Loading...
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#include <linux/migrate.h>
34
35#include <asm/page.h>
36#include <asm/pgalloc.h>
37#include <asm/tlb.h>
38
39#include <linux/io.h>
40#include <linux/hugetlb.h>
41#include <linux/hugetlb_cgroup.h>
42#include <linux/node.h>
43#include <linux/page_owner.h>
44#include "internal.h"
45#include "hugetlb_vmemmap.h"
46
47int hugetlb_max_hstate __read_mostly;
48unsigned int default_hstate_idx;
49struct hstate hstates[HUGE_MAX_HSTATE];
50
51#ifdef CONFIG_CMA
52static struct cma *hugetlb_cma[MAX_NUMNODES];
53#endif
54static unsigned long hugetlb_cma_size __initdata;
55
56/*
57 * Minimum page order among possible hugepage sizes, set to a proper value
58 * at boot time.
59 */
60static unsigned int minimum_order __read_mostly = UINT_MAX;
61
62__initdata LIST_HEAD(huge_boot_pages);
63
64/* for command line parsing */
65static struct hstate * __initdata parsed_hstate;
66static unsigned long __initdata default_hstate_max_huge_pages;
67static bool __initdata parsed_valid_hugepagesz = true;
68static bool __initdata parsed_default_hugepagesz;
69
70/*
71 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
72 * free_huge_pages, and surplus_huge_pages.
73 */
74DEFINE_SPINLOCK(hugetlb_lock);
75
76/*
77 * Serializes faults on the same logical page. This is used to
78 * prevent spurious OOMs when the hugepage pool is fully utilized.
79 */
80static int num_fault_mutexes;
81struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
82
83/* Forward declaration */
84static int hugetlb_acct_memory(struct hstate *h, long delta);
85
86static inline bool subpool_is_free(struct hugepage_subpool *spool)
87{
88 if (spool->count)
89 return false;
90 if (spool->max_hpages != -1)
91 return spool->used_hpages == 0;
92 if (spool->min_hpages != -1)
93 return spool->rsv_hpages == spool->min_hpages;
94
95 return true;
96}
97
98static inline void unlock_or_release_subpool(struct hugepage_subpool *spool,
99 unsigned long irq_flags)
100{
101 spin_unlock_irqrestore(&spool->lock, irq_flags);
102
103 /* If no pages are used, and no other handles to the subpool
104 * remain, give up any reservations based on minimum size and
105 * free the subpool */
106 if (subpool_is_free(spool)) {
107 if (spool->min_hpages != -1)
108 hugetlb_acct_memory(spool->hstate,
109 -spool->min_hpages);
110 kfree(spool);
111 }
112}
113
114struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
115 long min_hpages)
116{
117 struct hugepage_subpool *spool;
118
119 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
120 if (!spool)
121 return NULL;
122
123 spin_lock_init(&spool->lock);
124 spool->count = 1;
125 spool->max_hpages = max_hpages;
126 spool->hstate = h;
127 spool->min_hpages = min_hpages;
128
129 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
130 kfree(spool);
131 return NULL;
132 }
133 spool->rsv_hpages = min_hpages;
134
135 return spool;
136}
137
138void hugepage_put_subpool(struct hugepage_subpool *spool)
139{
140 unsigned long flags;
141
142 spin_lock_irqsave(&spool->lock, flags);
143 BUG_ON(!spool->count);
144 spool->count--;
145 unlock_or_release_subpool(spool, flags);
146}
147
148/*
149 * Subpool accounting for allocating and reserving pages.
150 * Return -ENOMEM if there are not enough resources to satisfy the
151 * request. Otherwise, return the number of pages by which the
152 * global pools must be adjusted (upward). The returned value may
153 * only be different than the passed value (delta) in the case where
154 * a subpool minimum size must be maintained.
155 */
156static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
157 long delta)
158{
159 long ret = delta;
160
161 if (!spool)
162 return ret;
163
164 spin_lock_irq(&spool->lock);
165
166 if (spool->max_hpages != -1) { /* maximum size accounting */
167 if ((spool->used_hpages + delta) <= spool->max_hpages)
168 spool->used_hpages += delta;
169 else {
170 ret = -ENOMEM;
171 goto unlock_ret;
172 }
173 }
174
175 /* minimum size accounting */
176 if (spool->min_hpages != -1 && spool->rsv_hpages) {
177 if (delta > spool->rsv_hpages) {
178 /*
179 * Asking for more reserves than those already taken on
180 * behalf of subpool. Return difference.
181 */
182 ret = delta - spool->rsv_hpages;
183 spool->rsv_hpages = 0;
184 } else {
185 ret = 0; /* reserves already accounted for */
186 spool->rsv_hpages -= delta;
187 }
188 }
189
190unlock_ret:
191 spin_unlock_irq(&spool->lock);
192 return ret;
193}
194
195/*
196 * Subpool accounting for freeing and unreserving pages.
197 * Return the number of global page reservations that must be dropped.
198 * The return value may only be different than the passed value (delta)
199 * in the case where a subpool minimum size must be maintained.
200 */
201static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
202 long delta)
203{
204 long ret = delta;
205 unsigned long flags;
206
207 if (!spool)
208 return delta;
209
210 spin_lock_irqsave(&spool->lock, flags);
211
212 if (spool->max_hpages != -1) /* maximum size accounting */
213 spool->used_hpages -= delta;
214
215 /* minimum size accounting */
216 if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
217 if (spool->rsv_hpages + delta <= spool->min_hpages)
218 ret = 0;
219 else
220 ret = spool->rsv_hpages + delta - spool->min_hpages;
221
222 spool->rsv_hpages += delta;
223 if (spool->rsv_hpages > spool->min_hpages)
224 spool->rsv_hpages = spool->min_hpages;
225 }
226
227 /*
228 * If hugetlbfs_put_super couldn't free spool due to an outstanding
229 * quota reference, free it now.
230 */
231 unlock_or_release_subpool(spool, flags);
232
233 return ret;
234}
235
236static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
237{
238 return HUGETLBFS_SB(inode->i_sb)->spool;
239}
240
241static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
242{
243 return subpool_inode(file_inode(vma->vm_file));
244}
245
246/* Helper that removes a struct file_region from the resv_map cache and returns
247 * it for use.
248 */
249static struct file_region *
250get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
251{
252 struct file_region *nrg = NULL;
253
254 VM_BUG_ON(resv->region_cache_count <= 0);
255
256 resv->region_cache_count--;
257 nrg = list_first_entry(&resv->region_cache, struct file_region, link);
258 list_del(&nrg->link);
259
260 nrg->from = from;
261 nrg->to = to;
262
263 return nrg;
264}
265
266static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg,
267 struct file_region *rg)
268{
269#ifdef CONFIG_CGROUP_HUGETLB
270 nrg->reservation_counter = rg->reservation_counter;
271 nrg->css = rg->css;
272 if (rg->css)
273 css_get(rg->css);
274#endif
275}
276
277/* Helper that records hugetlb_cgroup uncharge info. */
278static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
279 struct hstate *h,
280 struct resv_map *resv,
281 struct file_region *nrg)
282{
283#ifdef CONFIG_CGROUP_HUGETLB
284 if (h_cg) {
285 nrg->reservation_counter =
286 &h_cg->rsvd_hugepage[hstate_index(h)];
287 nrg->css = &h_cg->css;
288 /*
289 * The caller will hold exactly one h_cg->css reference for the
290 * whole contiguous reservation region. But this area might be
291 * scattered when there are already some file_regions reside in
292 * it. As a result, many file_regions may share only one css
293 * reference. In order to ensure that one file_region must hold
294 * exactly one h_cg->css reference, we should do css_get for
295 * each file_region and leave the reference held by caller
296 * untouched.
297 */
298 css_get(&h_cg->css);
299 if (!resv->pages_per_hpage)
300 resv->pages_per_hpage = pages_per_huge_page(h);
301 /* pages_per_hpage should be the same for all entries in
302 * a resv_map.
303 */
304 VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h));
305 } else {
306 nrg->reservation_counter = NULL;
307 nrg->css = NULL;
308 }
309#endif
310}
311
312static void put_uncharge_info(struct file_region *rg)
313{
314#ifdef CONFIG_CGROUP_HUGETLB
315 if (rg->css)
316 css_put(rg->css);
317#endif
318}
319
320static bool has_same_uncharge_info(struct file_region *rg,
321 struct file_region *org)
322{
323#ifdef CONFIG_CGROUP_HUGETLB
324 return rg && org &&
325 rg->reservation_counter == org->reservation_counter &&
326 rg->css == org->css;
327
328#else
329 return true;
330#endif
331}
332
333static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
334{
335 struct file_region *nrg = NULL, *prg = NULL;
336
337 prg = list_prev_entry(rg, link);
338 if (&prg->link != &resv->regions && prg->to == rg->from &&
339 has_same_uncharge_info(prg, rg)) {
340 prg->to = rg->to;
341
342 list_del(&rg->link);
343 put_uncharge_info(rg);
344 kfree(rg);
345
346 rg = prg;
347 }
348
349 nrg = list_next_entry(rg, link);
350 if (&nrg->link != &resv->regions && nrg->from == rg->to &&
351 has_same_uncharge_info(nrg, rg)) {
352 nrg->from = rg->from;
353
354 list_del(&rg->link);
355 put_uncharge_info(rg);
356 kfree(rg);
357 }
358}
359
360static inline long
361hugetlb_resv_map_add(struct resv_map *map, struct file_region *rg, long from,
362 long to, struct hstate *h, struct hugetlb_cgroup *cg,
363 long *regions_needed)
364{
365 struct file_region *nrg;
366
367 if (!regions_needed) {
368 nrg = get_file_region_entry_from_cache(map, from, to);
369 record_hugetlb_cgroup_uncharge_info(cg, h, map, nrg);
370 list_add(&nrg->link, rg->link.prev);
371 coalesce_file_region(map, nrg);
372 } else
373 *regions_needed += 1;
374
375 return to - from;
376}
377
378/*
379 * Must be called with resv->lock held.
380 *
381 * Calling this with regions_needed != NULL will count the number of pages
382 * to be added but will not modify the linked list. And regions_needed will
383 * indicate the number of file_regions needed in the cache to carry out to add
384 * the regions for this range.
385 */
386static long add_reservation_in_range(struct resv_map *resv, long f, long t,
387 struct hugetlb_cgroup *h_cg,
388 struct hstate *h, long *regions_needed)
389{
390 long add = 0;
391 struct list_head *head = &resv->regions;
392 long last_accounted_offset = f;
393 struct file_region *rg = NULL, *trg = NULL;
394
395 if (regions_needed)
396 *regions_needed = 0;
397
398 /* In this loop, we essentially handle an entry for the range
399 * [last_accounted_offset, rg->from), at every iteration, with some
400 * bounds checking.
401 */
402 list_for_each_entry_safe(rg, trg, head, link) {
403 /* Skip irrelevant regions that start before our range. */
404 if (rg->from < f) {
405 /* If this region ends after the last accounted offset,
406 * then we need to update last_accounted_offset.
407 */
408 if (rg->to > last_accounted_offset)
409 last_accounted_offset = rg->to;
410 continue;
411 }
412
413 /* When we find a region that starts beyond our range, we've
414 * finished.
415 */
416 if (rg->from >= t)
417 break;
418
419 /* Add an entry for last_accounted_offset -> rg->from, and
420 * update last_accounted_offset.
421 */
422 if (rg->from > last_accounted_offset)
423 add += hugetlb_resv_map_add(resv, rg,
424 last_accounted_offset,
425 rg->from, h, h_cg,
426 regions_needed);
427
428 last_accounted_offset = rg->to;
429 }
430
431 /* Handle the case where our range extends beyond
432 * last_accounted_offset.
433 */
434 if (last_accounted_offset < t)
435 add += hugetlb_resv_map_add(resv, rg, last_accounted_offset,
436 t, h, h_cg, regions_needed);
437
438 VM_BUG_ON(add < 0);
439 return add;
440}
441
442/* Must be called with resv->lock acquired. Will drop lock to allocate entries.
443 */
444static int allocate_file_region_entries(struct resv_map *resv,
445 int regions_needed)
446 __must_hold(&resv->lock)
447{
448 struct list_head allocated_regions;
449 int to_allocate = 0, i = 0;
450 struct file_region *trg = NULL, *rg = NULL;
451
452 VM_BUG_ON(regions_needed < 0);
453
454 INIT_LIST_HEAD(&allocated_regions);
455
456 /*
457 * Check for sufficient descriptors in the cache to accommodate
458 * the number of in progress add operations plus regions_needed.
459 *
460 * This is a while loop because when we drop the lock, some other call
461 * to region_add or region_del may have consumed some region_entries,
462 * so we keep looping here until we finally have enough entries for
463 * (adds_in_progress + regions_needed).
464 */
465 while (resv->region_cache_count <
466 (resv->adds_in_progress + regions_needed)) {
467 to_allocate = resv->adds_in_progress + regions_needed -
468 resv->region_cache_count;
469
470 /* At this point, we should have enough entries in the cache
471 * for all the existing adds_in_progress. We should only be
472 * needing to allocate for regions_needed.
473 */
474 VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress);
475
476 spin_unlock(&resv->lock);
477 for (i = 0; i < to_allocate; i++) {
478 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
479 if (!trg)
480 goto out_of_memory;
481 list_add(&trg->link, &allocated_regions);
482 }
483
484 spin_lock(&resv->lock);
485
486 list_splice(&allocated_regions, &resv->region_cache);
487 resv->region_cache_count += to_allocate;
488 }
489
490 return 0;
491
492out_of_memory:
493 list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
494 list_del(&rg->link);
495 kfree(rg);
496 }
497 return -ENOMEM;
498}
499
500/*
501 * Add the huge page range represented by [f, t) to the reserve
502 * map. Regions will be taken from the cache to fill in this range.
503 * Sufficient regions should exist in the cache due to the previous
504 * call to region_chg with the same range, but in some cases the cache will not
505 * have sufficient entries due to races with other code doing region_add or
506 * region_del. The extra needed entries will be allocated.
507 *
508 * regions_needed is the out value provided by a previous call to region_chg.
509 *
510 * Return the number of new huge pages added to the map. This number is greater
511 * than or equal to zero. If file_region entries needed to be allocated for
512 * this operation and we were not able to allocate, it returns -ENOMEM.
513 * region_add of regions of length 1 never allocate file_regions and cannot
514 * fail; region_chg will always allocate at least 1 entry and a region_add for
515 * 1 page will only require at most 1 entry.
516 */
517static long region_add(struct resv_map *resv, long f, long t,
518 long in_regions_needed, struct hstate *h,
519 struct hugetlb_cgroup *h_cg)
520{
521 long add = 0, actual_regions_needed = 0;
522
523 spin_lock(&resv->lock);
524retry:
525
526 /* Count how many regions are actually needed to execute this add. */
527 add_reservation_in_range(resv, f, t, NULL, NULL,
528 &actual_regions_needed);
529
530 /*
531 * Check for sufficient descriptors in the cache to accommodate
532 * this add operation. Note that actual_regions_needed may be greater
533 * than in_regions_needed, as the resv_map may have been modified since
534 * the region_chg call. In this case, we need to make sure that we
535 * allocate extra entries, such that we have enough for all the
536 * existing adds_in_progress, plus the excess needed for this
537 * operation.
538 */
539 if (actual_regions_needed > in_regions_needed &&
540 resv->region_cache_count <
541 resv->adds_in_progress +
542 (actual_regions_needed - in_regions_needed)) {
543 /* region_add operation of range 1 should never need to
544 * allocate file_region entries.
545 */
546 VM_BUG_ON(t - f <= 1);
547
548 if (allocate_file_region_entries(
549 resv, actual_regions_needed - in_regions_needed)) {
550 return -ENOMEM;
551 }
552
553 goto retry;
554 }
555
556 add = add_reservation_in_range(resv, f, t, h_cg, h, NULL);
557
558 resv->adds_in_progress -= in_regions_needed;
559
560 spin_unlock(&resv->lock);
561 return add;
562}
563
564/*
565 * Examine the existing reserve map and determine how many
566 * huge pages in the specified range [f, t) are NOT currently
567 * represented. This routine is called before a subsequent
568 * call to region_add that will actually modify the reserve
569 * map to add the specified range [f, t). region_chg does
570 * not change the number of huge pages represented by the
571 * map. A number of new file_region structures is added to the cache as a
572 * placeholder, for the subsequent region_add call to use. At least 1
573 * file_region structure is added.
574 *
575 * out_regions_needed is the number of regions added to the
576 * resv->adds_in_progress. This value needs to be provided to a follow up call
577 * to region_add or region_abort for proper accounting.
578 *
579 * Returns the number of huge pages that need to be added to the existing
580 * reservation map for the range [f, t). This number is greater or equal to
581 * zero. -ENOMEM is returned if a new file_region structure or cache entry
582 * is needed and can not be allocated.
583 */
584static long region_chg(struct resv_map *resv, long f, long t,
585 long *out_regions_needed)
586{
587 long chg = 0;
588
589 spin_lock(&resv->lock);
590
591 /* Count how many hugepages in this range are NOT represented. */
592 chg = add_reservation_in_range(resv, f, t, NULL, NULL,
593 out_regions_needed);
594
595 if (*out_regions_needed == 0)
596 *out_regions_needed = 1;
597
598 if (allocate_file_region_entries(resv, *out_regions_needed))
599 return -ENOMEM;
600
601 resv->adds_in_progress += *out_regions_needed;
602
603 spin_unlock(&resv->lock);
604 return chg;
605}
606
607/*
608 * Abort the in progress add operation. The adds_in_progress field
609 * of the resv_map keeps track of the operations in progress between
610 * calls to region_chg and region_add. Operations are sometimes
611 * aborted after the call to region_chg. In such cases, region_abort
612 * is called to decrement the adds_in_progress counter. regions_needed
613 * is the value returned by the region_chg call, it is used to decrement
614 * the adds_in_progress counter.
615 *
616 * NOTE: The range arguments [f, t) are not needed or used in this
617 * routine. They are kept to make reading the calling code easier as
618 * arguments will match the associated region_chg call.
619 */
620static void region_abort(struct resv_map *resv, long f, long t,
621 long regions_needed)
622{
623 spin_lock(&resv->lock);
624 VM_BUG_ON(!resv->region_cache_count);
625 resv->adds_in_progress -= regions_needed;
626 spin_unlock(&resv->lock);
627}
628
629/*
630 * Delete the specified range [f, t) from the reserve map. If the
631 * t parameter is LONG_MAX, this indicates that ALL regions after f
632 * should be deleted. Locate the regions which intersect [f, t)
633 * and either trim, delete or split the existing regions.
634 *
635 * Returns the number of huge pages deleted from the reserve map.
636 * In the normal case, the return value is zero or more. In the
637 * case where a region must be split, a new region descriptor must
638 * be allocated. If the allocation fails, -ENOMEM will be returned.
639 * NOTE: If the parameter t == LONG_MAX, then we will never split
640 * a region and possibly return -ENOMEM. Callers specifying
641 * t == LONG_MAX do not need to check for -ENOMEM error.
642 */
643static long region_del(struct resv_map *resv, long f, long t)
644{
645 struct list_head *head = &resv->regions;
646 struct file_region *rg, *trg;
647 struct file_region *nrg = NULL;
648 long del = 0;
649
650retry:
651 spin_lock(&resv->lock);
652 list_for_each_entry_safe(rg, trg, head, link) {
653 /*
654 * Skip regions before the range to be deleted. file_region
655 * ranges are normally of the form [from, to). However, there
656 * may be a "placeholder" entry in the map which is of the form
657 * (from, to) with from == to. Check for placeholder entries
658 * at the beginning of the range to be deleted.
659 */
660 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
661 continue;
662
663 if (rg->from >= t)
664 break;
665
666 if (f > rg->from && t < rg->to) { /* Must split region */
667 /*
668 * Check for an entry in the cache before dropping
669 * lock and attempting allocation.
670 */
671 if (!nrg &&
672 resv->region_cache_count > resv->adds_in_progress) {
673 nrg = list_first_entry(&resv->region_cache,
674 struct file_region,
675 link);
676 list_del(&nrg->link);
677 resv->region_cache_count--;
678 }
679
680 if (!nrg) {
681 spin_unlock(&resv->lock);
682 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
683 if (!nrg)
684 return -ENOMEM;
685 goto retry;
686 }
687
688 del += t - f;
689 hugetlb_cgroup_uncharge_file_region(
690 resv, rg, t - f, false);
691
692 /* New entry for end of split region */
693 nrg->from = t;
694 nrg->to = rg->to;
695
696 copy_hugetlb_cgroup_uncharge_info(nrg, rg);
697
698 INIT_LIST_HEAD(&nrg->link);
699
700 /* Original entry is trimmed */
701 rg->to = f;
702
703 list_add(&nrg->link, &rg->link);
704 nrg = NULL;
705 break;
706 }
707
708 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
709 del += rg->to - rg->from;
710 hugetlb_cgroup_uncharge_file_region(resv, rg,
711 rg->to - rg->from, true);
712 list_del(&rg->link);
713 kfree(rg);
714 continue;
715 }
716
717 if (f <= rg->from) { /* Trim beginning of region */
718 hugetlb_cgroup_uncharge_file_region(resv, rg,
719 t - rg->from, false);
720
721 del += t - rg->from;
722 rg->from = t;
723 } else { /* Trim end of region */
724 hugetlb_cgroup_uncharge_file_region(resv, rg,
725 rg->to - f, false);
726
727 del += rg->to - f;
728 rg->to = f;
729 }
730 }
731
732 spin_unlock(&resv->lock);
733 kfree(nrg);
734 return del;
735}
736
737/*
738 * A rare out of memory error was encountered which prevented removal of
739 * the reserve map region for a page. The huge page itself was free'ed
740 * and removed from the page cache. This routine will adjust the subpool
741 * usage count, and the global reserve count if needed. By incrementing
742 * these counts, the reserve map entry which could not be deleted will
743 * appear as a "reserved" entry instead of simply dangling with incorrect
744 * counts.
745 */
746void hugetlb_fix_reserve_counts(struct inode *inode)
747{
748 struct hugepage_subpool *spool = subpool_inode(inode);
749 long rsv_adjust;
750 bool reserved = false;
751
752 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
753 if (rsv_adjust > 0) {
754 struct hstate *h = hstate_inode(inode);
755
756 if (!hugetlb_acct_memory(h, 1))
757 reserved = true;
758 } else if (!rsv_adjust) {
759 reserved = true;
760 }
761
762 if (!reserved)
763 pr_warn("hugetlb: Huge Page Reserved count may go negative.\n");
764}
765
766/*
767 * Count and return the number of huge pages in the reserve map
768 * that intersect with the range [f, t).
769 */
770static long region_count(struct resv_map *resv, long f, long t)
771{
772 struct list_head *head = &resv->regions;
773 struct file_region *rg;
774 long chg = 0;
775
776 spin_lock(&resv->lock);
777 /* Locate each segment we overlap with, and count that overlap. */
778 list_for_each_entry(rg, head, link) {
779 long seg_from;
780 long seg_to;
781
782 if (rg->to <= f)
783 continue;
784 if (rg->from >= t)
785 break;
786
787 seg_from = max(rg->from, f);
788 seg_to = min(rg->to, t);
789
790 chg += seg_to - seg_from;
791 }
792 spin_unlock(&resv->lock);
793
794 return chg;
795}
796
797/*
798 * Convert the address within this vma to the page offset within
799 * the mapping, in pagecache page units; huge pages here.
800 */
801static pgoff_t vma_hugecache_offset(struct hstate *h,
802 struct vm_area_struct *vma, unsigned long address)
803{
804 return ((address - vma->vm_start) >> huge_page_shift(h)) +
805 (vma->vm_pgoff >> huge_page_order(h));
806}
807
808pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
809 unsigned long address)
810{
811 return vma_hugecache_offset(hstate_vma(vma), vma, address);
812}
813EXPORT_SYMBOL_GPL(linear_hugepage_index);
814
815/*
816 * Return the size of the pages allocated when backing a VMA. In the majority
817 * cases this will be same size as used by the page table entries.
818 */
819unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
820{
821 if (vma->vm_ops && vma->vm_ops->pagesize)
822 return vma->vm_ops->pagesize(vma);
823 return PAGE_SIZE;
824}
825EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
826
827/*
828 * Return the page size being used by the MMU to back a VMA. In the majority
829 * of cases, the page size used by the kernel matches the MMU size. On
830 * architectures where it differs, an architecture-specific 'strong'
831 * version of this symbol is required.
832 */
833__weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
834{
835 return vma_kernel_pagesize(vma);
836}
837
838/*
839 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
840 * bits of the reservation map pointer, which are always clear due to
841 * alignment.
842 */
843#define HPAGE_RESV_OWNER (1UL << 0)
844#define HPAGE_RESV_UNMAPPED (1UL << 1)
845#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
846
847/*
848 * These helpers are used to track how many pages are reserved for
849 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
850 * is guaranteed to have their future faults succeed.
851 *
852 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
853 * the reserve counters are updated with the hugetlb_lock held. It is safe
854 * to reset the VMA at fork() time as it is not in use yet and there is no
855 * chance of the global counters getting corrupted as a result of the values.
856 *
857 * The private mapping reservation is represented in a subtly different
858 * manner to a shared mapping. A shared mapping has a region map associated
859 * with the underlying file, this region map represents the backing file
860 * pages which have ever had a reservation assigned which this persists even
861 * after the page is instantiated. A private mapping has a region map
862 * associated with the original mmap which is attached to all VMAs which
863 * reference it, this region map represents those offsets which have consumed
864 * reservation ie. where pages have been instantiated.
865 */
866static unsigned long get_vma_private_data(struct vm_area_struct *vma)
867{
868 return (unsigned long)vma->vm_private_data;
869}
870
871static void set_vma_private_data(struct vm_area_struct *vma,
872 unsigned long value)
873{
874 vma->vm_private_data = (void *)value;
875}
876
877static void
878resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map,
879 struct hugetlb_cgroup *h_cg,
880 struct hstate *h)
881{
882#ifdef CONFIG_CGROUP_HUGETLB
883 if (!h_cg || !h) {
884 resv_map->reservation_counter = NULL;
885 resv_map->pages_per_hpage = 0;
886 resv_map->css = NULL;
887 } else {
888 resv_map->reservation_counter =
889 &h_cg->rsvd_hugepage[hstate_index(h)];
890 resv_map->pages_per_hpage = pages_per_huge_page(h);
891 resv_map->css = &h_cg->css;
892 }
893#endif
894}
895
896struct resv_map *resv_map_alloc(void)
897{
898 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
899 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
900
901 if (!resv_map || !rg) {
902 kfree(resv_map);
903 kfree(rg);
904 return NULL;
905 }
906
907 kref_init(&resv_map->refs);
908 spin_lock_init(&resv_map->lock);
909 INIT_LIST_HEAD(&resv_map->regions);
910
911 resv_map->adds_in_progress = 0;
912 /*
913 * Initialize these to 0. On shared mappings, 0's here indicate these
914 * fields don't do cgroup accounting. On private mappings, these will be
915 * re-initialized to the proper values, to indicate that hugetlb cgroup
916 * reservations are to be un-charged from here.
917 */
918 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL);
919
920 INIT_LIST_HEAD(&resv_map->region_cache);
921 list_add(&rg->link, &resv_map->region_cache);
922 resv_map->region_cache_count = 1;
923
924 return resv_map;
925}
926
927void resv_map_release(struct kref *ref)
928{
929 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
930 struct list_head *head = &resv_map->region_cache;
931 struct file_region *rg, *trg;
932
933 /* Clear out any active regions before we release the map. */
934 region_del(resv_map, 0, LONG_MAX);
935
936 /* ... and any entries left in the cache */
937 list_for_each_entry_safe(rg, trg, head, link) {
938 list_del(&rg->link);
939 kfree(rg);
940 }
941
942 VM_BUG_ON(resv_map->adds_in_progress);
943
944 kfree(resv_map);
945}
946
947static inline struct resv_map *inode_resv_map(struct inode *inode)
948{
949 /*
950 * At inode evict time, i_mapping may not point to the original
951 * address space within the inode. This original address space
952 * contains the pointer to the resv_map. So, always use the
953 * address space embedded within the inode.
954 * The VERY common case is inode->mapping == &inode->i_data but,
955 * this may not be true for device special inodes.
956 */
957 return (struct resv_map *)(&inode->i_data)->private_data;
958}
959
960static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
961{
962 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
963 if (vma->vm_flags & VM_MAYSHARE) {
964 struct address_space *mapping = vma->vm_file->f_mapping;
965 struct inode *inode = mapping->host;
966
967 return inode_resv_map(inode);
968
969 } else {
970 return (struct resv_map *)(get_vma_private_data(vma) &
971 ~HPAGE_RESV_MASK);
972 }
973}
974
975static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
976{
977 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
978 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
979
980 set_vma_private_data(vma, (get_vma_private_data(vma) &
981 HPAGE_RESV_MASK) | (unsigned long)map);
982}
983
984static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
985{
986 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
987 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
988
989 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
990}
991
992static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
993{
994 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
995
996 return (get_vma_private_data(vma) & flag) != 0;
997}
998
999/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
1000void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
1001{
1002 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1003 if (!(vma->vm_flags & VM_MAYSHARE))
1004 vma->vm_private_data = (void *)0;
1005}
1006
1007/* Returns true if the VMA has associated reserve pages */
1008static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
1009{
1010 if (vma->vm_flags & VM_NORESERVE) {
1011 /*
1012 * This address is already reserved by other process(chg == 0),
1013 * so, we should decrement reserved count. Without decrementing,
1014 * reserve count remains after releasing inode, because this
1015 * allocated page will go into page cache and is regarded as
1016 * coming from reserved pool in releasing step. Currently, we
1017 * don't have any other solution to deal with this situation
1018 * properly, so add work-around here.
1019 */
1020 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
1021 return true;
1022 else
1023 return false;
1024 }
1025
1026 /* Shared mappings always use reserves */
1027 if (vma->vm_flags & VM_MAYSHARE) {
1028 /*
1029 * We know VM_NORESERVE is not set. Therefore, there SHOULD
1030 * be a region map for all pages. The only situation where
1031 * there is no region map is if a hole was punched via
1032 * fallocate. In this case, there really are no reserves to
1033 * use. This situation is indicated if chg != 0.
1034 */
1035 if (chg)
1036 return false;
1037 else
1038 return true;
1039 }
1040
1041 /*
1042 * Only the process that called mmap() has reserves for
1043 * private mappings.
1044 */
1045 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1046 /*
1047 * Like the shared case above, a hole punch or truncate
1048 * could have been performed on the private mapping.
1049 * Examine the value of chg to determine if reserves
1050 * actually exist or were previously consumed.
1051 * Very Subtle - The value of chg comes from a previous
1052 * call to vma_needs_reserves(). The reserve map for
1053 * private mappings has different (opposite) semantics
1054 * than that of shared mappings. vma_needs_reserves()
1055 * has already taken this difference in semantics into
1056 * account. Therefore, the meaning of chg is the same
1057 * as in the shared case above. Code could easily be
1058 * combined, but keeping it separate draws attention to
1059 * subtle differences.
1060 */
1061 if (chg)
1062 return false;
1063 else
1064 return true;
1065 }
1066
1067 return false;
1068}
1069
1070static void enqueue_huge_page(struct hstate *h, struct page *page)
1071{
1072 int nid = page_to_nid(page);
1073
1074 lockdep_assert_held(&hugetlb_lock);
1075 list_move(&page->lru, &h->hugepage_freelists[nid]);
1076 h->free_huge_pages++;
1077 h->free_huge_pages_node[nid]++;
1078 SetHPageFreed(page);
1079}
1080
1081static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
1082{
1083 struct page *page;
1084 bool pin = !!(current->flags & PF_MEMALLOC_PIN);
1085
1086 lockdep_assert_held(&hugetlb_lock);
1087 list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
1088 if (pin && !is_pinnable_page(page))
1089 continue;
1090
1091 if (PageHWPoison(page))
1092 continue;
1093
1094 list_move(&page->lru, &h->hugepage_activelist);
1095 set_page_refcounted(page);
1096 ClearHPageFreed(page);
1097 h->free_huge_pages--;
1098 h->free_huge_pages_node[nid]--;
1099 return page;
1100 }
1101
1102 return NULL;
1103}
1104
1105static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
1106 nodemask_t *nmask)
1107{
1108 unsigned int cpuset_mems_cookie;
1109 struct zonelist *zonelist;
1110 struct zone *zone;
1111 struct zoneref *z;
1112 int node = NUMA_NO_NODE;
1113
1114 zonelist = node_zonelist(nid, gfp_mask);
1115
1116retry_cpuset:
1117 cpuset_mems_cookie = read_mems_allowed_begin();
1118 for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) {
1119 struct page *page;
1120
1121 if (!cpuset_zone_allowed(zone, gfp_mask))
1122 continue;
1123 /*
1124 * no need to ask again on the same node. Pool is node rather than
1125 * zone aware
1126 */
1127 if (zone_to_nid(zone) == node)
1128 continue;
1129 node = zone_to_nid(zone);
1130
1131 page = dequeue_huge_page_node_exact(h, node);
1132 if (page)
1133 return page;
1134 }
1135 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
1136 goto retry_cpuset;
1137
1138 return NULL;
1139}
1140
1141static struct page *dequeue_huge_page_vma(struct hstate *h,
1142 struct vm_area_struct *vma,
1143 unsigned long address, int avoid_reserve,
1144 long chg)
1145{
1146 struct page *page;
1147 struct mempolicy *mpol;
1148 gfp_t gfp_mask;
1149 nodemask_t *nodemask;
1150 int nid;
1151
1152 /*
1153 * A child process with MAP_PRIVATE mappings created by their parent
1154 * have no page reserves. This check ensures that reservations are
1155 * not "stolen". The child may still get SIGKILLed
1156 */
1157 if (!vma_has_reserves(vma, chg) &&
1158 h->free_huge_pages - h->resv_huge_pages == 0)
1159 goto err;
1160
1161 /* If reserves cannot be used, ensure enough pages are in the pool */
1162 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
1163 goto err;
1164
1165 gfp_mask = htlb_alloc_mask(h);
1166 nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1167 page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask);
1168 if (page && !avoid_reserve && vma_has_reserves(vma, chg)) {
1169 SetHPageRestoreReserve(page);
1170 h->resv_huge_pages--;
1171 }
1172
1173 mpol_cond_put(mpol);
1174 return page;
1175
1176err:
1177 return NULL;
1178}
1179
1180/*
1181 * common helper functions for hstate_next_node_to_{alloc|free}.
1182 * We may have allocated or freed a huge page based on a different
1183 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1184 * be outside of *nodes_allowed. Ensure that we use an allowed
1185 * node for alloc or free.
1186 */
1187static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
1188{
1189 nid = next_node_in(nid, *nodes_allowed);
1190 VM_BUG_ON(nid >= MAX_NUMNODES);
1191
1192 return nid;
1193}
1194
1195static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
1196{
1197 if (!node_isset(nid, *nodes_allowed))
1198 nid = next_node_allowed(nid, nodes_allowed);
1199 return nid;
1200}
1201
1202/*
1203 * returns the previously saved node ["this node"] from which to
1204 * allocate a persistent huge page for the pool and advance the
1205 * next node from which to allocate, handling wrap at end of node
1206 * mask.
1207 */
1208static int hstate_next_node_to_alloc(struct hstate *h,
1209 nodemask_t *nodes_allowed)
1210{
1211 int nid;
1212
1213 VM_BUG_ON(!nodes_allowed);
1214
1215 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
1216 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
1217
1218 return nid;
1219}
1220
1221/*
1222 * helper for remove_pool_huge_page() - return the previously saved
1223 * node ["this node"] from which to free a huge page. Advance the
1224 * next node id whether or not we find a free huge page to free so
1225 * that the next attempt to free addresses the next node.
1226 */
1227static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
1228{
1229 int nid;
1230
1231 VM_BUG_ON(!nodes_allowed);
1232
1233 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
1234 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
1235
1236 return nid;
1237}
1238
1239#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1240 for (nr_nodes = nodes_weight(*mask); \
1241 nr_nodes > 0 && \
1242 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1243 nr_nodes--)
1244
1245#define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1246 for (nr_nodes = nodes_weight(*mask); \
1247 nr_nodes > 0 && \
1248 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1249 nr_nodes--)
1250
1251#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1252static void destroy_compound_gigantic_page(struct page *page,
1253 unsigned int order)
1254{
1255 int i;
1256 int nr_pages = 1 << order;
1257 struct page *p = page + 1;
1258
1259 atomic_set(compound_mapcount_ptr(page), 0);
1260 atomic_set(compound_pincount_ptr(page), 0);
1261
1262 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1263 clear_compound_head(p);
1264 set_page_refcounted(p);
1265 }
1266
1267 set_compound_order(page, 0);
1268 page[1].compound_nr = 0;
1269 __ClearPageHead(page);
1270}
1271
1272static void free_gigantic_page(struct page *page, unsigned int order)
1273{
1274 /*
1275 * If the page isn't allocated using the cma allocator,
1276 * cma_release() returns false.
1277 */
1278#ifdef CONFIG_CMA
1279 if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order))
1280 return;
1281#endif
1282
1283 free_contig_range(page_to_pfn(page), 1 << order);
1284}
1285
1286#ifdef CONFIG_CONTIG_ALLOC
1287static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1288 int nid, nodemask_t *nodemask)
1289{
1290 unsigned long nr_pages = pages_per_huge_page(h);
1291 if (nid == NUMA_NO_NODE)
1292 nid = numa_mem_id();
1293
1294#ifdef CONFIG_CMA
1295 {
1296 struct page *page;
1297 int node;
1298
1299 if (hugetlb_cma[nid]) {
1300 page = cma_alloc(hugetlb_cma[nid], nr_pages,
1301 huge_page_order(h), true);
1302 if (page)
1303 return page;
1304 }
1305
1306 if (!(gfp_mask & __GFP_THISNODE)) {
1307 for_each_node_mask(node, *nodemask) {
1308 if (node == nid || !hugetlb_cma[node])
1309 continue;
1310
1311 page = cma_alloc(hugetlb_cma[node], nr_pages,
1312 huge_page_order(h), true);
1313 if (page)
1314 return page;
1315 }
1316 }
1317 }
1318#endif
1319
1320 return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1321}
1322
1323#else /* !CONFIG_CONTIG_ALLOC */
1324static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1325 int nid, nodemask_t *nodemask)
1326{
1327 return NULL;
1328}
1329#endif /* CONFIG_CONTIG_ALLOC */
1330
1331#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1332static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1333 int nid, nodemask_t *nodemask)
1334{
1335 return NULL;
1336}
1337static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1338static inline void destroy_compound_gigantic_page(struct page *page,
1339 unsigned int order) { }
1340#endif
1341
1342/*
1343 * Remove hugetlb page from lists, and update dtor so that page appears
1344 * as just a compound page. A reference is held on the page.
1345 *
1346 * Must be called with hugetlb lock held.
1347 */
1348static void remove_hugetlb_page(struct hstate *h, struct page *page,
1349 bool adjust_surplus)
1350{
1351 int nid = page_to_nid(page);
1352
1353 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1354 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
1355
1356 lockdep_assert_held(&hugetlb_lock);
1357 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1358 return;
1359
1360 list_del(&page->lru);
1361
1362 if (HPageFreed(page)) {
1363 h->free_huge_pages--;
1364 h->free_huge_pages_node[nid]--;
1365 }
1366 if (adjust_surplus) {
1367 h->surplus_huge_pages--;
1368 h->surplus_huge_pages_node[nid]--;
1369 }
1370
1371 set_page_refcounted(page);
1372 set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
1373
1374 h->nr_huge_pages--;
1375 h->nr_huge_pages_node[nid]--;
1376}
1377
1378static void add_hugetlb_page(struct hstate *h, struct page *page,
1379 bool adjust_surplus)
1380{
1381 int zeroed;
1382 int nid = page_to_nid(page);
1383
1384 VM_BUG_ON_PAGE(!HPageVmemmapOptimized(page), page);
1385
1386 lockdep_assert_held(&hugetlb_lock);
1387
1388 INIT_LIST_HEAD(&page->lru);
1389 h->nr_huge_pages++;
1390 h->nr_huge_pages_node[nid]++;
1391
1392 if (adjust_surplus) {
1393 h->surplus_huge_pages++;
1394 h->surplus_huge_pages_node[nid]++;
1395 }
1396
1397 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1398 set_page_private(page, 0);
1399 SetHPageVmemmapOptimized(page);
1400
1401 /*
1402 * This page is now managed by the hugetlb allocator and has
1403 * no users -- drop the last reference.
1404 */
1405 zeroed = put_page_testzero(page);
1406 VM_BUG_ON_PAGE(!zeroed, page);
1407 arch_clear_hugepage_flags(page);
1408 enqueue_huge_page(h, page);
1409}
1410
1411static void __update_and_free_page(struct hstate *h, struct page *page)
1412{
1413 int i;
1414 struct page *subpage = page;
1415
1416 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1417 return;
1418
1419 if (alloc_huge_page_vmemmap(h, page)) {
1420 spin_lock_irq(&hugetlb_lock);
1421 /*
1422 * If we cannot allocate vmemmap pages, just refuse to free the
1423 * page and put the page back on the hugetlb free list and treat
1424 * as a surplus page.
1425 */
1426 add_hugetlb_page(h, page, true);
1427 spin_unlock_irq(&hugetlb_lock);
1428 return;
1429 }
1430
1431 for (i = 0; i < pages_per_huge_page(h);
1432 i++, subpage = mem_map_next(subpage, page, i)) {
1433 subpage->flags &= ~(1 << PG_locked | 1 << PG_error |
1434 1 << PG_referenced | 1 << PG_dirty |
1435 1 << PG_active | 1 << PG_private |
1436 1 << PG_writeback);
1437 }
1438 if (hstate_is_gigantic(h)) {
1439 destroy_compound_gigantic_page(page, huge_page_order(h));
1440 free_gigantic_page(page, huge_page_order(h));
1441 } else {
1442 __free_pages(page, huge_page_order(h));
1443 }
1444}
1445
1446/*
1447 * As update_and_free_page() can be called under any context, so we cannot
1448 * use GFP_KERNEL to allocate vmemmap pages. However, we can defer the
1449 * actual freeing in a workqueue to prevent from using GFP_ATOMIC to allocate
1450 * the vmemmap pages.
1451 *
1452 * free_hpage_workfn() locklessly retrieves the linked list of pages to be
1453 * freed and frees them one-by-one. As the page->mapping pointer is going
1454 * to be cleared in free_hpage_workfn() anyway, it is reused as the llist_node
1455 * structure of a lockless linked list of huge pages to be freed.
