
229 /* Round our left edge to the current segment if it encloses us. */
230 if (f > rg->from)
231 f = rg->from;
232 chg = t - f;
233
234 /* Check for and consume any regions we now overlap with. */
235 list_for_each_entry(rg, rg->link.prev, link) {
236 if (&rg->link == head)
237 break;
238 if (rg->from > t)
239 goto out;
240
241 /* We overlap with this area, if it extends further than
242 * us then we must extend ourselves. Account for its
243 * existing reservation. */
244 if (rg->to > t) {
245 chg += rg->to - t;
246 t = rg->to;
247 }
248 chg -= rg->to - rg->from;
249 }
250
251out:
252 spin_unlock(&resv->lock);
253 /* We already know we raced and no longer need the new region */
254 kfree(nrg);
255 return chg;
256out_nrg:
257 spin_unlock(&resv->lock);
258 return chg;
259}
260
261static long region_truncate(struct resv_map *resv, long end)
262{
263 struct list_head *head = &resv->regions;
264 struct file_region *rg, *trg;
265 long chg = 0;
266
267 spin_lock(&resv->lock);
268 /* Locate the region we are either in or before. */
269 list_for_each_entry(rg, head, link)
270 if (end <= rg->to)
271 break;
272 if (&rg->link == head)
273 goto out;
274
275 /* If we are in the middle of a region then adjust it. */
276 if (end > rg->from) {
277 chg = rg->to - end;
278 rg->to = end;
279 rg = list_entry(rg->link.next, typeof(*rg), link);
280 }
281
282 /* Drop any remaining regions. */
283 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
284 if (&rg->link == head)
285 break;
286 chg += rg->to - rg->from;
287 list_del(&rg->link);
288 kfree(rg);
289 }
290
291out:
292 spin_unlock(&resv->lock);
293 return chg;
294}
295
296static long region_count(struct resv_map *resv, long f, long t)
297{
298 struct list_head *head = &resv->regions;
299 struct file_region *rg;
300 long chg = 0;
301
302 spin_lock(&resv->lock);
303 /* Locate each segment we overlap with, and count that overlap. */
304 list_for_each_entry(rg, head, link) {
305 long seg_from;
306 long seg_to;
307
308 if (rg->to <= f)
309 continue;
310 if (rg->from >= t)
311 break;
312
313 seg_from = max(rg->from, f);
314 seg_to = min(rg->to, t);
315
316 chg += seg_to - seg_from;
317 }
318 spin_unlock(&resv->lock);
319
320 return chg;
321}
322
323/*
324 * Convert the address within this vma to the page offset within
325 * the mapping, in pagecache page units; huge pages here.
326 */
327static pgoff_t vma_hugecache_offset(struct hstate *h,
328 struct vm_area_struct *vma, unsigned long address)
329{
330 return ((address - vma->vm_start) >> huge_page_shift(h)) +
331 (vma->vm_pgoff >> huge_page_order(h));
332}
333
334pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
335 unsigned long address)
336{
337 return vma_hugecache_offset(hstate_vma(vma), vma, address);
338}
339
340/*
341 * Return the size of the pages allocated when backing a VMA. In the majority
342 * cases this will be same size as used by the page table entries.
343 */
344unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
345{
346 struct hstate *hstate;
347
348 if (!is_vm_hugetlb_page(vma))
349 return PAGE_SIZE;
350
351 hstate = hstate_vma(vma);
352
353 return 1UL << huge_page_shift(hstate);
354}
355EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
356
357/*
358 * Return the page size being used by the MMU to back a VMA. In the majority
359 * of cases, the page size used by the kernel matches the MMU size. On
360 * architectures where it differs, an architecture-specific version of this
361 * function is required.
362 */
363#ifndef vma_mmu_pagesize
364unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
365{
366 return vma_kernel_pagesize(vma);
367}
368#endif
369
370/*
371 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
372 * bits of the reservation map pointer, which are always clear due to
373 * alignment.
374 */
375#define HPAGE_RESV_OWNER (1UL << 0)
376#define HPAGE_RESV_UNMAPPED (1UL << 1)
377#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
378
379/*
380 * These helpers are used to track how many pages are reserved for
381 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
382 * is guaranteed to have their future faults succeed.
383 *
384 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
385 * the reserve counters are updated with the hugetlb_lock held. It is safe
386 * to reset the VMA at fork() time as it is not in use yet and there is no
387 * chance of the global counters getting corrupted as a result of the values.
388 *
389 * The private mapping reservation is represented in a subtly different
390 * manner to a shared mapping. A shared mapping has a region map associated
391 * with the underlying file, this region map represents the backing file
392 * pages which have ever had a reservation assigned which this persists even
393 * after the page is instantiated. A private mapping has a region map
394 * associated with the original mmap which is attached to all VMAs which
395 * reference it, this region map represents those offsets which have consumed
396 * reservation ie. where pages have been instantiated.
397 */
398static unsigned long get_vma_private_data(struct vm_area_struct *vma)
399{
400 return (unsigned long)vma->vm_private_data;
401}
402
403static void set_vma_private_data(struct vm_area_struct *vma,
404 unsigned long value)
405{
406 vma->vm_private_data = (void *)value;
407}
408
409struct resv_map *resv_map_alloc(void)
410{
411 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
412 if (!resv_map)
413 return NULL;
414
415 kref_init(&resv_map->refs);
416 spin_lock_init(&resv_map->lock);
417 INIT_LIST_HEAD(&resv_map->regions);
418
419 return resv_map;
420}
421
422void resv_map_release(struct kref *ref)
423{
424 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
425
426 /* Clear out any active regions before we release the map. */
427 region_truncate(resv_map, 0);
428 kfree(resv_map);
429}
430
431static inline struct resv_map *inode_resv_map(struct inode *inode)
432{
433 return inode->i_mapping->private_data;
434}
435
436static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
437{
438 VM_BUG_ON(!is_vm_hugetlb_page(vma));
439 if (vma->vm_flags & VM_MAYSHARE) {
440 struct address_space *mapping = vma->vm_file->f_mapping;
441 struct inode *inode = mapping->host;
442
443 return inode_resv_map(inode);
444
445 } else {
446 return (struct resv_map *)(get_vma_private_data(vma) &
447 ~HPAGE_RESV_MASK);
448 }
449}
450
451static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
452{
453 VM_BUG_ON(!is_vm_hugetlb_page(vma));
454 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
455
456 set_vma_private_data(vma, (get_vma_private_data(vma) &
457 HPAGE_RESV_MASK) | (unsigned long)map);
458}
459
460static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
461{
462 VM_BUG_ON(!is_vm_hugetlb_page(vma));
463 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
464
465 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
466}
467
468static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
469{
470 VM_BUG_ON(!is_vm_hugetlb_page(vma));
471
472 return (get_vma_private_data(vma) & flag) != 0;
473}
474
475/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
476void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
477{
478 VM_BUG_ON(!is_vm_hugetlb_page(vma));
479 if (!(vma->vm_flags & VM_MAYSHARE))
480 vma->vm_private_data = (void *)0;
481}
482
483/* Returns true if the VMA has associated reserve pages */
484static int vma_has_reserves(struct vm_area_struct *vma, long chg)
485{
486 if (vma->vm_flags & VM_NORESERVE) {
487 /*
488 * This address is already reserved by other process(chg == 0),
489 * so, we should decrement reserved count. Without decrementing,
490 * reserve count remains after releasing inode, because this
491 * allocated page will go into page cache and is regarded as
492 * coming from reserved pool in releasing step. Currently, we
493 * don't have any other solution to deal with this situation
494 * properly, so add work-around here.
495 */
496 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
497 return 1;
498 else
499 return 0;
500 }
501
502 /* Shared mappings always use reserves */
503 if (vma->vm_flags & VM_MAYSHARE)
504 return 1;
505
506 /*
507 * Only the process that called mmap() has reserves for
508 * private mappings.
509 */
510 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
511 return 1;
512
513 return 0;
514}
515
516static void enqueue_huge_page(struct hstate *h, struct page *page)
517{
518 int nid = page_to_nid(page);
519 list_move(&page->lru, &h->hugepage_freelists[nid]);
520 h->free_huge_pages++;
521 h->free_huge_pages_node[nid]++;
522}
523
524static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
525{
526 struct page *page;
527
528 list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
529 if (!is_migrate_isolate_page(page))
530 break;
531 /*
532 * if 'non-isolated free hugepage' not found on the list,
533 * the allocation fails.
534 */
535 if (&h->hugepage_freelists[nid] == &page->lru)
536 return NULL;
537 list_move(&page->lru, &h->hugepage_activelist);
538 set_page_refcounted(page);
539 h->free_huge_pages--;
540 h->free_huge_pages_node[nid]--;
541 return page;
542}
543
544/* Movability of hugepages depends on migration support. */
545static inline gfp_t htlb_alloc_mask(struct hstate *h)
546{
547 if (hugepages_treat_as_movable || hugepage_migration_support(h))
548 return GFP_HIGHUSER_MOVABLE;
549 else
550 return GFP_HIGHUSER;
551}
552
553static struct page *dequeue_huge_page_vma(struct hstate *h,
554 struct vm_area_struct *vma,
555 unsigned long address, int avoid_reserve,
556 long chg)
557{
558 struct page *page = NULL;
559 struct mempolicy *mpol;
560 nodemask_t *nodemask;
561 struct zonelist *zonelist;
562 struct zone *zone;
563 struct zoneref *z;
564 unsigned int cpuset_mems_cookie;
565
566 /*
567 * A child process with MAP_PRIVATE mappings created by their parent
568 * have no page reserves. This check ensures that reservations are
569 * not "stolen". The child may still get SIGKILLed
570 */
571 if (!vma_has_reserves(vma, chg) &&
572 h->free_huge_pages - h->resv_huge_pages == 0)
573 goto err;
574
575 /* If reserves cannot be used, ensure enough pages are in the pool */
576 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
577 goto err;
578
579retry_cpuset:
580 cpuset_mems_cookie = read_mems_allowed_begin();
581 zonelist = huge_zonelist(vma, address,
582 htlb_alloc_mask(h), &mpol, &nodemask);
583
584 for_each_zone_zonelist_nodemask(zone, z, zonelist,
585 MAX_NR_ZONES - 1, nodemask) {
586 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask(h))) {
587 page = dequeue_huge_page_node(h, zone_to_nid(zone));
588 if (page) {
589 if (avoid_reserve)
590 break;
591 if (!vma_has_reserves(vma, chg))
592 break;
593
594 SetPagePrivate(page);
595 h->resv_huge_pages--;
596 break;
597 }
598 }
599 }
600
601 mpol_cond_put(mpol);
602 if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
603 goto retry_cpuset;
604 return page;
605
606err:
607 return NULL;
608}
609
610static void update_and_free_page(struct hstate *h, struct page *page)
611{
612 int i;
613
614 VM_BUG_ON(h->order >= MAX_ORDER);
615
616 h->nr_huge_pages--;
617 h->nr_huge_pages_node[page_to_nid(page)]--;
618 for (i = 0; i < pages_per_huge_page(h); i++) {
619 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
620 1 << PG_referenced | 1 << PG_dirty |
621 1 << PG_active | 1 << PG_reserved |
622 1 << PG_private | 1 << PG_writeback);
623 }
624 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
625 set_compound_page_dtor(page, NULL);
626 set_page_refcounted(page);
627 arch_release_hugepage(page);
628 __free_pages(page, huge_page_order(h));
629}
630
631struct hstate *size_to_hstate(unsigned long size)
632{
633 struct hstate *h;
634
635 for_each_hstate(h) {
636 if (huge_page_size(h) == size)
637 return h;
638 }
639 return NULL;
640}
641
642static void free_huge_page(struct page *page)
643{
644 /*
645 * Can't pass hstate in here because it is called from the
646 * compound page destructor.
647 */
648 struct hstate *h = page_hstate(page);
649 int nid = page_to_nid(page);
650 struct hugepage_subpool *spool =
651 (struct hugepage_subpool *)page_private(page);
652 bool restore_reserve;
653
654 set_page_private(page, 0);
655 page->mapping = NULL;
656 BUG_ON(page_count(page));
657 BUG_ON(page_mapcount(page));
658 restore_reserve = PagePrivate(page);
659 ClearPagePrivate(page);
660
661 spin_lock(&hugetlb_lock);
662 hugetlb_cgroup_uncharge_page(hstate_index(h),
663 pages_per_huge_page(h), page);
664 if (restore_reserve)
665 h->resv_huge_pages++;
666
667 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
668 /* remove the page from active list */
669 list_del(&page->lru);
670 update_and_free_page(h, page);
671 h->surplus_huge_pages--;
672 h->surplus_huge_pages_node[nid]--;
673 } else {
674 arch_clear_hugepage_flags(page);
675 enqueue_huge_page(h, page);
676 }
677 spin_unlock(&hugetlb_lock);
678 hugepage_subpool_put_pages(spool, 1);
679}
680
681static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
682{
683 INIT_LIST_HEAD(&page->lru);
684 set_compound_page_dtor(page, free_huge_page);
685 spin_lock(&hugetlb_lock);
686 set_hugetlb_cgroup(page, NULL);
687 h->nr_huge_pages++;
688 h->nr_huge_pages_node[nid]++;
689 spin_unlock(&hugetlb_lock);
690 put_page(page); /* free it into the hugepage allocator */
691}
692
693static void __init prep_compound_gigantic_page(struct page *page,
694 unsigned long order)
695{
696 int i;
697 int nr_pages = 1 << order;
698 struct page *p = page + 1;
699
700 /* we rely on prep_new_huge_page to set the destructor */
701 set_compound_order(page, order);
702 __SetPageHead(page);
703 __ClearPageReserved(page);
704 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
705 __SetPageTail(p);
706 /*
707 * For gigantic hugepages allocated through bootmem at
708 * boot, it's safer to be consistent with the not-gigantic
709 * hugepages and clear the PG_reserved bit from all tail pages
710 * too. Otherwse drivers using get_user_pages() to access tail
711 * pages may get the reference counting wrong if they see
712 * PG_reserved set on a tail page (despite the head page not
713 * having PG_reserved set). Enforcing this consistency between
714 * head and tail pages allows drivers to optimize away a check
715 * on the head page when they need know if put_page() is needed
716 * after get_user_pages().
717 */
718 __ClearPageReserved(p);
719 set_page_count(p, 0);
720 p->first_page = page;
721 }
722}
723
724/*
725 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
726 * transparent huge pages. See the PageTransHuge() documentation for more
727 * details.
728 */
729int PageHuge(struct page *page)
730{
731 if (!PageCompound(page))
732 return 0;
733
734 page = compound_head(page);
735 return get_compound_page_dtor(page) == free_huge_page;
736}
737EXPORT_SYMBOL_GPL(PageHuge);
738
739/*
740 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
741 * normal or transparent huge pages.
742 */
743int PageHeadHuge(struct page *page_head)
744{
745 if (!PageHead(page_head))
746 return 0;
747
748 return get_compound_page_dtor(page_head) == free_huge_page;
749}
750
751pgoff_t __basepage_index(struct page *page)
752{
753 struct page *page_head = compound_head(page);
754 pgoff_t index = page_index(page_head);
755 unsigned long compound_idx;
756
757 if (!PageHuge(page_head))
758 return page_index(page);
759
760 if (compound_order(page_head) >= MAX_ORDER)
761 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
762 else
763 compound_idx = page - page_head;
764
765 return (index << compound_order(page_head)) + compound_idx;
766}
767
768static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
769{
770 struct page *page;
771
772 if (h->order >= MAX_ORDER)
773 return NULL;
774
775 page = alloc_pages_exact_node(nid,
776 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
777 __GFP_REPEAT|__GFP_NOWARN,
778 huge_page_order(h));
779 if (page) {
780 if (arch_prepare_hugepage(page)) {
781 __free_pages(page, huge_page_order(h));
782 return NULL;
783 }
784 prep_new_huge_page(h, page, nid);
785 }
786
787 return page;
788}
789
790/*
791 * common helper functions for hstate_next_node_to_{alloc|free}.
792 * We may have allocated or freed a huge page based on a different
793 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
794 * be outside of *nodes_allowed. Ensure that we use an allowed
795 * node for alloc or free.
796 */
797static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
798{
799 nid = next_node(nid, *nodes_allowed);
800 if (nid == MAX_NUMNODES)
801 nid = first_node(*nodes_allowed);
802 VM_BUG_ON(nid >= MAX_NUMNODES);
803
804 return nid;
805}
806
807static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
808{
809 if (!node_isset(nid, *nodes_allowed))
810 nid = next_node_allowed(nid, nodes_allowed);
811 return nid;
812}
813
814/*
815 * returns the previously saved node ["this node"] from which to
816 * allocate a persistent huge page for the pool and advance the
817 * next node from which to allocate, handling wrap at end of node
818 * mask.
819 */
820static int hstate_next_node_to_alloc(struct hstate *h,
821 nodemask_t *nodes_allowed)
822{
823 int nid;
824
825 VM_BUG_ON(!nodes_allowed);
826
827 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
828 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
829
830 return nid;
831}
832
833/*
834 * helper for free_pool_huge_page() - return the previously saved
835 * node ["this node"] from which to free a huge page. Advance the
836 * next node id whether or not we find a free huge page to free so
837 * that the next attempt to free addresses the next node.
838 */
839static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
840{
841 int nid;
842
843 VM_BUG_ON(!nodes_allowed);
844
845 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
846 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
847
848 return nid;
849}
850
851#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
852 for (nr_nodes = nodes_weight(*mask); \
853 nr_nodes > 0 && \
854 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
855 nr_nodes--)
856
857#define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
858 for (nr_nodes = nodes_weight(*mask); \
859 nr_nodes > 0 && \
860 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
861 nr_nodes--)
862
863static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
864{
865 struct page *page;
866 int nr_nodes, node;
867 int ret = 0;
868
869 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
870 page = alloc_fresh_huge_page_node(h, node);
871 if (page) {
872 ret = 1;
873 break;
874 }
875 }
876
877 if (ret)
878 count_vm_event(HTLB_BUDDY_PGALLOC);
879 else
880 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
881
882 return ret;
883}
884
885/*
886 * Free huge page from pool from next node to free.
887 * Attempt to keep persistent huge pages more or less
888 * balanced over allowed nodes.
889 * Called with hugetlb_lock locked.
890 */
891static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
892 bool acct_surplus)
893{
894 int nr_nodes, node;
895 int ret = 0;
896
897 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
898 /*
899 * If we're returning unused surplus pages, only examine
900 * nodes with surplus pages.
901 */
902 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
903 !list_empty(&h->hugepage_freelists[node])) {
904 struct page *page =
905 list_entry(h->hugepage_freelists[node].next,
906 struct page, lru);
907 list_del(&page->lru);
908 h->free_huge_pages--;
909 h->free_huge_pages_node[node]--;
910 if (acct_surplus) {
911 h->surplus_huge_pages--;
912 h->surplus_huge_pages_node[node]--;
913 }
914 update_and_free_page(h, page);
915 ret = 1;
916 break;
917 }
918 }
919
920 return ret;
921}
922
923/*
924 * Dissolve a given free hugepage into free buddy pages. This function does
925 * nothing for in-use (including surplus) hugepages.
926 */
927static void dissolve_free_huge_page(struct page *page)
928{
929 spin_lock(&hugetlb_lock);
930 if (PageHuge(page) && !page_count(page)) {
931 struct hstate *h = page_hstate(page);
932 int nid = page_to_nid(page);
933 list_del(&page->lru);
934 h->free_huge_pages--;
935 h->free_huge_pages_node[nid]--;
936 update_and_free_page(h, page);
937 }
938 spin_unlock(&hugetlb_lock);
939}
940
941/*
942 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
943 * make specified memory blocks removable from the system.
944 * Note that start_pfn should aligned with (minimum) hugepage size.
945 */
946void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
947{
948 unsigned int order = 8 * sizeof(void *);
949 unsigned long pfn;
950 struct hstate *h;
951
952 /* Set scan step to minimum hugepage size */
953 for_each_hstate(h)
954 if (order > huge_page_order(h))
955 order = huge_page_order(h);
956 VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order));
957 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order)
958 dissolve_free_huge_page(pfn_to_page(pfn));
959}
960
961static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
962{
963 struct page *page;
964 unsigned int r_nid;
965
966 if (h->order >= MAX_ORDER)
967 return NULL;
968
969 /*
970 * Assume we will successfully allocate the surplus page to
971 * prevent racing processes from causing the surplus to exceed
972 * overcommit
973 *
974 * This however introduces a different race, where a process B
975 * tries to grow the static hugepage pool while alloc_pages() is
976 * called by process A. B will only examine the per-node
977 * counters in determining if surplus huge pages can be
978 * converted to normal huge pages in adjust_pool_surplus(). A
979 * won't be able to increment the per-node counter, until the
980 * lock is dropped by B, but B doesn't drop hugetlb_lock until
981 * no more huge pages can be converted from surplus to normal
982 * state (and doesn't try to convert again). Thus, we have a
983 * case where a surplus huge page exists, the pool is grown, and
984 * the surplus huge page still exists after, even though it
985 * should just have been converted to a normal huge page. This
986 * does not leak memory, though, as the hugepage will be freed
987 * once it is out of use. It also does not allow the counters to
988 * go out of whack in adjust_pool_surplus() as we don't modify
989 * the node values until we've gotten the hugepage and only the
990 * per-node value is checked there.
991 */
992 spin_lock(&hugetlb_lock);
993 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
994 spin_unlock(&hugetlb_lock);
995 return NULL;
996 } else {
997 h->nr_huge_pages++;
998 h->surplus_huge_pages++;
999 }
1000 spin_unlock(&hugetlb_lock);
1001
1002 if (nid == NUMA_NO_NODE)
1003 page = alloc_pages(htlb_alloc_mask(h)|__GFP_COMP|
1004 __GFP_REPEAT|__GFP_NOWARN,
1005 huge_page_order(h));
1006 else
1007 page = alloc_pages_exact_node(nid,
1008 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
1009 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
1010
1011 if (page && arch_prepare_hugepage(page)) {
1012 __free_pages(page, huge_page_order(h));
1013 page = NULL;
1014 }
1015
1016 spin_lock(&hugetlb_lock);
1017 if (page) {
1018 INIT_LIST_HEAD(&page->lru);
1019 r_nid = page_to_nid(page);
1020 set_compound_page_dtor(page, free_huge_page);
1021 set_hugetlb_cgroup(page, NULL);
1022 /*
1023 * We incremented the global counters already
1024 */
1025 h->nr_huge_pages_node[r_nid]++;
1026 h->surplus_huge_pages_node[r_nid]++;
1027 __count_vm_event(HTLB_BUDDY_PGALLOC);
1028 } else {
1029 h->nr_huge_pages--;
1030 h->surplus_huge_pages--;
1031 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1032 }
1033 spin_unlock(&hugetlb_lock);
1034
1035 return page;
1036}
1037
1038/*
1039 * This allocation function is useful in the context where vma is irrelevant.
1040 * E.g. soft-offlining uses this function because it only cares physical
1041 * address of error page.
1042 */
1043struct page *alloc_huge_page_node(struct hstate *h, int nid)
1044{
1045 struct page *page = NULL;
1046
1047 spin_lock(&hugetlb_lock);
1048 if (h->free_huge_pages - h->resv_huge_pages > 0)
1049 page = dequeue_huge_page_node(h, nid);
1050 spin_unlock(&hugetlb_lock);
1051
1052 if (!page)
1053 page = alloc_buddy_huge_page(h, nid);
1054
1055 return page;
1056}
1057
1058/*
1059 * Increase the hugetlb pool such that it can accommodate a reservation
1060 * of size 'delta'.
1061 */
1062static int gather_surplus_pages(struct hstate *h, int delta)
1063{
1064 struct list_head surplus_list;
1065 struct page *page, *tmp;
1066 int ret, i;
1067 int needed, allocated;
1068 bool alloc_ok = true;
1069
1070 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1071 if (needed <= 0) {
1072 h->resv_huge_pages += delta;
1073 return 0;
1074 }
1075
1076 allocated = 0;
1077 INIT_LIST_HEAD(&surplus_list);
1078
1079 ret = -ENOMEM;
1080retry:
1081 spin_unlock(&hugetlb_lock);
1082 for (i = 0; i < needed; i++) {
1083 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1084 if (!page) {
1085 alloc_ok = false;
1086 break;
1087 }
1088 list_add(&page->lru, &surplus_list);
1089 }
1090 allocated += i;
1091
1092 /*
1093 * After retaking hugetlb_lock, we need to recalculate 'needed'
1094 * because either resv_huge_pages or free_huge_pages may have changed.
1095 */
1096 spin_lock(&hugetlb_lock);
1097 needed = (h->resv_huge_pages + delta) -
1098 (h->free_huge_pages + allocated);
1099 if (needed > 0) {
1100 if (alloc_ok)
1101 goto retry;
1102 /*
1103 * We were not able to allocate enough pages to
1104 * satisfy the entire reservation so we free what
1105 * we've allocated so far.
1106 */
1107 goto free;
1108 }
1109 /*
1110 * The surplus_list now contains _at_least_ the number of extra pages
1111 * needed to accommodate the reservation. Add the appropriate number
1112 * of pages to the hugetlb pool and free the extras back to the buddy
1113 * allocator. Commit the entire reservation here to prevent another
1114 * process from stealing the pages as they are added to the pool but
1115 * before they are reserved.
1116 */
1117 needed += allocated;
1118 h->resv_huge_pages += delta;
1119 ret = 0;
1120
1121 /* Free the needed pages to the hugetlb pool */
1122 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1123 if ((--needed) < 0)
1124 break;
1125 /*
1126 * This page is now managed by the hugetlb allocator and has
1127 * no users -- drop the buddy allocator's reference.
1128 */
1129 put_page_testzero(page);
1130 VM_BUG_ON_PAGE(page_count(page), page);
1131 enqueue_huge_page(h, page);
1132 }
1133free:
1134 spin_unlock(&hugetlb_lock);
1135
1136 /* Free unnecessary surplus pages to the buddy allocator */
1137 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
1138 put_page(page);
1139 spin_lock(&hugetlb_lock);
1140
1141 return ret;
1142}
1143
1144/*
1145 * When releasing a hugetlb pool reservation, any surplus pages that were
1146 * allocated to satisfy the reservation must be explicitly freed if they were
1147 * never used.