1456 */
1457static LLIST_HEAD(hpage_freelist);
1458
1459static void free_hpage_workfn(struct work_struct *work)
1460{
1461 struct llist_node *node;
1462
1463 node = llist_del_all(&hpage_freelist);
1464
1465 while (node) {
1466 struct page *page;
1467 struct hstate *h;
1468
1469 page = container_of((struct address_space **)node,
1470 struct page, mapping);
1471 node = node->next;
1472 page->mapping = NULL;
1473 /*
1474 * The VM_BUG_ON_PAGE(!PageHuge(page), page) in page_hstate()
1475 * is going to trigger because a previous call to
1476 * remove_hugetlb_page() will set_compound_page_dtor(page,
1477 * NULL_COMPOUND_DTOR), so do not use page_hstate() directly.
1478 */
1479 h = size_to_hstate(page_size(page));
1480
1481 __update_and_free_page(h, page);
1482
1483 cond_resched();
1484 }
1485}
1486static DECLARE_WORK(free_hpage_work, free_hpage_workfn);
1487
1488static inline void flush_free_hpage_work(struct hstate *h)
1489{
1490 if (free_vmemmap_pages_per_hpage(h))
1491 flush_work(&free_hpage_work);
1492}
1493
1494static void update_and_free_page(struct hstate *h, struct page *page,
1495 bool atomic)
1496{
1497 if (!HPageVmemmapOptimized(page) || !atomic) {
1498 __update_and_free_page(h, page);
1499 return;
1500 }
1501
1502 /*
1503 * Defer freeing to avoid using GFP_ATOMIC to allocate vmemmap pages.
1504 *
1505 * Only call schedule_work() if hpage_freelist is previously
1506 * empty. Otherwise, schedule_work() had been called but the workfn
1507 * hasn't retrieved the list yet.
1508 */
1509 if (llist_add((struct llist_node *)&page->mapping, &hpage_freelist))
1510 schedule_work(&free_hpage_work);
1511}
1512
1513static void update_and_free_pages_bulk(struct hstate *h, struct list_head *list)
1514{
1515 struct page *page, *t_page;
1516
1517 list_for_each_entry_safe(page, t_page, list, lru) {
1518 update_and_free_page(h, page, false);
1519 cond_resched();
1520 }
1521}
1522
1523struct hstate *size_to_hstate(unsigned long size)
1524{
1525 struct hstate *h;
1526
1527 for_each_hstate(h) {
1528 if (huge_page_size(h) == size)
1529 return h;
1530 }
1531 return NULL;
1532}
1533
1534void free_huge_page(struct page *page)
1535{
1536 /*
1537 * Can't pass hstate in here because it is called from the
1538 * compound page destructor.
1539 */
1540 struct hstate *h = page_hstate(page);
1541 int nid = page_to_nid(page);
1542 struct hugepage_subpool *spool = hugetlb_page_subpool(page);
1543 bool restore_reserve;
1544 unsigned long flags;
1545
1546 VM_BUG_ON_PAGE(page_count(page), page);
1547 VM_BUG_ON_PAGE(page_mapcount(page), page);
1548
1549 hugetlb_set_page_subpool(page, NULL);
1550 page->mapping = NULL;
1551 restore_reserve = HPageRestoreReserve(page);
1552 ClearHPageRestoreReserve(page);
1553
1554 /*
1555 * If HPageRestoreReserve was set on page, page allocation consumed a
1556 * reservation. If the page was associated with a subpool, there
1557 * would have been a page reserved in the subpool before allocation
1558 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1559 * reservation, do not call hugepage_subpool_put_pages() as this will
1560 * remove the reserved page from the subpool.
1561 */
1562 if (!restore_reserve) {
1563 /*
1564 * A return code of zero implies that the subpool will be
1565 * under its minimum size if the reservation is not restored
1566 * after page is free. Therefore, force restore_reserve
1567 * operation.
1568 */
1569 if (hugepage_subpool_put_pages(spool, 1) == 0)
1570 restore_reserve = true;
1571 }
1572
1573 spin_lock_irqsave(&hugetlb_lock, flags);
1574 ClearHPageMigratable(page);
1575 hugetlb_cgroup_uncharge_page(hstate_index(h),
1576 pages_per_huge_page(h), page);
1577 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
1578 pages_per_huge_page(h), page);
1579 if (restore_reserve)
1580 h->resv_huge_pages++;
1581
1582 if (HPageTemporary(page)) {
1583 remove_hugetlb_page(h, page, false);
1584 spin_unlock_irqrestore(&hugetlb_lock, flags);
1585 update_and_free_page(h, page, true);
1586 } else if (h->surplus_huge_pages_node[nid]) {
1587 /* remove the page from active list */
1588 remove_hugetlb_page(h, page, true);
1589 spin_unlock_irqrestore(&hugetlb_lock, flags);
1590 update_and_free_page(h, page, true);
1591 } else {
1592 arch_clear_hugepage_flags(page);
1593 enqueue_huge_page(h, page);
1594 spin_unlock_irqrestore(&hugetlb_lock, flags);
1595 }
1596}
1597
1598/*
1599 * Must be called with the hugetlb lock held
1600 */
1601static void __prep_account_new_huge_page(struct hstate *h, int nid)
1602{
1603 lockdep_assert_held(&hugetlb_lock);
1604 h->nr_huge_pages++;
1605 h->nr_huge_pages_node[nid]++;
1606}
1607
1608static void __prep_new_huge_page(struct hstate *h, struct page *page)
1609{
1610 free_huge_page_vmemmap(h, page);
1611 INIT_LIST_HEAD(&page->lru);
1612 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1613 hugetlb_set_page_subpool(page, NULL);
1614 set_hugetlb_cgroup(page, NULL);
1615 set_hugetlb_cgroup_rsvd(page, NULL);
1616}
1617
1618static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1619{
1620 __prep_new_huge_page(h, page);
1621 spin_lock_irq(&hugetlb_lock);
1622 __prep_account_new_huge_page(h, nid);
1623 spin_unlock_irq(&hugetlb_lock);
1624}
1625
1626static bool prep_compound_gigantic_page(struct page *page, unsigned int order)
1627{
1628 int i, j;
1629 int nr_pages = 1 << order;
1630 struct page *p = page + 1;
1631
1632 /* we rely on prep_new_huge_page to set the destructor */
1633 set_compound_order(page, order);
1634 __ClearPageReserved(page);
1635 __SetPageHead(page);
1636 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1637 /*
1638 * For gigantic hugepages allocated through bootmem at
1639 * boot, it's safer to be consistent with the not-gigantic
1640 * hugepages and clear the PG_reserved bit from all tail pages
1641 * too. Otherwise drivers using get_user_pages() to access tail
1642 * pages may get the reference counting wrong if they see
1643 * PG_reserved set on a tail page (despite the head page not
1644 * having PG_reserved set). Enforcing this consistency between
1645 * head and tail pages allows drivers to optimize away a check
1646 * on the head page when they need know if put_page() is needed
1647 * after get_user_pages().
1648 */
1649 __ClearPageReserved(p);
1650 /*
1651 * Subtle and very unlikely
1652 *
1653 * Gigantic 'page allocators' such as memblock or cma will
1654 * return a set of pages with each page ref counted. We need
1655 * to turn this set of pages into a compound page with tail
1656 * page ref counts set to zero. Code such as speculative page
1657 * cache adding could take a ref on a 'to be' tail page.
1658 * We need to respect any increased ref count, and only set
1659 * the ref count to zero if count is currently 1. If count
1660 * is not 1, we call synchronize_rcu in the hope that a rcu
1661 * grace period will cause ref count to drop and then retry.
1662 * If count is still inflated on retry we return an error and
1663 * must discard the pages.
1664 */
1665 if (!page_ref_freeze(p, 1)) {
1666 pr_info("HugeTLB unexpected inflated ref count on freshly allocated page\n");
1667 synchronize_rcu();
1668 if (!page_ref_freeze(p, 1))
1669 goto out_error;
1670 }
1671 set_page_count(p, 0);
1672 set_compound_head(p, page);
1673 }
1674 atomic_set(compound_mapcount_ptr(page), -1);
1675 atomic_set(compound_pincount_ptr(page), 0);
1676 return true;
1677
1678out_error:
1679 /* undo tail page modifications made above */
1680 p = page + 1;
1681 for (j = 1; j < i; j++, p = mem_map_next(p, page, j)) {
1682 clear_compound_head(p);
1683 set_page_refcounted(p);
1684 }
1685 /* need to clear PG_reserved on remaining tail pages */
1686 for (; j < nr_pages; j++, p = mem_map_next(p, page, j))
1687 __ClearPageReserved(p);
1688 set_compound_order(page, 0);
1689 page[1].compound_nr = 0;
1690 __ClearPageHead(page);
1691 return false;
1692}
1693
1694/*
1695 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1696 * transparent huge pages. See the PageTransHuge() documentation for more
1697 * details.
1698 */
1699int PageHuge(struct page *page)
1700{
1701 if (!PageCompound(page))
1702 return 0;
1703
1704 page = compound_head(page);
1705 return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1706}
1707EXPORT_SYMBOL_GPL(PageHuge);
1708
1709/*
1710 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1711 * normal or transparent huge pages.
1712 */
1713int PageHeadHuge(struct page *page_head)
1714{
1715 if (!PageHead(page_head))
1716 return 0;
1717
1718 return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
1719}
1720
1721/*
1722 * Find and lock address space (mapping) in write mode.
1723 *
1724 * Upon entry, the page is locked which means that page_mapping() is
1725 * stable. Due to locking order, we can only trylock_write. If we can
1726 * not get the lock, simply return NULL to caller.
1727 */
1728struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
1729{
1730 struct address_space *mapping = page_mapping(hpage);
1731
1732 if (!mapping)
1733 return mapping;
1734
1735 if (i_mmap_trylock_write(mapping))
1736 return mapping;
1737
1738 return NULL;
1739}
1740
1741pgoff_t hugetlb_basepage_index(struct page *page)
1742{
1743 struct page *page_head = compound_head(page);
1744 pgoff_t index = page_index(page_head);
1745 unsigned long compound_idx;
1746
1747 if (compound_order(page_head) >= MAX_ORDER)
1748 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
1749 else
1750 compound_idx = page - page_head;
1751
1752 return (index << compound_order(page_head)) + compound_idx;
1753}
1754
1755static struct page *alloc_buddy_huge_page(struct hstate *h,
1756 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1757 nodemask_t *node_alloc_noretry)
1758{
1759 int order = huge_page_order(h);
1760 struct page *page;
1761 bool alloc_try_hard = true;
1762
1763 /*
1764 * By default we always try hard to allocate the page with
1765 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
1766 * a loop (to adjust global huge page counts) and previous allocation
1767 * failed, do not continue to try hard on the same node. Use the
1768 * node_alloc_noretry bitmap to manage this state information.
1769 */
1770 if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry))
1771 alloc_try_hard = false;
1772 gfp_mask |= __GFP_COMP|__GFP_NOWARN;
1773 if (alloc_try_hard)
1774 gfp_mask |= __GFP_RETRY_MAYFAIL;
1775 if (nid == NUMA_NO_NODE)
1776 nid = numa_mem_id();
1777 page = __alloc_pages(gfp_mask, order, nid, nmask);
1778 if (page)
1779 __count_vm_event(HTLB_BUDDY_PGALLOC);
1780 else
1781 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1782
1783 /*
1784 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
1785 * indicates an overall state change. Clear bit so that we resume
1786 * normal 'try hard' allocations.
1787 */
1788 if (node_alloc_noretry && page && !alloc_try_hard)
1789 node_clear(nid, *node_alloc_noretry);
1790
1791 /*
1792 * If we tried hard to get a page but failed, set bit so that
1793 * subsequent attempts will not try as hard until there is an
1794 * overall state change.
1795 */
1796 if (node_alloc_noretry && !page && alloc_try_hard)
1797 node_set(nid, *node_alloc_noretry);
1798
1799 return page;
1800}
1801
1802/*
1803 * Common helper to allocate a fresh hugetlb page. All specific allocators
1804 * should use this function to get new hugetlb pages
1805 */
1806static struct page *alloc_fresh_huge_page(struct hstate *h,
1807 gfp_t gfp_mask, int nid, nodemask_t *nmask,
1808 nodemask_t *node_alloc_noretry)
1809{
1810 struct page *page;
1811 bool retry = false;
1812
1813retry:
1814 if (hstate_is_gigantic(h))
1815 page = alloc_gigantic_page(h, gfp_mask, nid, nmask);
1816 else
1817 page = alloc_buddy_huge_page(h, gfp_mask,
1818 nid, nmask, node_alloc_noretry);
1819 if (!page)
1820 return NULL;
1821
1822 if (hstate_is_gigantic(h)) {
1823 if (!prep_compound_gigantic_page(page, huge_page_order(h))) {
1824 /*
1825 * Rare failure to convert pages to compound page.
1826 * Free pages and try again - ONCE!
1827 */
1828 free_gigantic_page(page, huge_page_order(h));
1829 if (!retry) {
1830 retry = true;
1831 goto retry;
1832 }
1833 pr_warn("HugeTLB page can not be used due to unexpected inflated ref count\n");
1834 return NULL;
1835 }
1836 }
1837 prep_new_huge_page(h, page, page_to_nid(page));
1838
1839 return page;
1840}
1841
1842/*
1843 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
1844 * manner.
1845 */
1846static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1847 nodemask_t *node_alloc_noretry)
1848{
1849 struct page *page;
1850 int nr_nodes, node;
1851 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1852
1853 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1854 page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
1855 node_alloc_noretry);
1856 if (page)
1857 break;
1858 }
1859
1860 if (!page)
1861 return 0;
1862
1863 put_page(page); /* free it into the hugepage allocator */
1864
1865 return 1;
1866}
1867
1868/*
1869 * Remove huge page from pool from next node to free. Attempt to keep
1870 * persistent huge pages more or less balanced over allowed nodes.
1871 * This routine only 'removes' the hugetlb page. The caller must make
1872 * an additional call to free the page to low level allocators.
1873 * Called with hugetlb_lock locked.
1874 */
1875static struct page *remove_pool_huge_page(struct hstate *h,
1876 nodemask_t *nodes_allowed,
1877 bool acct_surplus)
1878{
1879 int nr_nodes, node;
1880 struct page *page = NULL;
1881
1882 lockdep_assert_held(&hugetlb_lock);
1883 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1884 /*
1885 * If we're returning unused surplus pages, only examine
1886 * nodes with surplus pages.
1887 */
1888 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1889 !list_empty(&h->hugepage_freelists[node])) {
1890 page = list_entry(h->hugepage_freelists[node].next,
1891 struct page, lru);
1892 remove_hugetlb_page(h, page, acct_surplus);
1893 break;
1894 }
1895 }
1896
1897 return page;
1898}
1899
1900/*
1901 * Dissolve a given free hugepage into free buddy pages. This function does
1902 * nothing for in-use hugepages and non-hugepages.
1903 * This function returns values like below:
1904 *
1905 * -ENOMEM: failed to allocate vmemmap pages to free the freed hugepages
1906 * when the system is under memory pressure and the feature of
1907 * freeing unused vmemmap pages associated with each hugetlb page
1908 * is enabled.
1909 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
1910 * (allocated or reserved.)
1911 * 0: successfully dissolved free hugepages or the page is not a
1912 * hugepage (considered as already dissolved)
1913 */
1914int dissolve_free_huge_page(struct page *page)
1915{
1916 int rc = -EBUSY;
1917
1918retry:
1919 /* Not to disrupt normal path by vainly holding hugetlb_lock */
1920 if (!PageHuge(page))
1921 return 0;
1922
1923 spin_lock_irq(&hugetlb_lock);
1924 if (!PageHuge(page)) {
1925 rc = 0;
1926 goto out;
1927 }
1928
1929 if (!page_count(page)) {
1930 struct page *head = compound_head(page);
1931 struct hstate *h = page_hstate(head);
1932 if (h->free_huge_pages - h->resv_huge_pages == 0)
1933 goto out;
1934
1935 /*
1936 * We should make sure that the page is already on the free list
1937 * when it is dissolved.
1938 */
1939 if (unlikely(!HPageFreed(head))) {
1940 spin_unlock_irq(&hugetlb_lock);
1941 cond_resched();
1942
1943 /*
1944 * Theoretically, we should return -EBUSY when we
1945 * encounter this race. In fact, we have a chance
1946 * to successfully dissolve the page if we do a
1947 * retry. Because the race window is quite small.
1948 * If we seize this opportunity, it is an optimization
1949 * for increasing the success rate of dissolving page.
1950 */
1951 goto retry;
1952 }
1953
1954 remove_hugetlb_page(h, head, false);
1955 h->max_huge_pages--;
1956 spin_unlock_irq(&hugetlb_lock);
1957
1958 /*
1959 * Normally update_and_free_page will allocate required vmemmmap
1960 * before freeing the page. update_and_free_page will fail to
1961 * free the page if it can not allocate required vmemmap. We
1962 * need to adjust max_huge_pages if the page is not freed.
1963 * Attempt to allocate vmemmmap here so that we can take
1964 * appropriate action on failure.
1965 */
1966 rc = alloc_huge_page_vmemmap(h, head);
1967 if (!rc) {
1968 /*
1969 * Move PageHWPoison flag from head page to the raw
1970 * error page, which makes any subpages rather than
1971 * the error page reusable.
1972 */
1973 if (PageHWPoison(head) && page != head) {
1974 SetPageHWPoison(page);
1975 ClearPageHWPoison(head);
1976 }
1977 update_and_free_page(h, head, false);
1978 } else {
1979 spin_lock_irq(&hugetlb_lock);
1980 add_hugetlb_page(h, head, false);
1981 h->max_huge_pages++;
1982 spin_unlock_irq(&hugetlb_lock);
1983 }
1984
1985 return rc;
1986 }
1987out:
1988 spin_unlock_irq(&hugetlb_lock);
1989 return rc;
1990}
1991
1992/*
1993 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1994 * make specified memory blocks removable from the system.
1995 * Note that this will dissolve a free gigantic hugepage completely, if any
1996 * part of it lies within the given range.
1997 * Also note that if dissolve_free_huge_page() returns with an error, all
1998 * free hugepages that were dissolved before that error are lost.
1999 */
2000int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
2001{
2002 unsigned long pfn;
2003 struct page *page;
2004 int rc = 0;
2005
2006 if (!hugepages_supported())
2007 return rc;
2008
2009 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
2010 page = pfn_to_page(pfn);
2011 rc = dissolve_free_huge_page(page);
2012 if (rc)
2013 break;
2014 }
2015
2016 return rc;
2017}
2018
2019/*
2020 * Allocates a fresh surplus page from the page allocator.
2021 */
2022static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
2023 int nid, nodemask_t *nmask)
2024{
2025 struct page *page = NULL;
2026
2027 if (hstate_is_gigantic(h))
2028 return NULL;
2029
2030 spin_lock_irq(&hugetlb_lock);
2031 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
2032 goto out_unlock;
2033 spin_unlock_irq(&hugetlb_lock);
2034
2035 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
2036 if (!page)
2037 return NULL;
2038
2039 spin_lock_irq(&hugetlb_lock);
2040 /*
2041 * We could have raced with the pool size change.
2042 * Double check that and simply deallocate the new page
2043 * if we would end up overcommiting the surpluses. Abuse
2044 * temporary page to workaround the nasty free_huge_page
2045 * codeflow
2046 */
2047 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
2048 SetHPageTemporary(page);
2049 spin_unlock_irq(&hugetlb_lock);
2050 put_page(page);
2051 return NULL;
2052 } else {
2053 h->surplus_huge_pages++;
2054 h->surplus_huge_pages_node[page_to_nid(page)]++;
2055 }
2056
2057out_unlock:
2058 spin_unlock_irq(&hugetlb_lock);
2059
2060 return page;
2061}
2062
2063static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
2064 int nid, nodemask_t *nmask)
2065{
2066 struct page *page;
2067
2068 if (hstate_is_gigantic(h))
2069 return NULL;
2070
2071 page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
2072 if (!page)
2073 return NULL;
2074
2075 /*
2076 * We do not account these pages as surplus because they are only
2077 * temporary and will be released properly on the last reference
2078 */
2079 SetHPageTemporary(page);
2080
2081 return page;
2082}
2083
2084/*
2085 * Use the VMA's mpolicy to allocate a huge page from the buddy.
2086 */
2087static
2088struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
2089 struct vm_area_struct *vma, unsigned long addr)
2090{
2091 struct page *page;
2092 struct mempolicy *mpol;
2093 gfp_t gfp_mask = htlb_alloc_mask(h);
2094 int nid;
2095 nodemask_t *nodemask;
2096
2097 nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
2098 page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
2099 mpol_cond_put(mpol);
2100
2101 return page;
2102}
2103
2104/* page migration callback function */
2105struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
2106 nodemask_t *nmask, gfp_t gfp_mask)
2107{
2108 spin_lock_irq(&hugetlb_lock);
2109 if (h->free_huge_pages - h->resv_huge_pages > 0) {
2110 struct page *page;
2111
2112 page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
2113 if (page) {
2114 spin_unlock_irq(&hugetlb_lock);
2115 return page;
2116 }
2117 }
2118 spin_unlock_irq(&hugetlb_lock);
2119
2120 return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
2121}
2122
2123/* mempolicy aware migration callback */
2124struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
2125 unsigned long address)
2126{
2127 struct mempolicy *mpol;
2128 nodemask_t *nodemask;
2129 struct page *page;
2130 gfp_t gfp_mask;
2131 int node;
2132
2133 gfp_mask = htlb_alloc_mask(h);
2134 node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
2135 page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask);
2136 mpol_cond_put(mpol);
2137
2138 return page;
2139}
2140
2141/*
2142 * Increase the hugetlb pool such that it can accommodate a reservation
2143 * of size 'delta'.
2144 */
2145static int gather_surplus_pages(struct hstate *h, long delta)
2146 __must_hold(&hugetlb_lock)
2147{
2148 struct list_head surplus_list;
2149 struct page *page, *tmp;
2150 int ret;
2151 long i;
2152 long needed, allocated;
2153 bool alloc_ok = true;
2154
2155 lockdep_assert_held(&hugetlb_lock);
2156 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
2157 if (needed <= 0) {
2158 h->resv_huge_pages += delta;
2159 return 0;
2160 }
2161
2162 allocated = 0;
2163 INIT_LIST_HEAD(&surplus_list);
2164
2165 ret = -ENOMEM;
2166retry:
2167 spin_unlock_irq(&hugetlb_lock);
2168 for (i = 0; i < needed; i++) {
2169 page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
2170 NUMA_NO_NODE, NULL);
2171 if (!page) {
2172 alloc_ok = false;
2173 break;
2174 }
2175 list_add(&page->lru, &surplus_list);
2176 cond_resched();
2177 }
2178 allocated += i;
2179
2180 /*
2181 * After retaking hugetlb_lock, we need to recalculate 'needed'
2182 * because either resv_huge_pages or free_huge_pages may have changed.
2183 */
2184 spin_lock_irq(&hugetlb_lock);
2185 needed = (h->resv_huge_pages + delta) -
2186 (h->free_huge_pages + allocated);
2187 if (needed > 0) {
2188 if (alloc_ok)
2189 goto retry;
2190 /*
2191 * We were not able to allocate enough pages to
2192 * satisfy the entire reservation so we free what
2193 * we've allocated so far.
2194 */
2195 goto free;
2196 }
2197 /*
2198 * The surplus_list now contains _at_least_ the number of extra pages
2199 * needed to accommodate the reservation. Add the appropriate number
2200 * of pages to the hugetlb pool and free the extras back to the buddy
2201 * allocator. Commit the entire reservation here to prevent another
2202 * process from stealing the pages as they are added to the pool but
2203 * before they are reserved.
2204 */
2205 needed += allocated;
2206 h->resv_huge_pages += delta;
2207 ret = 0;
2208
2209 /* Free the needed pages to the hugetlb pool */
2210 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
2211 int zeroed;
2212
2213 if ((--needed) < 0)
2214 break;
2215 /*
2216 * This page is now managed by the hugetlb allocator and has
2217 * no users -- drop the buddy allocator's reference.
2218 */
2219 zeroed = put_page_testzero(page);
2220 VM_BUG_ON_PAGE(!zeroed, page);
2221 enqueue_huge_page(h, page);
2222 }
2223free:
2224 spin_unlock_irq(&hugetlb_lock);
2225
2226 /* Free unnecessary surplus pages to the buddy allocator */
2227 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
2228 put_page(page);
2229 spin_lock_irq(&hugetlb_lock);
2230
2231 return ret;
2232}
2233
2234/*
2235 * This routine has two main purposes:
2236 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2237 * in unused_resv_pages. This corresponds to the prior adjustments made
2238 * to the associated reservation map.
2239 * 2) Free any unused surplus pages that may have been allocated to satisfy
2240 * the reservation. As many as unused_resv_pages may be freed.
2241 */
2242static void return_unused_surplus_pages(struct hstate *h,
2243 unsigned long unused_resv_pages)
2244{
2245 unsigned long nr_pages;
2246 struct page *page;
2247 LIST_HEAD(page_list);
2248
2249 lockdep_assert_held(&hugetlb_lock);
2250 /* Uncommit the reservation */
2251 h->resv_huge_pages -= unused_resv_pages;
2252
2253 /* Cannot return gigantic pages currently */
2254 if (hstate_is_gigantic(h))
2255 goto out;
2256
2257 /*
2258 * Part (or even all) of the reservation could have been backed
2259 * by pre-allocated pages. Only free surplus pages.
2260 */
2261 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2262
2263 /*
2264 * We want to release as many surplus pages as possible, spread
2265 * evenly across all nodes with memory. Iterate across these nodes
2266 * until we can no longer free unreserved surplus pages. This occurs
2267 * when the nodes with surplus pages have no free pages.
2268 * remove_pool_huge_page() will balance the freed pages across the
2269 * on-line nodes with memory and will handle the hstate accounting.
2270 */
2271 while (nr_pages--) {
2272 page = remove_pool_huge_page(h, &node_states[N_MEMORY], 1);
2273 if (!page)
2274 goto out;
2275
2276 list_add(&page->lru, &page_list);
2277 }
2278
2279out:
2280 spin_unlock_irq(&hugetlb_lock);
2281 update_and_free_pages_bulk(h, &page_list);
2282 spin_lock_irq(&hugetlb_lock);
2283}
2284
2285
2286/*
2287 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2288 * are used by the huge page allocation routines to manage reservations.
2289 *
2290 * vma_needs_reservation is called to determine if the huge page at addr
2291 * within the vma has an associated reservation. If a reservation is
2292 * needed, the value 1 is returned. The caller is then responsible for
2293 * managing the global reservation and subpool usage counts. After
2294 * the huge page has been allocated, vma_commit_reservation is called
2295 * to add the page to the reservation map. If the page allocation fails,
2296 * the reservation must be ended instead of committed. vma_end_reservation
2297 * is called in such cases.
2298 *
2299 * In the normal case, vma_commit_reservation returns the same value
2300 * as the preceding vma_needs_reservation call. The only time this
2301 * is not the case is if a reserve map was changed between calls. It
2302 * is the responsibility of the caller to notice the difference and
2303 * take appropriate action.
2304 *
2305 * vma_add_reservation is used in error paths where a reservation must
2306 * be restored when a newly allocated huge page must be freed. It is
2307 * to be called after calling vma_needs_reservation to determine if a
2308 * reservation exists.
2309 *
2310 * vma_del_reservation is used in error paths where an entry in the reserve
2311 * map was created during huge page allocation and must be removed. It is to
2312 * be called after calling vma_needs_reservation to determine if a reservation
2313 * exists.
2314 */
2315enum vma_resv_mode {
2316 VMA_NEEDS_RESV,
2317 VMA_COMMIT_RESV,
2318 VMA_END_RESV,
2319 VMA_ADD_RESV,
2320 VMA_DEL_RESV,
2321};
2322static long __vma_reservation_common(struct hstate *h,
2323 struct vm_area_struct *vma, unsigned long addr,
2324 enum vma_resv_mode mode)
2325{
2326 struct resv_map *resv;
2327 pgoff_t idx;
2328 long ret;
2329 long dummy_out_regions_needed;
2330
2331 resv = vma_resv_map(vma);
2332 if (!resv)
2333 return 1;
2334
2335 idx = vma_hugecache_offset(h, vma, addr);
2336 switch (mode) {
2337 case VMA_NEEDS_RESV:
2338 ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed);
2339 /* We assume that vma_reservation_* routines always operate on
2340 * 1 page, and that adding to resv map a 1 page entry can only
2341 * ever require 1 region.
2342 */
2343 VM_BUG_ON(dummy_out_regions_needed != 1);
2344 break;
2345 case VMA_COMMIT_RESV:
2346 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2347 /* region_add calls of range 1 should never fail. */
2348 VM_BUG_ON(ret < 0);
2349 break;
2350 case VMA_END_RESV:
2351 region_abort(resv, idx, idx + 1, 1);
2352 ret = 0;
2353 break;
2354 case VMA_ADD_RESV:
2355 if (vma->vm_flags & VM_MAYSHARE) {
2356 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2357 /* region_add calls of range 1 should never fail. */
2358 VM_BUG_ON(ret < 0);
2359 } else {
2360 region_abort(resv, idx, idx + 1, 1);
2361 ret = region_del(resv, idx, idx + 1);
2362 }
2363 break;
2364 case VMA_DEL_RESV:
2365 if (vma->vm_flags & VM_MAYSHARE) {
2366 region_abort(resv, idx, idx + 1, 1);
2367 ret = region_del(resv, idx, idx + 1);
2368 } else {
2369 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2370 /* region_add calls of range 1 should never fail. */
2371 VM_BUG_ON(ret < 0);
2372 }
2373 break;
2374 default:
2375 BUG();
2376 }
2377
2378 if (vma->vm_flags & VM_MAYSHARE || mode == VMA_DEL_RESV)
2379 return ret;
2380 /*
2381 * We know private mapping must have HPAGE_RESV_OWNER set.
2382 *
2383 * In most cases, reserves always exist for private mappings.
2384 * However, a file associated with mapping could have been
2385 * hole punched or truncated after reserves were consumed.
2386 * As subsequent fault on such a range will not use reserves.
2387 * Subtle - The reserve map for private mappings has the
2388 * opposite meaning than that of shared mappings. If NO
2389 * entry is in the reserve map, it means a reservation exists.
2390 * If an entry exists in the reserve map, it means the
2391 * reservation has already been consumed. As a result, the
2392 * return value of this routine is the opposite of the
2393 * value returned from reserve map manipulation routines above.
2394 */
2395 if (ret > 0)
2396 return 0;
2397 if (ret == 0)
2398 return 1;
2399 return ret;
2400}
2401
2402static long vma_needs_reservation(struct hstate *h,
2403 struct vm_area_struct *vma, unsigned long addr)
2404{
2405 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2406}
2407
2408static long vma_commit_reservation(struct hstate *h,
2409 struct vm_area_struct *vma, unsigned long addr)
2410{
2411 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
2412}
2413
2414static void vma_end_reservation(struct hstate *h,
2415 struct vm_area_struct *vma, unsigned long addr)
2416{
2417 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2418}
2419
2420static long vma_add_reservation(struct hstate *h,
2421 struct vm_area_struct *vma, unsigned long addr)
2422{
2423 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
2424}
2425
2426static long vma_del_reservation(struct hstate *h,
2427 struct vm_area_struct *vma, unsigned long addr)
2428{
2429 return __vma_reservation_common(h, vma, addr, VMA_DEL_RESV);
2430}
2431
2432/*
2433 * This routine is called to restore reservation information on error paths.
2434 * It should ONLY be called for pages allocated via alloc_huge_page(), and
2435 * the hugetlb mutex should remain held when calling this routine.
2436 *
2437 * It handles two specific cases:
2438 * 1) A reservation was in place and the page consumed the reservation.
2439 * HPageRestoreReserve is set in the page.
2440 * 2) No reservation was in place for the page, so HPageRestoreReserve is
2441 * not set. However, alloc_huge_page always updates the reserve map.
2442 *
2443 * In case 1, free_huge_page later in the error path will increment the
2444 * global reserve count. But, free_huge_page does not have enough context
2445 * to adjust the reservation map. This case deals primarily with private
2446 * mappings. Adjust the reserve map here to be consistent with global
2447 * reserve count adjustments to be made by free_huge_page. Make sure the
2448 * reserve map indicates there is a reservation present.
2449 *
2450 * In case 2, simply undo reserve map modifications done by alloc_huge_page.
2451 */
2452void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma,
2453 unsigned long address, struct page *page)
2454{
2455 long rc = vma_needs_reservation(h, vma, address);
2456
2457 if (HPageRestoreReserve(page)) {
2458 if (unlikely(rc < 0))
2459 /*
2460 * Rare out of memory condition in reserve map
2461 * manipulation. Clear HPageRestoreReserve so that
2462 * global reserve count will not be incremented
2463 * by free_huge_page. This will make it appear
2464 * as though the reservation for this page was
2465 * consumed. This may prevent the task from
2466 * faulting in the page at a later time. This
2467 * is better than inconsistent global huge page
2468 * accounting of reserve counts.
2469 */
2470 ClearHPageRestoreReserve(page);
2471 else if (rc)
2472 (void)vma_add_reservation(h, vma, address);
2473 else
2474 vma_end_reservation(h, vma, address);
2475 } else {
2476 if (!rc) {
2477 /*
2478 * This indicates there is an entry in the reserve map
2479 * not added by alloc_huge_page. We know it was added
2480 * before the alloc_huge_page call, otherwise
2481 * HPageRestoreReserve would be set on the page.
2482 * Remove the entry so that a subsequent allocation
2483 * does not consume a reservation.
2484 */
2485 rc = vma_del_reservation(h, vma, address);
2486 if (rc < 0)
2487 /*
2488 * VERY rare out of memory condition. Since
2489 * we can not delete the entry, set
2490 * HPageRestoreReserve so that the reserve
2491 * count will be incremented when the page
2492 * is freed. This reserve will be consumed
2493 * on a subsequent allocation.
2494 */
2495 SetHPageRestoreReserve(page);
2496 } else if (rc < 0) {
2497 /*
2498 * Rare out of memory condition from
2499 * vma_needs_reservation call. Memory allocation is
2500 * only attempted if a new entry is needed. Therefore,
2501 * this implies there is not an entry in the
2502 * reserve map.
2503 *
2504 * For shared mappings, no entry in the map indicates
2505 * no reservation. We are done.
2506 */
2507 if (!(vma->vm_flags & VM_MAYSHARE))
2508 /*
2509 * For private mappings, no entry indicates
2510 * a reservation is present. Since we can
2511 * not add an entry, set SetHPageRestoreReserve
2512 * on the page so reserve count will be
2513 * incremented when freed. This reserve will
2514 * be consumed on a subsequent allocation.
2515 */
2516 SetHPageRestoreReserve(page);
2517 } else
2518 /*
2519 * No reservation present, do nothing
2520 */
2521 vma_end_reservation(h, vma, address);
2522 }
2523}
2524
2525/*
2526 * alloc_and_dissolve_huge_page - Allocate a new page and dissolve the old one
2527 * @h: struct hstate old page belongs to
2528 * @old_page: Old page to dissolve
2529 * @list: List to isolate the page in case we need to
2530 * Returns 0 on success, otherwise negated error.
2531 */
2532static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
2533 struct list_head *list)
2534{
2535 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
2536 int nid = page_to_nid(old_page);
2537 struct page *new_page;
2538 int ret = 0;
2539
2540 /*
2541 * Before dissolving the page, we need to allocate a new one for the
2542 * pool to remain stable. Here, we allocate the page and 'prep' it
2543 * by doing everything but actually updating counters and adding to
2544 * the pool. This simplifies and let us do most of the processing
2545 * under the lock.
2546 */
2547 new_page = alloc_buddy_huge_page(h, gfp_mask, nid, NULL, NULL);
2548 if (!new_page)
2549 return -ENOMEM;
2550 __prep_new_huge_page(h, new_page);
2551
2552retry:
2553 spin_lock_irq(&hugetlb_lock);
2554 if (!PageHuge(old_page)) {
2555 /*
2556 * Freed from under us. Drop new_page too.
2557 */
2558 goto free_new;
2559 } else if (page_count(old_page)) {
2560 /*
2561 * Someone has grabbed the page, try to isolate it here.
2562 * Fail with -EBUSY if not possible.
2563 */
2564 spin_unlock_irq(&hugetlb_lock);
2565 if (!isolate_huge_page(old_page, list))
2566 ret = -EBUSY;
2567 spin_lock_irq(&hugetlb_lock);
2568 goto free_new;
2569 } else if (!HPageFreed(old_page)) {
2570 /*
2571 * Page's refcount is 0 but it has not been enqueued in the
2572 * freelist yet. Race window is small, so we can succeed here if
2573 * we retry.
2574 */
2575 spin_unlock_irq(&hugetlb_lock);
2576 cond_resched();
2577 goto retry;
2578 } else {
2579 /*
2580 * Ok, old_page is still a genuine free hugepage. Remove it from
2581 * the freelist and decrease the counters. These will be
2582 * incremented again when calling __prep_account_new_huge_page()
2583 * and enqueue_huge_page() for new_page. The counters will remain
2584 * stable since this happens under the lock.
2585 */
2586 remove_hugetlb_page(h, old_page, false);
2587
2588 /*
2589 * Reference count trick is needed because allocator gives us
2590 * referenced page but the pool requires pages with 0 refcount.
2591 */
2592 __prep_account_new_huge_page(h, nid);
2593 page_ref_dec(new_page);
2594 enqueue_huge_page(h, new_page);
2595
2596 /*
2597 * Pages have been replaced, we can safely free the old one.
2598 */
2599 spin_unlock_irq(&hugetlb_lock);
2600 update_and_free_page(h, old_page, false);
2601 }
2602
2603 return ret;
2604
2605free_new:
2606 spin_unlock_irq(&hugetlb_lock);
2607 update_and_free_page(h, new_page, false);
2608
2609 return ret;
2610}
2611
2612int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
2613{
2614 struct hstate *h;
2615 struct page *head;
2616 int ret = -EBUSY;
2617
2618 /*
2619 * The page might have been dissolved from under our feet, so make sure
2620 * to carefully check the state under the lock.
2621 * Return success when racing as if we dissolved the page ourselves.
2622 */
2623 spin_lock_irq(&hugetlb_lock);
2624 if (PageHuge(page)) {
2625 head = compound_head(page);
2626 h = page_hstate(head);
2627 } else {
2628 spin_unlock_irq(&hugetlb_lock);
2629 return 0;
2630 }
2631 spin_unlock_irq(&hugetlb_lock);
2632
2633 /*
2634 * Fence off gigantic pages as there is a cyclic dependency between
2635 * alloc_contig_range and them. Return -ENOMEM as this has the effect
2636 * of bailing out right away without further retrying.
2637 */
2638 if (hstate_is_gigantic(h))
2639 return -ENOMEM;
2640
2641 if (page_count(head) && isolate_huge_page(head, list))
2642 ret = 0;
2643 else if (!page_count(head))
2644 ret = alloc_and_dissolve_huge_page(h, head, list);
2645
2646 return ret;
2647}
2648
2649struct page *alloc_huge_page(struct vm_area_struct *vma,
2650 unsigned long addr, int avoid_reserve)
2651{
2652 struct hugepage_subpool *spool = subpool_vma(vma);
2653 struct hstate *h = hstate_vma(vma);
2654 struct page *page;
2655 long map_chg, map_commit;
2656 long gbl_chg;
2657 int ret, idx;
2658 struct hugetlb_cgroup *h_cg;
2659 bool deferred_reserve;
2660
2661 idx = hstate_index(h);
2662 /*
2663 * Examine the region/reserve map to determine if the process
2664 * has a reservation for the page to be allocated. A return
2665 * code of zero indicates a reservation exists (no change).
2666 */
2667 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
2668 if (map_chg < 0)
2669 return ERR_PTR(-ENOMEM);
2670
2671 /*
2672 * Processes that did not create the mapping will have no
2673 * reserves as indicated by the region/reserve map. Check
2674 * that the allocation will not exceed the subpool limit.
2675 * Allocations for MAP_NORESERVE mappings also need to be
2676 * checked against any subpool limit.
2677 */
2678 if (map_chg || avoid_reserve) {
2679 gbl_chg = hugepage_subpool_get_pages(spool, 1);
2680 if (gbl_chg < 0) {
2681 vma_end_reservation(h, vma, addr);
2682 return ERR_PTR(-ENOSPC);
2683 }
2684
2685 /*
2686 * Even though there was no reservation in the region/reserve
2687 * map, there could be reservations associated with the
2688 * subpool that can be used. This would be indicated if the
2689 * return value of hugepage_subpool_get_pages() is zero.
2690 * However, if avoid_reserve is specified we still avoid even
2691 * the subpool reservations.
2692 */
2693 if (avoid_reserve)
2694 gbl_chg = 1;
2695 }
2696
2697 /* If this allocation is not consuming a reservation, charge it now.
2698 */
2699 deferred_reserve = map_chg || avoid_reserve;
2700 if (deferred_reserve) {
2701 ret = hugetlb_cgroup_charge_cgroup_rsvd(
2702 idx, pages_per_huge_page(h), &h_cg);
2703 if (ret)
2704 goto out_subpool_put;
2705 }
2706
2707 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2708 if (ret)
2709 goto out_uncharge_cgroup_reservation;
2710
2711 spin_lock_irq(&hugetlb_lock);
2712 /*
2713 * glb_chg is passed to indicate whether or not a page must be taken
2714 * from the global free pool (global change). gbl_chg == 0 indicates
2715 * a reservation exists for the allocation.
2716 */
2717 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
2718 if (!page) {
2719 spin_unlock_irq(&hugetlb_lock);
2720 page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2721 if (!page)
2722 goto out_uncharge_cgroup;
2723 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
2724 SetHPageRestoreReserve(page);
2725 h->resv_huge_pages--;
2726 }
2727 spin_lock_irq(&hugetlb_lock);
2728 list_add(&page->lru, &h->hugepage_activelist);
2729 /* Fall through */
2730 }
2731 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2732 /* If allocation is not consuming a reservation, also store the
2733 * hugetlb_cgroup pointer on the page.
2734 */
2735 if (deferred_reserve) {
2736 hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h),
2737 h_cg, page);
2738 }
2739
2740 spin_unlock_irq(&hugetlb_lock);
2741
2742 hugetlb_set_page_subpool(page, spool);
2743
2744 map_commit = vma_commit_reservation(h, vma, addr);
2745 if (unlikely(map_chg > map_commit)) {
2746 /*
2747 * The page was added to the reservation map between
2748 * vma_needs_reservation and vma_commit_reservation.
2749 * This indicates a race with hugetlb_reserve_pages.
2750 * Adjust for the subpool count incremented above AND
2751 * in hugetlb_reserve_pages for the same page. Also,
2752 * the reservation count added in hugetlb_reserve_pages
2753 * no longer applies.