1148 * Called with hugetlb_lock held.
1149 */
1150static void return_unused_surplus_pages(struct hstate *h,
1151 unsigned long unused_resv_pages)
1152{
1153 unsigned long nr_pages;
1154
1155 /* Uncommit the reservation */
1156 h->resv_huge_pages -= unused_resv_pages;
1157
1158 /* Cannot return gigantic pages currently */
1159 if (h->order >= MAX_ORDER)
1160 return;
1161
1162 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1163
1164 /*
1165 * We want to release as many surplus pages as possible, spread
1166 * evenly across all nodes with memory. Iterate across these nodes
1167 * until we can no longer free unreserved surplus pages. This occurs
1168 * when the nodes with surplus pages have no free pages.
1169 * free_pool_huge_page() will balance the the freed pages across the
1170 * on-line nodes with memory and will handle the hstate accounting.
1171 */
1172 while (nr_pages--) {
1173 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1174 break;
1175 cond_resched_lock(&hugetlb_lock);
1176 }
1177}
1178
1179/*
1180 * Determine if the huge page at addr within the vma has an associated
1181 * reservation. Where it does not we will need to logically increase
1182 * reservation and actually increase subpool usage before an allocation
1183 * can occur. Where any new reservation would be required the
1184 * reservation change is prepared, but not committed. Once the page
1185 * has been allocated from the subpool and instantiated the change should
1186 * be committed via vma_commit_reservation. No action is required on
1187 * failure.
1188 */
1189static long vma_needs_reservation(struct hstate *h,
1190 struct vm_area_struct *vma, unsigned long addr)
1191{
1192 struct resv_map *resv;
1193 pgoff_t idx;
1194 long chg;
1195
1196 resv = vma_resv_map(vma);
1197 if (!resv)
1198 return 1;
1199
1200 idx = vma_hugecache_offset(h, vma, addr);
1201 chg = region_chg(resv, idx, idx + 1);
1202
1203 if (vma->vm_flags & VM_MAYSHARE)
1204 return chg;
1205 else
1206 return chg < 0 ? chg : 0;
1207}
1208static void vma_commit_reservation(struct hstate *h,
1209 struct vm_area_struct *vma, unsigned long addr)
1210{
1211 struct resv_map *resv;
1212 pgoff_t idx;
1213
1214 resv = vma_resv_map(vma);
1215 if (!resv)
1216 return;
1217
1218 idx = vma_hugecache_offset(h, vma, addr);
1219 region_add(resv, idx, idx + 1);
1220}
1221
1222static struct page *alloc_huge_page(struct vm_area_struct *vma,
1223 unsigned long addr, int avoid_reserve)
1224{
1225 struct hugepage_subpool *spool = subpool_vma(vma);
1226 struct hstate *h = hstate_vma(vma);
1227 struct page *page;
1228 long chg;
1229 int ret, idx;
1230 struct hugetlb_cgroup *h_cg;
1231
1232 idx = hstate_index(h);
1233 /*
1234 * Processes that did not create the mapping will have no
1235 * reserves and will not have accounted against subpool
1236 * limit. Check that the subpool limit can be made before
1237 * satisfying the allocation MAP_NORESERVE mappings may also
1238 * need pages and subpool limit allocated allocated if no reserve
1239 * mapping overlaps.
1240 */
1241 chg = vma_needs_reservation(h, vma, addr);
1242 if (chg < 0)
1243 return ERR_PTR(-ENOMEM);
1244 if (chg || avoid_reserve)
1245 if (hugepage_subpool_get_pages(spool, 1))
1246 return ERR_PTR(-ENOSPC);
1247
1248 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
1249 if (ret) {
1250 if (chg || avoid_reserve)
1251 hugepage_subpool_put_pages(spool, 1);
1252 return ERR_PTR(-ENOSPC);
1253 }
1254 spin_lock(&hugetlb_lock);
1255 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg);
1256 if (!page) {
1257 spin_unlock(&hugetlb_lock);
1258 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1259 if (!page) {
1260 hugetlb_cgroup_uncharge_cgroup(idx,
1261 pages_per_huge_page(h),
1262 h_cg);
1263 if (chg || avoid_reserve)
1264 hugepage_subpool_put_pages(spool, 1);
1265 return ERR_PTR(-ENOSPC);
1266 }
1267 spin_lock(&hugetlb_lock);
1268 list_move(&page->lru, &h->hugepage_activelist);
1269 /* Fall through */
1270 }
1271 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
1272 spin_unlock(&hugetlb_lock);
1273
1274 set_page_private(page, (unsigned long)spool);
1275
1276 vma_commit_reservation(h, vma, addr);
1277 return page;
1278}
1279
1280/*
1281 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1282 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1283 * where no ERR_VALUE is expected to be returned.
1284 */
1285struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
1286 unsigned long addr, int avoid_reserve)
1287{
1288 struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
1289 if (IS_ERR(page))
1290 page = NULL;
1291 return page;
1292}
1293
1294int __weak alloc_bootmem_huge_page(struct hstate *h)
1295{
1296 struct huge_bootmem_page *m;
1297 int nr_nodes, node;
1298
1299 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
1300 void *addr;
1301
1302 addr = memblock_virt_alloc_try_nid_nopanic(
1303 huge_page_size(h), huge_page_size(h),
1304 0, BOOTMEM_ALLOC_ACCESSIBLE, node);
1305 if (addr) {
1306 /*
1307 * Use the beginning of the huge page to store the
1308 * huge_bootmem_page struct (until gather_bootmem
1309 * puts them into the mem_map).
1310 */
1311 m = addr;
1312 goto found;
1313 }
1314 }
1315 return 0;
1316
1317found:
1318 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
1319 /* Put them into a private list first because mem_map is not up yet */
1320 list_add(&m->list, &huge_boot_pages);
1321 m->hstate = h;
1322 return 1;
1323}
1324
1325static void __init prep_compound_huge_page(struct page *page, int order)
1326{
1327 if (unlikely(order > (MAX_ORDER - 1)))
1328 prep_compound_gigantic_page(page, order);
1329 else
1330 prep_compound_page(page, order);
1331}
1332
1333/* Put bootmem huge pages into the standard lists after mem_map is up */
1334static void __init gather_bootmem_prealloc(void)
1335{
1336 struct huge_bootmem_page *m;
1337
1338 list_for_each_entry(m, &huge_boot_pages, list) {
1339 struct hstate *h = m->hstate;
1340 struct page *page;
1341
1342#ifdef CONFIG_HIGHMEM
1343 page = pfn_to_page(m->phys >> PAGE_SHIFT);
1344 memblock_free_late(__pa(m),
1345 sizeof(struct huge_bootmem_page));
1346#else
1347 page = virt_to_page(m);
1348#endif
1349 WARN_ON(page_count(page) != 1);
1350 prep_compound_huge_page(page, h->order);
1351 WARN_ON(PageReserved(page));
1352 prep_new_huge_page(h, page, page_to_nid(page));
1353 /*
1354 * If we had gigantic hugepages allocated at boot time, we need
1355 * to restore the 'stolen' pages to totalram_pages in order to
1356 * fix confusing memory reports from free(1) and another
1357 * side-effects, like CommitLimit going negative.
1358 */
1359 if (h->order > (MAX_ORDER - 1))
1360 adjust_managed_page_count(page, 1 << h->order);
1361 }
1362}
1363
1364static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
1365{
1366 unsigned long i;
1367
1368 for (i = 0; i < h->max_huge_pages; ++i) {
1369 if (h->order >= MAX_ORDER) {
1370 if (!alloc_bootmem_huge_page(h))
1371 break;
1372 } else if (!alloc_fresh_huge_page(h,
1373 &node_states[N_MEMORY]))
1374 break;
1375 }
1376 h->max_huge_pages = i;
1377}
1378
1379static void __init hugetlb_init_hstates(void)
1380{
1381 struct hstate *h;
1382
1383 for_each_hstate(h) {
1384 /* oversize hugepages were init'ed in early boot */
1385 if (h->order < MAX_ORDER)
1386 hugetlb_hstate_alloc_pages(h);
1387 }
1388}
1389
1390static char * __init memfmt(char *buf, unsigned long n)
1391{
1392 if (n >= (1UL << 30))
1393 sprintf(buf, "%lu GB", n >> 30);
1394 else if (n >= (1UL << 20))
1395 sprintf(buf, "%lu MB", n >> 20);
1396 else
1397 sprintf(buf, "%lu KB", n >> 10);
1398 return buf;
1399}
1400
1401static void __init report_hugepages(void)
1402{
1403 struct hstate *h;
1404
1405 for_each_hstate(h) {
1406 char buf[32];
1407 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1408 memfmt(buf, huge_page_size(h)),
1409 h->free_huge_pages);
1410 }
1411}
1412
1413#ifdef CONFIG_HIGHMEM
1414static void try_to_free_low(struct hstate *h, unsigned long count,
1415 nodemask_t *nodes_allowed)
1416{
1417 int i;
1418
1419 if (h->order >= MAX_ORDER)
1420 return;
1421
1422 for_each_node_mask(i, *nodes_allowed) {
1423 struct page *page, *next;
1424 struct list_head *freel = &h->hugepage_freelists[i];
1425 list_for_each_entry_safe(page, next, freel, lru) {
1426 if (count >= h->nr_huge_pages)
1427 return;
1428 if (PageHighMem(page))
1429 continue;
1430 list_del(&page->lru);
1431 update_and_free_page(h, page);
1432 h->free_huge_pages--;
1433 h->free_huge_pages_node[page_to_nid(page)]--;
1434 }
1435 }
1436}
1437#else
1438static inline void try_to_free_low(struct hstate *h, unsigned long count,
1439 nodemask_t *nodes_allowed)
1440{
1441}
1442#endif
1443
1444/*
1445 * Increment or decrement surplus_huge_pages. Keep node-specific counters
1446 * balanced by operating on them in a round-robin fashion.
1447 * Returns 1 if an adjustment was made.
1448 */
1449static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1450 int delta)
1451{
1452 int nr_nodes, node;
1453
1454 VM_BUG_ON(delta != -1 && delta != 1);
1455
1456 if (delta < 0) {
1457 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1458 if (h->surplus_huge_pages_node[node])
1459 goto found;
1460 }
1461 } else {
1462 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1463 if (h->surplus_huge_pages_node[node] <
1464 h->nr_huge_pages_node[node])
1465 goto found;
1466 }
1467 }
1468 return 0;
1469
1470found:
1471 h->surplus_huge_pages += delta;
1472 h->surplus_huge_pages_node[node] += delta;
1473 return 1;
1474}
1475
1476#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1477static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1478 nodemask_t *nodes_allowed)
1479{
1480 unsigned long min_count, ret;
1481
1482 if (h->order >= MAX_ORDER)
1483 return h->max_huge_pages;
1484
1485 /*
1486 * Increase the pool size
1487 * First take pages out of surplus state. Then make up the
1488 * remaining difference by allocating fresh huge pages.
1489 *
1490 * We might race with alloc_buddy_huge_page() here and be unable
1491 * to convert a surplus huge page to a normal huge page. That is
1492 * not critical, though, it just means the overall size of the
1493 * pool might be one hugepage larger than it needs to be, but
1494 * within all the constraints specified by the sysctls.
1495 */
1496 spin_lock(&hugetlb_lock);
1497 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1498 if (!adjust_pool_surplus(h, nodes_allowed, -1))
1499 break;
1500 }
1501
1502 while (count > persistent_huge_pages(h)) {
1503 /*
1504 * If this allocation races such that we no longer need the
1505 * page, free_huge_page will handle it by freeing the page
1506 * and reducing the surplus.
1507 */
1508 spin_unlock(&hugetlb_lock);
1509 ret = alloc_fresh_huge_page(h, nodes_allowed);
1510 spin_lock(&hugetlb_lock);
1511 if (!ret)
1512 goto out;
1513
1514 /* Bail for signals. Probably ctrl-c from user */
1515 if (signal_pending(current))
1516 goto out;
1517 }
1518
1519 /*
1520 * Decrease the pool size
1521 * First return free pages to the buddy allocator (being careful
1522 * to keep enough around to satisfy reservations). Then place
1523 * pages into surplus state as needed so the pool will shrink
1524 * to the desired size as pages become free.
1525 *
1526 * By placing pages into the surplus state independent of the
1527 * overcommit value, we are allowing the surplus pool size to
1528 * exceed overcommit. There are few sane options here. Since
1529 * alloc_buddy_huge_page() is checking the global counter,
1530 * though, we'll note that we're not allowed to exceed surplus
1531 * and won't grow the pool anywhere else. Not until one of the
1532 * sysctls are changed, or the surplus pages go out of use.
1533 */
1534 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1535 min_count = max(count, min_count);
1536 try_to_free_low(h, min_count, nodes_allowed);
1537 while (min_count < persistent_huge_pages(h)) {
1538 if (!free_pool_huge_page(h, nodes_allowed, 0))
1539 break;
1540 cond_resched_lock(&hugetlb_lock);
1541 }
1542 while (count < persistent_huge_pages(h)) {
1543 if (!adjust_pool_surplus(h, nodes_allowed, 1))
1544 break;
1545 }
1546out:
1547 ret = persistent_huge_pages(h);
1548 spin_unlock(&hugetlb_lock);
1549 return ret;
1550}
1551
1552#define HSTATE_ATTR_RO(_name) \
1553 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1554
1555#define HSTATE_ATTR(_name) \
1556 static struct kobj_attribute _name##_attr = \
1557 __ATTR(_name, 0644, _name##_show, _name##_store)
1558
1559static struct kobject *hugepages_kobj;
1560static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1561
1562static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1563
1564static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1565{
1566 int i;
1567
1568 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1569 if (hstate_kobjs[i] == kobj) {
1570 if (nidp)
1571 *nidp = NUMA_NO_NODE;
1572 return &hstates[i];
1573 }
1574
1575 return kobj_to_node_hstate(kobj, nidp);
1576}
1577
1578static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1579 struct kobj_attribute *attr, char *buf)
1580{
1581 struct hstate *h;
1582 unsigned long nr_huge_pages;
1583 int nid;
1584
1585 h = kobj_to_hstate(kobj, &nid);
1586 if (nid == NUMA_NO_NODE)
1587 nr_huge_pages = h->nr_huge_pages;
1588 else
1589 nr_huge_pages = h->nr_huge_pages_node[nid];
1590
1591 return sprintf(buf, "%lu\n", nr_huge_pages);
1592}
1593
1594static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1595 struct kobject *kobj, struct kobj_attribute *attr,
1596 const char *buf, size_t len)
1597{
1598 int err;
1599 int nid;
1600 unsigned long count;
1601 struct hstate *h;
1602 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1603
1604 err = kstrtoul(buf, 10, &count);
1605 if (err)
1606 goto out;
1607
1608 h = kobj_to_hstate(kobj, &nid);
1609 if (h->order >= MAX_ORDER) {
1610 err = -EINVAL;
1611 goto out;
1612 }
1613
1614 if (nid == NUMA_NO_NODE) {
1615 /*
1616 * global hstate attribute
1617 */
1618 if (!(obey_mempolicy &&
1619 init_nodemask_of_mempolicy(nodes_allowed))) {
1620 NODEMASK_FREE(nodes_allowed);
1621 nodes_allowed = &node_states[N_MEMORY];
1622 }
1623 } else if (nodes_allowed) {
1624 /*
1625 * per node hstate attribute: adjust count to global,
1626 * but restrict alloc/free to the specified node.
1627 */
1628 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1629 init_nodemask_of_node(nodes_allowed, nid);
1630 } else
1631 nodes_allowed = &node_states[N_MEMORY];
1632
1633 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1634
1635 if (nodes_allowed != &node_states[N_MEMORY])
1636 NODEMASK_FREE(nodes_allowed);
1637
1638 return len;
1639out:
1640 NODEMASK_FREE(nodes_allowed);
1641 return err;
1642}
1643
1644static ssize_t nr_hugepages_show(struct kobject *kobj,
1645 struct kobj_attribute *attr, char *buf)
1646{
1647 return nr_hugepages_show_common(kobj, attr, buf);
1648}
1649
1650static ssize_t nr_hugepages_store(struct kobject *kobj,
1651 struct kobj_attribute *attr, const char *buf, size_t len)
1652{
1653 return nr_hugepages_store_common(false, kobj, attr, buf, len);
1654}
1655HSTATE_ATTR(nr_hugepages);
1656
1657#ifdef CONFIG_NUMA
1658
1659/*
1660 * hstate attribute for optionally mempolicy-based constraint on persistent
1661 * huge page alloc/free.
1662 */
1663static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1664 struct kobj_attribute *attr, char *buf)
1665{
1666 return nr_hugepages_show_common(kobj, attr, buf);
1667}
1668
1669static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1670 struct kobj_attribute *attr, const char *buf, size_t len)
1671{
1672 return nr_hugepages_store_common(true, kobj, attr, buf, len);
1673}
1674HSTATE_ATTR(nr_hugepages_mempolicy);
1675#endif
1676
1677
1678static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1679 struct kobj_attribute *attr, char *buf)
1680{
1681 struct hstate *h = kobj_to_hstate(kobj, NULL);
1682 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1683}
1684
1685static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1686 struct kobj_attribute *attr, const char *buf, size_t count)
1687{
1688 int err;
1689 unsigned long input;
1690 struct hstate *h = kobj_to_hstate(kobj, NULL);
1691
1692 if (h->order >= MAX_ORDER)
1693 return -EINVAL;
1694
1695 err = kstrtoul(buf, 10, &input);
1696 if (err)
1697 return err;
1698
1699 spin_lock(&hugetlb_lock);
1700 h->nr_overcommit_huge_pages = input;
1701 spin_unlock(&hugetlb_lock);
1702
1703 return count;
1704}
1705HSTATE_ATTR(nr_overcommit_hugepages);
1706
1707static ssize_t free_hugepages_show(struct kobject *kobj,
1708 struct kobj_attribute *attr, char *buf)
1709{
1710 struct hstate *h;
1711 unsigned long free_huge_pages;
1712 int nid;
1713
1714 h = kobj_to_hstate(kobj, &nid);
1715 if (nid == NUMA_NO_NODE)
1716 free_huge_pages = h->free_huge_pages;
1717 else
1718 free_huge_pages = h->free_huge_pages_node[nid];
1719
1720 return sprintf(buf, "%lu\n", free_huge_pages);
1721}
1722HSTATE_ATTR_RO(free_hugepages);
1723
1724static ssize_t resv_hugepages_show(struct kobject *kobj,
1725 struct kobj_attribute *attr, char *buf)
1726{
1727 struct hstate *h = kobj_to_hstate(kobj, NULL);
1728 return sprintf(buf, "%lu\n", h->resv_huge_pages);
1729}
1730HSTATE_ATTR_RO(resv_hugepages);
1731
1732static ssize_t surplus_hugepages_show(struct kobject *kobj,
1733 struct kobj_attribute *attr, char *buf)
1734{
1735 struct hstate *h;
1736 unsigned long surplus_huge_pages;
1737 int nid;
1738
1739 h = kobj_to_hstate(kobj, &nid);
1740 if (nid == NUMA_NO_NODE)
1741 surplus_huge_pages = h->surplus_huge_pages;
1742 else
1743 surplus_huge_pages = h->surplus_huge_pages_node[nid];
1744
1745 return sprintf(buf, "%lu\n", surplus_huge_pages);
1746}
1747HSTATE_ATTR_RO(surplus_hugepages);
1748
1749static struct attribute *hstate_attrs[] = {
1750 &nr_hugepages_attr.attr,
1751 &nr_overcommit_hugepages_attr.attr,
1752 &free_hugepages_attr.attr,
1753 &resv_hugepages_attr.attr,
1754 &surplus_hugepages_attr.attr,
1755#ifdef CONFIG_NUMA
1756 &nr_hugepages_mempolicy_attr.attr,
1757#endif
1758 NULL,
1759};
1760
1761static struct attribute_group hstate_attr_group = {
1762 .attrs = hstate_attrs,
1763};
1764
1765static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
1766 struct kobject **hstate_kobjs,
1767 struct attribute_group *hstate_attr_group)
1768{
1769 int retval;
1770 int hi = hstate_index(h);
1771
1772 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1773 if (!hstate_kobjs[hi])
1774 return -ENOMEM;
1775
1776 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1777 if (retval)
1778 kobject_put(hstate_kobjs[hi]);
1779
1780 return retval;
1781}
1782
1783static void __init hugetlb_sysfs_init(void)
1784{
1785 struct hstate *h;
1786 int err;
1787
1788 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1789 if (!hugepages_kobj)
1790 return;
1791
1792 for_each_hstate(h) {
1793 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1794 hstate_kobjs, &hstate_attr_group);
1795 if (err)
1796 pr_err("Hugetlb: Unable to add hstate %s", h->name);
1797 }
1798}
1799
1800#ifdef CONFIG_NUMA
1801
1802/*
1803 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1804 * with node devices in node_devices[] using a parallel array. The array
1805 * index of a node device or _hstate == node id.
1806 * This is here to avoid any static dependency of the node device driver, in
1807 * the base kernel, on the hugetlb module.
1808 */
1809struct node_hstate {
1810 struct kobject *hugepages_kobj;
1811 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1812};
1813struct node_hstate node_hstates[MAX_NUMNODES];
1814
1815/*
1816 * A subset of global hstate attributes for node devices
1817 */
1818static struct attribute *per_node_hstate_attrs[] = {
1819 &nr_hugepages_attr.attr,
1820 &free_hugepages_attr.attr,
1821 &surplus_hugepages_attr.attr,
1822 NULL,
1823};
1824
1825static struct attribute_group per_node_hstate_attr_group = {
1826 .attrs = per_node_hstate_attrs,
1827};
1828
1829/*
1830 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1831 * Returns node id via non-NULL nidp.
1832 */
1833static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1834{
1835 int nid;
1836
1837 for (nid = 0; nid < nr_node_ids; nid++) {
1838 struct node_hstate *nhs = &node_hstates[nid];
1839 int i;
1840 for (i = 0; i < HUGE_MAX_HSTATE; i++)
1841 if (nhs->hstate_kobjs[i] == kobj) {
1842 if (nidp)
1843 *nidp = nid;
1844 return &hstates[i];
1845 }
1846 }
1847
1848 BUG();
1849 return NULL;
1850}
1851
1852/*
1853 * Unregister hstate attributes from a single node device.
1854 * No-op if no hstate attributes attached.
1855 */
1856static void hugetlb_unregister_node(struct node *node)
1857{
1858 struct hstate *h;
1859 struct node_hstate *nhs = &node_hstates[node->dev.id];
1860
1861 if (!nhs->hugepages_kobj)
1862 return; /* no hstate attributes */
1863
1864 for_each_hstate(h) {
1865 int idx = hstate_index(h);
1866 if (nhs->hstate_kobjs[idx]) {
1867 kobject_put(nhs->hstate_kobjs[idx]);
1868 nhs->hstate_kobjs[idx] = NULL;
1869 }
1870 }
1871
1872 kobject_put(nhs->hugepages_kobj);
1873 nhs->hugepages_kobj = NULL;
1874}
1875
1876/*
1877 * hugetlb module exit: unregister hstate attributes from node devices
1878 * that have them.
1879 */
1880static void hugetlb_unregister_all_nodes(void)
1881{
1882 int nid;
1883
1884 /*
1885 * disable node device registrations.
1886 */
1887 register_hugetlbfs_with_node(NULL, NULL);
1888
1889 /*
1890 * remove hstate attributes from any nodes that have them.
1891 */
1892 for (nid = 0; nid < nr_node_ids; nid++)
1893 hugetlb_unregister_node(node_devices[nid]);
1894}
1895
1896/*
1897 * Register hstate attributes for a single node device.
1898 * No-op if attributes already registered.
1899 */
1900static void hugetlb_register_node(struct node *node)
1901{
1902 struct hstate *h;
1903 struct node_hstate *nhs = &node_hstates[node->dev.id];
1904 int err;
1905
1906 if (nhs->hugepages_kobj)
1907 return; /* already allocated */
1908
1909 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1910 &node->dev.kobj);
1911 if (!nhs->hugepages_kobj)
1912 return;
1913
1914 for_each_hstate(h) {
1915 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
1916 nhs->hstate_kobjs,
1917 &per_node_hstate_attr_group);
1918 if (err) {
1919 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1920 h->name, node->dev.id);
1921 hugetlb_unregister_node(node);
1922 break;
1923 }
1924 }
1925}
1926
1927/*
1928 * hugetlb init time: register hstate attributes for all registered node
1929 * devices of nodes that have memory. All on-line nodes should have
1930 * registered their associated device by this time.
1931 */
1932static void hugetlb_register_all_nodes(void)
1933{
1934 int nid;
1935
1936 for_each_node_state(nid, N_MEMORY) {
1937 struct node *node = node_devices[nid];
1938 if (node->dev.id == nid)
1939 hugetlb_register_node(node);
1940 }
1941
1942 /*
1943 * Let the node device driver know we're here so it can
1944 * [un]register hstate attributes on node hotplug.