2754 */
2755 long rsv_adjust;
2756
2757 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
2758 hugetlb_acct_memory(h, -rsv_adjust);
2759 if (deferred_reserve)
2760 hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
2761 pages_per_huge_page(h), page);
2762 }
2763 return page;
2764
2765out_uncharge_cgroup:
2766 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2767out_uncharge_cgroup_reservation:
2768 if (deferred_reserve)
2769 hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
2770 h_cg);
2771out_subpool_put:
2772 if (map_chg || avoid_reserve)
2773 hugepage_subpool_put_pages(spool, 1);
2774 vma_end_reservation(h, vma, addr);
2775 return ERR_PTR(-ENOSPC);
2776}
2777
2778int alloc_bootmem_huge_page(struct hstate *h)
2779 __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
2780int __alloc_bootmem_huge_page(struct hstate *h)
2781{
2782 struct huge_bootmem_page *m;
2783 int nr_nodes, node;
2784
2785 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2786 void *addr;
2787
2788 addr = memblock_alloc_try_nid_raw(
2789 huge_page_size(h), huge_page_size(h),
2790 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2791 if (addr) {
2792 /*
2793 * Use the beginning of the huge page to store the
2794 * huge_bootmem_page struct (until gather_bootmem
2795 * puts them into the mem_map).
2796 */
2797 m = addr;
2798 goto found;
2799 }
2800 }
2801 return 0;
2802
2803found:
2804 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2805 /* Put them into a private list first because mem_map is not up yet */
2806 INIT_LIST_HEAD(&m->list);
2807 list_add(&m->list, &huge_boot_pages);
2808 m->hstate = h;
2809 return 1;
2810}
2811
2812/*
2813 * Put bootmem huge pages into the standard lists after mem_map is up.
2814 * Note: This only applies to gigantic (order > MAX_ORDER) pages.
2815 */
2816static void __init gather_bootmem_prealloc(void)
2817{
2818 struct huge_bootmem_page *m;
2819
2820 list_for_each_entry(m, &huge_boot_pages, list) {
2821 struct page *page = virt_to_page(m);
2822 struct hstate *h = m->hstate;
2823
2824 VM_BUG_ON(!hstate_is_gigantic(h));
2825 WARN_ON(page_count(page) != 1);
2826 if (prep_compound_gigantic_page(page, huge_page_order(h))) {
2827 WARN_ON(PageReserved(page));
2828 prep_new_huge_page(h, page, page_to_nid(page));
2829 put_page(page); /* add to the hugepage allocator */
2830 } else {
2831 free_gigantic_page(page, huge_page_order(h));
2832 pr_warn("HugeTLB page can not be used due to unexpected inflated ref count\n");
2833 }
2834
2835 /*
2836 * We need to restore the 'stolen' pages to totalram_pages
2837 * in order to fix confusing memory reports from free(1) and
2838 * other side-effects, like CommitLimit going negative.
2839 */
2840 adjust_managed_page_count(page, pages_per_huge_page(h));
2841 cond_resched();
2842 }
2843}
2844
2845static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
2846{
2847 unsigned long i;
2848 nodemask_t *node_alloc_noretry;
2849
2850 if (!hstate_is_gigantic(h)) {
2851 /*
2852 * Bit mask controlling how hard we retry per-node allocations.
2853 * Ignore errors as lower level routines can deal with
2854 * node_alloc_noretry == NULL. If this kmalloc fails at boot
2855 * time, we are likely in bigger trouble.
2856 */
2857 node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry),
2858 GFP_KERNEL);
2859 } else {
2860 /* allocations done at boot time */
2861 node_alloc_noretry = NULL;
2862 }
2863
2864 /* bit mask controlling how hard we retry per-node allocations */
2865 if (node_alloc_noretry)
2866 nodes_clear(*node_alloc_noretry);
2867
2868 for (i = 0; i < h->max_huge_pages; ++i) {
2869 if (hstate_is_gigantic(h)) {
2870 if (hugetlb_cma_size) {
2871 pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
2872 goto free;
2873 }
2874 if (!alloc_bootmem_huge_page(h))
2875 break;
2876 } else if (!alloc_pool_huge_page(h,
2877 &node_states[N_MEMORY],
2878 node_alloc_noretry))
2879 break;
2880 cond_resched();
2881 }
2882 if (i < h->max_huge_pages) {
2883 char buf[32];
2884
2885 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2886 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
2887 h->max_huge_pages, buf, i);
2888 h->max_huge_pages = i;
2889 }
2890free:
2891 kfree(node_alloc_noretry);
2892}
2893
2894static void __init hugetlb_init_hstates(void)
2895{
2896 struct hstate *h;
2897
2898 for_each_hstate(h) {
2899 if (minimum_order > huge_page_order(h))
2900 minimum_order = huge_page_order(h);
2901
2902 /* oversize hugepages were init'ed in early boot */
2903 if (!hstate_is_gigantic(h))
2904 hugetlb_hstate_alloc_pages(h);
2905 }
2906 VM_BUG_ON(minimum_order == UINT_MAX);
2907}
2908
2909static void __init report_hugepages(void)
2910{
2911 struct hstate *h;
2912
2913 for_each_hstate(h) {
2914 char buf[32];
2915
2916 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2917 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2918 buf, h->free_huge_pages);
2919 }
2920}
2921
2922#ifdef CONFIG_HIGHMEM
2923static void try_to_free_low(struct hstate *h, unsigned long count,
2924 nodemask_t *nodes_allowed)
2925{
2926 int i;
2927 LIST_HEAD(page_list);
2928
2929 lockdep_assert_held(&hugetlb_lock);
2930 if (hstate_is_gigantic(h))
2931 return;
2932
2933 /*
2934 * Collect pages to be freed on a list, and free after dropping lock
2935 */
2936 for_each_node_mask(i, *nodes_allowed) {
2937 struct page *page, *next;
2938 struct list_head *freel = &h->hugepage_freelists[i];
2939 list_for_each_entry_safe(page, next, freel, lru) {
2940 if (count >= h->nr_huge_pages)
2941 goto out;
2942 if (PageHighMem(page))
2943 continue;
2944 remove_hugetlb_page(h, page, false);
2945 list_add(&page->lru, &page_list);
2946 }
2947 }
2948
2949out:
2950 spin_unlock_irq(&hugetlb_lock);
2951 update_and_free_pages_bulk(h, &page_list);
2952 spin_lock_irq(&hugetlb_lock);
2953}
2954#else
2955static inline void try_to_free_low(struct hstate *h, unsigned long count,
2956 nodemask_t *nodes_allowed)
2957{
2958}
2959#endif
2960
2961/*
2962 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2963 * balanced by operating on them in a round-robin fashion.
2964 * Returns 1 if an adjustment was made.
2965 */
2966static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
2967 int delta)
2968{
2969 int nr_nodes, node;
2970
2971 lockdep_assert_held(&hugetlb_lock);
2972 VM_BUG_ON(delta != -1 && delta != 1);
2973
2974 if (delta < 0) {
2975 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2976 if (h->surplus_huge_pages_node[node])
2977 goto found;
2978 }
2979 } else {
2980 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2981 if (h->surplus_huge_pages_node[node] <
2982 h->nr_huge_pages_node[node])
2983 goto found;
2984 }
2985 }
2986 return 0;
2987
2988found:
2989 h->surplus_huge_pages += delta;
2990 h->surplus_huge_pages_node[node] += delta;
2991 return 1;
2992}
2993
2994#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2995static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2996 nodemask_t *nodes_allowed)
2997{
2998 unsigned long min_count, ret;
2999 struct page *page;
3000 LIST_HEAD(page_list);
3001 NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL);
3002
3003 /*
3004 * Bit mask controlling how hard we retry per-node allocations.
3005 * If we can not allocate the bit mask, do not attempt to allocate
3006 * the requested huge pages.
3007 */
3008 if (node_alloc_noretry)
3009 nodes_clear(*node_alloc_noretry);
3010 else
3011 return -ENOMEM;
3012
3013 /*
3014 * resize_lock mutex prevents concurrent adjustments to number of
3015 * pages in hstate via the proc/sysfs interfaces.
3016 */
3017 mutex_lock(&h->resize_lock);
3018 flush_free_hpage_work(h);
3019 spin_lock_irq(&hugetlb_lock);
3020
3021 /*
3022 * Check for a node specific request.
3023 * Changing node specific huge page count may require a corresponding
3024 * change to the global count. In any case, the passed node mask
3025 * (nodes_allowed) will restrict alloc/free to the specified node.
3026 */
3027 if (nid != NUMA_NO_NODE) {
3028 unsigned long old_count = count;
3029
3030 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
3031 /*
3032 * User may have specified a large count value which caused the
3033 * above calculation to overflow. In this case, they wanted
3034 * to allocate as many huge pages as possible. Set count to
3035 * largest possible value to align with their intention.
3036 */
3037 if (count < old_count)
3038 count = ULONG_MAX;
3039 }
3040
3041 /*
3042 * Gigantic pages runtime allocation depend on the capability for large
3043 * page range allocation.
3044 * If the system does not provide this feature, return an error when
3045 * the user tries to allocate gigantic pages but let the user free the
3046 * boottime allocated gigantic pages.
3047 */
3048 if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
3049 if (count > persistent_huge_pages(h)) {
3050 spin_unlock_irq(&hugetlb_lock);
3051 mutex_unlock(&h->resize_lock);
3052 NODEMASK_FREE(node_alloc_noretry);
3053 return -EINVAL;
3054 }
3055 /* Fall through to decrease pool */
3056 }
3057
3058 /*
3059 * Increase the pool size
3060 * First take pages out of surplus state. Then make up the
3061 * remaining difference by allocating fresh huge pages.
3062 *
3063 * We might race with alloc_surplus_huge_page() here and be unable
3064 * to convert a surplus huge page to a normal huge page. That is
3065 * not critical, though, it just means the overall size of the
3066 * pool might be one hugepage larger than it needs to be, but
3067 * within all the constraints specified by the sysctls.
3068 */
3069 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
3070 if (!adjust_pool_surplus(h, nodes_allowed, -1))
3071 break;
3072 }
3073
3074 while (count > persistent_huge_pages(h)) {
3075 /*
3076 * If this allocation races such that we no longer need the
3077 * page, free_huge_page will handle it by freeing the page
3078 * and reducing the surplus.
3079 */
3080 spin_unlock_irq(&hugetlb_lock);
3081
3082 /* yield cpu to avoid soft lockup */
3083 cond_resched();
3084
3085 ret = alloc_pool_huge_page(h, nodes_allowed,
3086 node_alloc_noretry);
3087 spin_lock_irq(&hugetlb_lock);
3088 if (!ret)
3089 goto out;
3090
3091 /* Bail for signals. Probably ctrl-c from user */
3092 if (signal_pending(current))
3093 goto out;
3094 }
3095
3096 /*
3097 * Decrease the pool size
3098 * First return free pages to the buddy allocator (being careful
3099 * to keep enough around to satisfy reservations). Then place
3100 * pages into surplus state as needed so the pool will shrink
3101 * to the desired size as pages become free.
3102 *
3103 * By placing pages into the surplus state independent of the
3104 * overcommit value, we are allowing the surplus pool size to
3105 * exceed overcommit. There are few sane options here. Since
3106 * alloc_surplus_huge_page() is checking the global counter,
3107 * though, we'll note that we're not allowed to exceed surplus
3108 * and won't grow the pool anywhere else. Not until one of the
3109 * sysctls are changed, or the surplus pages go out of use.
3110 */
3111 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
3112 min_count = max(count, min_count);
3113 try_to_free_low(h, min_count, nodes_allowed);
3114
3115 /*
3116 * Collect pages to be removed on list without dropping lock
3117 */
3118 while (min_count < persistent_huge_pages(h)) {
3119 page = remove_pool_huge_page(h, nodes_allowed, 0);
3120 if (!page)
3121 break;
3122
3123 list_add(&page->lru, &page_list);
3124 }
3125 /* free the pages after dropping lock */
3126 spin_unlock_irq(&hugetlb_lock);
3127 update_and_free_pages_bulk(h, &page_list);
3128 flush_free_hpage_work(h);
3129 spin_lock_irq(&hugetlb_lock);
3130
3131 while (count < persistent_huge_pages(h)) {
3132 if (!adjust_pool_surplus(h, nodes_allowed, 1))
3133 break;
3134 }
3135out:
3136 h->max_huge_pages = persistent_huge_pages(h);
3137 spin_unlock_irq(&hugetlb_lock);
3138 mutex_unlock(&h->resize_lock);
3139
3140 NODEMASK_FREE(node_alloc_noretry);
3141
3142 return 0;
3143}
3144
3145#define HSTATE_ATTR_RO(_name) \
3146 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
3147
3148#define HSTATE_ATTR(_name) \
3149 static struct kobj_attribute _name##_attr = \
3150 __ATTR(_name, 0644, _name##_show, _name##_store)
3151
3152static struct kobject *hugepages_kobj;
3153static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
3154
3155static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
3156
3157static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
3158{
3159 int i;
3160
3161 for (i = 0; i < HUGE_MAX_HSTATE; i++)
3162 if (hstate_kobjs[i] == kobj) {
3163 if (nidp)
3164 *nidp = NUMA_NO_NODE;
3165 return &hstates[i];
3166 }
3167
3168 return kobj_to_node_hstate(kobj, nidp);
3169}
3170
3171static ssize_t nr_hugepages_show_common(struct kobject *kobj,
3172 struct kobj_attribute *attr, char *buf)
3173{
3174 struct hstate *h;
3175 unsigned long nr_huge_pages;
3176 int nid;
3177
3178 h = kobj_to_hstate(kobj, &nid);
3179 if (nid == NUMA_NO_NODE)
3180 nr_huge_pages = h->nr_huge_pages;
3181 else
3182 nr_huge_pages = h->nr_huge_pages_node[nid];
3183
3184 return sysfs_emit(buf, "%lu\n", nr_huge_pages);
3185}
3186
3187static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
3188 struct hstate *h, int nid,
3189 unsigned long count, size_t len)
3190{
3191 int err;
3192 nodemask_t nodes_allowed, *n_mask;
3193
3194 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
3195 return -EINVAL;
3196
3197 if (nid == NUMA_NO_NODE) {
3198 /*
3199 * global hstate attribute
3200 */
3201 if (!(obey_mempolicy &&
3202 init_nodemask_of_mempolicy(&nodes_allowed)))
3203 n_mask = &node_states[N_MEMORY];
3204 else
3205 n_mask = &nodes_allowed;
3206 } else {
3207 /*
3208 * Node specific request. count adjustment happens in
3209 * set_max_huge_pages() after acquiring hugetlb_lock.
3210 */
3211 init_nodemask_of_node(&nodes_allowed, nid);
3212 n_mask = &nodes_allowed;
3213 }
3214
3215 err = set_max_huge_pages(h, count, nid, n_mask);
3216
3217 return err ? err : len;
3218}
3219
3220static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
3221 struct kobject *kobj, const char *buf,
3222 size_t len)
3223{
3224 struct hstate *h;
3225 unsigned long count;
3226 int nid;
3227 int err;
3228
3229 err = kstrtoul(buf, 10, &count);
3230 if (err)
3231 return err;
3232
3233 h = kobj_to_hstate(kobj, &nid);
3234 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
3235}
3236
3237static ssize_t nr_hugepages_show(struct kobject *kobj,
3238 struct kobj_attribute *attr, char *buf)
3239{
3240 return nr_hugepages_show_common(kobj, attr, buf);
3241}
3242
3243static ssize_t nr_hugepages_store(struct kobject *kobj,
3244 struct kobj_attribute *attr, const char *buf, size_t len)
3245{
3246 return nr_hugepages_store_common(false, kobj, buf, len);
3247}
3248HSTATE_ATTR(nr_hugepages);
3249
3250#ifdef CONFIG_NUMA
3251
3252/*
3253 * hstate attribute for optionally mempolicy-based constraint on persistent
3254 * huge page alloc/free.
3255 */
3256static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
3257 struct kobj_attribute *attr,
3258 char *buf)
3259{
3260 return nr_hugepages_show_common(kobj, attr, buf);
3261}
3262
3263static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
3264 struct kobj_attribute *attr, const char *buf, size_t len)
3265{
3266 return nr_hugepages_store_common(true, kobj, buf, len);
3267}
3268HSTATE_ATTR(nr_hugepages_mempolicy);
3269#endif
3270
3271
3272static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
3273 struct kobj_attribute *attr, char *buf)
3274{
3275 struct hstate *h = kobj_to_hstate(kobj, NULL);
3276 return sysfs_emit(buf, "%lu\n", h->nr_overcommit_huge_pages);
3277}
3278
3279static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
3280 struct kobj_attribute *attr, const char *buf, size_t count)
3281{
3282 int err;
3283 unsigned long input;
3284 struct hstate *h = kobj_to_hstate(kobj, NULL);
3285
3286 if (hstate_is_gigantic(h))
3287 return -EINVAL;
3288
3289 err = kstrtoul(buf, 10, &input);
3290 if (err)
3291 return err;
3292
3293 spin_lock_irq(&hugetlb_lock);
3294 h->nr_overcommit_huge_pages = input;
3295 spin_unlock_irq(&hugetlb_lock);
3296
3297 return count;
3298}
3299HSTATE_ATTR(nr_overcommit_hugepages);
3300
3301static ssize_t free_hugepages_show(struct kobject *kobj,
3302 struct kobj_attribute *attr, char *buf)
3303{
3304 struct hstate *h;
3305 unsigned long free_huge_pages;
3306 int nid;
3307
3308 h = kobj_to_hstate(kobj, &nid);
3309 if (nid == NUMA_NO_NODE)
3310 free_huge_pages = h->free_huge_pages;
3311 else
3312 free_huge_pages = h->free_huge_pages_node[nid];
3313
3314 return sysfs_emit(buf, "%lu\n", free_huge_pages);
3315}
3316HSTATE_ATTR_RO(free_hugepages);
3317
3318static ssize_t resv_hugepages_show(struct kobject *kobj,
3319 struct kobj_attribute *attr, char *buf)
3320{
3321 struct hstate *h = kobj_to_hstate(kobj, NULL);
3322 return sysfs_emit(buf, "%lu\n", h->resv_huge_pages);
3323}
3324HSTATE_ATTR_RO(resv_hugepages);
3325
3326static ssize_t surplus_hugepages_show(struct kobject *kobj,
3327 struct kobj_attribute *attr, char *buf)
3328{
3329 struct hstate *h;
3330 unsigned long surplus_huge_pages;
3331 int nid;
3332
3333 h = kobj_to_hstate(kobj, &nid);
3334 if (nid == NUMA_NO_NODE)
3335 surplus_huge_pages = h->surplus_huge_pages;
3336 else
3337 surplus_huge_pages = h->surplus_huge_pages_node[nid];
3338
3339 return sysfs_emit(buf, "%lu\n", surplus_huge_pages);
3340}
3341HSTATE_ATTR_RO(surplus_hugepages);
3342
3343static struct attribute *hstate_attrs[] = {
3344 &nr_hugepages_attr.attr,
3345 &nr_overcommit_hugepages_attr.attr,
3346 &free_hugepages_attr.attr,
3347 &resv_hugepages_attr.attr,
3348 &surplus_hugepages_attr.attr,
3349#ifdef CONFIG_NUMA
3350 &nr_hugepages_mempolicy_attr.attr,
3351#endif
3352 NULL,
3353};
3354
3355static const struct attribute_group hstate_attr_group = {
3356 .attrs = hstate_attrs,
3357};
3358
3359static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
3360 struct kobject **hstate_kobjs,
3361 const struct attribute_group *hstate_attr_group)
3362{
3363 int retval;
3364 int hi = hstate_index(h);
3365
3366 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
3367 if (!hstate_kobjs[hi])
3368 return -ENOMEM;
3369
3370 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
3371 if (retval) {
3372 kobject_put(hstate_kobjs[hi]);
3373 hstate_kobjs[hi] = NULL;
3374 }
3375
3376 return retval;
3377}
3378
3379static void __init hugetlb_sysfs_init(void)
3380{
3381 struct hstate *h;
3382 int err;
3383
3384 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
3385 if (!hugepages_kobj)
3386 return;
3387
3388 for_each_hstate(h) {
3389 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
3390 hstate_kobjs, &hstate_attr_group);
3391 if (err)
3392 pr_err("HugeTLB: Unable to add hstate %s", h->name);
3393 }
3394}
3395
3396#ifdef CONFIG_NUMA
3397
3398/*
3399 * node_hstate/s - associate per node hstate attributes, via their kobjects,
3400 * with node devices in node_devices[] using a parallel array. The array
3401 * index of a node device or _hstate == node id.
3402 * This is here to avoid any static dependency of the node device driver, in
3403 * the base kernel, on the hugetlb module.
3404 */
3405struct node_hstate {
3406 struct kobject *hugepages_kobj;
3407 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
3408};
3409static struct node_hstate node_hstates[MAX_NUMNODES];
3410
3411/*
3412 * A subset of global hstate attributes for node devices
3413 */
3414static struct attribute *per_node_hstate_attrs[] = {
3415 &nr_hugepages_attr.attr,
3416 &free_hugepages_attr.attr,
3417 &surplus_hugepages_attr.attr,
3418 NULL,
3419};
3420
3421static const struct attribute_group per_node_hstate_attr_group = {
3422 .attrs = per_node_hstate_attrs,
3423};
3424
3425/*
3426 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3427 * Returns node id via non-NULL nidp.
3428 */
3429static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3430{
3431 int nid;
3432
3433 for (nid = 0; nid < nr_node_ids; nid++) {
3434 struct node_hstate *nhs = &node_hstates[nid];
3435 int i;
3436 for (i = 0; i < HUGE_MAX_HSTATE; i++)
3437 if (nhs->hstate_kobjs[i] == kobj) {
3438 if (nidp)
3439 *nidp = nid;
3440 return &hstates[i];
3441 }
3442 }
3443
3444 BUG();
3445 return NULL;
3446}
3447
3448/*
3449 * Unregister hstate attributes from a single node device.
3450 * No-op if no hstate attributes attached.
3451 */
3452static void hugetlb_unregister_node(struct node *node)
3453{
3454 struct hstate *h;
3455 struct node_hstate *nhs = &node_hstates[node->dev.id];
3456
3457 if (!nhs->hugepages_kobj)
3458 return; /* no hstate attributes */
3459
3460 for_each_hstate(h) {
3461 int idx = hstate_index(h);
3462 if (nhs->hstate_kobjs[idx]) {
3463 kobject_put(nhs->hstate_kobjs[idx]);
3464 nhs->hstate_kobjs[idx] = NULL;
3465 }
3466 }
3467
3468 kobject_put(nhs->hugepages_kobj);
3469 nhs->hugepages_kobj = NULL;
3470}
3471
3472
3473/*
3474 * Register hstate attributes for a single node device.
3475 * No-op if attributes already registered.
3476 */
3477static void hugetlb_register_node(struct node *node)
3478{
3479 struct hstate *h;
3480 struct node_hstate *nhs = &node_hstates[node->dev.id];
3481 int err;
3482
3483 if (nhs->hugepages_kobj)
3484 return; /* already allocated */
3485
3486 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
3487 &node->dev.kobj);
3488 if (!nhs->hugepages_kobj)
3489 return;
3490
3491 for_each_hstate(h) {
3492 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
3493 nhs->hstate_kobjs,
3494 &per_node_hstate_attr_group);
3495 if (err) {
3496 pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3497 h->name, node->dev.id);
3498 hugetlb_unregister_node(node);
3499 break;
3500 }
3501 }
3502}
3503
3504/*
3505 * hugetlb init time: register hstate attributes for all registered node
3506 * devices of nodes that have memory. All on-line nodes should have
3507 * registered their associated device by this time.
3508 */
3509static void __init hugetlb_register_all_nodes(void)
3510{
3511 int nid;
3512
3513 for_each_node_state(nid, N_MEMORY) {
3514 struct node *node = node_devices[nid];
3515 if (node->dev.id == nid)
3516 hugetlb_register_node(node);
3517 }
3518
3519 /*
3520 * Let the node device driver know we're here so it can
3521 * [un]register hstate attributes on node hotplug.
3522 */
3523 register_hugetlbfs_with_node(hugetlb_register_node,
3524 hugetlb_unregister_node);
3525}
3526#else /* !CONFIG_NUMA */
3527
3528static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
3529{
3530 BUG();
3531 if (nidp)
3532 *nidp = -1;
3533 return NULL;
3534}
3535
3536static void hugetlb_register_all_nodes(void) { }
3537
3538#endif
3539
3540static int __init hugetlb_init(void)
3541{
3542 int i;
3543
3544 BUILD_BUG_ON(sizeof_field(struct page, private) * BITS_PER_BYTE <
3545 __NR_HPAGEFLAGS);
3546
3547 if (!hugepages_supported()) {
3548 if (hugetlb_max_hstate || default_hstate_max_huge_pages)
3549 pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
3550 return 0;
3551 }
3552
3553 /*
3554 * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some
3555 * architectures depend on setup being done here.
3556 */
3557 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
3558 if (!parsed_default_hugepagesz) {
3559 /*
3560 * If we did not parse a default huge page size, set
3561 * default_hstate_idx to HPAGE_SIZE hstate. And, if the
3562 * number of huge pages for this default size was implicitly
3563 * specified, set that here as well.
3564 * Note that the implicit setting will overwrite an explicit
3565 * setting. A warning will be printed in this case.
3566 */
3567 default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE));
3568 if (default_hstate_max_huge_pages) {
3569 if (default_hstate.max_huge_pages) {
3570 char buf[32];
3571
3572 string_get_size(huge_page_size(&default_hstate),
3573 1, STRING_UNITS_2, buf, 32);
3574 pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
3575 default_hstate.max_huge_pages, buf);
3576 pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
3577 default_hstate_max_huge_pages);
3578 }
3579 default_hstate.max_huge_pages =
3580 default_hstate_max_huge_pages;
3581 }
3582 }
3583
3584 hugetlb_cma_check();
3585 hugetlb_init_hstates();
3586 gather_bootmem_prealloc();
3587 report_hugepages();
3588
3589 hugetlb_sysfs_init();
3590 hugetlb_register_all_nodes();
3591 hugetlb_cgroup_file_init();
3592
3593#ifdef CONFIG_SMP
3594 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
3595#else
3596 num_fault_mutexes = 1;
3597#endif
3598 hugetlb_fault_mutex_table =
3599 kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
3600 GFP_KERNEL);
3601 BUG_ON(!hugetlb_fault_mutex_table);
3602
3603 for (i = 0; i < num_fault_mutexes; i++)
3604 mutex_init(&hugetlb_fault_mutex_table[i]);
3605 return 0;
3606}
3607subsys_initcall(hugetlb_init);
3608
3609/* Overwritten by architectures with more huge page sizes */
3610bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
3611{
3612 return size == HPAGE_SIZE;
3613}
3614
3615void __init hugetlb_add_hstate(unsigned int order)
3616{
3617 struct hstate *h;
3618 unsigned long i;
3619
3620 if (size_to_hstate(PAGE_SIZE << order)) {
3621 return;
3622 }
3623 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
3624 BUG_ON(order == 0);
3625 h = &hstates[hugetlb_max_hstate++];
3626 mutex_init(&h->resize_lock);
3627 h->order = order;
3628 h->mask = ~(huge_page_size(h) - 1);
3629 for (i = 0; i < MAX_NUMNODES; ++i)
3630 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
3631 INIT_LIST_HEAD(&h->hugepage_activelist);
3632 h->next_nid_to_alloc = first_memory_node;
3633 h->next_nid_to_free = first_memory_node;
3634 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
3635 huge_page_size(h)/1024);
3636 hugetlb_vmemmap_init(h);
3637
3638 parsed_hstate = h;
3639}
3640
3641/*
3642 * hugepages command line processing
3643 * hugepages normally follows a valid hugepagsz or default_hugepagsz
3644 * specification. If not, ignore the hugepages value. hugepages can also
3645 * be the first huge page command line option in which case it implicitly
3646 * specifies the number of huge pages for the default size.
3647 */
3648static int __init hugepages_setup(char *s)
3649{
3650 unsigned long *mhp;
3651 static unsigned long *last_mhp;
3652
3653 if (!parsed_valid_hugepagesz) {
3654 pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
3655 parsed_valid_hugepagesz = true;
3656 return 0;
3657 }
3658
3659 /*
3660 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
3661 * yet, so this hugepages= parameter goes to the "default hstate".
3662 * Otherwise, it goes with the previously parsed hugepagesz or
3663 * default_hugepagesz.
3664 */
3665 else if (!hugetlb_max_hstate)
3666 mhp = &default_hstate_max_huge_pages;
3667 else
3668 mhp = &parsed_hstate->max_huge_pages;
3669
3670 if (mhp == last_mhp) {
3671 pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
3672 return 0;
3673 }
3674
3675 if (sscanf(s, "%lu", mhp) <= 0)
3676 *mhp = 0;
3677
3678 /*
3679 * Global state is always initialized later in hugetlb_init.
3680 * But we need to allocate gigantic hstates here early to still
3681 * use the bootmem allocator.
3682 */
3683 if (hugetlb_max_hstate && hstate_is_gigantic(parsed_hstate))
3684 hugetlb_hstate_alloc_pages(parsed_hstate);
3685
3686 last_mhp = mhp;
3687
3688 return 1;
3689}
3690__setup("hugepages=", hugepages_setup);
3691
3692/*
3693 * hugepagesz command line processing
3694 * A specific huge page size can only be specified once with hugepagesz.
3695 * hugepagesz is followed by hugepages on the command line. The global
3696 * variable 'parsed_valid_hugepagesz' is used to determine if prior
3697 * hugepagesz argument was valid.
3698 */
3699static int __init hugepagesz_setup(char *s)
3700{
3701 unsigned long size;
3702 struct hstate *h;
3703
3704 parsed_valid_hugepagesz = false;
3705 size = (unsigned long)memparse(s, NULL);
3706
3707 if (!arch_hugetlb_valid_size(size)) {
3708 pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
3709 return 0;
3710 }
3711
3712 h = size_to_hstate(size);
3713 if (h) {
3714 /*
3715 * hstate for this size already exists. This is normally
3716 * an error, but is allowed if the existing hstate is the
3717 * default hstate. More specifically, it is only allowed if
3718 * the number of huge pages for the default hstate was not
3719 * previously specified.
3720 */
3721 if (!parsed_default_hugepagesz || h != &default_hstate ||
3722 default_hstate.max_huge_pages) {
3723 pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s);
3724 return 0;
3725 }
3726
3727 /*
3728 * No need to call hugetlb_add_hstate() as hstate already
3729 * exists. But, do set parsed_hstate so that a following
3730 * hugepages= parameter will be applied to this hstate.
3731 */
3732 parsed_hstate = h;
3733 parsed_valid_hugepagesz = true;
3734 return 1;
3735 }
3736
3737 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3738 parsed_valid_hugepagesz = true;
3739 return 1;
3740}
3741__setup("hugepagesz=", hugepagesz_setup);
3742
3743/*
3744 * default_hugepagesz command line input
3745 * Only one instance of default_hugepagesz allowed on command line.
3746 */
3747static int __init default_hugepagesz_setup(char *s)
3748{
3749 unsigned long size;
3750
3751 parsed_valid_hugepagesz = false;
3752 if (parsed_default_hugepagesz) {
3753 pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
3754 return 0;
3755 }
3756
3757 size = (unsigned long)memparse(s, NULL);
3758
3759 if (!arch_hugetlb_valid_size(size)) {
3760 pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
3761 return 0;
3762 }
3763
3764 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3765 parsed_valid_hugepagesz = true;
3766 parsed_default_hugepagesz = true;
3767 default_hstate_idx = hstate_index(size_to_hstate(size));
3768
3769 /*
3770 * The number of default huge pages (for this size) could have been
3771 * specified as the first hugetlb parameter: hugepages=X. If so,
3772 * then default_hstate_max_huge_pages is set. If the default huge
3773 * page size is gigantic (>= MAX_ORDER), then the pages must be
3774 * allocated here from bootmem allocator.
3775 */
3776 if (default_hstate_max_huge_pages) {
3777 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
3778 if (hstate_is_gigantic(&default_hstate))
3779 hugetlb_hstate_alloc_pages(&default_hstate);
3780 default_hstate_max_huge_pages = 0;
3781 }
3782
3783 return 1;
3784}
3785__setup("default_hugepagesz=", default_hugepagesz_setup);
3786
3787static unsigned int allowed_mems_nr(struct hstate *h)
3788{
3789 int node;
3790 unsigned int nr = 0;
3791 nodemask_t *mpol_allowed;
3792 unsigned int *array = h->free_huge_pages_node;
3793 gfp_t gfp_mask = htlb_alloc_mask(h);
3794
3795 mpol_allowed = policy_nodemask_current(gfp_mask);
3796
3797 for_each_node_mask(node, cpuset_current_mems_allowed) {
3798 if (!mpol_allowed || node_isset(node, *mpol_allowed))
3799 nr += array[node];
3800 }
3801
3802 return nr;
3803}
3804
3805#ifdef CONFIG_SYSCTL
3806static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
3807 void *buffer, size_t *length,
3808 loff_t *ppos, unsigned long *out)
3809{
3810 struct ctl_table dup_table;
3811
3812 /*
3813 * In order to avoid races with __do_proc_doulongvec_minmax(), we
3814 * can duplicate the @table and alter the duplicate of it.
3815 */
3816 dup_table = *table;
3817 dup_table.data = out;
3818
3819 return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
3820}
3821
3822static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
3823 struct ctl_table *table, int write,
3824 void *buffer, size_t *length, loff_t *ppos)
3825{
3826 struct hstate *h = &default_hstate;
3827 unsigned long tmp = h->max_huge_pages;
3828 int ret;
3829
3830 if (!hugepages_supported())
3831 return -EOPNOTSUPP;
3832
3833 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3834 &tmp);
3835 if (ret)
3836 goto out;
3837
3838 if (write)
3839 ret = __nr_hugepages_store_common(obey_mempolicy, h,
3840 NUMA_NO_NODE, tmp, *length);
3841out:
3842 return ret;
3843}
3844
3845int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3846 void *buffer, size_t *length, loff_t *ppos)
3847{
3848
3849 return hugetlb_sysctl_handler_common(false, table, write,
3850 buffer, length, ppos);
3851}
3852
3853#ifdef CONFIG_NUMA
3854int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
3855 void *buffer, size_t *length, loff_t *ppos)
3856{
3857 return hugetlb_sysctl_handler_common(true, table, write,
3858 buffer, length, ppos);
3859}
3860#endif /* CONFIG_NUMA */
3861
3862int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3863 void *buffer, size_t *length, loff_t *ppos)
3864{
3865 struct hstate *h = &default_hstate;
3866 unsigned long tmp;
3867 int ret;
3868
3869 if (!hugepages_supported())
3870 return -EOPNOTSUPP;
3871
3872 tmp = h->nr_overcommit_huge_pages;
3873
3874 if (write && hstate_is_gigantic(h))
3875 return -EINVAL;
3876
3877 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
3878 &tmp);
3879 if (ret)
3880 goto out;
3881
3882 if (write) {
3883 spin_lock_irq(&hugetlb_lock);
3884 h->nr_overcommit_huge_pages = tmp;
3885 spin_unlock_irq(&hugetlb_lock);
3886 }
3887out:
3888 return ret;
3889}
3890
3891#endif /* CONFIG_SYSCTL */
3892
3893void hugetlb_report_meminfo(struct seq_file *m)
3894{
3895 struct hstate *h;
3896 unsigned long total = 0;
3897
3898 if (!hugepages_supported())
3899 return;
3900
3901 for_each_hstate(h) {
3902 unsigned long count = h->nr_huge_pages;
3903
3904 total += huge_page_size(h) * count;
3905
3906 if (h == &default_hstate)
3907 seq_printf(m,
3908 "HugePages_Total: %5lu\n"
3909 "HugePages_Free: %5lu\n"
3910 "HugePages_Rsvd: %5lu\n"
3911 "HugePages_Surp: %5lu\n"
3912 "Hugepagesize: %8lu kB\n",
3913 count,
3914 h->free_huge_pages,
3915 h->resv_huge_pages,
3916 h->surplus_huge_pages,
3917 huge_page_size(h) / SZ_1K);
3918 }
3919
3920 seq_printf(m, "Hugetlb: %8lu kB\n", total / SZ_1K);
3921}
3922
3923int hugetlb_report_node_meminfo(char *buf, int len, int nid)
3924{
3925 struct hstate *h = &default_hstate;
3926
3927 if (!hugepages_supported())
3928 return 0;
3929
3930 return sysfs_emit_at(buf, len,
3931 "Node %d HugePages_Total: %5u\n"
3932 "Node %d HugePages_Free: %5u\n"
3933 "Node %d HugePages_Surp: %5u\n",
3934 nid, h->nr_huge_pages_node[nid],
3935 nid, h->free_huge_pages_node[nid],
3936 nid, h->surplus_huge_pages_node[nid]);
3937}
3938
3939void hugetlb_show_meminfo(void)
3940{
3941 struct hstate *h;
3942 int nid;
3943
3944 if (!hugepages_supported())
3945 return;
3946
3947 for_each_node_state(nid, N_MEMORY)
3948 for_each_hstate(h)
3949 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3950 nid,
3951 h->nr_huge_pages_node[nid],
3952 h->free_huge_pages_node[nid],
3953 h->surplus_huge_pages_node[nid],
3954 huge_page_size(h) / SZ_1K);
3955}
3956
3957void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
3958{
3959 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
3960 atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
3961}
3962
3963/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3964unsigned long hugetlb_total_pages(void)
3965{
3966 struct hstate *h;
3967 unsigned long nr_total_pages = 0;
3968
3969 for_each_hstate(h)
3970 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
3971 return nr_total_pages;
3972}
3973
3974static int hugetlb_acct_memory(struct hstate *h, long delta)
3975{
3976 int ret = -ENOMEM;
3977
3978 if (!delta)
3979 return 0;
3980
3981 spin_lock_irq(&hugetlb_lock);
3982 /*
3983 * When cpuset is configured, it breaks the strict hugetlb page
3984 * reservation as the accounting is done on a global variable. Such
3985 * reservation is completely rubbish in the presence of cpuset because
3986 * the reservation is not checked against page availability for the
3987 * current cpuset. Application can still potentially OOM'ed by kernel
3988 * with lack of free htlb page in cpuset that the task is in.
3989 * Attempt to enforce strict accounting with cpuset is almost
3990 * impossible (or too ugly) because cpuset is too fluid that
3991 * task or memory node can be dynamically moved between cpusets.
3992 *
3993 * The change of semantics for shared hugetlb mapping with cpuset is
3994 * undesirable. However, in order to preserve some of the semantics,
3995 * we fall back to check against current free page availability as
3996 * a best attempt and hopefully to minimize the impact of changing
3997 * semantics that cpuset has.
3998 *
3999 * Apart from cpuset, we also have memory policy mechanism that
4000 * also determines from which node the kernel will allocate memory
4001 * in a NUMA system. So similar to cpuset, we also should consider
4002 * the memory policy of the current task. Similar to the description
4003 * above.
4004 */
4005 if (delta > 0) {
4006 if (gather_surplus_pages(h, delta) < 0)
4007 goto out;
4008
4009 if (delta > allowed_mems_nr(h)) {
4010 return_unused_surplus_pages(h, delta);
4011 goto out;
4012 }
4013 }
4014
4015 ret = 0;
4016 if (delta < 0)
4017 return_unused_surplus_pages(h, (unsigned long) -delta);
4018
4019out:
4020 spin_unlock_irq(&hugetlb_lock);
4021 return ret;
4022}
4023
4024static void hugetlb_vm_op_open(struct vm_area_struct *vma)
4025{
4026 struct resv_map *resv = vma_resv_map(vma);
4027
4028 /*
4029 * This new VMA should share its siblings reservation map if present.
4030 * The VMA will only ever have a valid reservation map pointer where
4031 * it is being copied for another still existing VMA. As that VMA
4032 * has a reference to the reservation map it cannot disappear until
4033 * after this open call completes. It is therefore safe to take a
4034 * new reference here without additional locking.
4035 */
4036 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
4037 resv_map_dup_hugetlb_cgroup_uncharge_info(resv);
4038 kref_get(&resv->refs);
4039 }
4040}
4041
4042static void hugetlb_vm_op_close(struct vm_area_struct *vma)
4043{
4044 struct hstate *h = hstate_vma(vma);
4045 struct resv_map *resv = vma_resv_map(vma);
4046 struct hugepage_subpool *spool = subpool_vma(vma);
4047 unsigned long reserve, start, end;
4048 long gbl_reserve;
4049
4050 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
4051 return;
4052
4053 start = vma_hugecache_offset(h, vma, vma->vm_start);
4054 end = vma_hugecache_offset(h, vma, vma->vm_end);
4055
4056 reserve = (end - start) - region_count(resv, start, end);
4057 hugetlb_cgroup_uncharge_counter(resv, start, end);
4058 if (reserve) {
4059 /*
4060 * Decrement reserve counts. The global reserve count may be
4061 * adjusted if the subpool has a minimum size.
4062 */
4063 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
4064 hugetlb_acct_memory(h, -gbl_reserve);
4065 }
4066
4067 kref_put(&resv->refs, resv_map_release);
4068}
4069
4070static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
4071{
4072 if (addr & ~(huge_page_mask(hstate_vma(vma))))
4073 return -EINVAL;
4074 return 0;
4075}
4076
4077static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
4078{
4079 return huge_page_size(hstate_vma(vma));
4080}
4081
4082/*
4083 * We cannot handle pagefaults against hugetlb pages at all. They cause
4084 * handle_mm_fault() to try to instantiate regular-sized pages in the
4085 * hugepage VMA. do_page_fault() is supposed to trap this, so BUG is we get
4086 * this far.
4087 */
4088static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
4089{
4090 BUG();
4091 return 0;
4092}
4093
4094/*
4095 * When a new function is introduced to vm_operations_struct and added
4096 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
4097 * This is because under System V memory model, mappings created via
4098 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
4099 * their original vm_ops are overwritten with shm_vm_ops.