1945 */
1946 register_hugetlbfs_with_node(hugetlb_register_node,
1947 hugetlb_unregister_node);
1948}
1949#else /* !CONFIG_NUMA */
1950
1951static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1952{
1953 BUG();
1954 if (nidp)
1955 *nidp = -1;
1956 return NULL;
1957}
1958
1959static void hugetlb_unregister_all_nodes(void) { }
1960
1961static void hugetlb_register_all_nodes(void) { }
1962
1963#endif
1964
1965static void __exit hugetlb_exit(void)
1966{
1967 struct hstate *h;
1968
1969 hugetlb_unregister_all_nodes();
1970
1971 for_each_hstate(h) {
1972 kobject_put(hstate_kobjs[hstate_index(h)]);
1973 }
1974
1975 kobject_put(hugepages_kobj);
1976 kfree(htlb_fault_mutex_table);
1977}
1978module_exit(hugetlb_exit);
1979
1980static int __init hugetlb_init(void)
1981{
1982 int i;
1983
1984 if (!hugepages_supported())
1985 return 0;
1986
1987 if (!size_to_hstate(default_hstate_size)) {
1988 default_hstate_size = HPAGE_SIZE;
1989 if (!size_to_hstate(default_hstate_size))
1990 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1991 }
1992 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
1993 if (default_hstate_max_huge_pages)
1994 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1995
1996 hugetlb_init_hstates();
1997 gather_bootmem_prealloc();
1998 report_hugepages();
1999
2000 hugetlb_sysfs_init();
2001 hugetlb_register_all_nodes();
2002 hugetlb_cgroup_file_init();
2003
2004#ifdef CONFIG_SMP
2005 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
2006#else
2007 num_fault_mutexes = 1;
2008#endif
2009 htlb_fault_mutex_table =
2010 kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
2011 BUG_ON(!htlb_fault_mutex_table);
2012
2013 for (i = 0; i < num_fault_mutexes; i++)
2014 mutex_init(&htlb_fault_mutex_table[i]);
2015 return 0;
2016}
2017module_init(hugetlb_init);
2018
2019/* Should be called on processing a hugepagesz=... option */
2020void __init hugetlb_add_hstate(unsigned order)
2021{
2022 struct hstate *h;
2023 unsigned long i;
2024
2025 if (size_to_hstate(PAGE_SIZE << order)) {
2026 pr_warning("hugepagesz= specified twice, ignoring\n");
2027 return;
2028 }
2029 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2030 BUG_ON(order == 0);
2031 h = &hstates[hugetlb_max_hstate++];
2032 h->order = order;
2033 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2034 h->nr_huge_pages = 0;
2035 h->free_huge_pages = 0;
2036 for (i = 0; i < MAX_NUMNODES; ++i)
2037 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2038 INIT_LIST_HEAD(&h->hugepage_activelist);
2039 h->next_nid_to_alloc = first_node(node_states[N_MEMORY]);
2040 h->next_nid_to_free = first_node(node_states[N_MEMORY]);
2041 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
2042 huge_page_size(h)/1024);
2043
2044 parsed_hstate = h;
2045}
2046
2047static int __init hugetlb_nrpages_setup(char *s)
2048{
2049 unsigned long *mhp;
2050 static unsigned long *last_mhp;
2051
2052 /*
2053 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2054 * so this hugepages= parameter goes to the "default hstate".
2055 */
2056 if (!hugetlb_max_hstate)
2057 mhp = &default_hstate_max_huge_pages;
2058 else
2059 mhp = &parsed_hstate->max_huge_pages;
2060
2061 if (mhp == last_mhp) {
2062 pr_warning("hugepages= specified twice without "
2063 "interleaving hugepagesz=, ignoring\n");
2064 return 1;
2065 }
2066
2067 if (sscanf(s, "%lu", mhp) <= 0)
2068 *mhp = 0;
2069
2070 /*
2071 * Global state is always initialized later in hugetlb_init.
2072 * But we need to allocate >= MAX_ORDER hstates here early to still
2073 * use the bootmem allocator.
2074 */
2075 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2076 hugetlb_hstate_alloc_pages(parsed_hstate);
2077
2078 last_mhp = mhp;
2079
2080 return 1;
2081}
2082__setup("hugepages=", hugetlb_nrpages_setup);
2083
2084static int __init hugetlb_default_setup(char *s)
2085{
2086 default_hstate_size = memparse(s, &s);
2087 return 1;
2088}
2089__setup("default_hugepagesz=", hugetlb_default_setup);
2090
2091static unsigned int cpuset_mems_nr(unsigned int *array)
2092{
2093 int node;
2094 unsigned int nr = 0;
2095
2096 for_each_node_mask(node, cpuset_current_mems_allowed)
2097 nr += array[node];
2098
2099 return nr;
2100}
2101
2102#ifdef CONFIG_SYSCTL
2103static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
2104 struct ctl_table *table, int write,
2105 void __user *buffer, size_t *length, loff_t *ppos)
2106{
2107 struct hstate *h = &default_hstate;
2108 unsigned long tmp;
2109 int ret;
2110
2111 if (!hugepages_supported())
2112 return -ENOTSUPP;
2113
2114 tmp = h->max_huge_pages;
2115
2116 if (write && h->order >= MAX_ORDER)
2117 return -EINVAL;
2118
2119 table->data = &tmp;
2120 table->maxlen = sizeof(unsigned long);
2121 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2122 if (ret)
2123 goto out;
2124
2125 if (write) {
2126 NODEMASK_ALLOC(nodemask_t, nodes_allowed,
2127 GFP_KERNEL | __GFP_NORETRY);
2128 if (!(obey_mempolicy &&
2129 init_nodemask_of_mempolicy(nodes_allowed))) {
2130 NODEMASK_FREE(nodes_allowed);
2131 nodes_allowed = &node_states[N_MEMORY];
2132 }
2133 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
2134
2135 if (nodes_allowed != &node_states[N_MEMORY])
2136 NODEMASK_FREE(nodes_allowed);
2137 }
2138out:
2139 return ret;
2140}
2141
2142int hugetlb_sysctl_handler(struct ctl_table *table, int write,
2143 void __user *buffer, size_t *length, loff_t *ppos)
2144{
2145
2146 return hugetlb_sysctl_handler_common(false, table, write,
2147 buffer, length, ppos);
2148}
2149
2150#ifdef CONFIG_NUMA
2151int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
2152 void __user *buffer, size_t *length, loff_t *ppos)
2153{
2154 return hugetlb_sysctl_handler_common(true, table, write,
2155 buffer, length, ppos);
2156}
2157#endif /* CONFIG_NUMA */
2158
2159int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2160 void __user *buffer,
2161 size_t *length, loff_t *ppos)
2162{
2163 struct hstate *h = &default_hstate;
2164 unsigned long tmp;
2165 int ret;
2166
2167 if (!hugepages_supported())
2168 return -ENOTSUPP;
2169
2170 tmp = h->nr_overcommit_huge_pages;
2171
2172 if (write && h->order >= MAX_ORDER)
2173 return -EINVAL;
2174
2175 table->data = &tmp;
2176 table->maxlen = sizeof(unsigned long);
2177 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2178 if (ret)
2179 goto out;
2180
2181 if (write) {
2182 spin_lock(&hugetlb_lock);
2183 h->nr_overcommit_huge_pages = tmp;
2184 spin_unlock(&hugetlb_lock);
2185 }
2186out:
2187 return ret;
2188}
2189
2190#endif /* CONFIG_SYSCTL */
2191
2192void hugetlb_report_meminfo(struct seq_file *m)
2193{
2194 struct hstate *h = &default_hstate;
2195 if (!hugepages_supported())
2196 return;
2197 seq_printf(m,
2198 "HugePages_Total: %5lu\n"
2199 "HugePages_Free: %5lu\n"
2200 "HugePages_Rsvd: %5lu\n"
2201 "HugePages_Surp: %5lu\n"
2202 "Hugepagesize: %8lu kB\n",
2203 h->nr_huge_pages,
2204 h->free_huge_pages,
2205 h->resv_huge_pages,
2206 h->surplus_huge_pages,
2207 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2208}
2209
2210int hugetlb_report_node_meminfo(int nid, char *buf)
2211{
2212 struct hstate *h = &default_hstate;
2213 if (!hugepages_supported())
2214 return 0;
2215 return sprintf(buf,
2216 "Node %d HugePages_Total: %5u\n"
2217 "Node %d HugePages_Free: %5u\n"
2218 "Node %d HugePages_Surp: %5u\n",
2219 nid, h->nr_huge_pages_node[nid],
2220 nid, h->free_huge_pages_node[nid],
2221 nid, h->surplus_huge_pages_node[nid]);
2222}
2223
2224void hugetlb_show_meminfo(void)
2225{
2226 struct hstate *h;
2227 int nid;
2228
2229 if (!hugepages_supported())
2230 return;
2231
2232 for_each_node_state(nid, N_MEMORY)
2233 for_each_hstate(h)
2234 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2235 nid,
2236 h->nr_huge_pages_node[nid],
2237 h->free_huge_pages_node[nid],
2238 h->surplus_huge_pages_node[nid],
2239 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
2240}
2241
2242/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2243unsigned long hugetlb_total_pages(void)
2244{
2245 struct hstate *h;
2246 unsigned long nr_total_pages = 0;
2247
2248 for_each_hstate(h)
2249 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
2250 return nr_total_pages;
2251}
2252
2253static int hugetlb_acct_memory(struct hstate *h, long delta)
2254{
2255 int ret = -ENOMEM;
2256
2257 spin_lock(&hugetlb_lock);
2258 /*
2259 * When cpuset is configured, it breaks the strict hugetlb page
2260 * reservation as the accounting is done on a global variable. Such
2261 * reservation is completely rubbish in the presence of cpuset because
2262 * the reservation is not checked against page availability for the
2263 * current cpuset. Application can still potentially OOM'ed by kernel
2264 * with lack of free htlb page in cpuset that the task is in.
2265 * Attempt to enforce strict accounting with cpuset is almost
2266 * impossible (or too ugly) because cpuset is too fluid that
2267 * task or memory node can be dynamically moved between cpusets.
2268 *
2269 * The change of semantics for shared hugetlb mapping with cpuset is
2270 * undesirable. However, in order to preserve some of the semantics,
2271 * we fall back to check against current free page availability as
2272 * a best attempt and hopefully to minimize the impact of changing
2273 * semantics that cpuset has.
2274 */
2275 if (delta > 0) {
2276 if (gather_surplus_pages(h, delta) < 0)
2277 goto out;
2278
2279 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2280 return_unused_surplus_pages(h, delta);
2281 goto out;
2282 }
2283 }
2284
2285 ret = 0;
2286 if (delta < 0)
2287 return_unused_surplus_pages(h, (unsigned long) -delta);
2288
2289out:
2290 spin_unlock(&hugetlb_lock);
2291 return ret;
2292}
2293
2294static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2295{
2296 struct resv_map *resv = vma_resv_map(vma);
2297
2298 /*
2299 * This new VMA should share its siblings reservation map if present.
2300 * The VMA will only ever have a valid reservation map pointer where
2301 * it is being copied for another still existing VMA. As that VMA
2302 * has a reference to the reservation map it cannot disappear until
2303 * after this open call completes. It is therefore safe to take a
2304 * new reference here without additional locking.
2305 */
2306 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
2307 kref_get(&resv->refs);
2308}
2309
2310static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2311{
2312 struct hstate *h = hstate_vma(vma);
2313 struct resv_map *resv = vma_resv_map(vma);
2314 struct hugepage_subpool *spool = subpool_vma(vma);
2315 unsigned long reserve, start, end;
2316
2317 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
2318 return;
2319
2320 start = vma_hugecache_offset(h, vma, vma->vm_start);
2321 end = vma_hugecache_offset(h, vma, vma->vm_end);
2322
2323 reserve = (end - start) - region_count(resv, start, end);
2324
2325 kref_put(&resv->refs, resv_map_release);
2326
2327 if (reserve) {
2328 hugetlb_acct_memory(h, -reserve);
2329 hugepage_subpool_put_pages(spool, reserve);
2330 }
2331}
2332
2333/*
2334 * We cannot handle pagefaults against hugetlb pages at all. They cause
2335 * handle_mm_fault() to try to instantiate regular-sized pages in the
2336 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
2337 * this far.