4100 */
4101const struct vm_operations_struct hugetlb_vm_ops = {
4102 .fault = hugetlb_vm_op_fault,
4103 .open = hugetlb_vm_op_open,
4104 .close = hugetlb_vm_op_close,
4105 .may_split = hugetlb_vm_op_split,
4106 .pagesize = hugetlb_vm_op_pagesize,
4107};
4108
4109static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
4110 int writable)
4111{
4112 pte_t entry;
4113 unsigned int shift = huge_page_shift(hstate_vma(vma));
4114
4115 if (writable) {
4116 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
4117 vma->vm_page_prot)));
4118 } else {
4119 entry = huge_pte_wrprotect(mk_huge_pte(page,
4120 vma->vm_page_prot));
4121 }
4122 entry = pte_mkyoung(entry);
4123 entry = pte_mkhuge(entry);
4124 entry = arch_make_huge_pte(entry, shift, vma->vm_flags);
4125
4126 return entry;
4127}
4128
4129static void set_huge_ptep_writable(struct vm_area_struct *vma,
4130 unsigned long address, pte_t *ptep)
4131{
4132 pte_t entry;
4133
4134 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
4135 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
4136 update_mmu_cache(vma, address, ptep);
4137}
4138
4139bool is_hugetlb_entry_migration(pte_t pte)
4140{
4141 swp_entry_t swp;
4142
4143 if (huge_pte_none(pte) || pte_present(pte))
4144 return false;
4145 swp = pte_to_swp_entry(pte);
4146 if (is_migration_entry(swp))
4147 return true;
4148 else
4149 return false;
4150}
4151
4152static bool is_hugetlb_entry_hwpoisoned(pte_t pte)
4153{
4154 swp_entry_t swp;
4155
4156 if (huge_pte_none(pte) || pte_present(pte))
4157 return false;
4158 swp = pte_to_swp_entry(pte);
4159 if (is_hwpoison_entry(swp))
4160 return true;
4161 else
4162 return false;
4163}
4164
4165static void
4166hugetlb_install_page(struct vm_area_struct *vma, pte_t *ptep, unsigned long addr,
4167 struct page *new_page)
4168{
4169 __SetPageUptodate(new_page);
4170 set_huge_pte_at(vma->vm_mm, addr, ptep, make_huge_pte(vma, new_page, 1));
4171 hugepage_add_new_anon_rmap(new_page, vma, addr);
4172 hugetlb_count_add(pages_per_huge_page(hstate_vma(vma)), vma->vm_mm);
4173 ClearHPageRestoreReserve(new_page);
4174 SetHPageMigratable(new_page);
4175}
4176
4177int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
4178 struct vm_area_struct *vma)
4179{
4180 pte_t *src_pte, *dst_pte, entry, dst_entry;
4181 struct page *ptepage;
4182 unsigned long addr;
4183 bool cow = is_cow_mapping(vma->vm_flags);
4184 struct hstate *h = hstate_vma(vma);
4185 unsigned long sz = huge_page_size(h);
4186 unsigned long npages = pages_per_huge_page(h);
4187 struct address_space *mapping = vma->vm_file->f_mapping;
4188 struct mmu_notifier_range range;
4189 int ret = 0;
4190
4191 if (cow) {
4192 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
4193 vma->vm_start,
4194 vma->vm_end);
4195 mmu_notifier_invalidate_range_start(&range);
4196 } else {
4197 /*
4198 * For shared mappings i_mmap_rwsem must be held to call
4199 * huge_pte_alloc, otherwise the returned ptep could go
4200 * away if part of a shared pmd and another thread calls
4201 * huge_pmd_unshare.
4202 */
4203 i_mmap_lock_read(mapping);
4204 }
4205
4206 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
4207 spinlock_t *src_ptl, *dst_ptl;
4208 src_pte = huge_pte_offset(src, addr, sz);
4209 if (!src_pte)
4210 continue;
4211 dst_pte = huge_pte_alloc(dst, vma, addr, sz);
4212 if (!dst_pte) {
4213 ret = -ENOMEM;
4214 break;
4215 }
4216
4217 /*
4218 * If the pagetables are shared don't copy or take references.
4219 * dst_pte == src_pte is the common case of src/dest sharing.
4220 *
4221 * However, src could have 'unshared' and dst shares with
4222 * another vma. If dst_pte !none, this implies sharing.
4223 * Check here before taking page table lock, and once again
4224 * after taking the lock below.
4225 */
4226 dst_entry = huge_ptep_get(dst_pte);
4227 if ((dst_pte == src_pte) || !huge_pte_none(dst_entry))
4228 continue;
4229
4230 dst_ptl = huge_pte_lock(h, dst, dst_pte);
4231 src_ptl = huge_pte_lockptr(h, src, src_pte);
4232 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
4233 entry = huge_ptep_get(src_pte);
4234 dst_entry = huge_ptep_get(dst_pte);
4235again:
4236 if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) {
4237 /*
4238 * Skip if src entry none. Also, skip in the
4239 * unlikely case dst entry !none as this implies
4240 * sharing with another vma.
4241 */
4242 ;
4243 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
4244 is_hugetlb_entry_hwpoisoned(entry))) {
4245 swp_entry_t swp_entry = pte_to_swp_entry(entry);
4246
4247 if (is_writable_migration_entry(swp_entry) && cow) {
4248 /*
4249 * COW mappings require pages in both
4250 * parent and child to be set to read.
4251 */
4252 swp_entry = make_readable_migration_entry(
4253 swp_offset(swp_entry));
4254 entry = swp_entry_to_pte(swp_entry);
4255 set_huge_swap_pte_at(src, addr, src_pte,
4256 entry, sz);
4257 }
4258 set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
4259 } else {
4260 entry = huge_ptep_get(src_pte);
4261 ptepage = pte_page(entry);
4262 get_page(ptepage);
4263
4264 /*
4265 * This is a rare case where we see pinned hugetlb
4266 * pages while they're prone to COW. We need to do the
4267 * COW earlier during fork.
4268 *
4269 * When pre-allocating the page or copying data, we
4270 * need to be without the pgtable locks since we could
4271 * sleep during the process.
4272 */
4273 if (unlikely(page_needs_cow_for_dma(vma, ptepage))) {
4274 pte_t src_pte_old = entry;
4275 struct page *new;
4276
4277 spin_unlock(src_ptl);
4278 spin_unlock(dst_ptl);
4279 /* Do not use reserve as it's private owned */
4280 new = alloc_huge_page(vma, addr, 1);
4281 if (IS_ERR(new)) {
4282 put_page(ptepage);
4283 ret = PTR_ERR(new);
4284 break;
4285 }
4286 copy_user_huge_page(new, ptepage, addr, vma,
4287 npages);
4288 put_page(ptepage);
4289
4290 /* Install the new huge page if src pte stable */
4291 dst_ptl = huge_pte_lock(h, dst, dst_pte);
4292 src_ptl = huge_pte_lockptr(h, src, src_pte);
4293 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
4294 entry = huge_ptep_get(src_pte);
4295 if (!pte_same(src_pte_old, entry)) {
4296 restore_reserve_on_error(h, vma, addr,
4297 new);
4298 put_page(new);
4299 /* dst_entry won't change as in child */
4300 goto again;
4301 }
4302 hugetlb_install_page(vma, dst_pte, addr, new);
4303 spin_unlock(src_ptl);
4304 spin_unlock(dst_ptl);
4305 continue;
4306 }
4307
4308 if (cow) {
4309 /*
4310 * No need to notify as we are downgrading page
4311 * table protection not changing it to point
4312 * to a new page.
4313 *
4314 * See Documentation/vm/mmu_notifier.rst
4315 */
4316 huge_ptep_set_wrprotect(src, addr, src_pte);
4317 entry = huge_pte_wrprotect(entry);
4318 }
4319
4320 page_dup_rmap(ptepage, true);
4321 set_huge_pte_at(dst, addr, dst_pte, entry);
4322 hugetlb_count_add(npages, dst);
4323 }
4324 spin_unlock(src_ptl);
4325 spin_unlock(dst_ptl);
4326 }
4327
4328 if (cow)
4329 mmu_notifier_invalidate_range_end(&range);
4330 else
4331 i_mmap_unlock_read(mapping);
4332
4333 return ret;
4334}
4335
4336void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
4337 unsigned long start, unsigned long end,
4338 struct page *ref_page)
4339{
4340 struct mm_struct *mm = vma->vm_mm;
4341 unsigned long address;
4342 pte_t *ptep;
4343 pte_t pte;
4344 spinlock_t *ptl;
4345 struct page *page;
4346 struct hstate *h = hstate_vma(vma);
4347 unsigned long sz = huge_page_size(h);
4348 struct mmu_notifier_range range;
4349
4350 WARN_ON(!is_vm_hugetlb_page(vma));
4351 BUG_ON(start & ~huge_page_mask(h));
4352 BUG_ON(end & ~huge_page_mask(h));
4353
4354 /*
4355 * This is a hugetlb vma, all the pte entries should point
4356 * to huge page.
4357 */
4358 tlb_change_page_size(tlb, sz);
4359 tlb_start_vma(tlb, vma);
4360
4361 /*
4362 * If sharing possible, alert mmu notifiers of worst case.
4363 */
4364 mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
4365 end);
4366 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
4367 mmu_notifier_invalidate_range_start(&range);
4368 address = start;
4369 for (; address < end; address += sz) {
4370 ptep = huge_pte_offset(mm, address, sz);
4371 if (!ptep)
4372 continue;
4373
4374 ptl = huge_pte_lock(h, mm, ptep);
4375 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
4376 spin_unlock(ptl);
4377 /*
4378 * We just unmapped a page of PMDs by clearing a PUD.
4379 * The caller's TLB flush range should cover this area.
4380 */
4381 continue;
4382 }
4383
4384 pte = huge_ptep_get(ptep);
4385 if (huge_pte_none(pte)) {
4386 spin_unlock(ptl);
4387 continue;
4388 }
4389
4390 /*
4391 * Migrating hugepage or HWPoisoned hugepage is already
4392 * unmapped and its refcount is dropped, so just clear pte here.
4393 */
4394 if (unlikely(!pte_present(pte))) {
4395 huge_pte_clear(mm, address, ptep, sz);
4396 spin_unlock(ptl);
4397 continue;
4398 }
4399
4400 page = pte_page(pte);
4401 /*
4402 * If a reference page is supplied, it is because a specific
4403 * page is being unmapped, not a range. Ensure the page we
4404 * are about to unmap is the actual page of interest.
4405 */
4406 if (ref_page) {
4407 if (page != ref_page) {
4408 spin_unlock(ptl);
4409 continue;
4410 }
4411 /*
4412 * Mark the VMA as having unmapped its page so that
4413 * future faults in this VMA will fail rather than
4414 * looking like data was lost
4415 */
4416 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
4417 }
4418
4419 pte = huge_ptep_get_and_clear(mm, address, ptep);
4420 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
4421 if (huge_pte_dirty(pte))
4422 set_page_dirty(page);
4423
4424 hugetlb_count_sub(pages_per_huge_page(h), mm);
4425 page_remove_rmap(page, true);
4426
4427 spin_unlock(ptl);
4428 tlb_remove_page_size(tlb, page, huge_page_size(h));
4429 /*
4430 * Bail out after unmapping reference page if supplied
4431 */
4432 if (ref_page)
4433 break;
4434 }
4435 mmu_notifier_invalidate_range_end(&range);
4436 tlb_end_vma(tlb, vma);
4437}
4438
4439void __unmap_hugepage_range_final(struct mmu_gather *tlb,
4440 struct vm_area_struct *vma, unsigned long start,
4441 unsigned long end, struct page *ref_page)
4442{
4443 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
4444
4445 /*
4446 * Clear this flag so that x86's huge_pmd_share page_table_shareable
4447 * test will fail on a vma being torn down, and not grab a page table
4448 * on its way out. We're lucky that the flag has such an appropriate
4449 * name, and can in fact be safely cleared here. We could clear it
4450 * before the __unmap_hugepage_range above, but all that's necessary
4451 * is to clear it before releasing the i_mmap_rwsem. This works
4452 * because in the context this is called, the VMA is about to be
4453 * destroyed and the i_mmap_rwsem is held.
4454 */
4455 vma->vm_flags &= ~VM_MAYSHARE;
4456}
4457
4458void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
4459 unsigned long end, struct page *ref_page)
4460{
4461 struct mmu_gather tlb;
4462
4463 tlb_gather_mmu(&tlb, vma->vm_mm);
4464 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
4465 tlb_finish_mmu(&tlb);
4466}
4467
4468/*
4469 * This is called when the original mapper is failing to COW a MAP_PRIVATE
4470 * mapping it owns the reserve page for. The intention is to unmap the page
4471 * from other VMAs and let the children be SIGKILLed if they are faulting the
4472 * same region.
4473 */
4474static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
4475 struct page *page, unsigned long address)
4476{
4477 struct hstate *h = hstate_vma(vma);
4478 struct vm_area_struct *iter_vma;
4479 struct address_space *mapping;
4480 pgoff_t pgoff;
4481
4482 /*
4483 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
4484 * from page cache lookup which is in HPAGE_SIZE units.
4485 */
4486 address = address & huge_page_mask(h);
4487 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
4488 vma->vm_pgoff;
4489 mapping = vma->vm_file->f_mapping;
4490
4491 /*
4492 * Take the mapping lock for the duration of the table walk. As
4493 * this mapping should be shared between all the VMAs,
4494 * __unmap_hugepage_range() is called as the lock is already held
4495 */
4496 i_mmap_lock_write(mapping);
4497 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
4498 /* Do not unmap the current VMA */
4499 if (iter_vma == vma)
4500 continue;
4501
4502 /*
4503 * Shared VMAs have their own reserves and do not affect
4504 * MAP_PRIVATE accounting but it is possible that a shared
4505 * VMA is using the same page so check and skip such VMAs.
4506 */
4507 if (iter_vma->vm_flags & VM_MAYSHARE)
4508 continue;
4509
4510 /*
4511 * Unmap the page from other VMAs without their own reserves.
4512 * They get marked to be SIGKILLed if they fault in these
4513 * areas. This is because a future no-page fault on this VMA
4514 * could insert a zeroed page instead of the data existing
4515 * from the time of fork. This would look like data corruption
4516 */
4517 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
4518 unmap_hugepage_range(iter_vma, address,
4519 address + huge_page_size(h), page);
4520 }
4521 i_mmap_unlock_write(mapping);
4522}
4523
4524/*
4525 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4526 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
4527 * cannot race with other handlers or page migration.
4528 * Keep the pte_same checks anyway to make transition from the mutex easier.
4529 */
4530static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
4531 unsigned long address, pte_t *ptep,
4532 struct page *pagecache_page, spinlock_t *ptl)
4533{
4534 pte_t pte;
4535 struct hstate *h = hstate_vma(vma);
4536 struct page *old_page, *new_page;
4537 int outside_reserve = 0;
4538 vm_fault_t ret = 0;
4539 unsigned long haddr = address & huge_page_mask(h);
4540 struct mmu_notifier_range range;
4541
4542 pte = huge_ptep_get(ptep);
4543 old_page = pte_page(pte);
4544
4545retry_avoidcopy:
4546 /* If no-one else is actually using this page, avoid the copy
4547 * and just make the page writable */
4548 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
4549 page_move_anon_rmap(old_page, vma);
4550 set_huge_ptep_writable(vma, haddr, ptep);
4551 return 0;
4552 }
4553
4554 /*
4555 * If the process that created a MAP_PRIVATE mapping is about to
4556 * perform a COW due to a shared page count, attempt to satisfy
4557 * the allocation without using the existing reserves. The pagecache
4558 * page is used to determine if the reserve at this address was
4559 * consumed or not. If reserves were used, a partial faulted mapping
4560 * at the time of fork() could consume its reserves on COW instead
4561 * of the full address range.
4562 */
4563 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
4564 old_page != pagecache_page)
4565 outside_reserve = 1;
4566
4567 get_page(old_page);
4568
4569 /*
4570 * Drop page table lock as buddy allocator may be called. It will
4571 * be acquired again before returning to the caller, as expected.
4572 */
4573 spin_unlock(ptl);
4574 new_page = alloc_huge_page(vma, haddr, outside_reserve);
4575
4576 if (IS_ERR(new_page)) {
4577 /*
4578 * If a process owning a MAP_PRIVATE mapping fails to COW,
4579 * it is due to references held by a child and an insufficient
4580 * huge page pool. To guarantee the original mappers
4581 * reliability, unmap the page from child processes. The child
4582 * may get SIGKILLed if it later faults.
4583 */
4584 if (outside_reserve) {
4585 struct address_space *mapping = vma->vm_file->f_mapping;
4586 pgoff_t idx;
4587 u32 hash;
4588
4589 put_page(old_page);
4590 BUG_ON(huge_pte_none(pte));
4591 /*
4592 * Drop hugetlb_fault_mutex and i_mmap_rwsem before
4593 * unmapping. unmapping needs to hold i_mmap_rwsem
4594 * in write mode. Dropping i_mmap_rwsem in read mode
4595 * here is OK as COW mappings do not interact with
4596 * PMD sharing.
4597 *
4598 * Reacquire both after unmap operation.
4599 */
4600 idx = vma_hugecache_offset(h, vma, haddr);
4601 hash = hugetlb_fault_mutex_hash(mapping, idx);
4602 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4603 i_mmap_unlock_read(mapping);
4604
4605 unmap_ref_private(mm, vma, old_page, haddr);
4606
4607 i_mmap_lock_read(mapping);
4608 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4609 spin_lock(ptl);
4610 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4611 if (likely(ptep &&
4612 pte_same(huge_ptep_get(ptep), pte)))
4613 goto retry_avoidcopy;
4614 /*
4615 * race occurs while re-acquiring page table
4616 * lock, and our job is done.
4617 */
4618 return 0;
4619 }
4620
4621 ret = vmf_error(PTR_ERR(new_page));
4622 goto out_release_old;
4623 }
4624
4625 /*
4626 * When the original hugepage is shared one, it does not have
4627 * anon_vma prepared.
4628 */
4629 if (unlikely(anon_vma_prepare(vma))) {
4630 ret = VM_FAULT_OOM;
4631 goto out_release_all;
4632 }
4633
4634 copy_user_huge_page(new_page, old_page, address, vma,
4635 pages_per_huge_page(h));
4636 __SetPageUptodate(new_page);
4637
4638 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
4639 haddr + huge_page_size(h));
4640 mmu_notifier_invalidate_range_start(&range);
4641
4642 /*
4643 * Retake the page table lock to check for racing updates
4644 * before the page tables are altered
4645 */
4646 spin_lock(ptl);
4647 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4648 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
4649 ClearHPageRestoreReserve(new_page);
4650
4651 /* Break COW */
4652 huge_ptep_clear_flush(vma, haddr, ptep);
4653 mmu_notifier_invalidate_range(mm, range.start, range.end);
4654 set_huge_pte_at(mm, haddr, ptep,
4655 make_huge_pte(vma, new_page, 1));
4656 page_remove_rmap(old_page, true);
4657 hugepage_add_new_anon_rmap(new_page, vma, haddr);
4658 SetHPageMigratable(new_page);
4659 /* Make the old page be freed below */
4660 new_page = old_page;
4661 }
4662 spin_unlock(ptl);
4663 mmu_notifier_invalidate_range_end(&range);
4664out_release_all:
4665 /* No restore in case of successful pagetable update (Break COW) */
4666 if (new_page != old_page)
4667 restore_reserve_on_error(h, vma, haddr, new_page);
4668 put_page(new_page);
4669out_release_old:
4670 put_page(old_page);
4671
4672 spin_lock(ptl); /* Caller expects lock to be held */
4673 return ret;
4674}
4675
4676/* Return the pagecache page at a given address within a VMA */
4677static struct page *hugetlbfs_pagecache_page(struct hstate *h,
4678 struct vm_area_struct *vma, unsigned long address)
4679{
4680 struct address_space *mapping;
4681 pgoff_t idx;
4682
4683 mapping = vma->vm_file->f_mapping;
4684 idx = vma_hugecache_offset(h, vma, address);
4685
4686 return find_lock_page(mapping, idx);
4687}
4688
4689/*
4690 * Return whether there is a pagecache page to back given address within VMA.
4691 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
4692 */
4693static bool hugetlbfs_pagecache_present(struct hstate *h,
4694 struct vm_area_struct *vma, unsigned long address)
4695{
4696 struct address_space *mapping;
4697 pgoff_t idx;
4698 struct page *page;
4699
4700 mapping = vma->vm_file->f_mapping;
4701 idx = vma_hugecache_offset(h, vma, address);
4702
4703 page = find_get_page(mapping, idx);
4704 if (page)
4705 put_page(page);
4706 return page != NULL;
4707}
4708
4709int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
4710 pgoff_t idx)
4711{
4712 struct inode *inode = mapping->host;
4713 struct hstate *h = hstate_inode(inode);
4714 int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
4715
4716 if (err)
4717 return err;
4718 ClearHPageRestoreReserve(page);
4719
4720 /*
4721 * set page dirty so that it will not be removed from cache/file
4722 * by non-hugetlbfs specific code paths.
4723 */
4724 set_page_dirty(page);
4725
4726 spin_lock(&inode->i_lock);
4727 inode->i_blocks += blocks_per_huge_page(h);
4728 spin_unlock(&inode->i_lock);
4729 return 0;
4730}
4731
4732static inline vm_fault_t hugetlb_handle_userfault(struct vm_area_struct *vma,
4733 struct address_space *mapping,
4734 pgoff_t idx,
4735 unsigned int flags,
4736 unsigned long haddr,
4737 unsigned long reason)
4738{
4739 vm_fault_t ret;
4740 u32 hash;
4741 struct vm_fault vmf = {
4742 .vma = vma,
4743 .address = haddr,
4744 .flags = flags,
4745
4746 /*
4747 * Hard to debug if it ends up being
4748 * used by a callee that assumes
4749 * something about the other
4750 * uninitialized fields... same as in
4751 * memory.c
4752 */
4753 };
4754
4755 /*
4756 * hugetlb_fault_mutex and i_mmap_rwsem must be
4757 * dropped before handling userfault. Reacquire
4758 * after handling fault to make calling code simpler.
4759 */
4760 hash = hugetlb_fault_mutex_hash(mapping, idx);
4761 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4762 i_mmap_unlock_read(mapping);
4763 ret = handle_userfault(&vmf, reason);
4764 i_mmap_lock_read(mapping);
4765 mutex_lock(&hugetlb_fault_mutex_table[hash]);
4766
4767 return ret;
4768}
4769
4770static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
4771 struct vm_area_struct *vma,
4772 struct address_space *mapping, pgoff_t idx,
4773 unsigned long address, pte_t *ptep, unsigned int flags)
4774{
4775 struct hstate *h = hstate_vma(vma);
4776 vm_fault_t ret = VM_FAULT_SIGBUS;
4777 int anon_rmap = 0;
4778 unsigned long size;
4779 struct page *page;
4780 pte_t new_pte;
4781 spinlock_t *ptl;
4782 unsigned long haddr = address & huge_page_mask(h);
4783 bool new_page, new_pagecache_page = false;
4784
4785 /*
4786 * Currently, we are forced to kill the process in the event the
4787 * original mapper has unmapped pages from the child due to a failed
4788 * COW. Warn that such a situation has occurred as it may not be obvious
4789 */
4790 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
4791 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4792 current->pid);
4793 return ret;
4794 }
4795
4796 /*
4797 * We can not race with truncation due to holding i_mmap_rwsem.
4798 * i_size is modified when holding i_mmap_rwsem, so check here
4799 * once for faults beyond end of file.
4800 */
4801 size = i_size_read(mapping->host) >> huge_page_shift(h);
4802 if (idx >= size)
4803 goto out;
4804
4805retry:
4806 new_page = false;
4807 page = find_lock_page(mapping, idx);
4808 if (!page) {
4809 /* Check for page in userfault range */
4810 if (userfaultfd_missing(vma)) {
4811 ret = hugetlb_handle_userfault(vma, mapping, idx,
4812 flags, haddr,
4813 VM_UFFD_MISSING);
4814 goto out;
4815 }
4816
4817 page = alloc_huge_page(vma, haddr, 0);
4818 if (IS_ERR(page)) {
4819 /*
4820 * Returning error will result in faulting task being
4821 * sent SIGBUS. The hugetlb fault mutex prevents two
4822 * tasks from racing to fault in the same page which
4823 * could result in false unable to allocate errors.
4824 * Page migration does not take the fault mutex, but
4825 * does a clear then write of pte's under page table
4826 * lock. Page fault code could race with migration,
4827 * notice the clear pte and try to allocate a page
4828 * here. Before returning error, get ptl and make
4829 * sure there really is no pte entry.
4830 */
4831 ptl = huge_pte_lock(h, mm, ptep);
4832 ret = 0;
4833 if (huge_pte_none(huge_ptep_get(ptep)))
4834 ret = vmf_error(PTR_ERR(page));
4835 spin_unlock(ptl);
4836 goto out;
4837 }
4838 clear_huge_page(page, address, pages_per_huge_page(h));
4839 __SetPageUptodate(page);
4840 new_page = true;
4841
4842 if (vma->vm_flags & VM_MAYSHARE) {
4843 int err = huge_add_to_page_cache(page, mapping, idx);
4844 if (err) {
4845 put_page(page);
4846 if (err == -EEXIST)
4847 goto retry;
4848 goto out;
4849 }
4850 new_pagecache_page = true;
4851 } else {
4852 lock_page(page);
4853 if (unlikely(anon_vma_prepare(vma))) {
4854 ret = VM_FAULT_OOM;
4855 goto backout_unlocked;
4856 }
4857 anon_rmap = 1;
4858 }
4859 } else {
4860 /*
4861 * If memory error occurs between mmap() and fault, some process
4862 * don't have hwpoisoned swap entry for errored virtual address.
4863 * So we need to block hugepage fault by PG_hwpoison bit check.
4864 */
4865 if (unlikely(PageHWPoison(page))) {
4866 ret = VM_FAULT_HWPOISON_LARGE |
4867 VM_FAULT_SET_HINDEX(hstate_index(h));
4868 goto backout_unlocked;
4869 }
4870
4871 /* Check for page in userfault range. */
4872 if (userfaultfd_minor(vma)) {
4873 unlock_page(page);
4874 put_page(page);
4875 ret = hugetlb_handle_userfault(vma, mapping, idx,
4876 flags, haddr,
4877 VM_UFFD_MINOR);
4878 goto out;
4879 }
4880 }
4881
4882 /*
4883 * If we are going to COW a private mapping later, we examine the
4884 * pending reservations for this page now. This will ensure that
4885 * any allocations necessary to record that reservation occur outside
4886 * the spinlock.
4887 */
4888 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4889 if (vma_needs_reservation(h, vma, haddr) < 0) {
4890 ret = VM_FAULT_OOM;
4891 goto backout_unlocked;
4892 }
4893 /* Just decrements count, does not deallocate */
4894 vma_end_reservation(h, vma, haddr);
4895 }
4896
4897 ptl = huge_pte_lock(h, mm, ptep);
4898 ret = 0;
4899 if (!huge_pte_none(huge_ptep_get(ptep)))
4900 goto backout;
4901
4902 if (anon_rmap) {
4903 ClearHPageRestoreReserve(page);
4904 hugepage_add_new_anon_rmap(page, vma, haddr);
4905 } else
4906 page_dup_rmap(page, true);
4907 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
4908 && (vma->vm_flags & VM_SHARED)));
4909 set_huge_pte_at(mm, haddr, ptep, new_pte);
4910
4911 hugetlb_count_add(pages_per_huge_page(h), mm);
4912 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4913 /* Optimization, do the COW without a second fault */
4914 ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
4915 }
4916
4917 spin_unlock(ptl);
4918
4919 /*
4920 * Only set HPageMigratable in newly allocated pages. Existing pages
4921 * found in the pagecache may not have HPageMigratableset if they have
4922 * been isolated for migration.
4923 */
4924 if (new_page)
4925 SetHPageMigratable(page);
4926
4927 unlock_page(page);
4928out:
4929 return ret;
4930
4931backout:
4932 spin_unlock(ptl);
4933backout_unlocked:
4934 unlock_page(page);
4935 /* restore reserve for newly allocated pages not in page cache */
4936 if (new_page && !new_pagecache_page)
4937 restore_reserve_on_error(h, vma, haddr, page);
4938 put_page(page);
4939 goto out;
4940}
4941
4942#ifdef CONFIG_SMP
4943u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4944{
4945 unsigned long key[2];
4946 u32 hash;
4947
4948 key[0] = (unsigned long) mapping;
4949 key[1] = idx;
4950
4951 hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
4952
4953 return hash & (num_fault_mutexes - 1);
4954}
4955#else
4956/*
4957 * For uniprocessor systems we always use a single mutex, so just
4958 * return 0 and avoid the hashing overhead.
4959 */
4960u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4961{
4962 return 0;
4963}
4964#endif
4965
4966vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
4967 unsigned long address, unsigned int flags)
4968{
4969 pte_t *ptep, entry;
4970 spinlock_t *ptl;
4971 vm_fault_t ret;
4972 u32 hash;
4973 pgoff_t idx;
4974 struct page *page = NULL;
4975 struct page *pagecache_page = NULL;
4976 struct hstate *h = hstate_vma(vma);
4977 struct address_space *mapping;
4978 int need_wait_lock = 0;
4979 unsigned long haddr = address & huge_page_mask(h);
4980
4981 ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4982 if (ptep) {
4983 /*
4984 * Since we hold no locks, ptep could be stale. That is
4985 * OK as we are only making decisions based on content and
4986 * not actually modifying content here.
4987 */
4988 entry = huge_ptep_get(ptep);
4989 if (unlikely(is_hugetlb_entry_migration(entry))) {
4990 migration_entry_wait_huge(vma, mm, ptep);
4991 return 0;
4992 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
4993 return VM_FAULT_HWPOISON_LARGE |
4994 VM_FAULT_SET_HINDEX(hstate_index(h));
4995 }
4996
4997 /*
4998 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4999 * until finished with ptep. This serves two purposes:
5000 * 1) It prevents huge_pmd_unshare from being called elsewhere
5001 * and making the ptep no longer valid.
5002 * 2) It synchronizes us with i_size modifications during truncation.
5003 *
5004 * ptep could have already be assigned via huge_pte_offset. That
5005 * is OK, as huge_pte_alloc will return the same value unless
5006 * something has changed.
5007 */
5008 mapping = vma->vm_file->f_mapping;
5009 i_mmap_lock_read(mapping);
5010 ptep = huge_pte_alloc(mm, vma, haddr, huge_page_size(h));
5011 if (!ptep) {
5012 i_mmap_unlock_read(mapping);
5013 return VM_FAULT_OOM;
5014 }
5015
5016 /*
5017 * Serialize hugepage allocation and instantiation, so that we don't
5018 * get spurious allocation failures if two CPUs race to instantiate
5019 * the same page in the page cache.
5020 */
5021 idx = vma_hugecache_offset(h, vma, haddr);
5022 hash = hugetlb_fault_mutex_hash(mapping, idx);
5023 mutex_lock(&hugetlb_fault_mutex_table[hash]);
5024
5025 entry = huge_ptep_get(ptep);
5026 if (huge_pte_none(entry)) {
5027 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
5028 goto out_mutex;
5029 }
5030
5031 ret = 0;
5032
5033 /*
5034 * entry could be a migration/hwpoison entry at this point, so this
5035 * check prevents the kernel from going below assuming that we have
5036 * an active hugepage in pagecache. This goto expects the 2nd page
5037 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
5038 * properly handle it.
5039 */
5040 if (!pte_present(entry))
5041 goto out_mutex;
5042
5043 /*
5044 * If we are going to COW the mapping later, we examine the pending
5045 * reservations for this page now. This will ensure that any
5046 * allocations necessary to record that reservation occur outside the
5047 * spinlock. For private mappings, we also lookup the pagecache
5048 * page now as it is used to determine if a reservation has been
5049 * consumed.
5050 */
5051 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
5052 if (vma_needs_reservation(h, vma, haddr) < 0) {
5053 ret = VM_FAULT_OOM;
5054 goto out_mutex;
5055 }
5056 /* Just decrements count, does not deallocate */
5057 vma_end_reservation(h, vma, haddr);
5058
5059 if (!(vma->vm_flags & VM_MAYSHARE))
5060 pagecache_page = hugetlbfs_pagecache_page(h,
5061 vma, haddr);
5062 }
5063
5064 ptl = huge_pte_lock(h, mm, ptep);
5065
5066 /* Check for a racing update before calling hugetlb_cow */
5067 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
5068 goto out_ptl;
5069
5070 /*
5071 * hugetlb_cow() requires page locks of pte_page(entry) and
5072 * pagecache_page, so here we need take the former one
5073 * when page != pagecache_page or !pagecache_page.
5074 */
5075 page = pte_page(entry);
5076 if (page != pagecache_page)
5077 if (!trylock_page(page)) {
5078 need_wait_lock = 1;
5079 goto out_ptl;
5080 }
5081
5082 get_page(page);
5083
5084 if (flags & FAULT_FLAG_WRITE) {
5085 if (!huge_pte_write(entry)) {
5086 ret = hugetlb_cow(mm, vma, address, ptep,
5087 pagecache_page, ptl);
5088 goto out_put_page;
5089 }
5090 entry = huge_pte_mkdirty(entry);
5091 }
5092 entry = pte_mkyoung(entry);
5093 if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
5094 flags & FAULT_FLAG_WRITE))
5095 update_mmu_cache(vma, haddr, ptep);
5096out_put_page:
5097 if (page != pagecache_page)
5098 unlock_page(page);
5099 put_page(page);
5100out_ptl:
5101 spin_unlock(ptl);
5102
5103 if (pagecache_page) {
5104 unlock_page(pagecache_page);
5105 put_page(pagecache_page);
5106 }
5107out_mutex:
5108 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
5109 i_mmap_unlock_read(mapping);
5110 /*
5111 * Generally it's safe to hold refcount during waiting page lock. But
5112 * here we just wait to defer the next page fault to avoid busy loop and
5113 * the page is not used after unlocked before returning from the current
5114 * page fault. So we are safe from accessing freed page, even if we wait
5115 * here without taking refcount.
5116 */
5117 if (need_wait_lock)
5118 wait_on_page_locked(page);
5119 return ret;
5120}
5121
5122#ifdef CONFIG_USERFAULTFD
5123/*
5124 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
5125 * modifications for huge pages.
5126 */
5127int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
5128 pte_t *dst_pte,
5129 struct vm_area_struct *dst_vma,
5130 unsigned long dst_addr,
5131 unsigned long src_addr,
5132 enum mcopy_atomic_mode mode,
5133 struct page **pagep)
5134{
5135 bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE);
5136 struct hstate *h = hstate_vma(dst_vma);
5137 struct address_space *mapping = dst_vma->vm_file->f_mapping;
5138 pgoff_t idx = vma_hugecache_offset(h, dst_vma, dst_addr);
5139 unsigned long size;
5140 int vm_shared = dst_vma->vm_flags & VM_SHARED;
5141 pte_t _dst_pte;
5142 spinlock_t *ptl;
5143 int ret = -ENOMEM;
5144 struct page *page;
5145 int writable;
5146 bool new_pagecache_page = false;
5147
5148 if (is_continue) {
5149 ret = -EFAULT;
5150 page = find_lock_page(mapping, idx);
5151 if (!page)
5152 goto out;
5153 } else if (!*pagep) {
5154 /* If a page already exists, then it's UFFDIO_COPY for
5155 * a non-missing case. Return -EEXIST.
5156 */
5157 if (vm_shared &&
5158 hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) {
5159 ret = -EEXIST;
5160 goto out;
5161 }
5162
5163 page = alloc_huge_page(dst_vma, dst_addr, 0);
5164 if (IS_ERR(page)) {
5165 ret = -ENOMEM;
5166 goto out;
5167 }
5168
5169 ret = copy_huge_page_from_user(page,
5170 (const void __user *) src_addr,
5171 pages_per_huge_page(h), false);
5172
5173 /* fallback to copy_from_user outside mmap_lock */
5174 if (unlikely(ret)) {
5175 ret = -ENOENT;
5176 /* Free the allocated page which may have
5177 * consumed a reservation.
5178 */
5179 restore_reserve_on_error(h, dst_vma, dst_addr, page);
5180 put_page(page);
5181
5182 /* Allocate a temporary page to hold the copied
5183 * contents.
5184 */
5185 page = alloc_huge_page_vma(h, dst_vma, dst_addr);
5186 if (!page) {
5187 ret = -ENOMEM;
5188 goto out;
5189 }
5190 *pagep = page;
5191 /* Set the outparam pagep and return to the caller to
5192 * copy the contents outside the lock. Don't free the
5193 * page.
5194 */
5195 goto out;
5196 }
5197 } else {
5198 if (vm_shared &&
5199 hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) {
5200 put_page(*pagep);
5201 ret = -EEXIST;
5202 *pagep = NULL;
5203 goto out;
5204 }
5205
5206 page = alloc_huge_page(dst_vma, dst_addr, 0);
5207 if (IS_ERR(page)) {
5208 ret = -ENOMEM;
5209 *pagep = NULL;
5210 goto out;
5211 }
5212 copy_huge_page(page, *pagep);
5213 put_page(*pagep);
5214 *pagep = NULL;
5215 }
5216
5217 /*
5218 * The memory barrier inside __SetPageUptodate makes sure that
5219 * preceding stores to the page contents become visible before
5220 * the set_pte_at() write.
5221 */
5222 __SetPageUptodate(page);
5223
5224 /* Add shared, newly allocated pages to the page cache. */
5225 if (vm_shared && !is_continue) {
5226 size = i_size_read(mapping->host) >> huge_page_shift(h);
5227 ret = -EFAULT;
5228 if (idx >= size)
5229 goto out_release_nounlock;
5230
5231 /*
5232 * Serialization between remove_inode_hugepages() and
5233 * huge_add_to_page_cache() below happens through the
5234 * hugetlb_fault_mutex_table that here must be hold by
5235 * the caller.
5236 */
5237 ret = huge_add_to_page_cache(page, mapping, idx);
5238 if (ret)
5239 goto out_release_nounlock;
5240 new_pagecache_page = true;
5241 }
5242
5243 ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
5244 spin_lock(ptl);
5245
5246 /*
5247 * Recheck the i_size after holding PT lock to make sure not
5248 * to leave any page mapped (as page_mapped()) beyond the end
5249 * of the i_size (remove_inode_hugepages() is strict about
5250 * enforcing that). If we bail out here, we'll also leave a
5251 * page in the radix tree in the vm_shared case beyond the end
5252 * of the i_size, but remove_inode_hugepages() will take care
5253 * of it as soon as we drop the hugetlb_fault_mutex_table.
5254 */
5255 size = i_size_read(mapping->host) >> huge_page_shift(h);
5256 ret = -EFAULT;
5257 if (idx >= size)
5258 goto out_release_unlock;
5259
5260 ret = -EEXIST;
5261 if (!huge_pte_none(huge_ptep_get(dst_pte)))
5262 goto out_release_unlock;
5263
5264 if (vm_shared) {
5265 page_dup_rmap(page, true);
5266 } else {
5267 ClearHPageRestoreReserve(page);
5268 hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
5269 }
5270
5271 /* For CONTINUE on a non-shared VMA, don't set VM_WRITE for CoW. */
5272 if (is_continue && !vm_shared)
5273 writable = 0;
5274 else
5275 writable = dst_vma->vm_flags & VM_WRITE;
5276
5277 _dst_pte = make_huge_pte(dst_vma, page, writable);
5278 if (writable)
5279 _dst_pte = huge_pte_mkdirty(_dst_pte);
5280 _dst_pte = pte_mkyoung(_dst_pte);
5281
5282 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
5283
5284 (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
5285 dst_vma->vm_flags & VM_WRITE);
5286 hugetlb_count_add(pages_per_huge_page(h), dst_mm);
5287
5288 /* No need to invalidate - it was non-present before */
5289 update_mmu_cache(dst_vma, dst_addr, dst_pte);
5290
5291 spin_unlock(ptl);
5292 if (!is_continue)
5293 SetHPageMigratable(page);
5294 if (vm_shared || is_continue)
5295 unlock_page(page);
5296 ret = 0;
5297out:
5298 return ret;
5299out_release_unlock:
5300 spin_unlock(ptl);
5301 if (vm_shared || is_continue)
5302 unlock_page(page);
5303out_release_nounlock:
5304 if (!new_pagecache_page)
5305 restore_reserve_on_error(h, dst_vma, dst_addr, page);
5306 put_page(page);
5307 goto out;
5308}
5309#endif /* CONFIG_USERFAULTFD */
5310
5311static void record_subpages_vmas(struct page *page, struct vm_area_struct *vma,
5312 int refs, struct page **pages,
5313 struct vm_area_struct **vmas)
5314{
5315 int nr;
5316
5317 for (nr = 0; nr < refs; nr++) {
5318 if (likely(pages))
5319 pages[nr] = mem_map_offset(page, nr);
5320 if (vmas)
5321 vmas[nr] = vma;
5322 }
5323}
5324
5325long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
5326 struct page **pages, struct vm_area_struct **vmas,
5327 unsigned long *position, unsigned long *nr_pages,
5328 long i, unsigned int flags, int *locked)
5329{
5330 unsigned long pfn_offset;
5331 unsigned long vaddr = *position;
5332 unsigned long remainder = *nr_pages;
5333 struct hstate *h = hstate_vma(vma);
5334 int err = -EFAULT, refs;
5335
5336 while (vaddr < vma->vm_end && remainder) {
5337 pte_t *pte;
5338 spinlock_t *ptl = NULL;
5339 int absent;
5340 struct page *page;
5341
5342 /*
5343 * If we have a pending SIGKILL, don't keep faulting pages and
5344 * potentially allocating memory.
5345 */
5346 if (fatal_signal_pending(current)) {
5347 remainder = 0;
5348 break;
5349 }
5350
5351 /*
5352 * Some archs (sparc64, sh*) have multiple pte_ts to
5353 * each hugepage. We have to make sure we get the
5354 * first, for the page indexing below to work.
5355 *
5356 * Note that page table lock is not held when pte is null.
5357 */
5358 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
5359 huge_page_size(h));
5360 if (pte)
5361 ptl = huge_pte_lock(h, mm, pte);
5362 absent = !pte || huge_pte_none(huge_ptep_get(pte));
5363
5364 /*
5365 * When coredumping, it suits get_dump_page if we just return
5366 * an error where there's an empty slot with no huge pagecache
5367 * to back it. This way, we avoid allocating a hugepage, and
5368 * the sparse dumpfile avoids allocating disk blocks, but its
5369 * huge holes still show up with zeroes where they need to be.
5370 */
5371 if (absent && (flags & FOLL_DUMP) &&
5372 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
5373 if (pte)
5374 spin_unlock(ptl);
5375 remainder = 0;
5376 break;
5377 }
5378
5379 /*
5380 * We need call hugetlb_fault for both hugepages under migration
5381 * (in which case hugetlb_fault waits for the migration,) and
5382 * hwpoisoned hugepages (in which case we need to prevent the
5383 * caller from accessing to them.) In order to do this, we use
5384 * here is_swap_pte instead of is_hugetlb_entry_migration and
5385 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
5386 * both cases, and because we can't follow correct pages
5387 * directly from any kind of swap entries.
5388 */
5389 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
5390 ((flags & FOLL_WRITE) &&
5391 !huge_pte_write(huge_ptep_get(pte)))) {
5392 vm_fault_t ret;
5393 unsigned int fault_flags = 0;
5394
5395 if (pte)
5396 spin_unlock(ptl);
5397 if (flags & FOLL_WRITE)
5398 fault_flags |= FAULT_FLAG_WRITE;
5399 if (locked)
5400 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
5401 FAULT_FLAG_KILLABLE;
5402 if (flags & FOLL_NOWAIT)
5403 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
5404 FAULT_FLAG_RETRY_NOWAIT;
5405 if (flags & FOLL_TRIED) {
5406 /*
5407 * Note: FAULT_FLAG_ALLOW_RETRY and
5408 * FAULT_FLAG_TRIED can co-exist
5409 */
5410 fault_flags |= FAULT_FLAG_TRIED;
5411 }
5412 ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
5413 if (ret & VM_FAULT_ERROR) {
5414 err = vm_fault_to_errno(ret, flags);
5415 remainder = 0;
5416 break;
5417 }
5418 if (ret & VM_FAULT_RETRY) {
5419 if (locked &&
5420 !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
5421 *locked = 0;
5422 *nr_pages = 0;
5423 /*
5424 * VM_FAULT_RETRY must not return an
5425 * error, it will return zero
5426 * instead.