2338 */
2339static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2340{
2341 BUG();
2342 return 0;
2343}
2344
2345const struct vm_operations_struct hugetlb_vm_ops = {
2346 .fault = hugetlb_vm_op_fault,
2347 .open = hugetlb_vm_op_open,
2348 .close = hugetlb_vm_op_close,
2349};
2350
2351static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2352 int writable)
2353{
2354 pte_t entry;
2355
2356 if (writable) {
2357 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
2358 vma->vm_page_prot)));
2359 } else {
2360 entry = huge_pte_wrprotect(mk_huge_pte(page,
2361 vma->vm_page_prot));
2362 }
2363 entry = pte_mkyoung(entry);
2364 entry = pte_mkhuge(entry);
2365 entry = arch_make_huge_pte(entry, vma, page, writable);
2366
2367 return entry;
2368}
2369
2370static void set_huge_ptep_writable(struct vm_area_struct *vma,
2371 unsigned long address, pte_t *ptep)
2372{
2373 pte_t entry;
2374
2375 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
2376 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
2377 update_mmu_cache(vma, address, ptep);
2378}
2379
2380
2381int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2382 struct vm_area_struct *vma)
2383{
2384 pte_t *src_pte, *dst_pte, entry;
2385 struct page *ptepage;
2386 unsigned long addr;
2387 int cow;
2388 struct hstate *h = hstate_vma(vma);
2389 unsigned long sz = huge_page_size(h);
2390 unsigned long mmun_start; /* For mmu_notifiers */
2391 unsigned long mmun_end; /* For mmu_notifiers */
2392 int ret = 0;
2393
2394 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2395
2396 mmun_start = vma->vm_start;
2397 mmun_end = vma->vm_end;
2398 if (cow)
2399 mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);
2400
2401 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
2402 spinlock_t *src_ptl, *dst_ptl;
2403 src_pte = huge_pte_offset(src, addr);
2404 if (!src_pte)
2405 continue;
2406 dst_pte = huge_pte_alloc(dst, addr, sz);
2407 if (!dst_pte) {
2408 ret = -ENOMEM;
2409 break;
2410 }
2411
2412 /* If the pagetables are shared don't copy or take references */
2413 if (dst_pte == src_pte)
2414 continue;
2415
2416 dst_ptl = huge_pte_lock(h, dst, dst_pte);
2417 src_ptl = huge_pte_lockptr(h, src, src_pte);
2418 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
2419 if (!huge_pte_none(huge_ptep_get(src_pte))) {
2420 if (cow)
2421 huge_ptep_set_wrprotect(src, addr, src_pte);
2422 entry = huge_ptep_get(src_pte);
2423 ptepage = pte_page(entry);
2424 get_page(ptepage);
2425 page_dup_rmap(ptepage);
2426 set_huge_pte_at(dst, addr, dst_pte, entry);
2427 }
2428 spin_unlock(src_ptl);
2429 spin_unlock(dst_ptl);
2430 }
2431
2432 if (cow)
2433 mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);
2434
2435 return ret;
2436}
2437
2438static int is_hugetlb_entry_migration(pte_t pte)
2439{
2440 swp_entry_t swp;
2441
2442 if (huge_pte_none(pte) || pte_present(pte))
2443 return 0;
2444 swp = pte_to_swp_entry(pte);
2445 if (non_swap_entry(swp) && is_migration_entry(swp))
2446 return 1;
2447 else
2448 return 0;
2449}
2450
2451static int is_hugetlb_entry_hwpoisoned(pte_t pte)
2452{
2453 swp_entry_t swp;
2454
2455 if (huge_pte_none(pte) || pte_present(pte))
2456 return 0;
2457 swp = pte_to_swp_entry(pte);
2458 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
2459 return 1;
2460 else
2461 return 0;
2462}
2463
2464void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
2465 unsigned long start, unsigned long end,
2466 struct page *ref_page)
2467{
2468 int force_flush = 0;
2469 struct mm_struct *mm = vma->vm_mm;
2470 unsigned long address;
2471 pte_t *ptep;
2472 pte_t pte;
2473 spinlock_t *ptl;
2474 struct page *page;
2475 struct hstate *h = hstate_vma(vma);
2476 unsigned long sz = huge_page_size(h);
2477 const unsigned long mmun_start = start; /* For mmu_notifiers */
2478 const unsigned long mmun_end = end; /* For mmu_notifiers */
2479
2480 WARN_ON(!is_vm_hugetlb_page(vma));
2481 BUG_ON(start & ~huge_page_mask(h));
2482 BUG_ON(end & ~huge_page_mask(h));
2483
2484 tlb_start_vma(tlb, vma);
2485 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2486again:
2487 for (address = start; address < end; address += sz) {
2488 ptep = huge_pte_offset(mm, address);
2489 if (!ptep)
2490 continue;
2491
2492 ptl = huge_pte_lock(h, mm, ptep);
2493 if (huge_pmd_unshare(mm, &address, ptep))
2494 goto unlock;
2495
2496 pte = huge_ptep_get(ptep);
2497 if (huge_pte_none(pte))
2498 goto unlock;
2499
2500 /*
2501 * HWPoisoned hugepage is already unmapped and dropped reference
2502 */
2503 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
2504 huge_pte_clear(mm, address, ptep);
2505 goto unlock;
2506 }
2507
2508 page = pte_page(pte);
2509 /*
2510 * If a reference page is supplied, it is because a specific
2511 * page is being unmapped, not a range. Ensure the page we
2512 * are about to unmap is the actual page of interest.
2513 */
2514 if (ref_page) {
2515 if (page != ref_page)
2516 goto unlock;
2517
2518 /*
2519 * Mark the VMA as having unmapped its page so that
2520 * future faults in this VMA will fail rather than
2521 * looking like data was lost
2522 */
2523 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2524 }
2525
2526 pte = huge_ptep_get_and_clear(mm, address, ptep);
2527 tlb_remove_tlb_entry(tlb, ptep, address);
2528 if (huge_pte_dirty(pte))
2529 set_page_dirty(page);
2530
2531 page_remove_rmap(page);
2532 force_flush = !__tlb_remove_page(tlb, page);
2533 if (force_flush) {
2534 spin_unlock(ptl);
2535 break;
2536 }
2537 /* Bail out after unmapping reference page if supplied */
2538 if (ref_page) {
2539 spin_unlock(ptl);
2540 break;
2541 }
2542unlock:
2543 spin_unlock(ptl);
2544 }
2545 /*
2546 * mmu_gather ran out of room to batch pages, we break out of
2547 * the PTE lock to avoid doing the potential expensive TLB invalidate
2548 * and page-free while holding it.
2549 */
2550 if (force_flush) {
2551 force_flush = 0;
2552 tlb_flush_mmu(tlb);
2553 if (address < end && !ref_page)
2554 goto again;
2555 }
2556 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2557 tlb_end_vma(tlb, vma);
2558}
2559
2560void __unmap_hugepage_range_final(struct mmu_gather *tlb,
2561 struct vm_area_struct *vma, unsigned long start,
2562 unsigned long end, struct page *ref_page)
2563{
2564 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
2565
2566 /*
2567 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2568 * test will fail on a vma being torn down, and not grab a page table
2569 * on its way out. We're lucky that the flag has such an appropriate
2570 * name, and can in fact be safely cleared here. We could clear it
2571 * before the __unmap_hugepage_range above, but all that's necessary
2572 * is to clear it before releasing the i_mmap_mutex. This works
2573 * because in the context this is called, the VMA is about to be
2574 * destroyed and the i_mmap_mutex is held.
2575 */
2576 vma->vm_flags &= ~VM_MAYSHARE;
2577}
2578
2579void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2580 unsigned long end, struct page *ref_page)
2581{
2582 struct mm_struct *mm;
2583 struct mmu_gather tlb;
2584
2585 mm = vma->vm_mm;
2586
2587 tlb_gather_mmu(&tlb, mm, start, end);
2588 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
2589 tlb_finish_mmu(&tlb, start, end);
2590}
2591
2592/*
2593 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2594 * mappping it owns the reserve page for. The intention is to unmap the page
2595 * from other VMAs and let the children be SIGKILLed if they are faulting the
2596 * same region.
2597 */
2598static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2599 struct page *page, unsigned long address)
2600{
2601 struct hstate *h = hstate_vma(vma);
2602 struct vm_area_struct *iter_vma;
2603 struct address_space *mapping;
2604 pgoff_t pgoff;
2605
2606 /*
2607 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2608 * from page cache lookup which is in HPAGE_SIZE units.
2609 */
2610 address = address & huge_page_mask(h);
2611 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
2612 vma->vm_pgoff;
2613 mapping = file_inode(vma->vm_file)->i_mapping;
2614
2615 /*
2616 * Take the mapping lock for the duration of the table walk. As
2617 * this mapping should be shared between all the VMAs,
2618 * __unmap_hugepage_range() is called as the lock is already held
2619 */
2620 mutex_lock(&mapping->i_mmap_mutex);
2621 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
2622 /* Do not unmap the current VMA */
2623 if (iter_vma == vma)
2624 continue;
2625
2626 /*
2627 * Unmap the page from other VMAs without their own reserves.
2628 * They get marked to be SIGKILLed if they fault in these
2629 * areas. This is because a future no-page fault on this VMA
2630 * could insert a zeroed page instead of the data existing
2631 * from the time of fork. This would look like data corruption
2632 */
2633 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2634 unmap_hugepage_range(iter_vma, address,
2635 address + huge_page_size(h), page);
2636 }
2637 mutex_unlock(&mapping->i_mmap_mutex);
2638
2639 return 1;
2640}
2641
2642/*
2643 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2644 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2645 * cannot race with other handlers or page migration.
2646 * Keep the pte_same checks anyway to make transition from the mutex easier.
2647 */
2648static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2649 unsigned long address, pte_t *ptep, pte_t pte,
2650 struct page *pagecache_page, spinlock_t *ptl)
2651{
2652 struct hstate *h = hstate_vma(vma);
2653 struct page *old_page, *new_page;
2654 int outside_reserve = 0;
2655 unsigned long mmun_start; /* For mmu_notifiers */
2656 unsigned long mmun_end; /* For mmu_notifiers */
2657
2658 old_page = pte_page(pte);
2659
2660retry_avoidcopy:
2661 /* If no-one else is actually using this page, avoid the copy
2662 * and just make the page writable */
2663 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
2664 page_move_anon_rmap(old_page, vma, address);
2665 set_huge_ptep_writable(vma, address, ptep);
2666 return 0;
2667 }
2668
2669 /*
2670 * If the process that created a MAP_PRIVATE mapping is about to
2671 * perform a COW due to a shared page count, attempt to satisfy
2672 * the allocation without using the existing reserves. The pagecache
2673 * page is used to determine if the reserve at this address was
2674 * consumed or not. If reserves were used, a partial faulted mapping
2675 * at the time of fork() could consume its reserves on COW instead
2676 * of the full address range.
2677 */
2678 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2679 old_page != pagecache_page)
2680 outside_reserve = 1;
2681
2682 page_cache_get(old_page);
2683
2684 /* Drop page table lock as buddy allocator may be called */
2685 spin_unlock(ptl);
2686 new_page = alloc_huge_page(vma, address, outside_reserve);
2687
2688 if (IS_ERR(new_page)) {
2689 long err = PTR_ERR(new_page);
2690 page_cache_release(old_page);
2691
2692 /*
2693 * If a process owning a MAP_PRIVATE mapping fails to COW,
2694 * it is due to references held by a child and an insufficient
2695 * huge page pool. To guarantee the original mappers
2696 * reliability, unmap the page from child processes. The child
2697 * may get SIGKILLed if it later faults.
2698 */
2699 if (outside_reserve) {
2700 BUG_ON(huge_pte_none(pte));
2701 if (unmap_ref_private(mm, vma, old_page, address)) {
2702 BUG_ON(huge_pte_none(pte));
2703 spin_lock(ptl);
2704 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2705 if (likely(ptep &&
2706 pte_same(huge_ptep_get(ptep), pte)))
2707 goto retry_avoidcopy;
2708 /*
2709 * race occurs while re-acquiring page table
2710 * lock, and our job is done.
2711 */
2712 return 0;
2713 }
2714 WARN_ON_ONCE(1);
2715 }
2716
2717 /* Caller expects lock to be held */
2718 spin_lock(ptl);
2719 if (err == -ENOMEM)
2720 return VM_FAULT_OOM;
2721 else
2722 return VM_FAULT_SIGBUS;
2723 }
2724
2725 /*
2726 * When the original hugepage is shared one, it does not have
2727 * anon_vma prepared.
2728 */
2729 if (unlikely(anon_vma_prepare(vma))) {
2730 page_cache_release(new_page);
2731 page_cache_release(old_page);
2732 /* Caller expects lock to be held */
2733 spin_lock(ptl);
2734 return VM_FAULT_OOM;
2735 }
2736
2737 copy_user_huge_page(new_page, old_page, address, vma,
2738 pages_per_huge_page(h));
2739 __SetPageUptodate(new_page);
2740
2741 mmun_start = address & huge_page_mask(h);
2742 mmun_end = mmun_start + huge_page_size(h);
2743 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2744 /*
2745 * Retake the page table lock to check for racing updates
2746 * before the page tables are altered
2747 */
2748 spin_lock(ptl);
2749 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2750 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
2751 ClearPagePrivate(new_page);
2752
2753 /* Break COW */
2754 huge_ptep_clear_flush(vma, address, ptep);
2755 set_huge_pte_at(mm, address, ptep,
2756 make_huge_pte(vma, new_page, 1));
2757 page_remove_rmap(old_page);
2758 hugepage_add_new_anon_rmap(new_page, vma, address);
2759 /* Make the old page be freed below */
2760 new_page = old_page;
2761 }
2762 spin_unlock(ptl);
2763 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2764 page_cache_release(new_page);
2765 page_cache_release(old_page);
2766
2767 /* Caller expects lock to be held */
2768 spin_lock(ptl);
2769 return 0;
2770}
2771
2772/* Return the pagecache page at a given address within a VMA */
2773static struct page *hugetlbfs_pagecache_page(struct hstate *h,
2774 struct vm_area_struct *vma, unsigned long address)
2775{
2776 struct address_space *mapping;
2777 pgoff_t idx;
2778
2779 mapping = vma->vm_file->f_mapping;
2780 idx = vma_hugecache_offset(h, vma, address);
2781
2782 return find_lock_page(mapping, idx);
2783}
2784
2785/*
2786 * Return whether there is a pagecache page to back given address within VMA.
2787 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2788 */
2789static bool hugetlbfs_pagecache_present(struct hstate *h,
2790 struct vm_area_struct *vma, unsigned long address)
2791{
2792 struct address_space *mapping;
2793 pgoff_t idx;
2794 struct page *page;
2795
2796 mapping = vma->vm_file->f_mapping;
2797 idx = vma_hugecache_offset(h, vma, address);
2798
2799 page = find_get_page(mapping, idx);
2800 if (page)
2801 put_page(page);
2802 return page != NULL;
2803}
2804
2805static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2806 struct address_space *mapping, pgoff_t idx,
2807 unsigned long address, pte_t *ptep, unsigned int flags)
2808{
2809 struct hstate *h = hstate_vma(vma);
2810 int ret = VM_FAULT_SIGBUS;
2811 int anon_rmap = 0;
2812 unsigned long size;
2813 struct page *page;
2814 pte_t new_pte;
2815 spinlock_t *ptl;
2816
2817 /*
2818 * Currently, we are forced to kill the process in the event the
2819 * original mapper has unmapped pages from the child due to a failed
2820 * COW. Warn that such a situation has occurred as it may not be obvious
2821 */
2822 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2823 pr_warning("PID %d killed due to inadequate hugepage pool\n",
2824 current->pid);
2825 return ret;
2826 }
2827
2828 /*
2829 * Use page lock to guard against racing truncation
2830 * before we get page_table_lock.
2831 */
2832retry:
2833 page = find_lock_page(mapping, idx);
2834 if (!page) {
2835 size = i_size_read(mapping->host) >> huge_page_shift(h);
2836 if (idx >= size)
2837 goto out;
2838 page = alloc_huge_page(vma, address, 0);
2839 if (IS_ERR(page)) {
2840 ret = PTR_ERR(page);
2841 if (ret == -ENOMEM)
2842 ret = VM_FAULT_OOM;
2843 else
2844 ret = VM_FAULT_SIGBUS;
2845 goto out;
2846 }
2847 clear_huge_page(page, address, pages_per_huge_page(h));
2848 __SetPageUptodate(page);
2849
2850 if (vma->vm_flags & VM_MAYSHARE) {
2851 int err;
2852 struct inode *inode = mapping->host;
2853
2854 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2855 if (err) {
2856 put_page(page);
2857 if (err == -EEXIST)
2858 goto retry;
2859 goto out;
2860 }
2861 ClearPagePrivate(page);
2862
2863 spin_lock(&inode->i_lock);
2864 inode->i_blocks += blocks_per_huge_page(h);
2865 spin_unlock(&inode->i_lock);
2866 } else {
2867 lock_page(page);
2868 if (unlikely(anon_vma_prepare(vma))) {
2869 ret = VM_FAULT_OOM;
2870 goto backout_unlocked;
2871 }
2872 anon_rmap = 1;
2873 }
2874 } else {
2875 /*
2876 * If memory error occurs between mmap() and fault, some process
2877 * don't have hwpoisoned swap entry for errored virtual address.
2878 * So we need to block hugepage fault by PG_hwpoison bit check.
2879 */
2880 if (unlikely(PageHWPoison(page))) {
2881 ret = VM_FAULT_HWPOISON |
2882 VM_FAULT_SET_HINDEX(hstate_index(h));
2883 goto backout_unlocked;
2884 }
2885 }
2886
2887 /*
2888 * If we are going to COW a private mapping later, we examine the
2889 * pending reservations for this page now. This will ensure that
2890 * any allocations necessary to record that reservation occur outside
2891 * the spinlock.
2892 */
2893 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2894 if (vma_needs_reservation(h, vma, address) < 0) {
2895 ret = VM_FAULT_OOM;
2896 goto backout_unlocked;
2897 }
2898
2899 ptl = huge_pte_lockptr(h, mm, ptep);
2900 spin_lock(ptl);
2901 size = i_size_read(mapping->host) >> huge_page_shift(h);
2902 if (idx >= size)
2903 goto backout;
2904
2905 ret = 0;
2906 if (!huge_pte_none(huge_ptep_get(ptep)))
2907 goto backout;
2908
2909 if (anon_rmap) {
2910 ClearPagePrivate(page);
2911 hugepage_add_new_anon_rmap(page, vma, address);
2912 } else
2913 page_dup_rmap(page);
2914 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2915 && (vma->vm_flags & VM_SHARED)));
2916 set_huge_pte_at(mm, address, ptep, new_pte);
2917
2918 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2919 /* Optimization, do the COW without a second fault */
2920 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl);
2921 }
2922
2923 spin_unlock(ptl);
2924 unlock_page(page);
2925out:
2926 return ret;
2927
2928backout:
2929 spin_unlock(ptl);
2930backout_unlocked:
2931 unlock_page(page);
2932 put_page(page);
2933 goto out;
2934}
2935
2936#ifdef CONFIG_SMP
2937static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
2938 struct vm_area_struct *vma,
2939 struct address_space *mapping,
2940 pgoff_t idx, unsigned long address)
2941{
2942 unsigned long key[2];
2943 u32 hash;
2944
2945 if (vma->vm_flags & VM_SHARED) {
2946 key[0] = (unsigned long) mapping;
2947 key[1] = idx;
2948 } else {
2949 key[0] = (unsigned long) mm;
2950 key[1] = address >> huge_page_shift(h);
2951 }
2952
2953 hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0);
2954
2955 return hash & (num_fault_mutexes - 1);
2956}
2957#else
2958/*
2959 * For uniprocesor systems we always use a single mutex, so just
2960 * return 0 and avoid the hashing overhead.
2961 */
2962static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
2963 struct vm_area_struct *vma,
2964 struct address_space *mapping,
2965 pgoff_t idx, unsigned long address)
2966{
2967 return 0;
2968}
2969#endif
2970
2971int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2972 unsigned long address, unsigned int flags)
2973{
2974 pte_t *ptep, entry;
2975 spinlock_t *ptl;
2976 int ret;
2977 u32 hash;
2978 pgoff_t idx;
2979 struct page *page = NULL;
2980 struct page *pagecache_page = NULL;
2981 struct hstate *h = hstate_vma(vma);
2982 struct address_space *mapping;
2983
2984 address &= huge_page_mask(h);
2985
2986 ptep = huge_pte_offset(mm, address);
2987 if (ptep) {
2988 entry = huge_ptep_get(ptep);
2989 if (unlikely(is_hugetlb_entry_migration(entry))) {
2990 migration_entry_wait_huge(vma, mm, ptep);
2991 return 0;
2992 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
2993 return VM_FAULT_HWPOISON_LARGE |
2994 VM_FAULT_SET_HINDEX(hstate_index(h));
2995 }
2996
2997 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2998 if (!ptep)
2999 return VM_FAULT_OOM;
3000
3001 mapping = vma->vm_file->f_mapping;
3002 idx = vma_hugecache_offset(h, vma, address);
3003
3004 /*
3005 * Serialize hugepage allocation and instantiation, so that we don't
3006 * get spurious allocation failures if two CPUs race to instantiate
3007 * the same page in the page cache.
3008 */
3009 hash = fault_mutex_hash(h, mm, vma, mapping, idx, address);
3010 mutex_lock(&htlb_fault_mutex_table[hash]);
3011
3012 entry = huge_ptep_get(ptep);
3013 if (huge_pte_none(entry)) {
3014 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3015 goto out_mutex;
3016 }
3017
3018 ret = 0;
3019
3020 /*
3021 * If we are going to COW the mapping later, we examine the pending
3022 * reservations for this page now. This will ensure that any
3023 * allocations necessary to record that reservation occur outside the
3024 * spinlock. For private mappings, we also lookup the pagecache
3025 * page now as it is used to determine if a reservation has been
3026 * consumed.
3027 */
3028 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3029 if (vma_needs_reservation(h, vma, address) < 0) {
3030 ret = VM_FAULT_OOM;
3031 goto out_mutex;
3032 }
3033
3034 if (!(vma->vm_flags & VM_MAYSHARE))
3035 pagecache_page = hugetlbfs_pagecache_page(h,
3036 vma, address);
3037 }
3038
3039 /*
3040 * hugetlb_cow() requires page locks of pte_page(entry) and
3041 * pagecache_page, so here we need take the former one
3042 * when page != pagecache_page or !pagecache_page.
3043 * Note that locking order is always pagecache_page -> page,
3044 * so no worry about deadlock.
3045 */
3046 page = pte_page(entry);
3047 get_page(page);
3048 if (page != pagecache_page)
3049 lock_page(page);
3050
3051 ptl = huge_pte_lockptr(h, mm, ptep);
3052 spin_lock(ptl);
3053 /* Check for a racing update before calling hugetlb_cow */
3054 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
3055 goto out_ptl;
3056
3057
3058 if (flags & FAULT_FLAG_WRITE) {
3059 if (!huge_pte_write(entry)) {
3060 ret = hugetlb_cow(mm, vma, address, ptep, entry,
3061 pagecache_page, ptl);
3062 goto out_ptl;
3063 }
3064 entry = huge_pte_mkdirty(entry);
3065 }
3066 entry = pte_mkyoung(entry);
3067 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
3068 flags & FAULT_FLAG_WRITE))
3069 update_mmu_cache(vma, address, ptep);
3070
3071out_ptl:
3072 spin_unlock(ptl);
3073
3074 if (pagecache_page) {
3075 unlock_page(pagecache_page);
3076 put_page(pagecache_page);
3077 }
3078 if (page != pagecache_page)
3079 unlock_page(page);
3080 put_page(page);
3081
3082out_mutex:
3083 mutex_unlock(&htlb_fault_mutex_table[hash]);
3084 return ret;
3085}
3086
3087long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
3088 struct page **pages, struct vm_area_struct **vmas,
3089 unsigned long *position, unsigned long *nr_pages,
3090 long i, unsigned int flags)
3091{
3092 unsigned long pfn_offset;
3093 unsigned long vaddr = *position;
3094 unsigned long remainder = *nr_pages;
3095 struct hstate *h = hstate_vma(vma);
3096
3097 while (vaddr < vma->vm_end && remainder) {
3098 pte_t *pte;
3099 spinlock_t *ptl = NULL;
3100 int absent;
3101 struct page *page;
3102
3103 /*
3104 * Some archs (sparc64, sh*) have multiple pte_ts to
3105 * each hugepage. We have to make sure we get the
3106 * first, for the page indexing below to work.
3107 *
3108 * Note that page table lock is not held when pte is null.
3109 */
3110 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
3111 if (pte)
3112 ptl = huge_pte_lock(h, mm, pte);
3113 absent = !pte || huge_pte_none(huge_ptep_get(pte));
3114
3115 /*
3116 * When coredumping, it suits get_dump_page if we just return
3117 * an error where there's an empty slot with no huge pagecache
3118 * to back it. This way, we avoid allocating a hugepage, and
3119 * the sparse dumpfile avoids allocating disk blocks, but its
3120 * huge holes still show up with zeroes where they need to be.
3121 */
3122 if (absent && (flags & FOLL_DUMP) &&
3123 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
3124 if (pte)
3125 spin_unlock(ptl);
3126 remainder = 0;
3127 break;
3128 }
3129
3130 /*
3131 * We need call hugetlb_fault for both hugepages under migration
3132 * (in which case hugetlb_fault waits for the migration,) and
3133 * hwpoisoned hugepages (in which case we need to prevent the
3134 * caller from accessing to them.) In order to do this, we use
3135 * here is_swap_pte instead of is_hugetlb_entry_migration and
3136 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3137 * both cases, and because we can't follow correct pages
3138 * directly from any kind of swap entries.
3139 */
3140 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
3141 ((flags & FOLL_WRITE) &&
3142 !huge_pte_write(huge_ptep_get(pte)))) {
3143 int ret;
3144
3145 if (pte)
3146 spin_unlock(ptl);
3147 ret = hugetlb_fault(mm, vma, vaddr,
3148 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
3149 if (!(ret & VM_FAULT_ERROR))
3150 continue;
3151
3152 remainder = 0;
3153 break;
3154 }
3155
3156 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
3157 page = pte_page(huge_ptep_get(pte));
3158same_page:
3159 if (pages) {
3160 pages[i] = mem_map_offset(page, pfn_offset);
3161 get_page_foll(pages[i]);
3162 }
3163
3164 if (vmas)
3165 vmas[i] = vma;
3166
3167 vaddr += PAGE_SIZE;
3168 ++pfn_offset;
3169 --remainder;
3170 ++i;
3171 if (vaddr < vma->vm_end && remainder &&
3172 pfn_offset < pages_per_huge_page(h)) {
3173 /*
3174 * We use pfn_offset to avoid touching the pageframes
3175 * of this compound page.
3176 */
3177 goto same_page;
3178 }
3179 spin_unlock(ptl);
3180 }
3181 *nr_pages = remainder;
3182 *position = vaddr;
3183
3184 return i ? i : -EFAULT;
3185}
3186
3187unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
3188 unsigned long address, unsigned long end, pgprot_t newprot)
3189{
3190 struct mm_struct *mm = vma->vm_mm;
3191 unsigned long start = address;
3192 pte_t *ptep;
3193 pte_t pte;
3194 struct hstate *h = hstate_vma(vma);
3195 unsigned long pages = 0;
3196
3197 BUG_ON(address >= end);
3198 flush_cache_range(vma, address, end);
3199
3200 mmu_notifier_invalidate_range_start(mm, start, end);
3201 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
3202 for (; address < end; address += huge_page_size(h)) {
3203 spinlock_t *ptl;
3204 ptep = huge_pte_offset(mm, address);
3205 if (!ptep)
3206 continue;
3207 ptl = huge_pte_lock(h, mm, ptep);
3208 if (huge_pmd_unshare(mm, &address, ptep)) {
3209 pages++;
3210 spin_unlock(ptl);
3211 continue;
3212 }
3213 if (!huge_pte_none(huge_ptep_get(ptep))) {
3214 pte = huge_ptep_get_and_clear(mm, address, ptep);
3215 pte = pte_mkhuge(huge_pte_modify(pte, newprot));
3216 pte = arch_make_huge_pte(pte, vma, NULL, 0);
3217 set_huge_pte_at(mm, address, ptep, pte);
3218 pages++;
3219 }
3220 spin_unlock(ptl);
3221 }
3222 /*
3223 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3224 * may have cleared our pud entry and done put_page on the page table:
3225 * once we release i_mmap_mutex, another task can do the final put_page
3226 * and that page table be reused and filled with junk.