5427 *
5428 * No need to update "position" as the
5429 * caller will not check it after
5430 * *nr_pages is set to 0.
5431 */
5432 return i;
5433 }
5434 continue;
5435 }
5436
5437 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
5438 page = pte_page(huge_ptep_get(pte));
5439
5440 /*
5441 * If subpage information not requested, update counters
5442 * and skip the same_page loop below.
5443 */
5444 if (!pages && !vmas && !pfn_offset &&
5445 (vaddr + huge_page_size(h) < vma->vm_end) &&
5446 (remainder >= pages_per_huge_page(h))) {
5447 vaddr += huge_page_size(h);
5448 remainder -= pages_per_huge_page(h);
5449 i += pages_per_huge_page(h);
5450 spin_unlock(ptl);
5451 continue;
5452 }
5453
5454 /* vaddr may not be aligned to PAGE_SIZE */
5455 refs = min3(pages_per_huge_page(h) - pfn_offset, remainder,
5456 (vma->vm_end - ALIGN_DOWN(vaddr, PAGE_SIZE)) >> PAGE_SHIFT);
5457
5458 if (pages || vmas)
5459 record_subpages_vmas(mem_map_offset(page, pfn_offset),
5460 vma, refs,
5461 likely(pages) ? pages + i : NULL,
5462 vmas ? vmas + i : NULL);
5463
5464 if (pages) {
5465 /*
5466 * try_grab_compound_head() should always succeed here,
5467 * because: a) we hold the ptl lock, and b) we've just
5468 * checked that the huge page is present in the page
5469 * tables. If the huge page is present, then the tail
5470 * pages must also be present. The ptl prevents the
5471 * head page and tail pages from being rearranged in
5472 * any way. So this page must be available at this
5473 * point, unless the page refcount overflowed:
5474 */
5475 if (WARN_ON_ONCE(!try_grab_compound_head(pages[i],
5476 refs,
5477 flags))) {
5478 spin_unlock(ptl);
5479 remainder = 0;
5480 err = -ENOMEM;
5481 break;
5482 }
5483 }
5484
5485 vaddr += (refs << PAGE_SHIFT);
5486 remainder -= refs;
5487 i += refs;
5488
5489 spin_unlock(ptl);
5490 }
5491 *nr_pages = remainder;
5492 /*
5493 * setting position is actually required only if remainder is
5494 * not zero but it's faster not to add a "if (remainder)"
5495 * branch.
5496 */
5497 *position = vaddr;
5498
5499 return i ? i : err;
5500}
5501
5502unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
5503 unsigned long address, unsigned long end, pgprot_t newprot)
5504{
5505 struct mm_struct *mm = vma->vm_mm;
5506 unsigned long start = address;
5507 pte_t *ptep;
5508 pte_t pte;
5509 struct hstate *h = hstate_vma(vma);
5510 unsigned long pages = 0;
5511 bool shared_pmd = false;
5512 struct mmu_notifier_range range;
5513
5514 /*
5515 * In the case of shared PMDs, the area to flush could be beyond
5516 * start/end. Set range.start/range.end to cover the maximum possible
5517 * range if PMD sharing is possible.
5518 */
5519 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
5520 0, vma, mm, start, end);
5521 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5522
5523 BUG_ON(address >= end);
5524 flush_cache_range(vma, range.start, range.end);
5525
5526 mmu_notifier_invalidate_range_start(&range);
5527 i_mmap_lock_write(vma->vm_file->f_mapping);
5528 for (; address < end; address += huge_page_size(h)) {
5529 spinlock_t *ptl;
5530 ptep = huge_pte_offset(mm, address, huge_page_size(h));
5531 if (!ptep)
5532 continue;
5533 ptl = huge_pte_lock(h, mm, ptep);
5534 if (huge_pmd_unshare(mm, vma, &address, ptep)) {
5535 pages++;
5536 spin_unlock(ptl);
5537 shared_pmd = true;
5538 continue;
5539 }
5540 pte = huge_ptep_get(ptep);
5541 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
5542 spin_unlock(ptl);
5543 continue;
5544 }
5545 if (unlikely(is_hugetlb_entry_migration(pte))) {
5546 swp_entry_t entry = pte_to_swp_entry(pte);
5547
5548 if (is_writable_migration_entry(entry)) {
5549 pte_t newpte;
5550
5551 entry = make_readable_migration_entry(
5552 swp_offset(entry));
5553 newpte = swp_entry_to_pte(entry);
5554 set_huge_swap_pte_at(mm, address, ptep,
5555 newpte, huge_page_size(h));
5556 pages++;
5557 }
5558 spin_unlock(ptl);
5559 continue;
5560 }
5561 if (!huge_pte_none(pte)) {
5562 pte_t old_pte;
5563 unsigned int shift = huge_page_shift(hstate_vma(vma));
5564
5565 old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
5566 pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
5567 pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
5568 huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
5569 pages++;
5570 }
5571 spin_unlock(ptl);
5572 }
5573 /*
5574 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
5575 * may have cleared our pud entry and done put_page on the page table:
5576 * once we release i_mmap_rwsem, another task can do the final put_page
5577 * and that page table be reused and filled with junk. If we actually
5578 * did unshare a page of pmds, flush the range corresponding to the pud.
5579 */
5580 if (shared_pmd)
5581 flush_hugetlb_tlb_range(vma, range.start, range.end);
5582 else
5583 flush_hugetlb_tlb_range(vma, start, end);
5584 /*
5585 * No need to call mmu_notifier_invalidate_range() we are downgrading
5586 * page table protection not changing it to point to a new page.
5587 *
5588 * See Documentation/vm/mmu_notifier.rst
5589 */
5590 i_mmap_unlock_write(vma->vm_file->f_mapping);
5591 mmu_notifier_invalidate_range_end(&range);
5592
5593 return pages << h->order;
5594}
5595
5596/* Return true if reservation was successful, false otherwise. */
5597bool hugetlb_reserve_pages(struct inode *inode,
5598 long from, long to,
5599 struct vm_area_struct *vma,
5600 vm_flags_t vm_flags)
5601{
5602 long chg, add = -1;
5603 struct hstate *h = hstate_inode(inode);
5604 struct hugepage_subpool *spool = subpool_inode(inode);
5605 struct resv_map *resv_map;
5606 struct hugetlb_cgroup *h_cg = NULL;
5607 long gbl_reserve, regions_needed = 0;
5608
5609 /* This should never happen */
5610 if (from > to) {
5611 VM_WARN(1, "%s called with a negative range\n", __func__);
5612 return false;
5613 }
5614
5615 /*
5616 * Only apply hugepage reservation if asked. At fault time, an
5617 * attempt will be made for VM_NORESERVE to allocate a page
5618 * without using reserves
5619 */
5620 if (vm_flags & VM_NORESERVE)
5621 return true;
5622
5623 /*
5624 * Shared mappings base their reservation on the number of pages that
5625 * are already allocated on behalf of the file. Private mappings need
5626 * to reserve the full area even if read-only as mprotect() may be
5627 * called to make the mapping read-write. Assume !vma is a shm mapping
5628 */
5629 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5630 /*
5631 * resv_map can not be NULL as hugetlb_reserve_pages is only
5632 * called for inodes for which resv_maps were created (see
5633 * hugetlbfs_get_inode).
5634 */
5635 resv_map = inode_resv_map(inode);
5636
5637 chg = region_chg(resv_map, from, to, ®ions_needed);
5638
5639 } else {
5640 /* Private mapping. */
5641 resv_map = resv_map_alloc();
5642 if (!resv_map)
5643 return false;
5644
5645 chg = to - from;
5646
5647 set_vma_resv_map(vma, resv_map);
5648 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
5649 }
5650
5651 if (chg < 0)
5652 goto out_err;
5653
5654 if (hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h),
5655 chg * pages_per_huge_page(h), &h_cg) < 0)
5656 goto out_err;
5657
5658 if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) {
5659 /* For private mappings, the hugetlb_cgroup uncharge info hangs
5660 * of the resv_map.
5661 */
5662 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
5663 }
5664
5665 /*
5666 * There must be enough pages in the subpool for the mapping. If
5667 * the subpool has a minimum size, there may be some global
5668 * reservations already in place (gbl_reserve).
5669 */
5670 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
5671 if (gbl_reserve < 0)
5672 goto out_uncharge_cgroup;
5673
5674 /*
5675 * Check enough hugepages are available for the reservation.
5676 * Hand the pages back to the subpool if there are not
5677 */
5678 if (hugetlb_acct_memory(h, gbl_reserve) < 0)
5679 goto out_put_pages;
5680
5681 /*
5682 * Account for the reservations made. Shared mappings record regions
5683 * that have reservations as they are shared by multiple VMAs.
5684 * When the last VMA disappears, the region map says how much
5685 * the reservation was and the page cache tells how much of
5686 * the reservation was consumed. Private mappings are per-VMA and
5687 * only the consumed reservations are tracked. When the VMA
5688 * disappears, the original reservation is the VMA size and the
5689 * consumed reservations are stored in the map. Hence, nothing
5690 * else has to be done for private mappings here
5691 */
5692 if (!vma || vma->vm_flags & VM_MAYSHARE) {
5693 add = region_add(resv_map, from, to, regions_needed, h, h_cg);
5694
5695 if (unlikely(add < 0)) {
5696 hugetlb_acct_memory(h, -gbl_reserve);
5697 goto out_put_pages;
5698 } else if (unlikely(chg > add)) {
5699 /*
5700 * pages in this range were added to the reserve
5701 * map between region_chg and region_add. This
5702 * indicates a race with alloc_huge_page. Adjust
5703 * the subpool and reserve counts modified above
5704 * based on the difference.
5705 */
5706 long rsv_adjust;
5707
5708 /*
5709 * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the
5710 * reference to h_cg->css. See comment below for detail.
5711 */
5712 hugetlb_cgroup_uncharge_cgroup_rsvd(
5713 hstate_index(h),
5714 (chg - add) * pages_per_huge_page(h), h_cg);
5715
5716 rsv_adjust = hugepage_subpool_put_pages(spool,
5717 chg - add);
5718 hugetlb_acct_memory(h, -rsv_adjust);
5719 } else if (h_cg) {
5720 /*
5721 * The file_regions will hold their own reference to
5722 * h_cg->css. So we should release the reference held
5723 * via hugetlb_cgroup_charge_cgroup_rsvd() when we are
5724 * done.
5725 */
5726 hugetlb_cgroup_put_rsvd_cgroup(h_cg);
5727 }
5728 }
5729 return true;
5730
5731out_put_pages:
5732 /* put back original number of pages, chg */
5733 (void)hugepage_subpool_put_pages(spool, chg);
5734out_uncharge_cgroup:
5735 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
5736 chg * pages_per_huge_page(h), h_cg);
5737out_err:
5738 if (!vma || vma->vm_flags & VM_MAYSHARE)
5739 /* Only call region_abort if the region_chg succeeded but the
5740 * region_add failed or didn't run.
5741 */
5742 if (chg >= 0 && add < 0)
5743 region_abort(resv_map, from, to, regions_needed);
5744 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
5745 kref_put(&resv_map->refs, resv_map_release);
5746 return false;
5747}
5748
5749long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
5750 long freed)
5751{
5752 struct hstate *h = hstate_inode(inode);
5753 struct resv_map *resv_map = inode_resv_map(inode);
5754 long chg = 0;
5755 struct hugepage_subpool *spool = subpool_inode(inode);
5756 long gbl_reserve;
5757
5758 /*
5759 * Since this routine can be called in the evict inode path for all
5760 * hugetlbfs inodes, resv_map could be NULL.
5761 */
5762 if (resv_map) {
5763 chg = region_del(resv_map, start, end);
5764 /*
5765 * region_del() can fail in the rare case where a region
5766 * must be split and another region descriptor can not be
5767 * allocated. If end == LONG_MAX, it will not fail.
5768 */
5769 if (chg < 0)
5770 return chg;
5771 }
5772
5773 spin_lock(&inode->i_lock);
5774 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
5775 spin_unlock(&inode->i_lock);
5776
5777 /*
5778 * If the subpool has a minimum size, the number of global
5779 * reservations to be released may be adjusted.
5780 *
5781 * Note that !resv_map implies freed == 0. So (chg - freed)
5782 * won't go negative.
5783 */
5784 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
5785 hugetlb_acct_memory(h, -gbl_reserve);
5786
5787 return 0;
5788}
5789
5790#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
5791static unsigned long page_table_shareable(struct vm_area_struct *svma,
5792 struct vm_area_struct *vma,
5793 unsigned long addr, pgoff_t idx)
5794{
5795 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
5796 svma->vm_start;
5797 unsigned long sbase = saddr & PUD_MASK;
5798 unsigned long s_end = sbase + PUD_SIZE;
5799
5800 /* Allow segments to share if only one is marked locked */
5801 unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
5802 unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
5803
5804 /*
5805 * match the virtual addresses, permission and the alignment of the
5806 * page table page.
5807 */
5808 if (pmd_index(addr) != pmd_index(saddr) ||
5809 vm_flags != svm_flags ||
5810 !range_in_vma(svma, sbase, s_end))
5811 return 0;
5812
5813 return saddr;
5814}
5815
5816static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
5817{
5818 unsigned long base = addr & PUD_MASK;
5819 unsigned long end = base + PUD_SIZE;
5820
5821 /*
5822 * check on proper vm_flags and page table alignment
5823 */
5824 if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
5825 return true;
5826 return false;
5827}
5828
5829bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
5830{
5831#ifdef CONFIG_USERFAULTFD
5832 if (uffd_disable_huge_pmd_share(vma))
5833 return false;
5834#endif
5835 return vma_shareable(vma, addr);
5836}
5837
5838/*
5839 * Determine if start,end range within vma could be mapped by shared pmd.
5840 * If yes, adjust start and end to cover range associated with possible
5841 * shared pmd mappings.
5842 */
5843void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5844 unsigned long *start, unsigned long *end)
5845{
5846 unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE),
5847 v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
5848
5849 /*
5850 * vma needs to span at least one aligned PUD size, and the range
5851 * must be at least partially within in.
5852 */
5853 if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) ||
5854 (*end <= v_start) || (*start >= v_end))
5855 return;
5856
5857 /* Extend the range to be PUD aligned for a worst case scenario */
5858 if (*start > v_start)
5859 *start = ALIGN_DOWN(*start, PUD_SIZE);
5860
5861 if (*end < v_end)
5862 *end = ALIGN(*end, PUD_SIZE);
5863}
5864
5865/*
5866 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
5867 * and returns the corresponding pte. While this is not necessary for the
5868 * !shared pmd case because we can allocate the pmd later as well, it makes the
5869 * code much cleaner.
5870 *
5871 * This routine must be called with i_mmap_rwsem held in at least read mode if
5872 * sharing is possible. For hugetlbfs, this prevents removal of any page
5873 * table entries associated with the address space. This is important as we
5874 * are setting up sharing based on existing page table entries (mappings).
5875 *
5876 * NOTE: This routine is only called from huge_pte_alloc. Some callers of
5877 * huge_pte_alloc know that sharing is not possible and do not take
5878 * i_mmap_rwsem as a performance optimization. This is handled by the
5879 * if !vma_shareable check at the beginning of the routine. i_mmap_rwsem is
5880 * only required for subsequent processing.
5881 */
5882pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
5883 unsigned long addr, pud_t *pud)
5884{
5885 struct address_space *mapping = vma->vm_file->f_mapping;
5886 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
5887 vma->vm_pgoff;
5888 struct vm_area_struct *svma;
5889 unsigned long saddr;
5890 pte_t *spte = NULL;
5891 pte_t *pte;
5892 spinlock_t *ptl;
5893
5894 i_mmap_assert_locked(mapping);
5895 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
5896 if (svma == vma)
5897 continue;
5898
5899 saddr = page_table_shareable(svma, vma, addr, idx);
5900 if (saddr) {
5901 spte = huge_pte_offset(svma->vm_mm, saddr,
5902 vma_mmu_pagesize(svma));
5903 if (spte) {
5904 get_page(virt_to_page(spte));
5905 break;
5906 }
5907 }
5908 }
5909
5910 if (!spte)
5911 goto out;
5912
5913 ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
5914 if (pud_none(*pud)) {
5915 pud_populate(mm, pud,
5916 (pmd_t *)((unsigned long)spte & PAGE_MASK));
5917 mm_inc_nr_pmds(mm);
5918 } else {
5919 put_page(virt_to_page(spte));
5920 }
5921 spin_unlock(ptl);
5922out:
5923 pte = (pte_t *)pmd_alloc(mm, pud, addr);
5924 return pte;
5925}
5926
5927/*
5928 * unmap huge page backed by shared pte.
5929 *
5930 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
5931 * indicated by page_count > 1, unmap is achieved by clearing pud and
5932 * decrementing the ref count. If count == 1, the pte page is not shared.
5933 *
5934 * Called with page table lock held and i_mmap_rwsem held in write mode.
5935 *
5936 * returns: 1 successfully unmapped a shared pte page
5937 * 0 the underlying pte page is not shared, or it is the last user
5938 */
5939int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5940 unsigned long *addr, pte_t *ptep)
5941{
5942 pgd_t *pgd = pgd_offset(mm, *addr);
5943 p4d_t *p4d = p4d_offset(pgd, *addr);
5944 pud_t *pud = pud_offset(p4d, *addr);
5945
5946 i_mmap_assert_write_locked(vma->vm_file->f_mapping);
5947 BUG_ON(page_count(virt_to_page(ptep)) == 0);
5948 if (page_count(virt_to_page(ptep)) == 1)
5949 return 0;
5950
5951 pud_clear(pud);
5952 put_page(virt_to_page(ptep));
5953 mm_dec_nr_pmds(mm);
5954 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
5955 return 1;
5956}
5957
5958#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5959pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
5960 unsigned long addr, pud_t *pud)
5961{
5962 return NULL;
5963}
5964
5965int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
5966 unsigned long *addr, pte_t *ptep)
5967{
5968 return 0;
5969}
5970
5971void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
5972 unsigned long *start, unsigned long *end)
5973{
5974}
5975
5976bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
5977{
5978 return false;
5979}
5980#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
5981
5982#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
5983pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
5984 unsigned long addr, unsigned long sz)
5985{
5986 pgd_t *pgd;
5987 p4d_t *p4d;
5988 pud_t *pud;
5989 pte_t *pte = NULL;
5990
5991 pgd = pgd_offset(mm, addr);
5992 p4d = p4d_alloc(mm, pgd, addr);
5993 if (!p4d)
5994 return NULL;
5995 pud = pud_alloc(mm, p4d, addr);
5996 if (pud) {
5997 if (sz == PUD_SIZE) {
5998 pte = (pte_t *)pud;
5999 } else {
6000 BUG_ON(sz != PMD_SIZE);
6001 if (want_pmd_share(vma, addr) && pud_none(*pud))
6002 pte = huge_pmd_share(mm, vma, addr, pud);
6003 else
6004 pte = (pte_t *)pmd_alloc(mm, pud, addr);
6005 }
6006 }
6007 BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
6008
6009 return pte;
6010}
6011
6012/*
6013 * huge_pte_offset() - Walk the page table to resolve the hugepage
6014 * entry at address @addr
6015 *
6016 * Return: Pointer to page table entry (PUD or PMD) for
6017 * address @addr, or NULL if a !p*d_present() entry is encountered and the
6018 * size @sz doesn't match the hugepage size at this level of the page
6019 * table.
6020 */
6021pte_t *huge_pte_offset(struct mm_struct *mm,
6022 unsigned long addr, unsigned long sz)
6023{
6024 pgd_t *pgd;
6025 p4d_t *p4d;
6026 pud_t *pud;
6027 pmd_t *pmd;
6028
6029 pgd = pgd_offset(mm, addr);
6030 if (!pgd_present(*pgd))
6031 return NULL;
6032 p4d = p4d_offset(pgd, addr);
6033 if (!p4d_present(*p4d))
6034 return NULL;
6035
6036 pud = pud_offset(p4d, addr);
6037 if (sz == PUD_SIZE)
6038 /* must be pud huge, non-present or none */
6039 return (pte_t *)pud;
6040 if (!pud_present(*pud))
6041 return NULL;
6042 /* must have a valid entry and size to go further */
6043
6044 pmd = pmd_offset(pud, addr);
6045 /* must be pmd huge, non-present or none */
6046 return (pte_t *)pmd;
6047}
6048
6049#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
6050
6051/*
6052 * These functions are overwritable if your architecture needs its own
6053 * behavior.
6054 */
6055struct page * __weak
6056follow_huge_addr(struct mm_struct *mm, unsigned long address,
6057 int write)
6058{
6059 return ERR_PTR(-EINVAL);
6060}
6061
6062struct page * __weak
6063follow_huge_pd(struct vm_area_struct *vma,
6064 unsigned long address, hugepd_t hpd, int flags, int pdshift)
6065{
6066 WARN(1, "hugepd follow called with no support for hugepage directory format\n");
6067 return NULL;
6068}
6069
6070struct page * __weak
6071follow_huge_pmd(struct mm_struct *mm, unsigned long address,
6072 pmd_t *pmd, int flags)
6073{
6074 struct page *page = NULL;
6075 spinlock_t *ptl;
6076 pte_t pte;
6077
6078 /* FOLL_GET and FOLL_PIN are mutually exclusive. */
6079 if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
6080 (FOLL_PIN | FOLL_GET)))
6081 return NULL;
6082
6083retry:
6084 ptl = pmd_lockptr(mm, pmd);
6085 spin_lock(ptl);
6086 /*
6087 * make sure that the address range covered by this pmd is not
6088 * unmapped from other threads.
6089 */
6090 if (!pmd_huge(*pmd))
6091 goto out;
6092 pte = huge_ptep_get((pte_t *)pmd);
6093 if (pte_present(pte)) {
6094 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
6095 /*
6096 * try_grab_page() should always succeed here, because: a) we
6097 * hold the pmd (ptl) lock, and b) we've just checked that the
6098 * huge pmd (head) page is present in the page tables. The ptl
6099 * prevents the head page and tail pages from being rearranged
6100 * in any way. So this page must be available at this point,
6101 * unless the page refcount overflowed:
6102 */
6103 if (WARN_ON_ONCE(!try_grab_page(page, flags))) {
6104 page = NULL;
6105 goto out;
6106 }
6107 } else {
6108 if (is_hugetlb_entry_migration(pte)) {
6109 spin_unlock(ptl);
6110 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
6111 goto retry;
6112 }
6113 /*
6114 * hwpoisoned entry is treated as no_page_table in
6115 * follow_page_mask().
6116 */
6117 }
6118out:
6119 spin_unlock(ptl);
6120 return page;
6121}
6122
6123struct page * __weak
6124follow_huge_pud(struct mm_struct *mm, unsigned long address,
6125 pud_t *pud, int flags)
6126{
6127 if (flags & (FOLL_GET | FOLL_PIN))
6128 return NULL;
6129
6130 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
6131}
6132
6133struct page * __weak
6134follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
6135{
6136 if (flags & (FOLL_GET | FOLL_PIN))
6137 return NULL;
6138
6139 return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
6140}
6141
6142bool isolate_huge_page(struct page *page, struct list_head *list)
6143{
6144 bool ret = true;
6145
6146 spin_lock_irq(&hugetlb_lock);
6147 if (!PageHeadHuge(page) ||
6148 !HPageMigratable(page) ||
6149 !get_page_unless_zero(page)) {
6150 ret = false;
6151 goto unlock;
6152 }
6153 ClearHPageMigratable(page);
6154 list_move_tail(&page->lru, list);
6155unlock:
6156 spin_unlock_irq(&hugetlb_lock);
6157 return ret;
6158}
6159
6160int get_hwpoison_huge_page(struct page *page, bool *hugetlb)
6161{
6162 int ret = 0;
6163
6164 *hugetlb = false;
6165 spin_lock_irq(&hugetlb_lock);
6166 if (PageHeadHuge(page)) {
6167 *hugetlb = true;
6168 if (HPageFreed(page) || HPageMigratable(page))
6169 ret = get_page_unless_zero(page);
6170 else
6171 ret = -EBUSY;
6172 }
6173 spin_unlock_irq(&hugetlb_lock);
6174 return ret;
6175}
6176
6177void putback_active_hugepage(struct page *page)
6178{
6179 spin_lock_irq(&hugetlb_lock);
6180 SetHPageMigratable(page);
6181 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
6182 spin_unlock_irq(&hugetlb_lock);
6183 put_page(page);
6184}
6185
6186void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
6187{
6188 struct hstate *h = page_hstate(oldpage);
6189
6190 hugetlb_cgroup_migrate(oldpage, newpage);
6191 set_page_owner_migrate_reason(newpage, reason);
6192
6193 /*
6194 * transfer temporary state of the new huge page. This is
6195 * reverse to other transitions because the newpage is going to
6196 * be final while the old one will be freed so it takes over
6197 * the temporary status.
6198 *
6199 * Also note that we have to transfer the per-node surplus state
6200 * here as well otherwise the global surplus count will not match
6201 * the per-node's.
6202 */
6203 if (HPageTemporary(newpage)) {
6204 int old_nid = page_to_nid(oldpage);
6205 int new_nid = page_to_nid(newpage);
6206
6207 SetHPageTemporary(oldpage);
6208 ClearHPageTemporary(newpage);
6209
6210 /*
6211 * There is no need to transfer the per-node surplus state
6212 * when we do not cross the node.
6213 */
6214 if (new_nid == old_nid)
6215 return;
6216 spin_lock_irq(&hugetlb_lock);
6217 if (h->surplus_huge_pages_node[old_nid]) {
6218 h->surplus_huge_pages_node[old_nid]--;
6219 h->surplus_huge_pages_node[new_nid]++;
6220 }
6221 spin_unlock_irq(&hugetlb_lock);
6222 }
6223}
6224
6225/*
6226 * This function will unconditionally remove all the shared pmd pgtable entries
6227 * within the specific vma for a hugetlbfs memory range.
6228 */
6229void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
6230{
6231 struct hstate *h = hstate_vma(vma);
6232 unsigned long sz = huge_page_size(h);
6233 struct mm_struct *mm = vma->vm_mm;
6234 struct mmu_notifier_range range;
6235 unsigned long address, start, end;
6236 spinlock_t *ptl;
6237 pte_t *ptep;
6238
6239 if (!(vma->vm_flags & VM_MAYSHARE))
6240 return;
6241
6242 start = ALIGN(vma->vm_start, PUD_SIZE);
6243 end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
6244
6245 if (start >= end)
6246 return;
6247
6248 /*
6249 * No need to call adjust_range_if_pmd_sharing_possible(), because
6250 * we have already done the PUD_SIZE alignment.
6251 */
6252 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm,
6253 start, end);
6254 mmu_notifier_invalidate_range_start(&range);
6255 i_mmap_lock_write(vma->vm_file->f_mapping);
6256 for (address = start; address < end; address += PUD_SIZE) {
6257 unsigned long tmp = address;
6258
6259 ptep = huge_pte_offset(mm, address, sz);
6260 if (!ptep)
6261 continue;
6262 ptl = huge_pte_lock(h, mm, ptep);
6263 /* We don't want 'address' to be changed */
6264 huge_pmd_unshare(mm, vma, &tmp, ptep);
6265 spin_unlock(ptl);
6266 }
6267 flush_hugetlb_tlb_range(vma, start, end);
6268 i_mmap_unlock_write(vma->vm_file->f_mapping);
6269 /*
6270 * No need to call mmu_notifier_invalidate_range(), see
6271 * Documentation/vm/mmu_notifier.rst.
6272 */
6273 mmu_notifier_invalidate_range_end(&range);
6274}
6275
6276#ifdef CONFIG_CMA
6277static bool cma_reserve_called __initdata;
6278
6279static int __init cmdline_parse_hugetlb_cma(char *p)
6280{
6281 hugetlb_cma_size = memparse(p, &p);
6282 return 0;
6283}
6284
6285early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
6286
6287void __init hugetlb_cma_reserve(int order)
6288{
6289 unsigned long size, reserved, per_node;
6290 int nid;
6291
6292 cma_reserve_called = true;
6293
6294 if (!hugetlb_cma_size)
6295 return;
6296
6297 if (hugetlb_cma_size < (PAGE_SIZE << order)) {
6298 pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
6299 (PAGE_SIZE << order) / SZ_1M);
6300 return;
6301 }
6302
6303 /*
6304 * If 3 GB area is requested on a machine with 4 numa nodes,
6305 * let's allocate 1 GB on first three nodes and ignore the last one.
6306 */
6307 per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
6308 pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
6309 hugetlb_cma_size / SZ_1M, per_node / SZ_1M);
6310
6311 reserved = 0;
6312 for_each_node_state(nid, N_ONLINE) {
6313 int res;
6314 char name[CMA_MAX_NAME];
6315
6316 size = min(per_node, hugetlb_cma_size - reserved);
6317 size = round_up(size, PAGE_SIZE << order);
6318
6319 snprintf(name, sizeof(name), "hugetlb%d", nid);
6320 res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order,
6321 0, false, name,
6322 &hugetlb_cma[nid], nid);
6323 if (res) {
6324 pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
6325 res, nid);
6326 continue;
6327 }
6328
6329 reserved += size;
6330 pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
6331 size / SZ_1M, nid);
6332
6333 if (reserved >= hugetlb_cma_size)
6334 break;
6335 }
6336}
6337
6338void __init hugetlb_cma_check(void)
6339{
6340 if (!hugetlb_cma_size || cma_reserve_called)
6341 return;
6342
6343 pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
6344}
6345
6346#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/mm.h>
8#include <linux/seq_file.h>
9#include <linux/sysctl.h>
10#include <linux/highmem.h>
11#include <linux/mmu_notifier.h>
12#include <linux/nodemask.h>
13#include <linux/pagemap.h>
14#include <linux/mempolicy.h>
15#include <linux/compiler.h>
16#include <linux/cpuset.h>
17#include <linux/mutex.h>
18#include <linux/bootmem.h>
19#include <linux/sysfs.h>
20#include <linux/slab.h>
21#include <linux/rmap.h>
22#include <linux/swap.h>
23#include <linux/swapops.h>
24#include <linux/page-isolation.h>
25#include <linux/jhash.h>
26
27#include <asm/page.h>
28#include <asm/pgtable.h>
29#include <asm/tlb.h>
30
31#include <linux/io.h>
32#include <linux/hugetlb.h>
33#include <linux/hugetlb_cgroup.h>
34#include <linux/node.h>
35#include "internal.h"
36
37int hugepages_treat_as_movable;
38
39int hugetlb_max_hstate __read_mostly;
40unsigned int default_hstate_idx;
41struct hstate hstates[HUGE_MAX_HSTATE];
42/*
43 * Minimum page order among possible hugepage sizes, set to a proper value
44 * at boot time.
45 */
46static unsigned int minimum_order __read_mostly = UINT_MAX;
47
48__initdata LIST_HEAD(huge_boot_pages);
49
50/* for command line parsing */
51static struct hstate * __initdata parsed_hstate;
52static unsigned long __initdata default_hstate_max_huge_pages;
53static unsigned long __initdata default_hstate_size;
54static bool __initdata parsed_valid_hugepagesz = true;
55
56/*
57 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
58 * free_huge_pages, and surplus_huge_pages.
59 */
60DEFINE_SPINLOCK(hugetlb_lock);
61
62/*
63 * Serializes faults on the same logical page. This is used to
64 * prevent spurious OOMs when the hugepage pool is fully utilized.
65 */
66static int num_fault_mutexes;
67struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
68
69/* Forward declaration */
70static int hugetlb_acct_memory(struct hstate *h, long delta);
71
72static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
73{
74 bool free = (spool->count == 0) && (spool->used_hpages == 0);
75
76 spin_unlock(&spool->lock);
77
78 /* If no pages are used, and no other handles to the subpool
79 * remain, give up any reservations mased on minimum size and
80 * free the subpool */
81 if (free) {
82 if (spool->min_hpages != -1)
83 hugetlb_acct_memory(spool->hstate,
84 -spool->min_hpages);
85 kfree(spool);
86 }
87}
88
89struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
90 long min_hpages)
91{
92 struct hugepage_subpool *spool;
93
94 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
95 if (!spool)
96 return NULL;
97
98 spin_lock_init(&spool->lock);
99 spool->count = 1;
100 spool->max_hpages = max_hpages;
101 spool->hstate = h;
102 spool->min_hpages = min_hpages;
103
104 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
105 kfree(spool);
106 return NULL;
107 }
108 spool->rsv_hpages = min_hpages;
109
110 return spool;
111}
112
113void hugepage_put_subpool(struct hugepage_subpool *spool)
114{
115 spin_lock(&spool->lock);
116 BUG_ON(!spool->count);
117 spool->count--;
118 unlock_or_release_subpool(spool);
119}
120
121/*
122 * Subpool accounting for allocating and reserving pages.
123 * Return -ENOMEM if there are not enough resources to satisfy the
124 * the request. Otherwise, return the number of pages by which the
125 * global pools must be adjusted (upward). The returned value may
126 * only be different than the passed value (delta) in the case where
127 * a subpool minimum size must be manitained.
128 */
129static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
130 long delta)
131{
132 long ret = delta;
133
134 if (!spool)
135 return ret;
136
137 spin_lock(&spool->lock);
138
139 if (spool->max_hpages != -1) { /* maximum size accounting */
140 if ((spool->used_hpages + delta) <= spool->max_hpages)
141 spool->used_hpages += delta;
142 else {
143 ret = -ENOMEM;
144 goto unlock_ret;
145 }
146 }
147
148 /* minimum size accounting */
149 if (spool->min_hpages != -1 && spool->rsv_hpages) {
150 if (delta > spool->rsv_hpages) {
151 /*
152 * Asking for more reserves than those already taken on
153 * behalf of subpool. Return difference.
154 */
155 ret = delta - spool->rsv_hpages;
156 spool->rsv_hpages = 0;
157 } else {
158 ret = 0; /* reserves already accounted for */
159 spool->rsv_hpages -= delta;
160 }
161 }
162
163unlock_ret:
164 spin_unlock(&spool->lock);
165 return ret;
166}
167
168/*
169 * Subpool accounting for freeing and unreserving pages.
170 * Return the number of global page reservations that must be dropped.
171 * The return value may only be different than the passed value (delta)
172 * in the case where a subpool minimum size must be maintained.
173 */
174static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
175 long delta)
176{
177 long ret = delta;
178
179 if (!spool)
180 return delta;
181
182 spin_lock(&spool->lock);
183
184 if (spool->max_hpages != -1) /* maximum size accounting */
185 spool->used_hpages -= delta;
186
187 /* minimum size accounting */
188 if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
189 if (spool->rsv_hpages + delta <= spool->min_hpages)
190 ret = 0;
191 else
192 ret = spool->rsv_hpages + delta - spool->min_hpages;
193
194 spool->rsv_hpages += delta;
195 if (spool->rsv_hpages > spool->min_hpages)
196 spool->rsv_hpages = spool->min_hpages;
197 }
198
199 /*
200 * If hugetlbfs_put_super couldn't free spool due to an outstanding
201 * quota reference, free it now.
202 */
203 unlock_or_release_subpool(spool);
204
205 return ret;
206}
207
208static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
209{
210 return HUGETLBFS_SB(inode->i_sb)->spool;
211}
212
213static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
214{
215 return subpool_inode(file_inode(vma->vm_file));
216}
217
218/*
219 * Region tracking -- allows tracking of reservations and instantiated pages
220 * across the pages in a mapping.
221 *
222 * The region data structures are embedded into a resv_map and protected
223 * by a resv_map's lock. The set of regions within the resv_map represent
224 * reservations for huge pages, or huge pages that have already been
225 * instantiated within the map. The from and to elements are huge page
226 * indicies into the associated mapping. from indicates the starting index
227 * of the region. to represents the first index past the end of the region.
228 *
229 * For example, a file region structure with from == 0 and to == 4 represents
230 * four huge pages in a mapping. It is important to note that the to element
231 * represents the first element past the end of the region. This is used in
232 * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
233 *
234 * Interval notation of the form [from, to) will be used to indicate that
235 * the endpoint from is inclusive and to is exclusive.
236 */
237struct file_region {
238 struct list_head link;
239 long from;
240 long to;
241};
242
243/*
244 * Add the huge page range represented by [f, t) to the reserve
245 * map. In the normal case, existing regions will be expanded
246 * to accommodate the specified range. Sufficient regions should
247 * exist for expansion due to the previous call to region_chg
248 * with the same range. However, it is possible that region_del
249 * could have been called after region_chg and modifed the map
250 * in such a way that no region exists to be expanded. In this
251 * case, pull a region descriptor from the cache associated with
252 * the map and use that for the new range.
253 *
254 * Return the number of new huge pages added to the map. This
255 * number is greater than or equal to zero.
256 */
257static long region_add(struct resv_map *resv, long f, long t)
258{
259 struct list_head *head = &resv->regions;
260 struct file_region *rg, *nrg, *trg;
261 long add = 0;
262
263 spin_lock(&resv->lock);
264 /* Locate the region we are either in or before. */
265 list_for_each_entry(rg, head, link)
266 if (f <= rg->to)
267 break;
268
269 /*
270 * If no region exists which can be expanded to include the
271 * specified range, the list must have been modified by an
272 * interleving call to region_del(). Pull a region descriptor
273 * from the cache and use it for this range.
274 */
275 if (&rg->link == head || t < rg->from) {
276 VM_BUG_ON(resv->region_cache_count <= 0);
277
278 resv->region_cache_count--;
279 nrg = list_first_entry(&resv->region_cache, struct file_region,
280 link);
281 list_del(&nrg->link);
282
283 nrg->from = f;
284 nrg->to = t;
285 list_add(&nrg->link, rg->link.prev);
286
287 add += t - f;
288 goto out_locked;
289 }
290
291 /* Round our left edge to the current segment if it encloses us. */
292 if (f > rg->from)
293 f = rg->from;
294
295 /* Check for and consume any regions we now overlap with. */
296 nrg = rg;
297 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
298 if (&rg->link == head)
299 break;
300 if (rg->from > t)
301 break;
302
303 /* If this area reaches higher then extend our area to
304 * include it completely. If this is not the first area
305 * which we intend to reuse, free it. */
306 if (rg->to > t)
307 t = rg->to;
308 if (rg != nrg) {
309 /* Decrement return value by the deleted range.
310 * Another range will span this area so that by
311 * end of routine add will be >= zero
312 */
313 add -= (rg->to - rg->from);
314 list_del(&rg->link);
315 kfree(rg);
316 }
317 }
318
319 add += (nrg->from - f); /* Added to beginning of region */
320 nrg->from = f;
321 add += t - nrg->to; /* Added to end of region */
322 nrg->to = t;
323
324out_locked:
325 resv->adds_in_progress--;
326 spin_unlock(&resv->lock);
327 VM_BUG_ON(add < 0);
328 return add;
329}
330
331/*
332 * Examine the existing reserve map and determine how many
333 * huge pages in the specified range [f, t) are NOT currently
334 * represented. This routine is called before a subsequent
335 * call to region_add that will actually modify the reserve
336 * map to add the specified range [f, t). region_chg does
337 * not change the number of huge pages represented by the
338 * map. However, if the existing regions in the map can not
339 * be expanded to represent the new range, a new file_region
340 * structure is added to the map as a placeholder. This is
341 * so that the subsequent region_add call will have all the
342 * regions it needs and will not fail.
343 *
344 * Upon entry, region_chg will also examine the cache of region descriptors
345 * associated with the map. If there are not enough descriptors cached, one
346 * will be allocated for the in progress add operation.
347 *
348 * Returns the number of huge pages that need to be added to the existing
349 * reservation map for the range [f, t). This number is greater or equal to
350 * zero. -ENOMEM is returned if a new file_region structure or cache entry
351 * is needed and can not be allocated.
352 */
353static long region_chg(struct resv_map *resv, long f, long t)
354{
355 struct list_head *head = &resv->regions;
356 struct file_region *rg, *nrg = NULL;
357 long chg = 0;
358
359retry:
360 spin_lock(&resv->lock);
361retry_locked:
362 resv->adds_in_progress++;
363
364 /*
365 * Check for sufficient descriptors in the cache to accommodate
366 * the number of in progress add operations.
367 */
368 if (resv->adds_in_progress > resv->region_cache_count) {
369 struct file_region *trg;
370
371 VM_BUG_ON(resv->adds_in_progress - resv->region_cache_count > 1);
372 /* Must drop lock to allocate a new descriptor. */
373 resv->adds_in_progress--;
374 spin_unlock(&resv->lock);
375
376 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
377 if (!trg) {
378 kfree(nrg);
379 return -ENOMEM;
380 }
381
382 spin_lock(&resv->lock);
383 list_add(&trg->link, &resv->region_cache);
384 resv->region_cache_count++;
385 goto retry_locked;
386 }
387
388 /* Locate the region we are before or in. */
389 list_for_each_entry(rg, head, link)
390 if (f <= rg->to)
391 break;
392
393 /* If we are below the current region then a new region is required.
394 * Subtle, allocate a new region at the position but make it zero
395 * size such that we can guarantee to record the reservation. */
396 if (&rg->link == head || t < rg->from) {
397 if (!nrg) {
398 resv->adds_in_progress--;
399 spin_unlock(&resv->lock);
400 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
401 if (!nrg)
402 return -ENOMEM;
403
404 nrg->from = f;
405 nrg->to = f;
406 INIT_LIST_HEAD(&nrg->link);
407 goto retry;
408 }
409
410 list_add(&nrg->link, rg->link.prev);
411 chg = t - f;
412 goto out_nrg;
413 }
414
415 /* Round our left edge to the current segment if it encloses us. */
416 if (f > rg->from)
417 f = rg->from;
418 chg = t - f;
419
420 /* Check for and consume any regions we now overlap with. */
421 list_for_each_entry(rg, rg->link.prev, link) {
422 if (&rg->link == head)
423 break;
424 if (rg->from > t)
425 goto out;
426
427 /* We overlap with this area, if it extends further than
428 * us then we must extend ourselves. Account for its
429 * existing reservation. */
430 if (rg->to > t) {
431 chg += rg->to - t;
432 t = rg->to;
433 }
434 chg -= rg->to - rg->from;
435 }
436
437out:
438 spin_unlock(&resv->lock);
439 /* We already know we raced and no longer need the new region */
440 kfree(nrg);
441 return chg;
442out_nrg:
443 spin_unlock(&resv->lock);
444 return chg;
445}
446
447/*
448 * Abort the in progress add operation. The adds_in_progress field
449 * of the resv_map keeps track of the operations in progress between
450 * calls to region_chg and region_add. Operations are sometimes
451 * aborted after the call to region_chg. In such cases, region_abort
452 * is called to decrement the adds_in_progress counter.
453 *
454 * NOTE: The range arguments [f, t) are not needed or used in this
455 * routine. They are kept to make reading the calling code easier as
456 * arguments will match the associated region_chg call.
457 */
458static void region_abort(struct resv_map *resv, long f, long t)
459{
460 spin_lock(&resv->lock);
461 VM_BUG_ON(!resv->region_cache_count);
462 resv->adds_in_progress--;
463 spin_unlock(&resv->lock);
464}
465
466/*
467 * Delete the specified range [f, t) from the reserve map. If the
468 * t parameter is LONG_MAX, this indicates that ALL regions after f
469 * should be deleted. Locate the regions which intersect [f, t)
470 * and either trim, delete or split the existing regions.
471 *
472 * Returns the number of huge pages deleted from the reserve map.
473 * In the normal case, the return value is zero or more. In the
474 * case where a region must be split, a new region descriptor must
475 * be allocated. If the allocation fails, -ENOMEM will be returned.
476 * NOTE: If the parameter t == LONG_MAX, then we will never split
477 * a region and possibly return -ENOMEM. Callers specifying
478 * t == LONG_MAX do not need to check for -ENOMEM error.
479 */
480static long region_del(struct resv_map *resv, long f, long t)
481{
482 struct list_head *head = &resv->regions;
483 struct file_region *rg, *trg;
484 struct file_region *nrg = NULL;
485 long del = 0;
486
487retry:
488 spin_lock(&resv->lock);
489 list_for_each_entry_safe(rg, trg, head, link) {
490 /*
491 * Skip regions before the range to be deleted. file_region
492 * ranges are normally of the form [from, to). However, there
493 * may be a "placeholder" entry in the map which is of the form
494 * (from, to) with from == to. Check for placeholder entries
495 * at the beginning of the range to be deleted.
496 */
497 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
498 continue;
499
500 if (rg->from >= t)
501 break;
502
503 if (f > rg->from && t < rg->to) { /* Must split region */
504 /*
505 * Check for an entry in the cache before dropping
506 * lock and attempting allocation.
507 */
508 if (!nrg &&
509 resv->region_cache_count > resv->adds_in_progress) {
510 nrg = list_first_entry(&resv->region_cache,
511 struct file_region,
512 link);
513 list_del(&nrg->link);
514 resv->region_cache_count--;
515 }
516
517 if (!nrg) {
518 spin_unlock(&resv->lock);
519 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
520 if (!nrg)
521 return -ENOMEM;
522 goto retry;
523 }
524
525 del += t - f;
526
527 /* New entry for end of split region */
528 nrg->from = t;
529 nrg->to = rg->to;
530 INIT_LIST_HEAD(&nrg->link);
531
532 /* Original entry is trimmed */
533 rg->to = f;
534
535 list_add(&nrg->link, &rg->link);
536 nrg = NULL;
537 break;
538 }
539
540 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
541 del += rg->to - rg->from;
542 list_del(&rg->link);
543 kfree(rg);
544 continue;
545 }
546
547 if (f <= rg->from) { /* Trim beginning of region */
548 del += t - rg->from;
549 rg->from = t;
550 } else { /* Trim end of region */
551 del += rg->to - f;
552 rg->to = f;
553 }
554 }
555
556 spin_unlock(&resv->lock);
557 kfree(nrg);
558 return del;
559}
560
561/*
562 * A rare out of memory error was encountered which prevented removal of
563 * the reserve map region for a page. The huge page itself was free'ed
564 * and removed from the page cache. This routine will adjust the subpool
565 * usage count, and the global reserve count if needed. By incrementing
566 * these counts, the reserve map entry which could not be deleted will
567 * appear as a "reserved" entry instead of simply dangling with incorrect
568 * counts.
569 */
570void hugetlb_fix_reserve_counts(struct inode *inode)
571{
572 struct hugepage_subpool *spool = subpool_inode(inode);
573 long rsv_adjust;
574
575 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
576 if (rsv_adjust) {
577 struct hstate *h = hstate_inode(inode);
578
579 hugetlb_acct_memory(h, 1);
580 }
581}
582
583/*
584 * Count and return the number of huge pages in the reserve map
585 * that intersect with the range [f, t).
586 */
587static long region_count(struct resv_map *resv, long f, long t)
588{
589 struct list_head *head = &resv->regions;
590 struct file_region *rg;
591 long chg = 0;
592
593 spin_lock(&resv->lock);
594 /* Locate each segment we overlap with, and count that overlap. */
595 list_for_each_entry(rg, head, link) {
596 long seg_from;
597 long seg_to;
598
599 if (rg->to <= f)
600 continue;
601 if (rg->from >= t)
602 break;
603
604 seg_from = max(rg->from, f);
605 seg_to = min(rg->to, t);
606
607 chg += seg_to - seg_from;
608 }
609 spin_unlock(&resv->lock);
610
611 return chg;
612}
613
614/*
615 * Convert the address within this vma to the page offset within
616 * the mapping, in pagecache page units; huge pages here.
617 */
618static pgoff_t vma_hugecache_offset(struct hstate *h,
619 struct vm_area_struct *vma, unsigned long address)
620{
621 return ((address - vma->vm_start) >> huge_page_shift(h)) +
622 (vma->vm_pgoff >> huge_page_order(h));
623}
624
625pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
626 unsigned long address)
627{
628 return vma_hugecache_offset(hstate_vma(vma), vma, address);
629}
630EXPORT_SYMBOL_GPL(linear_hugepage_index);
631
632/*
633 * Return the size of the pages allocated when backing a VMA. In the majority
634 * cases this will be same size as used by the page table entries.
635 */
636unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
637{
638 struct hstate *hstate;
639
640 if (!is_vm_hugetlb_page(vma))
641 return PAGE_SIZE;
642
643 hstate = hstate_vma(vma);
644
645 return 1UL << huge_page_shift(hstate);
646}
647EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
648
649/*
650 * Return the page size being used by the MMU to back a VMA. In the majority
651 * of cases, the page size used by the kernel matches the MMU size. On
652 * architectures where it differs, an architecture-specific version of this
653 * function is required.
654 */
655#ifndef vma_mmu_pagesize
656unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
657{
658 return vma_kernel_pagesize(vma);
659}
660#endif
661
662/*
663 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
664 * bits of the reservation map pointer, which are always clear due to
665 * alignment.
666 */
667#define HPAGE_RESV_OWNER (1UL << 0)
668#define HPAGE_RESV_UNMAPPED (1UL << 1)
669#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
670
671/*
672 * These helpers are used to track how many pages are reserved for
673 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
674 * is guaranteed to have their future faults succeed.
675 *
676 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
677 * the reserve counters are updated with the hugetlb_lock held. It is safe
678 * to reset the VMA at fork() time as it is not in use yet and there is no
679 * chance of the global counters getting corrupted as a result of the values.
680 *
681 * The private mapping reservation is represented in a subtly different
682 * manner to a shared mapping. A shared mapping has a region map associated
683 * with the underlying file, this region map represents the backing file
684 * pages which have ever had a reservation assigned which this persists even
685 * after the page is instantiated. A private mapping has a region map
686 * associated with the original mmap which is attached to all VMAs which
687 * reference it, this region map represents those offsets which have consumed
688 * reservation ie. where pages have been instantiated.
689 */
690static unsigned long get_vma_private_data(struct vm_area_struct *vma)
691{
692 return (unsigned long)vma->vm_private_data;
693}
694
695static void set_vma_private_data(struct vm_area_struct *vma,
696 unsigned long value)
697{
698 vma->vm_private_data = (void *)value;
699}
700
701struct resv_map *resv_map_alloc(void)
702{
703 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
704 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
705
706 if (!resv_map || !rg) {
707 kfree(resv_map);
708 kfree(rg);
709 return NULL;
710 }
711
712 kref_init(&resv_map->refs);
713 spin_lock_init(&resv_map->lock);
714 INIT_LIST_HEAD(&resv_map->regions);
715
716 resv_map->adds_in_progress = 0;
717
718 INIT_LIST_HEAD(&resv_map->region_cache);
719 list_add(&rg->link, &resv_map->region_cache);
720 resv_map->region_cache_count = 1;
721
722 return resv_map;
723}
724
725void resv_map_release(struct kref *ref)
726{
727 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
728 struct list_head *head = &resv_map->region_cache;
729 struct file_region *rg, *trg;
730
731 /* Clear out any active regions before we release the map. */
732 region_del(resv_map, 0, LONG_MAX);
733
734 /* ... and any entries left in the cache */
735 list_for_each_entry_safe(rg, trg, head, link) {
736 list_del(&rg->link);
737 kfree(rg);
738 }
739
740 VM_BUG_ON(resv_map->adds_in_progress);
741
742 kfree(resv_map);
743}
744
745static inline struct resv_map *inode_resv_map(struct inode *inode)
746{
747 return inode->i_mapping->private_data;
748}
749
750static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
751{
752 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
753 if (vma->vm_flags & VM_MAYSHARE) {
754 struct address_space *mapping = vma->vm_file->f_mapping;
755 struct inode *inode = mapping->host;
756
757 return inode_resv_map(inode);
758
759 } else {
760 return (struct resv_map *)(get_vma_private_data(vma) &
761 ~HPAGE_RESV_MASK);
762 }
763}
764
765static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
766{
767 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
768 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
769
770 set_vma_private_data(vma, (get_vma_private_data(vma) &
771 HPAGE_RESV_MASK) | (unsigned long)map);
772}
773
774static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
775{
776 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
777 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
778
779 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
780}
781
782static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
783{
784 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
785
786 return (get_vma_private_data(vma) & flag) != 0;
787}
788
789/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
790void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
791{
792 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
793 if (!(vma->vm_flags & VM_MAYSHARE))
794 vma->vm_private_data = (void *)0;
795}
796
797/* Returns true if the VMA has associated reserve pages */
798static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
799{
800 if (vma->vm_flags & VM_NORESERVE) {
801 /*
802 * This address is already reserved by other process(chg == 0),
803 * so, we should decrement reserved count. Without decrementing,
804 * reserve count remains after releasing inode, because this
805 * allocated page will go into page cache and is regarded as
806 * coming from reserved pool in releasing step. Currently, we
807 * don't have any other solution to deal with this situation
808 * properly, so add work-around here.
809 */
810 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
811 return true;
812 else
813 return false;
814 }
815
816 /* Shared mappings always use reserves */
817 if (vma->vm_flags & VM_MAYSHARE) {
818 /*
819 * We know VM_NORESERVE is not set. Therefore, there SHOULD
820 * be a region map for all pages. The only situation where
821 * there is no region map is if a hole was punched via
822 * fallocate. In this case, there really are no reverves to
823 * use. This situation is indicated if chg != 0.
824 */
825 if (chg)
826 return false;
827 else
828 return true;
829 }
830
831 /*
832 * Only the process that called mmap() has reserves for
833 * private mappings.
834 */
835 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
836 /*
837 * Like the shared case above, a hole punch or truncate
838 * could have been performed on the private mapping.
839 * Examine the value of chg to determine if reserves
840 * actually exist or were previously consumed.
841 * Very Subtle - The value of chg comes from a previous
842 * call to vma_needs_reserves(). The reserve map for
843 * private mappings has different (opposite) semantics
844 * than that of shared mappings. vma_needs_reserves()
845 * has already taken this difference in semantics into
846 * account. Therefore, the meaning of chg is the same
847 * as in the shared case above. Code could easily be
848 * combined, but keeping it separate draws attention to
849 * subtle differences.
850 */
851 if (chg)
852 return false;
853 else
854 return true;
855 }
856
857 return false;
858}
859
860static void enqueue_huge_page(struct hstate *h, struct page *page)
861{
862 int nid = page_to_nid(page);
863 list_move(&page->lru, &h->hugepage_freelists[nid]);
864 h->free_huge_pages++;
865 h->free_huge_pages_node[nid]++;
866}
867
868static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
869{
870 struct page *page;
871
872 list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
873 if (!is_migrate_isolate_page(page))
874 break;
875 /*
876 * if 'non-isolated free hugepage' not found on the list,
877 * the allocation fails.
878 */
879 if (&h->hugepage_freelists[nid] == &page->lru)
880 return NULL;
881 list_move(&page->lru, &h->hugepage_activelist);
882 set_page_refcounted(page);
883 h->free_huge_pages--;
884 h->free_huge_pages_node[nid]--;
885 return page;
886}
887
888/* Movability of hugepages depends on migration support. */
889static inline gfp_t htlb_alloc_mask(struct hstate *h)
890{
891 if (hugepages_treat_as_movable || hugepage_migration_supported(h))
892 return GFP_HIGHUSER_MOVABLE;
893 else
894 return GFP_HIGHUSER;
895}
896
897static struct page *dequeue_huge_page_vma(struct hstate *h,
898 struct vm_area_struct *vma,
899 unsigned long address, int avoid_reserve,
900 long chg)
901{
902 struct page *page = NULL;
903 struct mempolicy *mpol;
904 nodemask_t *nodemask;
905 struct zonelist *zonelist;
906 struct zone *zone;
907 struct zoneref *z;
908 unsigned int cpuset_mems_cookie;
909
910 /*
911 * A child process with MAP_PRIVATE mappings created by their parent
912 * have no page reserves. This check ensures that reservations are
913 * not "stolen". The child may still get SIGKILLed
914 */
915 if (!vma_has_reserves(vma, chg) &&
916 h->free_huge_pages - h->resv_huge_pages == 0)
917 goto err;
918
919 /* If reserves cannot be used, ensure enough pages are in the pool */
920 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
921 goto err;
922
923retry_cpuset:
924 cpuset_mems_cookie = read_mems_allowed_begin();
925 zonelist = huge_zonelist(vma, address,
926 htlb_alloc_mask(h), &mpol, &nodemask);
927
928 for_each_zone_zonelist_nodemask(zone, z, zonelist,
929 MAX_NR_ZONES - 1, nodemask) {
930 if (cpuset_zone_allowed(zone, htlb_alloc_mask(h))) {
931 page = dequeue_huge_page_node(h, zone_to_nid(zone));
932 if (page) {
933 if (avoid_reserve)
934 break;
935 if (!vma_has_reserves(vma, chg))
936 break;
937
938 SetPagePrivate(page);
939 h->resv_huge_pages--;
940 break;
941 }
942 }
943 }
944
945 mpol_cond_put(mpol);
946 if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
947 goto retry_cpuset;
948 return page;
949
950err:
951 return NULL;
952}
953
954/*
955 * common helper functions for hstate_next_node_to_{alloc|free}.
956 * We may have allocated or freed a huge page based on a different
957 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
958 * be outside of *nodes_allowed. Ensure that we use an allowed
959 * node for alloc or free.
960 */
961static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
962{
963 nid = next_node_in(nid, *nodes_allowed);
964 VM_BUG_ON(nid >= MAX_NUMNODES);
965
966 return nid;
967}
968
969static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
970{
971 if (!node_isset(nid, *nodes_allowed))
972 nid = next_node_allowed(nid, nodes_allowed);
973 return nid;
974}
975
976/*
977 * returns the previously saved node ["this node"] from which to
978 * allocate a persistent huge page for the pool and advance the
979 * next node from which to allocate, handling wrap at end of node
980 * mask.
981 */
982static int hstate_next_node_to_alloc(struct hstate *h,
983 nodemask_t *nodes_allowed)
984{
985 int nid;
986
987 VM_BUG_ON(!nodes_allowed);
988
989 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
990 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
991
992 return nid;
993}
994
995/*
996 * helper for free_pool_huge_page() - return the previously saved
997 * node ["this node"] from which to free a huge page. Advance the
998 * next node id whether or not we find a free huge page to free so
999 * that the next attempt to free addresses the next node.
1000 */
1001static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
1002{
1003 int nid;
1004
1005 VM_BUG_ON(!nodes_allowed);
1006
1007 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
1008 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
1009
1010 return nid;
1011}
1012
1013#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1014 for (nr_nodes = nodes_weight(*mask); \
1015 nr_nodes > 0 && \
1016 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1017 nr_nodes--)
1018
1019#define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1020 for (nr_nodes = nodes_weight(*mask); \
1021 nr_nodes > 0 && \
1022 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1023 nr_nodes--)
1024
1025#if defined(CONFIG_ARCH_HAS_GIGANTIC_PAGE) && \
1026 ((defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || \
1027 defined(CONFIG_CMA))
1028static void destroy_compound_gigantic_page(struct page *page,
1029 unsigned int order)
1030{
1031 int i;
1032 int nr_pages = 1 << order;
1033 struct page *p = page + 1;
1034
1035 atomic_set(compound_mapcount_ptr(page), 0);
1036 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1037 clear_compound_head(p);
1038 set_page_refcounted(p);
1039 }
1040
1041 set_compound_order(page, 0);
1042 __ClearPageHead(page);
1043}
1044
1045static void free_gigantic_page(struct page *page, unsigned int order)
1046{
1047 free_contig_range(page_to_pfn(page), 1 << order);
1048}
1049
1050static int __alloc_gigantic_page(unsigned long start_pfn,
1051 unsigned long nr_pages)
1052{
1053 unsigned long end_pfn = start_pfn + nr_pages;
1054 return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1055}
1056
1057static bool pfn_range_valid_gigantic(struct zone *z,
1058 unsigned long start_pfn, unsigned long nr_pages)
1059{
1060 unsigned long i, end_pfn = start_pfn + nr_pages;
1061 struct page *page;
1062
1063 for (i = start_pfn; i < end_pfn; i++) {
1064 if (!pfn_valid(i))
1065 return false;
1066
1067 page = pfn_to_page(i);
1068
1069 if (page_zone(page) != z)
1070 return false;
1071
1072 if (PageReserved(page))
1073 return false;
1074
1075 if (page_count(page) > 0)
1076 return false;
1077
1078 if (PageHuge(page))
1079 return false;
1080 }
1081
1082 return true;
1083}
1084
1085static bool zone_spans_last_pfn(const struct zone *zone,
1086 unsigned long start_pfn, unsigned long nr_pages)
1087{
1088 unsigned long last_pfn = start_pfn + nr_pages - 1;
1089 return zone_spans_pfn(zone, last_pfn);
1090}
1091
1092static struct page *alloc_gigantic_page(int nid, unsigned int order)
1093{
1094 unsigned long nr_pages = 1 << order;
1095 unsigned long ret, pfn, flags;
1096 struct zone *z;
1097
1098 z = NODE_DATA(nid)->node_zones;
1099 for (; z - NODE_DATA(nid)->node_zones < MAX_NR_ZONES; z++) {
1100 spin_lock_irqsave(&z->lock, flags);
1101
1102 pfn = ALIGN(z->zone_start_pfn, nr_pages);
1103 while (zone_spans_last_pfn(z, pfn, nr_pages)) {
1104 if (pfn_range_valid_gigantic(z, pfn, nr_pages)) {
1105 /*
1106 * We release the zone lock here because
1107 * alloc_contig_range() will also lock the zone
1108 * at some point. If there's an allocation
1109 * spinning on this lock, it may win the race
1110 * and cause alloc_contig_range() to fail...
1111 */
1112 spin_unlock_irqrestore(&z->lock, flags);
1113 ret = __alloc_gigantic_page(pfn, nr_pages);
1114 if (!ret)
1115 return pfn_to_page(pfn);
1116 spin_lock_irqsave(&z->lock, flags);
1117 }
1118 pfn += nr_pages;
1119 }
1120
1121 spin_unlock_irqrestore(&z->lock, flags);
1122 }
1123
1124 return NULL;
1125}
1126
1127static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1128static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1129
1130static struct page *alloc_fresh_gigantic_page_node(struct hstate *h, int nid)
1131{
1132 struct page *page;
1133
1134 page = alloc_gigantic_page(nid, huge_page_order(h));
1135 if (page) {
1136 prep_compound_gigantic_page(page, huge_page_order(h));
1137 prep_new_huge_page(h, page, nid);
1138 }
1139
1140 return page;
1141}
1142
1143static int alloc_fresh_gigantic_page(struct hstate *h,
1144 nodemask_t *nodes_allowed)
1145{
1146 struct page *page = NULL;
1147 int nr_nodes, node;
1148
1149 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1150 page = alloc_fresh_gigantic_page_node(h, node);
1151 if (page)
1152 return 1;
1153 }
1154
1155 return 0;
1156}
1157
1158static inline bool gigantic_page_supported(void) { return true; }
1159#else
1160static inline bool gigantic_page_supported(void) { return false; }
1161static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1162static inline void destroy_compound_gigantic_page(struct page *page,
1163 unsigned int order) { }
1164static inline int alloc_fresh_gigantic_page(struct hstate *h,
1165 nodemask_t *nodes_allowed) { return 0; }
1166#endif
1167
1168static void update_and_free_page(struct hstate *h, struct page *page)
1169{
1170 int i;
1171
1172 if (hstate_is_gigantic(h) && !gigantic_page_supported())
1173 return;
1174
1175 h->nr_huge_pages--;
1176 h->nr_huge_pages_node[page_to_nid(page)]--;
1177 for (i = 0; i < pages_per_huge_page(h); i++) {
1178 page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
1179 1 << PG_referenced | 1 << PG_dirty |
1180 1 << PG_active | 1 << PG_private |
1181 1 << PG_writeback);
1182 }
1183 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1184 set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
1185 set_page_refcounted(page);
1186 if (hstate_is_gigantic(h)) {
1187 destroy_compound_gigantic_page(page, huge_page_order(h));
1188 free_gigantic_page(page, huge_page_order(h));
1189 } else {
1190 __free_pages(page, huge_page_order(h));
1191 }
1192}
1193
1194struct hstate *size_to_hstate(unsigned long size)
1195{
1196 struct hstate *h;
1197
1198 for_each_hstate(h) {
1199 if (huge_page_size(h) == size)
1200 return h;
1201 }
1202 return NULL;
1203}
1204
1205/*
1206 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
1207 * to hstate->hugepage_activelist.)
1208 *
1209 * This function can be called for tail pages, but never returns true for them.
1210 */
1211bool page_huge_active(struct page *page)
1212{
1213 VM_BUG_ON_PAGE(!PageHuge(page), page);
1214 return PageHead(page) && PagePrivate(&page[1]);
1215}
1216
1217/* never called for tail page */
1218static void set_page_huge_active(struct page *page)
1219{
1220 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1221 SetPagePrivate(&page[1]);
1222}
1223
1224static void clear_page_huge_active(struct page *page)
1225{
1226 VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
1227 ClearPagePrivate(&page[1]);
1228}
1229
1230void free_huge_page(struct page *page)
1231{
1232 /*
1233 * Can't pass hstate in here because it is called from the
1234 * compound page destructor.
1235 */
1236 struct hstate *h = page_hstate(page);
1237 int nid = page_to_nid(page);
1238 struct hugepage_subpool *spool =
1239 (struct hugepage_subpool *)page_private(page);
1240 bool restore_reserve;
1241
1242 set_page_private(page, 0);
1243 page->mapping = NULL;
1244 VM_BUG_ON_PAGE(page_count(page), page);
1245 VM_BUG_ON_PAGE(page_mapcount(page), page);
1246 restore_reserve = PagePrivate(page);
1247 ClearPagePrivate(page);
1248
1249 /*
1250 * A return code of zero implies that the subpool will be under its
1251 * minimum size if the reservation is not restored after page is free.
1252 * Therefore, force restore_reserve operation.
1253 */
1254 if (hugepage_subpool_put_pages(spool, 1) == 0)
1255 restore_reserve = true;
1256
1257 spin_lock(&hugetlb_lock);
1258 clear_page_huge_active(page);
1259 hugetlb_cgroup_uncharge_page(hstate_index(h),
1260 pages_per_huge_page(h), page);
1261 if (restore_reserve)
1262 h->resv_huge_pages++;
1263
1264 if (h->surplus_huge_pages_node[nid]) {
1265 /* remove the page from active list */
1266 list_del(&page->lru);
1267 update_and_free_page(h, page);
1268 h->surplus_huge_pages--;
1269 h->surplus_huge_pages_node[nid]--;
1270 } else {
1271 arch_clear_hugepage_flags(page);
1272 enqueue_huge_page(h, page);
1273 }
1274 spin_unlock(&hugetlb_lock);
1275}
1276
1277static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1278{
1279 INIT_LIST_HEAD(&page->lru);
1280 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1281 spin_lock(&hugetlb_lock);
1282 set_hugetlb_cgroup(page, NULL);
1283 h->nr_huge_pages++;
1284 h->nr_huge_pages_node[nid]++;
1285 spin_unlock(&hugetlb_lock);
1286 put_page(page); /* free it into the hugepage allocator */
1287}
1288
1289static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1290{
1291 int i;
1292 int nr_pages = 1 << order;
1293 struct page *p = page + 1;
1294
1295 /* we rely on prep_new_huge_page to set the destructor */
1296 set_compound_order(page, order);
1297 __ClearPageReserved(page);
1298 __SetPageHead(page);
1299 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1300 /*
1301 * For gigantic hugepages allocated through bootmem at
1302 * boot, it's safer to be consistent with the not-gigantic
1303 * hugepages and clear the PG_reserved bit from all tail pages
1304 * too. Otherwse drivers using get_user_pages() to access tail
1305 * pages may get the reference counting wrong if they see
1306 * PG_reserved set on a tail page (despite the head page not
1307 * having PG_reserved set). Enforcing this consistency between
1308 * head and tail pages allows drivers to optimize away a check
1309 * on the head page when they need know if put_page() is needed
1310 * after get_user_pages().
1311 */
1312 __ClearPageReserved(p);
1313 set_page_count(p, 0);
1314 set_compound_head(p, page);
1315 }
1316 atomic_set(compound_mapcount_ptr(page), -1);
1317}
1318
1319/*
1320 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
1321 * transparent huge pages. See the PageTransHuge() documentation for more
1322 * details.
1323 */
1324int PageHuge(struct page *page)
1325{
1326 if (!PageCompound(page))
1327 return 0;
1328
1329 page = compound_head(page);
1330 return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1331}
1332EXPORT_SYMBOL_GPL(PageHuge);
1333
1334/*
1335 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
1336 * normal or transparent huge pages.
1337 */
1338int PageHeadHuge(struct page *page_head)
1339{
1340 if (!PageHead(page_head))
1341 return 0;
1342
1343 return get_compound_page_dtor(page_head) == free_huge_page;
1344}
1345
1346pgoff_t __basepage_index(struct page *page)
1347{
1348 struct page *page_head = compound_head(page);
1349 pgoff_t index = page_index(page_head);
1350 unsigned long compound_idx;
1351
1352 if (!PageHuge(page_head))
1353 return page_index(page);
1354
1355 if (compound_order(page_head) >= MAX_ORDER)
1356 compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
1357 else
1358 compound_idx = page - page_head;
1359
1360 return (index << compound_order(page_head)) + compound_idx;
1361}
1362
1363static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
1364{
1365 struct page *page;
1366
1367 page = __alloc_pages_node(nid,
1368 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
1369 __GFP_REPEAT|__GFP_NOWARN,
1370 huge_page_order(h));
1371 if (page) {
1372 prep_new_huge_page(h, page, nid);
1373 }
1374
1375 return page;
1376}
1377
1378static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
1379{
1380 struct page *page;
1381 int nr_nodes, node;
1382 int ret = 0;
1383
1384 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1385 page = alloc_fresh_huge_page_node(h, node);
1386 if (page) {
1387 ret = 1;
1388 break;
1389 }
1390 }
1391
1392 if (ret)
1393 count_vm_event(HTLB_BUDDY_PGALLOC);
1394 else
1395 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1396
1397 return ret;
1398}
1399
1400/*
1401 * Free huge page from pool from next node to free.
1402 * Attempt to keep persistent huge pages more or less
1403 * balanced over allowed nodes.
1404 * Called with hugetlb_lock locked.
1405 */
1406static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
1407 bool acct_surplus)
1408{
1409 int nr_nodes, node;
1410 int ret = 0;
1411
1412 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1413 /*
1414 * If we're returning unused surplus pages, only examine
1415 * nodes with surplus pages.
1416 */
1417 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
1418 !list_empty(&h->hugepage_freelists[node])) {
1419 struct page *page =
1420 list_entry(h->hugepage_freelists[node].next,
1421 struct page, lru);
1422 list_del(&page->lru);
1423 h->free_huge_pages--;
1424 h->free_huge_pages_node[node]--;
1425 if (acct_surplus) {
1426 h->surplus_huge_pages--;
1427 h->surplus_huge_pages_node[node]--;
1428 }
1429 update_and_free_page(h, page);
1430 ret = 1;
1431 break;
1432 }
1433 }
1434
1435 return ret;
1436}
1437
1438/*
1439 * Dissolve a given free hugepage into free buddy pages. This function does
1440 * nothing for in-use (including surplus) hugepages. Returns -EBUSY if the
1441 * number of free hugepages would be reduced below the number of reserved
1442 * hugepages.
1443 */
1444static int dissolve_free_huge_page(struct page *page)
1445{
1446 int rc = 0;
1447
1448 spin_lock(&hugetlb_lock);
1449 if (PageHuge(page) && !page_count(page)) {
1450 struct page *head = compound_head(page);
1451 struct hstate *h = page_hstate(head);
1452 int nid = page_to_nid(head);
1453 if (h->free_huge_pages - h->resv_huge_pages == 0) {
1454 rc = -EBUSY;
1455 goto out;
1456 }
1457 list_del(&head->lru);
1458 h->free_huge_pages--;
1459 h->free_huge_pages_node[nid]--;
1460 h->max_huge_pages--;
1461 update_and_free_page(h, head);
1462 }
1463out:
1464 spin_unlock(&hugetlb_lock);
1465 return rc;
1466}
1467
1468/*
1469 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
1470 * make specified memory blocks removable from the system.
1471 * Note that this will dissolve a free gigantic hugepage completely, if any
1472 * part of it lies within the given range.
1473 * Also note that if dissolve_free_huge_page() returns with an error, all
1474 * free hugepages that were dissolved before that error are lost.
1475 */
1476int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1477{
1478 unsigned long pfn;
1479 struct page *page;
1480 int rc = 0;
1481
1482 if (!hugepages_supported())
1483 return rc;
1484
1485 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
1486 page = pfn_to_page(pfn);
1487 if (PageHuge(page) && !page_count(page)) {
1488 rc = dissolve_free_huge_page(page);
1489 if (rc)
1490 break;
1491 }
1492 }
1493
1494 return rc;
1495}
1496
1497/*
1498 * There are 3 ways this can get called:
1499 * 1. With vma+addr: we use the VMA's memory policy
1500 * 2. With !vma, but nid=NUMA_NO_NODE: We try to allocate a huge
1501 * page from any node, and let the buddy allocator itself figure
1502 * it out.
1503 * 3. With !vma, but nid!=NUMA_NO_NODE. We allocate a huge page
1504 * strictly from 'nid'
1505 */
1506static struct page *__hugetlb_alloc_buddy_huge_page(struct hstate *h,
1507 struct vm_area_struct *vma, unsigned long addr, int nid)
1508{
1509 int order = huge_page_order(h);
1510 gfp_t gfp = htlb_alloc_mask(h)|__GFP_COMP|__GFP_REPEAT|__GFP_NOWARN;
1511 unsigned int cpuset_mems_cookie;
1512
1513 /*
1514 * We need a VMA to get a memory policy. If we do not
1515 * have one, we use the 'nid' argument.
1516 *
1517 * The mempolicy stuff below has some non-inlined bits
1518 * and calls ->vm_ops. That makes it hard to optimize at
1519 * compile-time, even when NUMA is off and it does
1520 * nothing. This helps the compiler optimize it out.
1521 */
1522 if (!IS_ENABLED(CONFIG_NUMA) || !vma) {
1523 /*
1524 * If a specific node is requested, make sure to
1525 * get memory from there, but only when a node
1526 * is explicitly specified.
1527 */
1528 if (nid != NUMA_NO_NODE)
1529 gfp |= __GFP_THISNODE;
1530 /*
1531 * Make sure to call something that can handle
1532 * nid=NUMA_NO_NODE
1533 */
1534 return alloc_pages_node(nid, gfp, order);
1535 }
1536
1537 /*
1538 * OK, so we have a VMA. Fetch the mempolicy and try to
1539 * allocate a huge page with it. We will only reach this
1540 * when CONFIG_NUMA=y.
1541 */
1542 do {
1543 struct page *page;
1544 struct mempolicy *mpol;
1545 struct zonelist *zl;
1546 nodemask_t *nodemask;
1547
1548 cpuset_mems_cookie = read_mems_allowed_begin();
1549 zl = huge_zonelist(vma, addr, gfp, &mpol, &nodemask);
1550 mpol_cond_put(mpol);
1551 page = __alloc_pages_nodemask(gfp, order, zl, nodemask);
1552 if (page)
1553 return page;
1554 } while (read_mems_allowed_retry(cpuset_mems_cookie));
1555
1556 return NULL;
1557}
1558
1559/*
1560 * There are two ways to allocate a huge page:
1561 * 1. When you have a VMA and an address (like a fault)
1562 * 2. When you have no VMA (like when setting /proc/.../nr_hugepages)
1563 *
1564 * 'vma' and 'addr' are only for (1). 'nid' is always NUMA_NO_NODE in
1565 * this case which signifies that the allocation should be done with
1566 * respect for the VMA's memory policy.
1567 *
1568 * For (2), we ignore 'vma' and 'addr' and use 'nid' exclusively. This
1569 * implies that memory policies will not be taken in to account.
1570 */
1571static struct page *__alloc_buddy_huge_page(struct hstate *h,
1572 struct vm_area_struct *vma, unsigned long addr, int nid)
1573{
1574 struct page *page;
1575 unsigned int r_nid;
1576
1577 if (hstate_is_gigantic(h))
1578 return NULL;
1579
1580 /*
1581 * Make sure that anyone specifying 'nid' is not also specifying a VMA.
1582 * This makes sure the caller is picking _one_ of the modes with which
1583 * we can call this function, not both.
1584 */
1585 if (vma || (addr != -1)) {
1586 VM_WARN_ON_ONCE(addr == -1);
1587 VM_WARN_ON_ONCE(nid != NUMA_NO_NODE);
1588 }
1589 /*
1590 * Assume we will successfully allocate the surplus page to
1591 * prevent racing processes from causing the surplus to exceed
1592 * overcommit
1593 *
1594 * This however introduces a different race, where a process B
1595 * tries to grow the static hugepage pool while alloc_pages() is
1596 * called by process A. B will only examine the per-node
1597 * counters in determining if surplus huge pages can be
1598 * converted to normal huge pages in adjust_pool_surplus(). A
1599 * won't be able to increment the per-node counter, until the
1600 * lock is dropped by B, but B doesn't drop hugetlb_lock until
1601 * no more huge pages can be converted from surplus to normal
1602 * state (and doesn't try to convert again). Thus, we have a
1603 * case where a surplus huge page exists, the pool is grown, and
1604 * the surplus huge page still exists after, even though it
1605 * should just have been converted to a normal huge page. This
1606 * does not leak memory, though, as the hugepage will be freed
1607 * once it is out of use. It also does not allow the counters to
1608 * go out of whack in adjust_pool_surplus() as we don't modify
1609 * the node values until we've gotten the hugepage and only the
1610 * per-node value is checked there.
1611 */
1612 spin_lock(&hugetlb_lock);
1613 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1614 spin_unlock(&hugetlb_lock);
1615 return NULL;
1616 } else {
1617 h->nr_huge_pages++;
1618 h->surplus_huge_pages++;
1619 }
1620 spin_unlock(&hugetlb_lock);
1621
1622 page = __hugetlb_alloc_buddy_huge_page(h, vma, addr, nid);
1623
1624 spin_lock(&hugetlb_lock);
1625 if (page) {
1626 INIT_LIST_HEAD(&page->lru);
1627 r_nid = page_to_nid(page);
1628 set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1629 set_hugetlb_cgroup(page, NULL);
1630 /*
1631 * We incremented the global counters already
1632 */
1633 h->nr_huge_pages_node[r_nid]++;
1634 h->surplus_huge_pages_node[r_nid]++;
1635 __count_vm_event(HTLB_BUDDY_PGALLOC);
1636 } else {
1637 h->nr_huge_pages--;
1638 h->surplus_huge_pages--;
1639 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1640 }
1641 spin_unlock(&hugetlb_lock);
1642
1643 return page;
1644}
1645
1646/*
1647 * Allocate a huge page from 'nid'. Note, 'nid' may be
1648 * NUMA_NO_NODE, which means that it may be allocated
1649 * anywhere.
1650 */
1651static
1652struct page *__alloc_buddy_huge_page_no_mpol(struct hstate *h, int nid)
1653{
1654 unsigned long addr = -1;
1655
1656 return __alloc_buddy_huge_page(h, NULL, addr, nid);
1657}
1658
1659/*
1660 * Use the VMA's mpolicy to allocate a huge page from the buddy.
1661 */
1662static
1663struct page *__alloc_buddy_huge_page_with_mpol(struct hstate *h,
1664 struct vm_area_struct *vma, unsigned long addr)
1665{
1666 return __alloc_buddy_huge_page(h, vma, addr, NUMA_NO_NODE);
1667}
1668
1669/*
1670 * This allocation function is useful in the context where vma is irrelevant.
1671 * E.g. soft-offlining uses this function because it only cares physical
1672 * address of error page.
1673 */
1674struct page *alloc_huge_page_node(struct hstate *h, int nid)
1675{
1676 struct page *page = NULL;
1677
1678 spin_lock(&hugetlb_lock);
1679 if (h->free_huge_pages - h->resv_huge_pages > 0)
1680 page = dequeue_huge_page_node(h, nid);
1681 spin_unlock(&hugetlb_lock);
1682
1683 if (!page)
1684 page = __alloc_buddy_huge_page_no_mpol(h, nid);
1685
1686 return page;
1687}
1688
1689/*
1690 * Increase the hugetlb pool such that it can accommodate a reservation
1691 * of size 'delta'.
1692 */
1693static int gather_surplus_pages(struct hstate *h, int delta)
1694{
1695 struct list_head surplus_list;
1696 struct page *page, *tmp;
1697 int ret, i;
1698 int needed, allocated;
1699 bool alloc_ok = true;
1700
1701 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1702 if (needed <= 0) {
1703 h->resv_huge_pages += delta;
1704 return 0;
1705 }
1706
1707 allocated = 0;
1708 INIT_LIST_HEAD(&surplus_list);
1709
1710 ret = -ENOMEM;
1711retry:
1712 spin_unlock(&hugetlb_lock);
1713 for (i = 0; i < needed; i++) {
1714 page = __alloc_buddy_huge_page_no_mpol(h, NUMA_NO_NODE);
1715 if (!page) {
1716 alloc_ok = false;
1717 break;
1718 }
1719 list_add(&page->lru, &surplus_list);
1720 }
1721 allocated += i;
1722
1723 /*
1724 * After retaking hugetlb_lock, we need to recalculate 'needed'
1725 * because either resv_huge_pages or free_huge_pages may have changed.
1726 */
1727 spin_lock(&hugetlb_lock);
1728 needed = (h->resv_huge_pages + delta) -
1729 (h->free_huge_pages + allocated);
1730 if (needed > 0) {
1731 if (alloc_ok)
1732 goto retry;
1733 /*
1734 * We were not able to allocate enough pages to
1735 * satisfy the entire reservation so we free what
1736 * we've allocated so far.
1737 */
1738 goto free;
1739 }
1740 /*
1741 * The surplus_list now contains _at_least_ the number of extra pages
1742 * needed to accommodate the reservation. Add the appropriate number
1743 * of pages to the hugetlb pool and free the extras back to the buddy
1744 * allocator. Commit the entire reservation here to prevent another
1745 * process from stealing the pages as they are added to the pool but
1746 * before they are reserved.
1747 */
1748 needed += allocated;
1749 h->resv_huge_pages += delta;
1750 ret = 0;
1751
1752 /* Free the needed pages to the hugetlb pool */
1753 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1754 if ((--needed) < 0)
1755 break;
1756 /*
1757 * This page is now managed by the hugetlb allocator and has
1758 * no users -- drop the buddy allocator's reference.
1759 */
1760 put_page_testzero(page);
1761 VM_BUG_ON_PAGE(page_count(page), page);
1762 enqueue_huge_page(h, page);
1763 }
1764free:
1765 spin_unlock(&hugetlb_lock);
1766
1767 /* Free unnecessary surplus pages to the buddy allocator */
1768 list_for_each_entry_safe(page, tmp, &surplus_list, lru)
1769 put_page(page);
1770 spin_lock(&hugetlb_lock);
1771
1772 return ret;
1773}
1774
1775/*
1776 * This routine has two main purposes:
1777 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
1778 * in unused_resv_pages. This corresponds to the prior adjustments made
1779 * to the associated reservation map.
1780 * 2) Free any unused surplus pages that may have been allocated to satisfy
1781 * the reservation. As many as unused_resv_pages may be freed.
1782 *
1783 * Called with hugetlb_lock held. However, the lock could be dropped (and
1784 * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
1785 * we must make sure nobody else can claim pages we are in the process of
1786 * freeing. Do this by ensuring resv_huge_page always is greater than the
1787 * number of huge pages we plan to free when dropping the lock.
1788 */
1789static void return_unused_surplus_pages(struct hstate *h,
1790 unsigned long unused_resv_pages)
1791{
1792 unsigned long nr_pages;
1793
1794 /* Cannot return gigantic pages currently */
1795 if (hstate_is_gigantic(h))
1796 goto out;
1797
1798 /*
1799 * Part (or even all) of the reservation could have been backed
1800 * by pre-allocated pages. Only free surplus pages.
1801 */
1802 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1803
1804 /*
1805 * We want to release as many surplus pages as possible, spread
1806 * evenly across all nodes with memory. Iterate across these nodes
1807 * until we can no longer free unreserved surplus pages. This occurs
1808 * when the nodes with surplus pages have no free pages.
1809 * free_pool_huge_page() will balance the the freed pages across the
1810 * on-line nodes with memory and will handle the hstate accounting.
1811 *
1812 * Note that we decrement resv_huge_pages as we free the pages. If
1813 * we drop the lock, resv_huge_pages will still be sufficiently large
1814 * to cover subsequent pages we may free.
1815 */
1816 while (nr_pages--) {
1817 h->resv_huge_pages--;
1818 unused_resv_pages--;
1819 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1820 goto out;
1821 cond_resched_lock(&hugetlb_lock);
1822 }
1823
1824out:
1825 /* Fully uncommit the reservation */
1826 h->resv_huge_pages -= unused_resv_pages;
1827}
1828
1829
1830/*
1831 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1832 * are used by the huge page allocation routines to manage reservations.
1833 *
1834 * vma_needs_reservation is called to determine if the huge page at addr
1835 * within the vma has an associated reservation. If a reservation is
1836 * needed, the value 1 is returned. The caller is then responsible for
1837 * managing the global reservation and subpool usage counts. After
1838 * the huge page has been allocated, vma_commit_reservation is called
1839 * to add the page to the reservation map. If the page allocation fails,
1840 * the reservation must be ended instead of committed. vma_end_reservation
1841 * is called in such cases.
1842 *
1843 * In the normal case, vma_commit_reservation returns the same value
1844 * as the preceding vma_needs_reservation call. The only time this
1845 * is not the case is if a reserve map was changed between calls. It
1846 * is the responsibility of the caller to notice the difference and
1847 * take appropriate action.