3227 */
3228 flush_tlb_range(vma, start, end);
3229 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
3230 mmu_notifier_invalidate_range_end(mm, start, end);
3231
3232 return pages << h->order;
3233}
3234
3235int hugetlb_reserve_pages(struct inode *inode,
3236 long from, long to,
3237 struct vm_area_struct *vma,
3238 vm_flags_t vm_flags)
3239{
3240 long ret, chg;
3241 struct hstate *h = hstate_inode(inode);
3242 struct hugepage_subpool *spool = subpool_inode(inode);
3243 struct resv_map *resv_map;
3244
3245 /*
3246 * Only apply hugepage reservation if asked. At fault time, an
3247 * attempt will be made for VM_NORESERVE to allocate a page
3248 * without using reserves
3249 */
3250 if (vm_flags & VM_NORESERVE)
3251 return 0;
3252
3253 /*
3254 * Shared mappings base their reservation on the number of pages that
3255 * are already allocated on behalf of the file. Private mappings need
3256 * to reserve the full area even if read-only as mprotect() may be
3257 * called to make the mapping read-write. Assume !vma is a shm mapping
3258 */
3259 if (!vma || vma->vm_flags & VM_MAYSHARE) {
3260 resv_map = inode_resv_map(inode);
3261
3262 chg = region_chg(resv_map, from, to);
3263
3264 } else {
3265 resv_map = resv_map_alloc();
3266 if (!resv_map)
3267 return -ENOMEM;
3268
3269 chg = to - from;
3270
3271 set_vma_resv_map(vma, resv_map);
3272 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
3273 }
3274
3275 if (chg < 0) {
3276 ret = chg;
3277 goto out_err;
3278 }
3279
3280 /* There must be enough pages in the subpool for the mapping */
3281 if (hugepage_subpool_get_pages(spool, chg)) {
3282 ret = -ENOSPC;
3283 goto out_err;
3284 }
3285
3286 /*
3287 * Check enough hugepages are available for the reservation.
3288 * Hand the pages back to the subpool if there are not
3289 */
3290 ret = hugetlb_acct_memory(h, chg);
3291 if (ret < 0) {
3292 hugepage_subpool_put_pages(spool, chg);
3293 goto out_err;
3294 }
3295
3296 /*
3297 * Account for the reservations made. Shared mappings record regions
3298 * that have reservations as they are shared by multiple VMAs.
3299 * When the last VMA disappears, the region map says how much
3300 * the reservation was and the page cache tells how much of
3301 * the reservation was consumed. Private mappings are per-VMA and
3302 * only the consumed reservations are tracked. When the VMA
3303 * disappears, the original reservation is the VMA size and the
3304 * consumed reservations are stored in the map. Hence, nothing
3305 * else has to be done for private mappings here
3306 */
3307 if (!vma || vma->vm_flags & VM_MAYSHARE)
3308 region_add(resv_map, from, to);
3309 return 0;
3310out_err:
3311 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3312 kref_put(&resv_map->refs, resv_map_release);
3313 return ret;
3314}
3315
3316void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
3317{
3318 struct hstate *h = hstate_inode(inode);
3319 struct resv_map *resv_map = inode_resv_map(inode);
3320 long chg = 0;
3321 struct hugepage_subpool *spool = subpool_inode(inode);
3322
3323 if (resv_map)
3324 chg = region_truncate(resv_map, offset);
3325 spin_lock(&inode->i_lock);
3326 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
3327 spin_unlock(&inode->i_lock);
3328
3329 hugepage_subpool_put_pages(spool, (chg - freed));
3330 hugetlb_acct_memory(h, -(chg - freed));
3331}
3332
3333#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3334static unsigned long page_table_shareable(struct vm_area_struct *svma,
3335 struct vm_area_struct *vma,
3336 unsigned long addr, pgoff_t idx)
3337{
3338 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
3339 svma->vm_start;
3340 unsigned long sbase = saddr & PUD_MASK;
3341 unsigned long s_end = sbase + PUD_SIZE;
3342
3343 /* Allow segments to share if only one is marked locked */
3344 unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
3345 unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
3346
3347 /*
3348 * match the virtual addresses, permission and the alignment of the
3349 * page table page.
3350 */
3351 if (pmd_index(addr) != pmd_index(saddr) ||
3352 vm_flags != svm_flags ||
3353 sbase < svma->vm_start || svma->vm_end < s_end)
3354 return 0;
3355
3356 return saddr;
3357}
3358
3359static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
3360{
3361 unsigned long base = addr & PUD_MASK;
3362 unsigned long end = base + PUD_SIZE;
3363
3364 /*
3365 * check on proper vm_flags and page table alignment
3366 */
3367 if (vma->vm_flags & VM_MAYSHARE &&
3368 vma->vm_start <= base && end <= vma->vm_end)
3369 return 1;
3370 return 0;
3371}
3372
3373/*
3374 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3375 * and returns the corresponding pte. While this is not necessary for the
3376 * !shared pmd case because we can allocate the pmd later as well, it makes the
3377 * code much cleaner. pmd allocation is essential for the shared case because
3378 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3379 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3380 * bad pmd for sharing.
3381 */
3382pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3383{
3384 struct vm_area_struct *vma = find_vma(mm, addr);
3385 struct address_space *mapping = vma->vm_file->f_mapping;
3386 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
3387 vma->vm_pgoff;
3388 struct vm_area_struct *svma;
3389 unsigned long saddr;
3390 pte_t *spte = NULL;
3391 pte_t *pte;
3392 spinlock_t *ptl;
3393
3394 if (!vma_shareable(vma, addr))
3395 return (pte_t *)pmd_alloc(mm, pud, addr);
3396
3397 mutex_lock(&mapping->i_mmap_mutex);
3398 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
3399 if (svma == vma)
3400 continue;
3401
3402 saddr = page_table_shareable(svma, vma, addr, idx);
3403 if (saddr) {
3404 spte = huge_pte_offset(svma->vm_mm, saddr);
3405 if (spte) {
3406 get_page(virt_to_page(spte));
3407 break;
3408 }
3409 }
3410 }
3411
3412 if (!spte)
3413 goto out;
3414
3415 ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte);
3416 spin_lock(ptl);
3417 if (pud_none(*pud))
3418 pud_populate(mm, pud,
3419 (pmd_t *)((unsigned long)spte & PAGE_MASK));
3420 else
3421 put_page(virt_to_page(spte));
3422 spin_unlock(ptl);
3423out:
3424 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3425 mutex_unlock(&mapping->i_mmap_mutex);
3426 return pte;
3427}
3428
3429/*
3430 * unmap huge page backed by shared pte.
3431 *
3432 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
3433 * indicated by page_count > 1, unmap is achieved by clearing pud and
3434 * decrementing the ref count. If count == 1, the pte page is not shared.
3435 *
3436 * called with page table lock held.
3437 *
3438 * returns: 1 successfully unmapped a shared pte page
3439 * 0 the underlying pte page is not shared, or it is the last user
3440 */
3441int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
3442{
3443 pgd_t *pgd = pgd_offset(mm, *addr);
3444 pud_t *pud = pud_offset(pgd, *addr);
3445
3446 BUG_ON(page_count(virt_to_page(ptep)) == 0);
3447 if (page_count(virt_to_page(ptep)) == 1)
3448 return 0;
3449
3450 pud_clear(pud);
3451 put_page(virt_to_page(ptep));
3452 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
3453 return 1;
3454}
3455#define want_pmd_share() (1)
3456#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3457pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
3458{
3459 return NULL;
3460}
3461#define want_pmd_share() (0)
3462#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3463
3464#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3465pte_t *huge_pte_alloc(struct mm_struct *mm,
3466 unsigned long addr, unsigned long sz)
3467{
3468 pgd_t *pgd;
3469 pud_t *pud;
3470 pte_t *pte = NULL;
3471
3472 pgd = pgd_offset(mm, addr);
3473 pud = pud_alloc(mm, pgd, addr);
3474 if (pud) {
3475 if (sz == PUD_SIZE) {
3476 pte = (pte_t *)pud;
3477 } else {
3478 BUG_ON(sz != PMD_SIZE);
3479 if (want_pmd_share() && pud_none(*pud))
3480 pte = huge_pmd_share(mm, addr, pud);
3481 else
3482 pte = (pte_t *)pmd_alloc(mm, pud, addr);
3483 }
3484 }
3485 BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
3486
3487 return pte;
3488}
3489
3490pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
3491{
3492 pgd_t *pgd;
3493 pud_t *pud;
3494 pmd_t *pmd = NULL;
3495
3496 pgd = pgd_offset(mm, addr);
3497 if (pgd_present(*pgd)) {
3498 pud = pud_offset(pgd, addr);
3499 if (pud_present(*pud)) {
3500 if (pud_huge(*pud))
3501 return (pte_t *)pud;
3502 pmd = pmd_offset(pud, addr);
3503 }
3504 }
3505 return (pte_t *) pmd;
3506}
3507
3508struct page *
3509follow_huge_pmd(struct mm_struct *mm, unsigned long address,
3510 pmd_t *pmd, int write)
3511{
3512 struct page *page;
3513
3514 page = pte_page(*(pte_t *)pmd);
3515 if (page)
3516 page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
3517 return page;
3518}
3519
3520struct page *
3521follow_huge_pud(struct mm_struct *mm, unsigned long address,
3522 pud_t *pud, int write)
3523{
3524 struct page *page;
3525
3526 page = pte_page(*(pte_t *)pud);
3527 if (page)
3528 page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
3529 return page;
3530}
3531
3532#else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3533
3534/* Can be overriden by architectures */
3535struct page * __weak
3536follow_huge_pud(struct mm_struct *mm, unsigned long address,
3537 pud_t *pud, int write)
3538{
3539 BUG();
3540 return NULL;
3541}
3542
3543#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3544
3545#ifdef CONFIG_MEMORY_FAILURE
3546
3547/* Should be called in hugetlb_lock */
3548static int is_hugepage_on_freelist(struct page *hpage)
3549{
3550 struct page *page;
3551 struct page *tmp;
3552 struct hstate *h = page_hstate(hpage);
3553 int nid = page_to_nid(hpage);
3554
3555 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
3556 if (page == hpage)
3557 return 1;
3558 return 0;
3559}
3560
3561/*
3562 * This function is called from memory failure code.
3563 * Assume the caller holds page lock of the head page.
3564 */
3565int dequeue_hwpoisoned_huge_page(struct page *hpage)
3566{
3567 struct hstate *h = page_hstate(hpage);
3568 int nid = page_to_nid(hpage);
3569 int ret = -EBUSY;
3570
3571 spin_lock(&hugetlb_lock);
3572 if (is_hugepage_on_freelist(hpage)) {
3573 /*
3574 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3575 * but dangling hpage->lru can trigger list-debug warnings
3576 * (this happens when we call unpoison_memory() on it),
3577 * so let it point to itself with list_del_init().
3578 */
3579 list_del_init(&hpage->lru);
3580 set_page_refcounted(hpage);
3581 h->free_huge_pages--;
3582 h->free_huge_pages_node[nid]--;
3583 ret = 0;
3584 }
3585 spin_unlock(&hugetlb_lock);
3586 return ret;
3587}
3588#endif
3589
3590bool isolate_huge_page(struct page *page, struct list_head *list)
3591{
3592 VM_BUG_ON_PAGE(!PageHead(page), page);
3593 if (!get_page_unless_zero(page))
3594 return false;
3595 spin_lock(&hugetlb_lock);
3596 list_move_tail(&page->lru, list);
3597 spin_unlock(&hugetlb_lock);
3598 return true;
3599}
3600
3601void putback_active_hugepage(struct page *page)
3602{
3603 VM_BUG_ON_PAGE(!PageHead(page), page);
3604 spin_lock(&hugetlb_lock);
3605 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
3606 spin_unlock(&hugetlb_lock);
3607 put_page(page);
3608}
3609
3610bool is_hugepage_active(struct page *page)
3611{
3612 VM_BUG_ON_PAGE(!PageHuge(page), page);
3613 /*
3614 * This function can be called for a tail page because the caller,
3615 * scan_movable_pages, scans through a given pfn-range which typically
3616 * covers one memory block. In systems using gigantic hugepage (1GB
3617 * for x86_64,) a hugepage is larger than a memory block, and we don't
3618 * support migrating such large hugepages for now, so return false
3619 * when called for tail pages.
3620 */
3621 if (PageTail(page))
3622 return false;
3623 /*
3624 * Refcount of a hwpoisoned hugepages is 1, but they are not active,
3625 * so we should return false for them.
3626 */
3627 if (unlikely(PageHWPoison(page)))
3628 return false;
3629 return page_count(page) > 0;
3630}