1848 *
1849 * vma_add_reservation is used in error paths where a reservation must
1850 * be restored when a newly allocated huge page must be freed. It is
1851 * to be called after calling vma_needs_reservation to determine if a
1852 * reservation exists.
1853 */
1854enum vma_resv_mode {
1855 VMA_NEEDS_RESV,
1856 VMA_COMMIT_RESV,
1857 VMA_END_RESV,
1858 VMA_ADD_RESV,
1859};
1860static long __vma_reservation_common(struct hstate *h,
1861 struct vm_area_struct *vma, unsigned long addr,
1862 enum vma_resv_mode mode)
1863{
1864 struct resv_map *resv;
1865 pgoff_t idx;
1866 long ret;
1867
1868 resv = vma_resv_map(vma);
1869 if (!resv)
1870 return 1;
1871
1872 idx = vma_hugecache_offset(h, vma, addr);
1873 switch (mode) {
1874 case VMA_NEEDS_RESV:
1875 ret = region_chg(resv, idx, idx + 1);
1876 break;
1877 case VMA_COMMIT_RESV:
1878 ret = region_add(resv, idx, idx + 1);
1879 break;
1880 case VMA_END_RESV:
1881 region_abort(resv, idx, idx + 1);
1882 ret = 0;
1883 break;
1884 case VMA_ADD_RESV:
1885 if (vma->vm_flags & VM_MAYSHARE)
1886 ret = region_add(resv, idx, idx + 1);
1887 else {
1888 region_abort(resv, idx, idx + 1);
1889 ret = region_del(resv, idx, idx + 1);
1890 }
1891 break;
1892 default:
1893 BUG();
1894 }
1895
1896 if (vma->vm_flags & VM_MAYSHARE)
1897 return ret;
1898 else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) {
1899 /*
1900 * In most cases, reserves always exist for private mappings.
1901 * However, a file associated with mapping could have been
1902 * hole punched or truncated after reserves were consumed.
1903 * As subsequent fault on such a range will not use reserves.
1904 * Subtle - The reserve map for private mappings has the
1905 * opposite meaning than that of shared mappings. If NO
1906 * entry is in the reserve map, it means a reservation exists.
1907 * If an entry exists in the reserve map, it means the
1908 * reservation has already been consumed. As a result, the
1909 * return value of this routine is the opposite of the
1910 * value returned from reserve map manipulation routines above.
1911 */
1912 if (ret)
1913 return 0;
1914 else
1915 return 1;
1916 }
1917 else
1918 return ret < 0 ? ret : 0;
1919}
1920
1921static long vma_needs_reservation(struct hstate *h,
1922 struct vm_area_struct *vma, unsigned long addr)
1923{
1924 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
1925}
1926
1927static long vma_commit_reservation(struct hstate *h,
1928 struct vm_area_struct *vma, unsigned long addr)
1929{
1930 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
1931}
1932
1933static void vma_end_reservation(struct hstate *h,
1934 struct vm_area_struct *vma, unsigned long addr)
1935{
1936 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
1937}
1938
1939static long vma_add_reservation(struct hstate *h,
1940 struct vm_area_struct *vma, unsigned long addr)
1941{
1942 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
1943}
1944
1945/*
1946 * This routine is called to restore a reservation on error paths. In the
1947 * specific error paths, a huge page was allocated (via alloc_huge_page)
1948 * and is about to be freed. If a reservation for the page existed,
1949 * alloc_huge_page would have consumed the reservation and set PagePrivate
1950 * in the newly allocated page. When the page is freed via free_huge_page,
1951 * the global reservation count will be incremented if PagePrivate is set.
1952 * However, free_huge_page can not adjust the reserve map. Adjust the
1953 * reserve map here to be consistent with global reserve count adjustments
1954 * to be made by free_huge_page.
1955 */
1956static void restore_reserve_on_error(struct hstate *h,
1957 struct vm_area_struct *vma, unsigned long address,
1958 struct page *page)
1959{
1960 if (unlikely(PagePrivate(page))) {
1961 long rc = vma_needs_reservation(h, vma, address);
1962
1963 if (unlikely(rc < 0)) {
1964 /*
1965 * Rare out of memory condition in reserve map
1966 * manipulation. Clear PagePrivate so that
1967 * global reserve count will not be incremented
1968 * by free_huge_page. This will make it appear
1969 * as though the reservation for this page was
1970 * consumed. This may prevent the task from
1971 * faulting in the page at a later time. This
1972 * is better than inconsistent global huge page
1973 * accounting of reserve counts.
1974 */
1975 ClearPagePrivate(page);
1976 } else if (rc) {
1977 rc = vma_add_reservation(h, vma, address);
1978 if (unlikely(rc < 0))
1979 /*
1980 * See above comment about rare out of
1981 * memory condition.
1982 */
1983 ClearPagePrivate(page);
1984 } else
1985 vma_end_reservation(h, vma, address);
1986 }
1987}
1988
1989struct page *alloc_huge_page(struct vm_area_struct *vma,
1990 unsigned long addr, int avoid_reserve)
1991{
1992 struct hugepage_subpool *spool = subpool_vma(vma);
1993 struct hstate *h = hstate_vma(vma);
1994 struct page *page;
1995 long map_chg, map_commit;
1996 long gbl_chg;
1997 int ret, idx;
1998 struct hugetlb_cgroup *h_cg;
1999
2000 idx = hstate_index(h);
2001 /*
2002 * Examine the region/reserve map to determine if the process
2003 * has a reservation for the page to be allocated. A return
2004 * code of zero indicates a reservation exists (no change).
2005 */
2006 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
2007 if (map_chg < 0)
2008 return ERR_PTR(-ENOMEM);
2009
2010 /*
2011 * Processes that did not create the mapping will have no
2012 * reserves as indicated by the region/reserve map. Check
2013 * that the allocation will not exceed the subpool limit.
2014 * Allocations for MAP_NORESERVE mappings also need to be
2015 * checked against any subpool limit.
2016 */
2017 if (map_chg || avoid_reserve) {
2018 gbl_chg = hugepage_subpool_get_pages(spool, 1);
2019 if (gbl_chg < 0) {
2020 vma_end_reservation(h, vma, addr);
2021 return ERR_PTR(-ENOSPC);
2022 }
2023
2024 /*
2025 * Even though there was no reservation in the region/reserve
2026 * map, there could be reservations associated with the
2027 * subpool that can be used. This would be indicated if the
2028 * return value of hugepage_subpool_get_pages() is zero.
2029 * However, if avoid_reserve is specified we still avoid even
2030 * the subpool reservations.
2031 */
2032 if (avoid_reserve)
2033 gbl_chg = 1;
2034 }
2035
2036 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2037 if (ret)
2038 goto out_subpool_put;
2039
2040 spin_lock(&hugetlb_lock);
2041 /*
2042 * glb_chg is passed to indicate whether or not a page must be taken
2043 * from the global free pool (global change). gbl_chg == 0 indicates
2044 * a reservation exists for the allocation.
2045 */
2046 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
2047 if (!page) {
2048 spin_unlock(&hugetlb_lock);
2049 page = __alloc_buddy_huge_page_with_mpol(h, vma, addr);
2050 if (!page)
2051 goto out_uncharge_cgroup;
2052 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
2053 SetPagePrivate(page);
2054 h->resv_huge_pages--;
2055 }
2056 spin_lock(&hugetlb_lock);
2057 list_move(&page->lru, &h->hugepage_activelist);
2058 /* Fall through */
2059 }
2060 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2061 spin_unlock(&hugetlb_lock);
2062
2063 set_page_private(page, (unsigned long)spool);
2064
2065 map_commit = vma_commit_reservation(h, vma, addr);
2066 if (unlikely(map_chg > map_commit)) {
2067 /*
2068 * The page was added to the reservation map between
2069 * vma_needs_reservation and vma_commit_reservation.
2070 * This indicates a race with hugetlb_reserve_pages.
2071 * Adjust for the subpool count incremented above AND
2072 * in hugetlb_reserve_pages for the same page. Also,
2073 * the reservation count added in hugetlb_reserve_pages
2074 * no longer applies.
2075 */
2076 long rsv_adjust;
2077
2078 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
2079 hugetlb_acct_memory(h, -rsv_adjust);
2080 }
2081 return page;
2082
2083out_uncharge_cgroup:
2084 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2085out_subpool_put:
2086 if (map_chg || avoid_reserve)
2087 hugepage_subpool_put_pages(spool, 1);
2088 vma_end_reservation(h, vma, addr);
2089 return ERR_PTR(-ENOSPC);
2090}
2091
2092/*
2093 * alloc_huge_page()'s wrapper which simply returns the page if allocation
2094 * succeeds, otherwise NULL. This function is called from new_vma_page(),
2095 * where no ERR_VALUE is expected to be returned.
2096 */
2097struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
2098 unsigned long addr, int avoid_reserve)
2099{
2100 struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
2101 if (IS_ERR(page))
2102 page = NULL;
2103 return page;
2104}
2105
2106int __weak alloc_bootmem_huge_page(struct hstate *h)
2107{
2108 struct huge_bootmem_page *m;
2109 int nr_nodes, node;
2110
2111 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2112 void *addr;
2113
2114 addr = memblock_virt_alloc_try_nid_nopanic(
2115 huge_page_size(h), huge_page_size(h),
2116 0, BOOTMEM_ALLOC_ACCESSIBLE, node);
2117 if (addr) {
2118 /*
2119 * Use the beginning of the huge page to store the
2120 * huge_bootmem_page struct (until gather_bootmem
2121 * puts them into the mem_map).
2122 */
2123 m = addr;
2124 goto found;
2125 }
2126 }
2127 return 0;
2128
2129found:
2130 BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2131 /* Put them into a private list first because mem_map is not up yet */
2132 list_add(&m->list, &huge_boot_pages);
2133 m->hstate = h;
2134 return 1;
2135}
2136
2137static void __init prep_compound_huge_page(struct page *page,
2138 unsigned int order)
2139{
2140 if (unlikely(order > (MAX_ORDER - 1)))
2141 prep_compound_gigantic_page(page, order);
2142 else
2143 prep_compound_page(page, order);
2144}
2145
2146/* Put bootmem huge pages into the standard lists after mem_map is up */
2147static void __init gather_bootmem_prealloc(void)
2148{
2149 struct huge_bootmem_page *m;
2150
2151 list_for_each_entry(m, &huge_boot_pages, list) {
2152 struct hstate *h = m->hstate;
2153 struct page *page;
2154
2155#ifdef CONFIG_HIGHMEM
2156 page = pfn_to_page(m->phys >> PAGE_SHIFT);
2157 memblock_free_late(__pa(m),
2158 sizeof(struct huge_bootmem_page));
2159#else
2160 page = virt_to_page(m);
2161#endif
2162 WARN_ON(page_count(page) != 1);
2163 prep_compound_huge_page(page, h->order);
2164 WARN_ON(PageReserved(page));
2165 prep_new_huge_page(h, page, page_to_nid(page));
2166 /*
2167 * If we had gigantic hugepages allocated at boot time, we need
2168 * to restore the 'stolen' pages to totalram_pages in order to
2169 * fix confusing memory reports from free(1) and another
2170 * side-effects, like CommitLimit going negative.
2171 */
2172 if (hstate_is_gigantic(h))
2173 adjust_managed_page_count(page, 1 << h->order);
2174 }
2175}
2176
2177static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
2178{
2179 unsigned long i;
2180
2181 for (i = 0; i < h->max_huge_pages; ++i) {
2182 if (hstate_is_gigantic(h)) {
2183 if (!alloc_bootmem_huge_page(h))
2184 break;
2185 } else if (!alloc_fresh_huge_page(h,
2186 &node_states[N_MEMORY]))
2187 break;
2188 }
2189 h->max_huge_pages = i;
2190}
2191
2192static void __init hugetlb_init_hstates(void)
2193{
2194 struct hstate *h;
2195
2196 for_each_hstate(h) {
2197 if (minimum_order > huge_page_order(h))
2198 minimum_order = huge_page_order(h);
2199
2200 /* oversize hugepages were init'ed in early boot */
2201 if (!hstate_is_gigantic(h))
2202 hugetlb_hstate_alloc_pages(h);
2203 }
2204 VM_BUG_ON(minimum_order == UINT_MAX);
2205}
2206
2207static char * __init memfmt(char *buf, unsigned long n)
2208{
2209 if (n >= (1UL << 30))
2210 sprintf(buf, "%lu GB", n >> 30);
2211 else if (n >= (1UL << 20))
2212 sprintf(buf, "%lu MB", n >> 20);
2213 else
2214 sprintf(buf, "%lu KB", n >> 10);
2215 return buf;
2216}
2217
2218static void __init report_hugepages(void)
2219{
2220 struct hstate *h;
2221
2222 for_each_hstate(h) {
2223 char buf[32];
2224 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2225 memfmt(buf, huge_page_size(h)),
2226 h->free_huge_pages);
2227 }
2228}
2229
2230#ifdef CONFIG_HIGHMEM
2231static void try_to_free_low(struct hstate *h, unsigned long count,
2232 nodemask_t *nodes_allowed)
2233{
2234 int i;
2235
2236 if (hstate_is_gigantic(h))
2237 return;
2238
2239 for_each_node_mask(i, *nodes_allowed) {
2240 struct page *page, *next;
2241 struct list_head *freel = &h->hugepage_freelists[i];
2242 list_for_each_entry_safe(page, next, freel, lru) {
2243 if (count >= h->nr_huge_pages)
2244 return;
2245 if (PageHighMem(page))
2246 continue;
2247 list_del(&page->lru);
2248 update_and_free_page(h, page);
2249 h->free_huge_pages--;
2250 h->free_huge_pages_node[page_to_nid(page)]--;
2251 }
2252 }
2253}
2254#else
2255static inline void try_to_free_low(struct hstate *h, unsigned long count,
2256 nodemask_t *nodes_allowed)
2257{
2258}
2259#endif
2260
2261/*
2262 * Increment or decrement surplus_huge_pages. Keep node-specific counters
2263 * balanced by operating on them in a round-robin fashion.
2264 * Returns 1 if an adjustment was made.
2265 */
2266static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
2267 int delta)
2268{
2269 int nr_nodes, node;
2270
2271 VM_BUG_ON(delta != -1 && delta != 1);
2272
2273 if (delta < 0) {
2274 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2275 if (h->surplus_huge_pages_node[node])
2276 goto found;
2277 }
2278 } else {
2279 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2280 if (h->surplus_huge_pages_node[node] <
2281 h->nr_huge_pages_node[node])
2282 goto found;
2283 }
2284 }
2285 return 0;
2286
2287found:
2288 h->surplus_huge_pages += delta;
2289 h->surplus_huge_pages_node[node] += delta;
2290 return 1;
2291}
2292
2293#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2294static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
2295 nodemask_t *nodes_allowed)
2296{
2297 unsigned long min_count, ret;
2298
2299 if (hstate_is_gigantic(h) && !gigantic_page_supported())
2300 return h->max_huge_pages;
2301
2302 /*
2303 * Increase the pool size
2304 * First take pages out of surplus state. Then make up the
2305 * remaining difference by allocating fresh huge pages.
2306 *
2307 * We might race with __alloc_buddy_huge_page() here and be unable
2308 * to convert a surplus huge page to a normal huge page. That is
2309 * not critical, though, it just means the overall size of the
2310 * pool might be one hugepage larger than it needs to be, but
2311 * within all the constraints specified by the sysctls.
2312 */
2313 spin_lock(&hugetlb_lock);
2314 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2315 if (!adjust_pool_surplus(h, nodes_allowed, -1))
2316 break;
2317 }
2318
2319 while (count > persistent_huge_pages(h)) {
2320 /*
2321 * If this allocation races such that we no longer need the
2322 * page, free_huge_page will handle it by freeing the page
2323 * and reducing the surplus.
2324 */
2325 spin_unlock(&hugetlb_lock);
2326
2327 /* yield cpu to avoid soft lockup */
2328 cond_resched();
2329
2330 if (hstate_is_gigantic(h))
2331 ret = alloc_fresh_gigantic_page(h, nodes_allowed);
2332 else
2333 ret = alloc_fresh_huge_page(h, nodes_allowed);
2334 spin_lock(&hugetlb_lock);
2335 if (!ret)
2336 goto out;
2337
2338 /* Bail for signals. Probably ctrl-c from user */
2339 if (signal_pending(current))
2340 goto out;
2341 }
2342
2343 /*
2344 * Decrease the pool size
2345 * First return free pages to the buddy allocator (being careful
2346 * to keep enough around to satisfy reservations). Then place
2347 * pages into surplus state as needed so the pool will shrink
2348 * to the desired size as pages become free.
2349 *
2350 * By placing pages into the surplus state independent of the
2351 * overcommit value, we are allowing the surplus pool size to
2352 * exceed overcommit. There are few sane options here. Since
2353 * __alloc_buddy_huge_page() is checking the global counter,
2354 * though, we'll note that we're not allowed to exceed surplus
2355 * and won't grow the pool anywhere else. Not until one of the
2356 * sysctls are changed, or the surplus pages go out of use.
2357 */
2358 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2359 min_count = max(count, min_count);
2360 try_to_free_low(h, min_count, nodes_allowed);
2361 while (min_count < persistent_huge_pages(h)) {
2362 if (!free_pool_huge_page(h, nodes_allowed, 0))
2363 break;
2364 cond_resched_lock(&hugetlb_lock);
2365 }
2366 while (count < persistent_huge_pages(h)) {
2367 if (!adjust_pool_surplus(h, nodes_allowed, 1))
2368 break;
2369 }
2370out:
2371 ret = persistent_huge_pages(h);
2372 spin_unlock(&hugetlb_lock);
2373 return ret;
2374}
2375
2376#define HSTATE_ATTR_RO(_name) \
2377 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
2378
2379#define HSTATE_ATTR(_name) \
2380 static struct kobj_attribute _name##_attr = \
2381 __ATTR(_name, 0644, _name##_show, _name##_store)
2382
2383static struct kobject *hugepages_kobj;
2384static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2385
2386static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
2387
2388static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2389{
2390 int i;
2391
2392 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2393 if (hstate_kobjs[i] == kobj) {
2394 if (nidp)
2395 *nidp = NUMA_NO_NODE;
2396 return &hstates[i];
2397 }
2398
2399 return kobj_to_node_hstate(kobj, nidp);
2400}
2401
2402static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2403 struct kobj_attribute *attr, char *buf)
2404{
2405 struct hstate *h;
2406 unsigned long nr_huge_pages;
2407 int nid;
2408
2409 h = kobj_to_hstate(kobj, &nid);
2410 if (nid == NUMA_NO_NODE)
2411 nr_huge_pages = h->nr_huge_pages;
2412 else
2413 nr_huge_pages = h->nr_huge_pages_node[nid];
2414
2415 return sprintf(buf, "%lu\n", nr_huge_pages);
2416}
2417
2418static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
2419 struct hstate *h, int nid,
2420 unsigned long count, size_t len)
2421{
2422 int err;
2423 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
2424
2425 if (hstate_is_gigantic(h) && !gigantic_page_supported()) {
2426 err = -EINVAL;
2427 goto out;
2428 }
2429
2430 if (nid == NUMA_NO_NODE) {
2431 /*
2432 * global hstate attribute
2433 */
2434 if (!(obey_mempolicy &&
2435 init_nodemask_of_mempolicy(nodes_allowed))) {
2436 NODEMASK_FREE(nodes_allowed);
2437 nodes_allowed = &node_states[N_MEMORY];
2438 }
2439 } else if (nodes_allowed) {
2440 /*
2441 * per node hstate attribute: adjust count to global,
2442 * but restrict alloc/free to the specified node.
2443 */
2444 count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
2445 init_nodemask_of_node(nodes_allowed, nid);
2446 } else
2447 nodes_allowed = &node_states[N_MEMORY];
2448
2449 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
2450
2451 if (nodes_allowed != &node_states[N_MEMORY])
2452 NODEMASK_FREE(nodes_allowed);
2453
2454 return len;
2455out:
2456 NODEMASK_FREE(nodes_allowed);
2457 return err;
2458}
2459
2460static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
2461 struct kobject *kobj, const char *buf,
2462 size_t len)
2463{
2464 struct hstate *h;
2465 unsigned long count;
2466 int nid;
2467 int err;
2468
2469 err = kstrtoul(buf, 10, &count);
2470 if (err)
2471 return err;
2472
2473 h = kobj_to_hstate(kobj, &nid);
2474 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
2475}
2476
2477static ssize_t nr_hugepages_show(struct kobject *kobj,
2478 struct kobj_attribute *attr, char *buf)
2479{
2480 return nr_hugepages_show_common(kobj, attr, buf);
2481}
2482
2483static ssize_t nr_hugepages_store(struct kobject *kobj,
2484 struct kobj_attribute *attr, const char *buf, size_t len)
2485{
2486 return nr_hugepages_store_common(false, kobj, buf, len);
2487}
2488HSTATE_ATTR(nr_hugepages);
2489
2490#ifdef CONFIG_NUMA
2491
2492/*
2493 * hstate attribute for optionally mempolicy-based constraint on persistent
2494 * huge page alloc/free.
2495 */
2496static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
2497 struct kobj_attribute *attr, char *buf)
2498{
2499 return nr_hugepages_show_common(kobj, attr, buf);
2500}
2501
2502static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
2503 struct kobj_attribute *attr, const char *buf, size_t len)
2504{
2505 return nr_hugepages_store_common(true, kobj, buf, len);
2506}
2507HSTATE_ATTR(nr_hugepages_mempolicy);
2508#endif
2509
2510
2511static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
2512 struct kobj_attribute *attr, char *buf)
2513{
2514 struct hstate *h = kobj_to_hstate(kobj, NULL);
2515 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
2516}
2517
2518static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
2519 struct kobj_attribute *attr, const char *buf, size_t count)
2520{
2521 int err;
2522 unsigned long input;
2523 struct hstate *h = kobj_to_hstate(kobj, NULL);
2524
2525 if (hstate_is_gigantic(h))
2526 return -EINVAL;
2527
2528 err = kstrtoul(buf, 10, &input);
2529 if (err)
2530 return err;
2531
2532 spin_lock(&hugetlb_lock);
2533 h->nr_overcommit_huge_pages = input;
2534 spin_unlock(&hugetlb_lock);
2535
2536 return count;
2537}
2538HSTATE_ATTR(nr_overcommit_hugepages);
2539
2540static ssize_t free_hugepages_show(struct kobject *kobj,
2541 struct kobj_attribute *attr, char *buf)
2542{
2543 struct hstate *h;
2544 unsigned long free_huge_pages;
2545 int nid;
2546
2547 h = kobj_to_hstate(kobj, &nid);
2548 if (nid == NUMA_NO_NODE)
2549 free_huge_pages = h->free_huge_pages;
2550 else
2551 free_huge_pages = h->free_huge_pages_node[nid];
2552
2553 return sprintf(buf, "%lu\n", free_huge_pages);
2554}
2555HSTATE_ATTR_RO(free_hugepages);
2556
2557static ssize_t resv_hugepages_show(struct kobject *kobj,
2558 struct kobj_attribute *attr, char *buf)
2559{
2560 struct hstate *h = kobj_to_hstate(kobj, NULL);
2561 return sprintf(buf, "%lu\n", h->resv_huge_pages);
2562}
2563HSTATE_ATTR_RO(resv_hugepages);
2564
2565static ssize_t surplus_hugepages_show(struct kobject *kobj,
2566 struct kobj_attribute *attr, char *buf)
2567{
2568 struct hstate *h;
2569 unsigned long surplus_huge_pages;
2570 int nid;
2571
2572 h = kobj_to_hstate(kobj, &nid);
2573 if (nid == NUMA_NO_NODE)
2574 surplus_huge_pages = h->surplus_huge_pages;
2575 else
2576 surplus_huge_pages = h->surplus_huge_pages_node[nid];
2577
2578 return sprintf(buf, "%lu\n", surplus_huge_pages);
2579}
2580HSTATE_ATTR_RO(surplus_hugepages);
2581
2582static struct attribute *hstate_attrs[] = {
2583 &nr_hugepages_attr.attr,
2584 &nr_overcommit_hugepages_attr.attr,
2585 &free_hugepages_attr.attr,
2586 &resv_hugepages_attr.attr,
2587 &surplus_hugepages_attr.attr,
2588#ifdef CONFIG_NUMA
2589 &nr_hugepages_mempolicy_attr.attr,
2590#endif
2591 NULL,
2592};
2593
2594static struct attribute_group hstate_attr_group = {
2595 .attrs = hstate_attrs,
2596};
2597
2598static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
2599 struct kobject **hstate_kobjs,
2600 struct attribute_group *hstate_attr_group)
2601{
2602 int retval;
2603 int hi = hstate_index(h);
2604
2605 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
2606 if (!hstate_kobjs[hi])
2607 return -ENOMEM;
2608
2609 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
2610 if (retval)
2611 kobject_put(hstate_kobjs[hi]);
2612
2613 return retval;
2614}
2615
2616static void __init hugetlb_sysfs_init(void)
2617{
2618 struct hstate *h;
2619 int err;
2620
2621 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
2622 if (!hugepages_kobj)
2623 return;
2624
2625 for_each_hstate(h) {
2626 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
2627 hstate_kobjs, &hstate_attr_group);
2628 if (err)
2629 pr_err("Hugetlb: Unable to add hstate %s", h->name);
2630 }
2631}
2632
2633#ifdef CONFIG_NUMA
2634
2635/*
2636 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2637 * with node devices in node_devices[] using a parallel array. The array
2638 * index of a node device or _hstate == node id.
2639 * This is here to avoid any static dependency of the node device driver, in
2640 * the base kernel, on the hugetlb module.
2641 */
2642struct node_hstate {
2643 struct kobject *hugepages_kobj;
2644 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
2645};
2646static struct node_hstate node_hstates[MAX_NUMNODES];
2647
2648/*
2649 * A subset of global hstate attributes for node devices
2650 */
2651static struct attribute *per_node_hstate_attrs[] = {
2652 &nr_hugepages_attr.attr,
2653 &free_hugepages_attr.attr,
2654 &surplus_hugepages_attr.attr,
2655 NULL,
2656};
2657
2658static struct attribute_group per_node_hstate_attr_group = {
2659 .attrs = per_node_hstate_attrs,
2660};
2661
2662/*
2663 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2664 * Returns node id via non-NULL nidp.
2665 */
2666static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
2667{
2668 int nid;
2669
2670 for (nid = 0; nid < nr_node_ids; nid++) {
2671 struct node_hstate *nhs = &node_hstates[nid];
2672 int i;
2673 for (i = 0; i < HUGE_MAX_HSTATE; i++)
2674 if (nhs->hstate_kobjs[i] == kobj) {
2675 if (nidp)
2676 *nidp = nid;
2677 return &hstates[i];
2678 }
2679 }
2680
2681 BUG();
2682 return NULL;
2683}
2684
2685/*
2686 * Unregister hstate attributes from a single node device.
2687 * No-op if no hstate attributes attached.
2688 */
2689static void hugetlb_unregister_node(struct node *node)
2690{
2691 struct hstate *h;
2692 struct node_hstate *nhs = &node_hstates[node->dev.id];
2693
2694 if (!nhs->hugepages_kobj)
2695 return; /* no hstate attributes */
2696
2697 for_each_hstate(h) {
2698 int idx = hstate_index(h);
2699 if (nhs->hstate_kobjs[idx]) {
2700 kobject_put(nhs->hstate_kobjs[idx]);
2701 nhs->hstate_kobjs[idx] = NULL;
2702 }
2703 }
2704
2705 kobject_put(nhs->hugepages_kobj);
2706 nhs->hugepages_kobj = NULL;
2707}
2708
2709
2710/*
2711 * Register hstate attributes for a single node device.
2712 * No-op if attributes already registered.
2713 */
2714static void hugetlb_register_node(struct node *node)
2715{
2716 struct hstate *h;
2717 struct node_hstate *nhs = &node_hstates[node->dev.id];
2718 int err;
2719
2720 if (nhs->hugepages_kobj)
2721 return; /* already allocated */
2722
2723 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
2724 &node->dev.kobj);
2725 if (!nhs->hugepages_kobj)
2726 return;
2727
2728 for_each_hstate(h) {
2729 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
2730 nhs->hstate_kobjs,
2731 &per_node_hstate_attr_group);
2732 if (err) {
2733 pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
2734 h->name, node->dev.id);
2735 hugetlb_unregister_node(node);
2736 break;
2737 }
2738 }
2739}
2740
2741/*
2742 * hugetlb init time: register hstate attributes for all registered node
2743 * devices of nodes that have memory. All on-line nodes should have
2744 * registered their associated device by this time.
2745 */
2746static void __init hugetlb_register_all_nodes(void)
2747{
2748 int nid;
2749
2750 for_each_node_state(nid, N_MEMORY) {
2751 struct node *node = node_devices[nid];
2752 if (node->dev.id == nid)
2753 hugetlb_register_node(node);
2754 }
2755
2756 /*
2757 * Let the node device driver know we're here so it can
2758 * [un]register hstate attributes on node hotplug.
2759 */
2760 register_hugetlbfs_with_node(hugetlb_register_node,
2761 hugetlb_unregister_node);
2762}
2763#else /* !CONFIG_NUMA */
2764
2765static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
2766{
2767 BUG();
2768 if (nidp)
2769 *nidp = -1;
2770 return NULL;
2771}
2772
2773static void hugetlb_register_all_nodes(void) { }
2774
2775#endif
2776
2777static int __init hugetlb_init(void)
2778{
2779 int i;
2780
2781 if (!hugepages_supported())
2782 return 0;
2783
2784 if (!size_to_hstate(default_hstate_size)) {
2785 default_hstate_size = HPAGE_SIZE;
2786 if (!size_to_hstate(default_hstate_size))
2787 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
2788 }
2789 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
2790 if (default_hstate_max_huge_pages) {
2791 if (!default_hstate.max_huge_pages)
2792 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
2793 }
2794
2795 hugetlb_init_hstates();
2796 gather_bootmem_prealloc();
2797 report_hugepages();
2798
2799 hugetlb_sysfs_init();
2800 hugetlb_register_all_nodes();
2801 hugetlb_cgroup_file_init();
2802
2803#ifdef CONFIG_SMP
2804 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
2805#else
2806 num_fault_mutexes = 1;
2807#endif
2808 hugetlb_fault_mutex_table =
2809 kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
2810 BUG_ON(!hugetlb_fault_mutex_table);
2811
2812 for (i = 0; i < num_fault_mutexes; i++)
2813 mutex_init(&hugetlb_fault_mutex_table[i]);
2814 return 0;
2815}
2816subsys_initcall(hugetlb_init);
2817
2818/* Should be called on processing a hugepagesz=... option */
2819void __init hugetlb_bad_size(void)
2820{
2821 parsed_valid_hugepagesz = false;
2822}
2823
2824void __init hugetlb_add_hstate(unsigned int order)
2825{
2826 struct hstate *h;
2827 unsigned long i;
2828
2829 if (size_to_hstate(PAGE_SIZE << order)) {
2830 pr_warn("hugepagesz= specified twice, ignoring\n");
2831 return;
2832 }
2833 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2834 BUG_ON(order == 0);
2835 h = &hstates[hugetlb_max_hstate++];
2836 h->order = order;
2837 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2838 h->nr_huge_pages = 0;
2839 h->free_huge_pages = 0;
2840 for (i = 0; i < MAX_NUMNODES; ++i)
2841 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2842 INIT_LIST_HEAD(&h->hugepage_activelist);
2843 h->next_nid_to_alloc = first_memory_node;
2844 h->next_nid_to_free = first_memory_node;
2845 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
2846 huge_page_size(h)/1024);
2847
2848 parsed_hstate = h;
2849}
2850
2851static int __init hugetlb_nrpages_setup(char *s)
2852{
2853 unsigned long *mhp;
2854 static unsigned long *last_mhp;
2855
2856 if (!parsed_valid_hugepagesz) {
2857 pr_warn("hugepages = %s preceded by "
2858 "an unsupported hugepagesz, ignoring\n", s);
2859 parsed_valid_hugepagesz = true;
2860 return 1;
2861 }
2862 /*
2863 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2864 * so this hugepages= parameter goes to the "default hstate".
2865 */
2866 else if (!hugetlb_max_hstate)
2867 mhp = &default_hstate_max_huge_pages;
2868 else
2869 mhp = &parsed_hstate->max_huge_pages;
2870
2871 if (mhp == last_mhp) {
2872 pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
2873 return 1;
2874 }
2875
2876 if (sscanf(s, "%lu", mhp) <= 0)
2877 *mhp = 0;
2878
2879 /*
2880 * Global state is always initialized later in hugetlb_init.
2881 * But we need to allocate >= MAX_ORDER hstates here early to still
2882 * use the bootmem allocator.
2883 */
2884 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2885 hugetlb_hstate_alloc_pages(parsed_hstate);
2886
2887 last_mhp = mhp;
2888
2889 return 1;
2890}
2891__setup("hugepages=", hugetlb_nrpages_setup);
2892
2893static int __init hugetlb_default_setup(char *s)
2894{
2895 default_hstate_size = memparse(s, &s);
2896 return 1;
2897}
2898__setup("default_hugepagesz=", hugetlb_default_setup);
2899
2900static unsigned int cpuset_mems_nr(unsigned int *array)
2901{
2902 int node;
2903 unsigned int nr = 0;
2904
2905 for_each_node_mask(node, cpuset_current_mems_allowed)
2906 nr += array[node];
2907
2908 return nr;
2909}
2910
2911#ifdef CONFIG_SYSCTL
2912static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
2913 struct ctl_table *table, int write,
2914 void __user *buffer, size_t *length, loff_t *ppos)
2915{
2916 struct hstate *h = &default_hstate;
2917 unsigned long tmp = h->max_huge_pages;
2918 int ret;
2919
2920 if (!hugepages_supported())
2921 return -EOPNOTSUPP;
2922
2923 table->data = &tmp;
2924 table->maxlen = sizeof(unsigned long);
2925 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2926 if (ret)
2927 goto out;
2928
2929 if (write)
2930 ret = __nr_hugepages_store_common(obey_mempolicy, h,
2931 NUMA_NO_NODE, tmp, *length);
2932out:
2933 return ret;
2934}
2935
2936int hugetlb_sysctl_handler(struct ctl_table *table, int write,
2937 void __user *buffer, size_t *length, loff_t *ppos)
2938{
2939
2940 return hugetlb_sysctl_handler_common(false, table, write,
2941 buffer, length, ppos);
2942}
2943
2944#ifdef CONFIG_NUMA
2945int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
2946 void __user *buffer, size_t *length, loff_t *ppos)
2947{
2948 return hugetlb_sysctl_handler_common(true, table, write,
2949 buffer, length, ppos);
2950}
2951#endif /* CONFIG_NUMA */
2952
2953int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2954 void __user *buffer,
2955 size_t *length, loff_t *ppos)
2956{
2957 struct hstate *h = &default_hstate;
2958 unsigned long tmp;
2959 int ret;
2960
2961 if (!hugepages_supported())
2962 return -EOPNOTSUPP;
2963
2964 tmp = h->nr_overcommit_huge_pages;
2965
2966 if (write && hstate_is_gigantic(h))
2967 return -EINVAL;
2968
2969 table->data = &tmp;
2970 table->maxlen = sizeof(unsigned long);
2971 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2972 if (ret)
2973 goto out;
2974
2975 if (write) {
2976 spin_lock(&hugetlb_lock);
2977 h->nr_overcommit_huge_pages = tmp;
2978 spin_unlock(&hugetlb_lock);
2979 }
2980out:
2981 return ret;
2982}
2983
2984#endif /* CONFIG_SYSCTL */
2985
2986void hugetlb_report_meminfo(struct seq_file *m)
2987{
2988 struct hstate *h = &default_hstate;
2989 if (!hugepages_supported())
2990 return;
2991 seq_printf(m,
2992 "HugePages_Total: %5lu\n"
2993 "HugePages_Free: %5lu\n"
2994 "HugePages_Rsvd: %5lu\n"
2995 "HugePages_Surp: %5lu\n"
2996 "Hugepagesize: %8lu kB\n",
2997 h->nr_huge_pages,
2998 h->free_huge_pages,
2999 h->resv_huge_pages,
3000 h->surplus_huge_pages,
3001 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
3002}
3003
3004int hugetlb_report_node_meminfo(int nid, char *buf)
3005{
3006 struct hstate *h = &default_hstate;
3007 if (!hugepages_supported())
3008 return 0;
3009 return sprintf(buf,
3010 "Node %d HugePages_Total: %5u\n"
3011 "Node %d HugePages_Free: %5u\n"
3012 "Node %d HugePages_Surp: %5u\n",
3013 nid, h->nr_huge_pages_node[nid],
3014 nid, h->free_huge_pages_node[nid],
3015 nid, h->surplus_huge_pages_node[nid]);
3016}
3017
3018void hugetlb_show_meminfo(void)
3019{
3020 struct hstate *h;
3021 int nid;
3022
3023 if (!hugepages_supported())
3024 return;
3025
3026 for_each_node_state(nid, N_MEMORY)
3027 for_each_hstate(h)
3028 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
3029 nid,
3030 h->nr_huge_pages_node[nid],
3031 h->free_huge_pages_node[nid],
3032 h->surplus_huge_pages_node[nid],
3033 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
3034}
3035
3036void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
3037{
3038 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
3039 atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
3040}
3041
3042/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
3043unsigned long hugetlb_total_pages(void)
3044{
3045 struct hstate *h;
3046 unsigned long nr_total_pages = 0;
3047
3048 for_each_hstate(h)
3049 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
3050 return nr_total_pages;
3051}
3052
3053static int hugetlb_acct_memory(struct hstate *h, long delta)
3054{
3055 int ret = -ENOMEM;
3056
3057 spin_lock(&hugetlb_lock);
3058 /*
3059 * When cpuset is configured, it breaks the strict hugetlb page
3060 * reservation as the accounting is done on a global variable. Such
3061 * reservation is completely rubbish in the presence of cpuset because
3062 * the reservation is not checked against page availability for the
3063 * current cpuset. Application can still potentially OOM'ed by kernel
3064 * with lack of free htlb page in cpuset that the task is in.
3065 * Attempt to enforce strict accounting with cpuset is almost
3066 * impossible (or too ugly) because cpuset is too fluid that
3067 * task or memory node can be dynamically moved between cpusets.
3068 *
3069 * The change of semantics for shared hugetlb mapping with cpuset is
3070 * undesirable. However, in order to preserve some of the semantics,
3071 * we fall back to check against current free page availability as
3072 * a best attempt and hopefully to minimize the impact of changing
3073 * semantics that cpuset has.
3074 */
3075 if (delta > 0) {
3076 if (gather_surplus_pages(h, delta) < 0)
3077 goto out;
3078
3079 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
3080 return_unused_surplus_pages(h, delta);
3081 goto out;
3082 }
3083 }
3084
3085 ret = 0;
3086 if (delta < 0)
3087 return_unused_surplus_pages(h, (unsigned long) -delta);
3088
3089out:
3090 spin_unlock(&hugetlb_lock);
3091 return ret;
3092}
3093
3094static void hugetlb_vm_op_open(struct vm_area_struct *vma)
3095{
3096 struct resv_map *resv = vma_resv_map(vma);
3097
3098 /*
3099 * This new VMA should share its siblings reservation map if present.
3100 * The VMA will only ever have a valid reservation map pointer where
3101 * it is being copied for another still existing VMA. As that VMA
3102 * has a reference to the reservation map it cannot disappear until
3103 * after this open call completes. It is therefore safe to take a
3104 * new reference here without additional locking.
3105 */
3106 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3107 kref_get(&resv->refs);
3108}
3109
3110static void hugetlb_vm_op_close(struct vm_area_struct *vma)
3111{
3112 struct hstate *h = hstate_vma(vma);
3113 struct resv_map *resv = vma_resv_map(vma);
3114 struct hugepage_subpool *spool = subpool_vma(vma);
3115 unsigned long reserve, start, end;
3116 long gbl_reserve;
3117
3118 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3119 return;
3120
3121 start = vma_hugecache_offset(h, vma, vma->vm_start);
3122 end = vma_hugecache_offset(h, vma, vma->vm_end);
3123
3124 reserve = (end - start) - region_count(resv, start, end);
3125
3126 kref_put(&resv->refs, resv_map_release);
3127
3128 if (reserve) {
3129 /*
3130 * Decrement reserve counts. The global reserve count may be
3131 * adjusted if the subpool has a minimum size.
3132 */
3133 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
3134 hugetlb_acct_memory(h, -gbl_reserve);
3135 }
3136}
3137
3138/*
3139 * We cannot handle pagefaults against hugetlb pages at all. They cause
3140 * handle_mm_fault() to try to instantiate regular-sized pages in the
3141 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
3142 * this far.
3143 */
3144static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
3145{
3146 BUG();
3147 return 0;
3148}
3149
3150const struct vm_operations_struct hugetlb_vm_ops = {
3151 .fault = hugetlb_vm_op_fault,
3152 .open = hugetlb_vm_op_open,
3153 .close = hugetlb_vm_op_close,
3154};
3155
3156static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
3157 int writable)
3158{
3159 pte_t entry;
3160
3161 if (writable) {
3162 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
3163 vma->vm_page_prot)));
3164 } else {
3165 entry = huge_pte_wrprotect(mk_huge_pte(page,
3166 vma->vm_page_prot));
3167 }
3168 entry = pte_mkyoung(entry);
3169 entry = pte_mkhuge(entry);
3170 entry = arch_make_huge_pte(entry, vma, page, writable);
3171
3172 return entry;
3173}
3174
3175static void set_huge_ptep_writable(struct vm_area_struct *vma,
3176 unsigned long address, pte_t *ptep)
3177{
3178 pte_t entry;
3179
3180 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3181 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3182 update_mmu_cache(vma, address, ptep);
3183}
3184
3185static int is_hugetlb_entry_migration(pte_t pte)
3186{
3187 swp_entry_t swp;
3188
3189 if (huge_pte_none(pte) || pte_present(pte))
3190 return 0;
3191 swp = pte_to_swp_entry(pte);
3192 if (non_swap_entry(swp) && is_migration_entry(swp))
3193 return 1;
3194 else
3195 return 0;
3196}
3197
3198static int is_hugetlb_entry_hwpoisoned(pte_t pte)
3199{
3200 swp_entry_t swp;
3201
3202 if (huge_pte_none(pte) || pte_present(pte))
3203 return 0;
3204 swp = pte_to_swp_entry(pte);
3205 if (non_swap_entry(swp) && is_hwpoison_entry(swp))
3206 return 1;
3207 else
3208 return 0;
3209}
3210
3211int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
3212 struct vm_area_struct *vma)
3213{
3214 pte_t *src_pte, *dst_pte, entry;
3215 struct page *ptepage;
3216 unsigned long addr;
3217 int cow;
3218 struct hstate *h = hstate_vma(vma);
3219 unsigned long sz = huge_page_size(h);
3220 unsigned long mmun_start; /* For mmu_notifiers */
3221 unsigned long mmun_end; /* For mmu_notifiers */
3222 int ret = 0;
3223
3224 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
3225
3226 mmun_start = vma->vm_start;
3227 mmun_end = vma->vm_end;
3228 if (cow)
3229 mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);
3230
3231 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3232 spinlock_t *src_ptl, *dst_ptl;
3233 src_pte = huge_pte_offset(src, addr);
3234 if (!src_pte)
3235 continue;
3236 dst_pte = huge_pte_alloc(dst, addr, sz);
3237 if (!dst_pte) {
3238 ret = -ENOMEM;
3239 break;
3240 }
3241
3242 /* If the pagetables are shared don't copy or take references */
3243 if (dst_pte == src_pte)
3244 continue;
3245
3246 dst_ptl = huge_pte_lock(h, dst, dst_pte);
3247 src_ptl = huge_pte_lockptr(h, src, src_pte);
3248 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
3249 entry = huge_ptep_get(src_pte);
3250 if (huge_pte_none(entry)) { /* skip none entry */
3251 ;
3252 } else if (unlikely(is_hugetlb_entry_migration(entry) ||
3253 is_hugetlb_entry_hwpoisoned(entry))) {
3254 swp_entry_t swp_entry = pte_to_swp_entry(entry);
3255
3256 if (is_write_migration_entry(swp_entry) && cow) {
3257 /*
3258 * COW mappings require pages in both
3259 * parent and child to be set to read.
3260 */
3261 make_migration_entry_read(&swp_entry);
3262 entry = swp_entry_to_pte(swp_entry);
3263 set_huge_pte_at(src, addr, src_pte, entry);
3264 }
3265 set_huge_pte_at(dst, addr, dst_pte, entry);
3266 } else {
3267 if (cow) {
3268 huge_ptep_set_wrprotect(src, addr, src_pte);
3269 mmu_notifier_invalidate_range(src, mmun_start,
3270 mmun_end);
3271 }
3272 entry = huge_ptep_get(src_pte);
3273 ptepage = pte_page(entry);
3274 get_page(ptepage);
3275 page_dup_rmap(ptepage, true);
3276 set_huge_pte_at(dst, addr, dst_pte, entry);
3277 hugetlb_count_add(pages_per_huge_page(h), dst);
3278 }
3279 spin_unlock(src_ptl);
3280 spin_unlock(dst_ptl);
3281 }
3282
3283 if (cow)
3284 mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);
3285
3286 return ret;
3287}
3288
3289void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
3290 unsigned long start, unsigned long end,
3291 struct page *ref_page)
3292{
3293 struct mm_struct *mm = vma->vm_mm;
3294 unsigned long address;
3295 pte_t *ptep;
3296 pte_t pte;
3297 spinlock_t *ptl;
3298 struct page *page;
3299 struct hstate *h = hstate_vma(vma);
3300 unsigned long sz = huge_page_size(h);
3301 const unsigned long mmun_start = start; /* For mmu_notifiers */
3302 const unsigned long mmun_end = end; /* For mmu_notifiers */
3303
3304 WARN_ON(!is_vm_hugetlb_page(vma));
3305 BUG_ON(start & ~huge_page_mask(h));
3306 BUG_ON(end & ~huge_page_mask(h));
3307
3308 /*
3309 * This is a hugetlb vma, all the pte entries should point
3310 * to huge page.
3311 */
3312 tlb_remove_check_page_size_change(tlb, sz);
3313 tlb_start_vma(tlb, vma);
3314 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3315 address = start;
3316 for (; address < end; address += sz) {
3317 ptep = huge_pte_offset(mm, address);
3318 if (!ptep)
3319 continue;
3320
3321 ptl = huge_pte_lock(h, mm, ptep);
3322 if (huge_pmd_unshare(mm, &address, ptep)) {
3323 spin_unlock(ptl);
3324 continue;
3325 }
3326
3327 pte = huge_ptep_get(ptep);
3328 if (huge_pte_none(pte)) {
3329 spin_unlock(ptl);
3330 continue;
3331 }
3332
3333 /*
3334 * Migrating hugepage or HWPoisoned hugepage is already
3335 * unmapped and its refcount is dropped, so just clear pte here.
3336 */
3337 if (unlikely(!pte_present(pte))) {
3338 huge_pte_clear(mm, address, ptep);
3339 spin_unlock(ptl);
3340 continue;
3341 }
3342
3343 page = pte_page(pte);
3344 /*
3345 * If a reference page is supplied, it is because a specific
3346 * page is being unmapped, not a range. Ensure the page we
3347 * are about to unmap is the actual page of interest.
3348 */
3349 if (ref_page) {
3350 if (page != ref_page) {
3351 spin_unlock(ptl);
3352 continue;
3353 }
3354 /*
3355 * Mark the VMA as having unmapped its page so that
3356 * future faults in this VMA will fail rather than
3357 * looking like data was lost
3358 */
3359 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
3360 }
3361
3362 pte = huge_ptep_get_and_clear(mm, address, ptep);
3363 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
3364 if (huge_pte_dirty(pte))
3365 set_page_dirty(page);
3366
3367 hugetlb_count_sub(pages_per_huge_page(h), mm);
3368 page_remove_rmap(page, true);
3369
3370 spin_unlock(ptl);
3371 tlb_remove_page_size(tlb, page, huge_page_size(h));
3372 /*
3373 * Bail out after unmapping reference page if supplied
3374 */
3375 if (ref_page)
3376 break;
3377 }
3378 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3379 tlb_end_vma(tlb, vma);
3380}
3381
3382void __unmap_hugepage_range_final(struct mmu_gather *tlb,
3383 struct vm_area_struct *vma, unsigned long start,
3384 unsigned long end, struct page *ref_page)
3385{
3386 __unmap_hugepage_range(tlb, vma, start, end, ref_page);
3387
3388 /*
3389 * Clear this flag so that x86's huge_pmd_share page_table_shareable
3390 * test will fail on a vma being torn down, and not grab a page table
3391 * on its way out. We're lucky that the flag has such an appropriate
3392 * name, and can in fact be safely cleared here. We could clear it
3393 * before the __unmap_hugepage_range above, but all that's necessary
3394 * is to clear it before releasing the i_mmap_rwsem. This works
3395 * because in the context this is called, the VMA is about to be
3396 * destroyed and the i_mmap_rwsem is held.
3397 */
3398 vma->vm_flags &= ~VM_MAYSHARE;
3399}
3400
3401void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
3402 unsigned long end, struct page *ref_page)
3403{
3404 struct mm_struct *mm;
3405 struct mmu_gather tlb;
3406
3407 mm = vma->vm_mm;
3408
3409 tlb_gather_mmu(&tlb, mm, start, end);
3410 __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
3411 tlb_finish_mmu(&tlb, start, end);
3412}
3413
3414/*
3415 * This is called when the original mapper is failing to COW a MAP_PRIVATE
3416 * mappping it owns the reserve page for. The intention is to unmap the page
3417 * from other VMAs and let the children be SIGKILLed if they are faulting the
3418 * same region.
3419 */
3420static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
3421 struct page *page, unsigned long address)
3422{
3423 struct hstate *h = hstate_vma(vma);
3424 struct vm_area_struct *iter_vma;
3425 struct address_space *mapping;
3426 pgoff_t pgoff;
3427
3428 /*
3429 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
3430 * from page cache lookup which is in HPAGE_SIZE units.
3431 */
3432 address = address & huge_page_mask(h);
3433 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
3434 vma->vm_pgoff;
3435 mapping = vma->vm_file->f_mapping;
3436
3437 /*
3438 * Take the mapping lock for the duration of the table walk. As
3439 * this mapping should be shared between all the VMAs,
3440 * __unmap_hugepage_range() is called as the lock is already held
3441 */
3442 i_mmap_lock_write(mapping);
3443 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
3444 /* Do not unmap the current VMA */
3445 if (iter_vma == vma)
3446 continue;
3447
3448 /*
3449 * Shared VMAs have their own reserves and do not affect
3450 * MAP_PRIVATE accounting but it is possible that a shared
3451 * VMA is using the same page so check and skip such VMAs.
3452 */
3453 if (iter_vma->vm_flags & VM_MAYSHARE)
3454 continue;
3455
3456 /*
3457 * Unmap the page from other VMAs without their own reserves.
3458 * They get marked to be SIGKILLed if they fault in these
3459 * areas. This is because a future no-page fault on this VMA
3460 * could insert a zeroed page instead of the data existing
3461 * from the time of fork. This would look like data corruption
3462 */
3463 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
3464 unmap_hugepage_range(iter_vma, address,
3465 address + huge_page_size(h), page);
3466 }
3467 i_mmap_unlock_write(mapping);
3468}
3469
3470/*
3471 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3472 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
3473 * cannot race with other handlers or page migration.
3474 * Keep the pte_same checks anyway to make transition from the mutex easier.
3475 */
3476static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
3477 unsigned long address, pte_t *ptep,
3478 struct page *pagecache_page, spinlock_t *ptl)
3479{
3480 pte_t pte;
3481 struct hstate *h = hstate_vma(vma);
3482 struct page *old_page, *new_page;
3483 int ret = 0, outside_reserve = 0;
3484 unsigned long mmun_start; /* For mmu_notifiers */
3485 unsigned long mmun_end; /* For mmu_notifiers */
3486
3487 pte = huge_ptep_get(ptep);
3488 old_page = pte_page(pte);
3489
3490retry_avoidcopy:
3491 /* If no-one else is actually using this page, avoid the copy
3492 * and just make the page writable */
3493 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
3494 page_move_anon_rmap(old_page, vma);
3495 set_huge_ptep_writable(vma, address, ptep);
3496 return 0;
3497 }
3498
3499 /*
3500 * If the process that created a MAP_PRIVATE mapping is about to
3501 * perform a COW due to a shared page count, attempt to satisfy
3502 * the allocation without using the existing reserves. The pagecache
3503 * page is used to determine if the reserve at this address was
3504 * consumed or not. If reserves were used, a partial faulted mapping
3505 * at the time of fork() could consume its reserves on COW instead
3506 * of the full address range.
3507 */
3508 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
3509 old_page != pagecache_page)
3510 outside_reserve = 1;
3511
3512 get_page(old_page);
3513
3514 /*
3515 * Drop page table lock as buddy allocator may be called. It will
3516 * be acquired again before returning to the caller, as expected.
3517 */
3518 spin_unlock(ptl);
3519 new_page = alloc_huge_page(vma, address, outside_reserve);
3520
3521 if (IS_ERR(new_page)) {
3522 /*
3523 * If a process owning a MAP_PRIVATE mapping fails to COW,
3524 * it is due to references held by a child and an insufficient
3525 * huge page pool. To guarantee the original mappers
3526 * reliability, unmap the page from child processes. The child
3527 * may get SIGKILLed if it later faults.
3528 */
3529 if (outside_reserve) {
3530 put_page(old_page);
3531 BUG_ON(huge_pte_none(pte));
3532 unmap_ref_private(mm, vma, old_page, address);
3533 BUG_ON(huge_pte_none(pte));
3534 spin_lock(ptl);
3535 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
3536 if (likely(ptep &&
3537 pte_same(huge_ptep_get(ptep), pte)))
3538 goto retry_avoidcopy;
3539 /*
3540 * race occurs while re-acquiring page table
3541 * lock, and our job is done.
3542 */
3543 return 0;
3544 }
3545
3546 ret = (PTR_ERR(new_page) == -ENOMEM) ?
3547 VM_FAULT_OOM : VM_FAULT_SIGBUS;
3548 goto out_release_old;
3549 }
3550
3551 /*
3552 * When the original hugepage is shared one, it does not have
3553 * anon_vma prepared.
3554 */
3555 if (unlikely(anon_vma_prepare(vma))) {
3556 ret = VM_FAULT_OOM;
3557 goto out_release_all;
3558 }
3559
3560 copy_user_huge_page(new_page, old_page, address, vma,
3561 pages_per_huge_page(h));
3562 __SetPageUptodate(new_page);
3563 set_page_huge_active(new_page);
3564
3565 mmun_start = address & huge_page_mask(h);
3566 mmun_end = mmun_start + huge_page_size(h);
3567 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3568
3569 /*
3570 * Retake the page table lock to check for racing updates
3571 * before the page tables are altered
3572 */
3573 spin_lock(ptl);
3574 ptep = huge_pte_offset(mm, address & huge_page_mask(h));
3575 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
3576 ClearPagePrivate(new_page);
3577
3578 /* Break COW */
3579 huge_ptep_clear_flush(vma, address, ptep);
3580 mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
3581 set_huge_pte_at(mm, address, ptep,
3582 make_huge_pte(vma, new_page, 1));
3583 page_remove_rmap(old_page, true);
3584 hugepage_add_new_anon_rmap(new_page, vma, address);
3585 /* Make the old page be freed below */
3586 new_page = old_page;
3587 }
3588 spin_unlock(ptl);
3589 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3590out_release_all:
3591 restore_reserve_on_error(h, vma, address, new_page);
3592 put_page(new_page);
3593out_release_old:
3594 put_page(old_page);
3595
3596 spin_lock(ptl); /* Caller expects lock to be held */
3597 return ret;
3598}
3599
3600/* Return the pagecache page at a given address within a VMA */
3601static struct page *hugetlbfs_pagecache_page(struct hstate *h,
3602 struct vm_area_struct *vma, unsigned long address)
3603{
3604 struct address_space *mapping;
3605 pgoff_t idx;
3606
3607 mapping = vma->vm_file->f_mapping;
3608 idx = vma_hugecache_offset(h, vma, address);
3609
3610 return find_lock_page(mapping, idx);
3611}
3612
3613/*
3614 * Return whether there is a pagecache page to back given address within VMA.
3615 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
3616 */
3617static bool hugetlbfs_pagecache_present(struct hstate *h,
3618 struct vm_area_struct *vma, unsigned long address)
3619{
3620 struct address_space *mapping;
3621 pgoff_t idx;
3622 struct page *page;
3623
3624 mapping = vma->vm_file->f_mapping;
3625 idx = vma_hugecache_offset(h, vma, address);
3626
3627 page = find_get_page(mapping, idx);
3628 if (page)
3629 put_page(page);
3630 return page != NULL;
3631}
3632
3633int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
3634 pgoff_t idx)
3635{
3636 struct inode *inode = mapping->host;
3637 struct hstate *h = hstate_inode(inode);
3638 int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
3639
3640 if (err)
3641 return err;
3642 ClearPagePrivate(page);
3643
3644 spin_lock(&inode->i_lock);
3645 inode->i_blocks += blocks_per_huge_page(h);
3646 spin_unlock(&inode->i_lock);
3647 return 0;
3648}
3649
3650static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
3651 struct address_space *mapping, pgoff_t idx,
3652 unsigned long address, pte_t *ptep, unsigned int flags)
3653{
3654 struct hstate *h = hstate_vma(vma);
3655 int ret = VM_FAULT_SIGBUS;
3656 int anon_rmap = 0;
3657 unsigned long size;
3658 struct page *page;
3659 pte_t new_pte;
3660 spinlock_t *ptl;
3661
3662 /*
3663 * Currently, we are forced to kill the process in the event the
3664 * original mapper has unmapped pages from the child due to a failed
3665 * COW. Warn that such a situation has occurred as it may not be obvious
3666 */
3667 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
3668 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
3669 current->pid);
3670 return ret;
3671 }
3672
3673 /*
3674 * Use page lock to guard against racing truncation
3675 * before we get page_table_lock.
3676 */
3677retry:
3678 page = find_lock_page(mapping, idx);
3679 if (!page) {
3680 size = i_size_read(mapping->host) >> huge_page_shift(h);
3681 if (idx >= size)
3682 goto out;
3683 page = alloc_huge_page(vma, address, 0);
3684 if (IS_ERR(page)) {
3685 ret = PTR_ERR(page);
3686 if (ret == -ENOMEM)
3687 ret = VM_FAULT_OOM;
3688 else
3689 ret = VM_FAULT_SIGBUS;
3690 goto out;
3691 }
3692 clear_huge_page(page, address, pages_per_huge_page(h));
3693 __SetPageUptodate(page);
3694 set_page_huge_active(page);
3695
3696 if (vma->vm_flags & VM_MAYSHARE) {
3697 int err = huge_add_to_page_cache(page, mapping, idx);
3698 if (err) {
3699 put_page(page);
3700 if (err == -EEXIST)
3701 goto retry;
3702 goto out;
3703 }
3704 } else {
3705 lock_page(page);
3706 if (unlikely(anon_vma_prepare(vma))) {
3707 ret = VM_FAULT_OOM;
3708 goto backout_unlocked;
3709 }
3710 anon_rmap = 1;
3711 }
3712 } else {
3713 /*
3714 * If memory error occurs between mmap() and fault, some process
3715 * don't have hwpoisoned swap entry for errored virtual address.
3716 * So we need to block hugepage fault by PG_hwpoison bit check.
3717 */
3718 if (unlikely(PageHWPoison(page))) {
3719 ret = VM_FAULT_HWPOISON |
3720 VM_FAULT_SET_HINDEX(hstate_index(h));
3721 goto backout_unlocked;
3722 }
3723 }
3724
3725 /*
3726 * If we are going to COW a private mapping later, we examine the
3727 * pending reservations for this page now. This will ensure that
3728 * any allocations necessary to record that reservation occur outside
3729 * the spinlock.
3730 */
3731 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3732 if (vma_needs_reservation(h, vma, address) < 0) {
3733 ret = VM_FAULT_OOM;
3734 goto backout_unlocked;
3735 }
3736 /* Just decrements count, does not deallocate */
3737 vma_end_reservation(h, vma, address);
3738 }
3739
3740 ptl = huge_pte_lock(h, mm, ptep);
3741 size = i_size_read(mapping->host) >> huge_page_shift(h);
3742 if (idx >= size)
3743 goto backout;
3744
3745 ret = 0;
3746 if (!huge_pte_none(huge_ptep_get(ptep)))
3747 goto backout;
3748
3749 if (anon_rmap) {
3750 ClearPagePrivate(page);
3751 hugepage_add_new_anon_rmap(page, vma, address);
3752 } else
3753 page_dup_rmap(page, true);
3754 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
3755 && (vma->vm_flags & VM_SHARED)));
3756 set_huge_pte_at(mm, address, ptep, new_pte);
3757
3758 hugetlb_count_add(pages_per_huge_page(h), mm);
3759 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3760 /* Optimization, do the COW without a second fault */
3761 ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
3762 }
3763
3764 spin_unlock(ptl);
3765 unlock_page(page);
3766out:
3767 return ret;
3768
3769backout:
3770 spin_unlock(ptl);
3771backout_unlocked:
3772 unlock_page(page);
3773 restore_reserve_on_error(h, vma, address, page);
3774 put_page(page);
3775 goto out;
3776}
3777
3778#ifdef CONFIG_SMP
3779u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3780 struct vm_area_struct *vma,
3781 struct address_space *mapping,
3782 pgoff_t idx, unsigned long address)
3783{
3784 unsigned long key[2];
3785 u32 hash;
3786
3787 if (vma->vm_flags & VM_SHARED) {
3788 key[0] = (unsigned long) mapping;
3789 key[1] = idx;
3790 } else {
3791 key[0] = (unsigned long) mm;
3792 key[1] = address >> huge_page_shift(h);
3793 }
3794
3795 hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0);
3796
3797 return hash & (num_fault_mutexes - 1);
3798}
3799#else
3800/*
3801 * For uniprocesor systems we always use a single mutex, so just
3802 * return 0 and avoid the hashing overhead.
3803 */
3804u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3805 struct vm_area_struct *vma,
3806 struct address_space *mapping,
3807 pgoff_t idx, unsigned long address)
3808{
3809 return 0;
3810}
3811#endif
3812
3813int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3814 unsigned long address, unsigned int flags)
3815{
3816 pte_t *ptep, entry;
3817 spinlock_t *ptl;
3818 int ret;
3819 u32 hash;
3820 pgoff_t idx;
3821 struct page *page = NULL;
3822 struct page *pagecache_page = NULL;
3823 struct hstate *h = hstate_vma(vma);
3824 struct address_space *mapping;
3825 int need_wait_lock = 0;
3826
3827 address &= huge_page_mask(h);
3828
3829 ptep = huge_pte_offset(mm, address);
3830 if (ptep) {
3831 entry = huge_ptep_get(ptep);
3832 if (unlikely(is_hugetlb_entry_migration(entry))) {
3833 migration_entry_wait_huge(vma, mm, ptep);
3834 return 0;
3835 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
3836 return VM_FAULT_HWPOISON_LARGE |
3837 VM_FAULT_SET_HINDEX(hstate_index(h));
3838 } else {
3839 ptep = huge_pte_alloc(mm, address, huge_page_size(h));
3840 if (!ptep)
3841 return VM_FAULT_OOM;
3842 }
3843
3844 mapping = vma->vm_file->f_mapping;
3845 idx = vma_hugecache_offset(h, vma, address);
3846
3847 /*
3848 * Serialize hugepage allocation and instantiation, so that we don't
3849 * get spurious allocation failures if two CPUs race to instantiate
3850 * the same page in the page cache.
3851 */
3852 hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping, idx, address);
3853 mutex_lock(&hugetlb_fault_mutex_table[hash]);
3854
3855 entry = huge_ptep_get(ptep);
3856 if (huge_pte_none(entry)) {
3857 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3858 goto out_mutex;
3859 }
3860
3861 ret = 0;
3862
3863 /*
3864 * entry could be a migration/hwpoison entry at this point, so this
3865 * check prevents the kernel from going below assuming that we have
3866 * a active hugepage in pagecache. This goto expects the 2nd page fault,
3867 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
3868 * handle it.
3869 */
3870 if (!pte_present(entry))
3871 goto out_mutex;
3872
3873 /*
3874 * If we are going to COW the mapping later, we examine the pending
3875 * reservations for this page now. This will ensure that any
3876 * allocations necessary to record that reservation occur outside the
3877 * spinlock. For private mappings, we also lookup the pagecache
3878 * page now as it is used to determine if a reservation has been
3879 * consumed.
3880 */
3881 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3882 if (vma_needs_reservation(h, vma, address) < 0) {
3883 ret = VM_FAULT_OOM;
3884 goto out_mutex;
3885 }
3886 /* Just decrements count, does not deallocate */
3887 vma_end_reservation(h, vma, address);
3888
3889 if (!(vma->vm_flags & VM_MAYSHARE))
3890 pagecache_page = hugetlbfs_pagecache_page(h,
3891 vma, address);
3892 }
3893
3894 ptl = huge_pte_lock(h, mm, ptep);
3895
3896 /* Check for a racing update before calling hugetlb_cow */
3897 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
3898 goto out_ptl;
3899
3900 /*
3901 * hugetlb_cow() requires page locks of pte_page(entry) and
3902 * pagecache_page, so here we need take the former one
3903 * when page != pagecache_page or !pagecache_page.
3904 */
3905 page = pte_page(entry);
3906 if (page != pagecache_page)
3907 if (!trylock_page(page)) {
3908 need_wait_lock = 1;
3909 goto out_ptl;
3910 }
3911
3912 get_page(page);
3913
3914 if (flags & FAULT_FLAG_WRITE) {
3915 if (!huge_pte_write(entry)) {
3916 ret = hugetlb_cow(mm, vma, address, ptep,
3917 pagecache_page, ptl);
3918 goto out_put_page;
3919 }
3920 entry = huge_pte_mkdirty(entry);
3921 }
3922 entry = pte_mkyoung(entry);
3923 if (huge_ptep_set_access_flags(vma, address, ptep, entry,
3924 flags & FAULT_FLAG_WRITE))
3925 update_mmu_cache(vma, address, ptep);
3926out_put_page:
3927 if (page != pagecache_page)
3928 unlock_page(page);
3929 put_page(page);
3930out_ptl:
3931 spin_unlock(ptl);
3932
3933 if (pagecache_page) {
3934 unlock_page(pagecache_page);
3935 put_page(pagecache_page);
3936 }
3937out_mutex:
3938 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
3939 /*
3940 * Generally it's safe to hold refcount during waiting page lock. But
3941 * here we just wait to defer the next page fault to avoid busy loop and
3942 * the page is not used after unlocked before returning from the current
3943 * page fault. So we are safe from accessing freed page, even if we wait
3944 * here without taking refcount.
3945 */
3946 if (need_wait_lock)
3947 wait_on_page_locked(page);
3948 return ret;
3949}
3950
3951long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
3952 struct page **pages, struct vm_area_struct **vmas,
3953 unsigned long *position, unsigned long *nr_pages,
3954 long i, unsigned int flags)
3955{
3956 unsigned long pfn_offset;
3957 unsigned long vaddr = *position;
3958 unsigned long remainder = *nr_pages;
3959 struct hstate *h = hstate_vma(vma);
3960
3961 while (vaddr < vma->vm_end && remainder) {
3962 pte_t *pte;
3963 spinlock_t *ptl = NULL;
3964 int absent;
3965 struct page *page;
3966
3967 /*
3968 * If we have a pending SIGKILL, don't keep faulting pages and
3969 * potentially allocating memory.
3970 */
3971 if (unlikely(fatal_signal_pending(current))) {
3972 remainder = 0;
3973 break;
3974 }
3975
3976 /*
3977 * Some archs (sparc64, sh*) have multiple pte_ts to
3978 * each hugepage. We have to make sure we get the
3979 * first, for the page indexing below to work.
3980 *
3981 * Note that page table lock is not held when pte is null.
3982 */
3983 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
3984 if (pte)
3985 ptl = huge_pte_lock(h, mm, pte);
3986 absent = !pte || huge_pte_none(huge_ptep_get(pte));
3987
3988 /*
3989 * When coredumping, it suits get_dump_page if we just return
3990 * an error where there's an empty slot with no huge pagecache
3991 * to back it. This way, we avoid allocating a hugepage, and
3992 * the sparse dumpfile avoids allocating disk blocks, but its
3993 * huge holes still show up with zeroes where they need to be.
3994 */
3995 if (absent && (flags & FOLL_DUMP) &&
3996 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
3997 if (pte)
3998 spin_unlock(ptl);
3999 remainder = 0;
4000 break;
4001 }
4002
4003 /*
4004 * We need call hugetlb_fault for both hugepages under migration
4005 * (in which case hugetlb_fault waits for the migration,) and
4006 * hwpoisoned hugepages (in which case we need to prevent the
4007 * caller from accessing to them.) In order to do this, we use
4008 * here is_swap_pte instead of is_hugetlb_entry_migration and
4009 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
4010 * both cases, and because we can't follow correct pages
4011 * directly from any kind of swap entries.
4012 */
4013 if (absent || is_swap_pte(huge_ptep_get(pte)) ||
4014 ((flags & FOLL_WRITE) &&
4015 !huge_pte_write(huge_ptep_get(pte)))) {
4016 int ret;
4017
4018 if (pte)
4019 spin_unlock(ptl);
4020 ret = hugetlb_fault(mm, vma, vaddr,
4021 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
4022 if (!(ret & VM_FAULT_ERROR))
4023 continue;
4024
4025 remainder = 0;
4026 break;
4027 }
4028
4029 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4030 page = pte_page(huge_ptep_get(pte));
4031same_page:
4032 if (pages) {
4033 pages[i] = mem_map_offset(page, pfn_offset);
4034 get_page(pages[i]);
4035 }
4036
4037 if (vmas)
4038 vmas[i] = vma;
4039
4040 vaddr += PAGE_SIZE;
4041 ++pfn_offset;
4042 --remainder;
4043 ++i;
4044 if (vaddr < vma->vm_end && remainder &&
4045 pfn_offset < pages_per_huge_page(h)) {
4046 /*
4047 * We use pfn_offset to avoid touching the pageframes
4048 * of this compound page.
4049 */
4050 goto same_page;
4051 }
4052 spin_unlock(ptl);
4053 }
4054 *nr_pages = remainder;
4055 *position = vaddr;
4056
4057 return i ? i : -EFAULT;
4058}
4059
4060#ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
4061/*
4062 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
4063 * implement this.
4064 */
4065#define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
4066#endif
4067
4068unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
4069 unsigned long address, unsigned long end, pgprot_t newprot)
4070{
4071 struct mm_struct *mm = vma->vm_mm;
4072 unsigned long start = address;
4073 pte_t *ptep;
4074 pte_t pte;
4075 struct hstate *h = hstate_vma(vma);
4076 unsigned long pages = 0;
4077
4078 BUG_ON(address >= end);
4079 flush_cache_range(vma, address, end);
4080
4081 mmu_notifier_invalidate_range_start(mm, start, end);
4082 i_mmap_lock_write(vma->vm_file->f_mapping);
4083 for (; address < end; address += huge_page_size(h)) {
4084 spinlock_t *ptl;
4085 ptep = huge_pte_offset(mm, address);
4086 if (!ptep)
4087 continue;
4088 ptl = huge_pte_lock(h, mm, ptep);
4089 if (huge_pmd_unshare(mm, &address, ptep)) {
4090 pages++;
4091 spin_unlock(ptl);
4092 continue;
4093 }
4094 pte = huge_ptep_get(ptep);
4095 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
4096 spin_unlock(ptl);
4097 continue;
4098 }
4099 if (unlikely(is_hugetlb_entry_migration(pte))) {
4100 swp_entry_t entry = pte_to_swp_entry(pte);
4101
4102 if (is_write_migration_entry(entry)) {
4103 pte_t newpte;
4104
4105 make_migration_entry_read(&entry);
4106 newpte = swp_entry_to_pte(entry);
4107 set_huge_pte_at(mm, address, ptep, newpte);
4108 pages++;
4109 }
4110 spin_unlock(ptl);
4111 continue;
4112 }
4113 if (!huge_pte_none(pte)) {
4114 pte = huge_ptep_get_and_clear(mm, address, ptep);
4115 pte = pte_mkhuge(huge_pte_modify(pte, newprot));
4116 pte = arch_make_huge_pte(pte, vma, NULL, 0);
4117 set_huge_pte_at(mm, address, ptep, pte);
4118 pages++;
4119 }
4120 spin_unlock(ptl);
4121 }
4122 /*
4123 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4124 * may have cleared our pud entry and done put_page on the page table:
4125 * once we release i_mmap_rwsem, another task can do the final put_page
4126 * and that page table be reused and filled with junk.
4127 */
4128 flush_hugetlb_tlb_range(vma, start, end);
4129 mmu_notifier_invalidate_range(mm, start, end);
4130 i_mmap_unlock_write(vma->vm_file->f_mapping);
4131 mmu_notifier_invalidate_range_end(mm, start, end);
4132
4133 return pages << h->order;
4134}
4135
4136int hugetlb_reserve_pages(struct inode *inode,
4137 long from, long to,
4138 struct vm_area_struct *vma,
4139 vm_flags_t vm_flags)
4140{
4141 long ret, chg;
4142 struct hstate *h = hstate_inode(inode);
4143 struct hugepage_subpool *spool = subpool_inode(inode);
4144 struct resv_map *resv_map;
4145 long gbl_reserve;
4146
4147 /*
4148 * Only apply hugepage reservation if asked. At fault time, an
4149 * attempt will be made for VM_NORESERVE to allocate a page
4150 * without using reserves
4151 */
4152 if (vm_flags & VM_NORESERVE)
4153 return 0;
4154
4155 /*
4156 * Shared mappings base their reservation on the number of pages that
4157 * are already allocated on behalf of the file. Private mappings need
4158 * to reserve the full area even if read-only as mprotect() may be
4159 * called to make the mapping read-write. Assume !vma is a shm mapping
4160 */
4161 if (!vma || vma->vm_flags & VM_MAYSHARE) {
4162 resv_map = inode_resv_map(inode);
4163
4164 chg = region_chg(resv_map, from, to);
4165
4166 } else {
4167 resv_map = resv_map_alloc();
4168 if (!resv_map)
4169 return -ENOMEM;
4170
4171 chg = to - from;
4172
4173 set_vma_resv_map(vma, resv_map);
4174 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
4175 }
4176
4177 if (chg < 0) {
4178 ret = chg;
4179 goto out_err;
4180 }
4181
4182 /*
4183 * There must be enough pages in the subpool for the mapping. If
4184 * the subpool has a minimum size, there may be some global
4185 * reservations already in place (gbl_reserve).
4186 */
4187 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
4188 if (gbl_reserve < 0) {
4189 ret = -ENOSPC;
4190 goto out_err;
4191 }
4192
4193 /*
4194 * Check enough hugepages are available for the reservation.
4195 * Hand the pages back to the subpool if there are not
4196 */
4197 ret = hugetlb_acct_memory(h, gbl_reserve);
4198 if (ret < 0) {
4199 /* put back original number of pages, chg */
4200 (void)hugepage_subpool_put_pages(spool, chg);
4201 goto out_err;
4202 }
4203
4204 /*
4205 * Account for the reservations made. Shared mappings record regions
4206 * that have reservations as they are shared by multiple VMAs.
4207 * When the last VMA disappears, the region map says how much
4208 * the reservation was and the page cache tells how much of
4209 * the reservation was consumed. Private mappings are per-VMA and
4210 * only the consumed reservations are tracked. When the VMA
4211 * disappears, the original reservation is the VMA size and the
4212 * consumed reservations are stored in the map. Hence, nothing
4213 * else has to be done for private mappings here
4214 */
4215 if (!vma || vma->vm_flags & VM_MAYSHARE) {
4216 long add = region_add(resv_map, from, to);
4217
4218 if (unlikely(chg > add)) {
4219 /*
4220 * pages in this range were added to the reserve
4221 * map between region_chg and region_add. This
4222 * indicates a race with alloc_huge_page. Adjust
4223 * the subpool and reserve counts modified above
4224 * based on the difference.
4225 */
4226 long rsv_adjust;
4227
4228 rsv_adjust = hugepage_subpool_put_pages(spool,
4229 chg - add);
4230 hugetlb_acct_memory(h, -rsv_adjust);
4231 }
4232 }
4233 return 0;
4234out_err:
4235 if (!vma || vma->vm_flags & VM_MAYSHARE)
4236 region_abort(resv_map, from, to);
4237 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
4238 kref_put(&resv_map->refs, resv_map_release);
4239 return ret;
4240}
4241
4242long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
4243 long freed)
4244{
4245 struct hstate *h = hstate_inode(inode);
4246 struct resv_map *resv_map = inode_resv_map(inode);
4247 long chg = 0;
4248 struct hugepage_subpool *spool = subpool_inode(inode);
4249 long gbl_reserve;
4250
4251 if (resv_map) {
4252 chg = region_del(resv_map, start, end);
4253 /*
4254 * region_del() can fail in the rare case where a region
4255 * must be split and another region descriptor can not be
4256 * allocated. If end == LONG_MAX, it will not fail.
4257 */
4258 if (chg < 0)
4259 return chg;
4260 }
4261
4262 spin_lock(&inode->i_lock);
4263 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
4264 spin_unlock(&inode->i_lock);
4265
4266 /*
4267 * If the subpool has a minimum size, the number of global
4268 * reservations to be released may be adjusted.
4269 */
4270 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
4271 hugetlb_acct_memory(h, -gbl_reserve);
4272
4273 return 0;
4274}
4275
4276#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
4277static unsigned long page_table_shareable(struct vm_area_struct *svma,
4278 struct vm_area_struct *vma,
4279 unsigned long addr, pgoff_t idx)
4280{
4281 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
4282 svma->vm_start;
4283 unsigned long sbase = saddr & PUD_MASK;
4284 unsigned long s_end = sbase + PUD_SIZE;
4285
4286 /* Allow segments to share if only one is marked locked */
4287 unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
4288 unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
4289
4290 /*
4291 * match the virtual addresses, permission and the alignment of the
4292 * page table page.
4293 */
4294 if (pmd_index(addr) != pmd_index(saddr) ||
4295 vm_flags != svm_flags ||
4296 sbase < svma->vm_start || svma->vm_end < s_end)
4297 return 0;
4298
4299 return saddr;
4300}
4301
4302static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
4303{
4304 unsigned long base = addr & PUD_MASK;
4305 unsigned long end = base + PUD_SIZE;
4306
4307 /*
4308 * check on proper vm_flags and page table alignment
4309 */
4310 if (vma->vm_flags & VM_MAYSHARE &&
4311 vma->vm_start <= base && end <= vma->vm_end)
4312 return true;
4313 return false;
4314}
4315
4316/*
4317 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
4318 * and returns the corresponding pte. While this is not necessary for the
4319 * !shared pmd case because we can allocate the pmd later as well, it makes the
4320 * code much cleaner. pmd allocation is essential for the shared case because
4321 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4322 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
4323 * bad pmd for sharing.
4324 */
4325pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
4326{
4327 struct vm_area_struct *vma = find_vma(mm, addr);
4328 struct address_space *mapping = vma->vm_file->f_mapping;
4329 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
4330 vma->vm_pgoff;
4331 struct vm_area_struct *svma;
4332 unsigned long saddr;
4333 pte_t *spte = NULL;
4334 pte_t *pte;
4335 spinlock_t *ptl;
4336
4337 if (!vma_shareable(vma, addr))
4338 return (pte_t *)pmd_alloc(mm, pud, addr);
4339
4340 i_mmap_lock_write(mapping);
4341 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
4342 if (svma == vma)
4343 continue;
4344
4345 saddr = page_table_shareable(svma, vma, addr, idx);
4346 if (saddr) {
4347 spte = huge_pte_offset(svma->vm_mm, saddr);
4348 if (spte) {
4349 get_page(virt_to_page(spte));
4350 break;
4351 }
4352 }
4353 }
4354
4355 if (!spte)
4356 goto out;
4357
4358 ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
4359 if (pud_none(*pud)) {
4360 pud_populate(mm, pud,
4361 (pmd_t *)((unsigned long)spte & PAGE_MASK));
4362 mm_inc_nr_pmds(mm);
4363 } else {
4364 put_page(virt_to_page(spte));
4365 }
4366 spin_unlock(ptl);
4367out:
4368 pte = (pte_t *)pmd_alloc(mm, pud, addr);
4369 i_mmap_unlock_write(mapping);
4370 return pte;
4371}
4372
4373/*
4374 * unmap huge page backed by shared pte.
4375 *
4376 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
4377 * indicated by page_count > 1, unmap is achieved by clearing pud and
4378 * decrementing the ref count. If count == 1, the pte page is not shared.
4379 *
4380 * called with page table lock held.
4381 *
4382 * returns: 1 successfully unmapped a shared pte page
4383 * 0 the underlying pte page is not shared, or it is the last user
4384 */
4385int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
4386{
4387 pgd_t *pgd = pgd_offset(mm, *addr);
4388 pud_t *pud = pud_offset(pgd, *addr);
4389
4390 BUG_ON(page_count(virt_to_page(ptep)) == 0);
4391 if (page_count(virt_to_page(ptep)) == 1)
4392 return 0;
4393
4394 pud_clear(pud);
4395 put_page(virt_to_page(ptep));
4396 mm_dec_nr_pmds(mm);
4397 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
4398 return 1;
4399}
4400#define want_pmd_share() (1)
4401#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4402pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
4403{
4404 return NULL;
4405}
4406
4407int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
4408{
4409 return 0;
4410}
4411#define want_pmd_share() (0)
4412#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
4413
4414#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
4415pte_t *huge_pte_alloc(struct mm_struct *mm,
4416 unsigned long addr, unsigned long sz)
4417{
4418 pgd_t *pgd;
4419 pud_t *pud;
4420 pte_t *pte = NULL;
4421
4422 pgd = pgd_offset(mm, addr);
4423 pud = pud_alloc(mm, pgd, addr);
4424 if (pud) {
4425 if (sz == PUD_SIZE) {
4426 pte = (pte_t *)pud;
4427 } else {
4428 BUG_ON(sz != PMD_SIZE);
4429 if (want_pmd_share() && pud_none(*pud))
4430 pte = huge_pmd_share(mm, addr, pud);
4431 else
4432 pte = (pte_t *)pmd_alloc(mm, pud, addr);
4433 }
4434 }
4435 BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
4436
4437 return pte;
4438}
4439
4440pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
4441{
4442 pgd_t *pgd;
4443 pud_t *pud;
4444 pmd_t *pmd = NULL;
4445
4446 pgd = pgd_offset(mm, addr);
4447 if (pgd_present(*pgd)) {
4448 pud = pud_offset(pgd, addr);
4449 if (pud_present(*pud)) {
4450 if (pud_huge(*pud))
4451 return (pte_t *)pud;
4452 pmd = pmd_offset(pud, addr);
4453 }
4454 }
4455 return (pte_t *) pmd;
4456}
4457
4458#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
4459
4460/*
4461 * These functions are overwritable if your architecture needs its own
4462 * behavior.
4463 */
4464struct page * __weak
4465follow_huge_addr(struct mm_struct *mm, unsigned long address,
4466 int write)
4467{
4468 return ERR_PTR(-EINVAL);
4469}
4470
4471struct page * __weak
4472follow_huge_pmd(struct mm_struct *mm, unsigned long address,
4473 pmd_t *pmd, int flags)
4474{
4475 struct page *page = NULL;
4476 spinlock_t *ptl;
4477 pte_t pte;
4478retry:
4479 ptl = pmd_lockptr(mm, pmd);
4480 spin_lock(ptl);
4481 /*
4482 * make sure that the address range covered by this pmd is not
4483 * unmapped from other threads.
4484 */
4485 if (!pmd_huge(*pmd))
4486 goto out;
4487 pte = huge_ptep_get((pte_t *)pmd);
4488 if (pte_present(pte)) {
4489 page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
4490 if (flags & FOLL_GET)
4491 get_page(page);
4492 } else {
4493 if (is_hugetlb_entry_migration(pte)) {
4494 spin_unlock(ptl);
4495 __migration_entry_wait(mm, (pte_t *)pmd, ptl);
4496 goto retry;
4497 }
4498 /*
4499 * hwpoisoned entry is treated as no_page_table in
4500 * follow_page_mask().
4501 */
4502 }
4503out:
4504 spin_unlock(ptl);
4505 return page;
4506}
4507
4508struct page * __weak
4509follow_huge_pud(struct mm_struct *mm, unsigned long address,
4510 pud_t *pud, int flags)
4511{
4512 if (flags & FOLL_GET)
4513 return NULL;
4514
4515 return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
4516}
4517
4518#ifdef CONFIG_MEMORY_FAILURE
4519
4520/*
4521 * This function is called from memory failure code.
4522 */
4523int dequeue_hwpoisoned_huge_page(struct page *hpage)
4524{
4525 struct hstate *h = page_hstate(hpage);
4526 int nid = page_to_nid(hpage);
4527 int ret = -EBUSY;
4528
4529 spin_lock(&hugetlb_lock);
4530 /*
4531 * Just checking !page_huge_active is not enough, because that could be
4532 * an isolated/hwpoisoned hugepage (which have >0 refcount).
4533 */
4534 if (!page_huge_active(hpage) && !page_count(hpage)) {
4535 /*
4536 * Hwpoisoned hugepage isn't linked to activelist or freelist,
4537 * but dangling hpage->lru can trigger list-debug warnings
4538 * (this happens when we call unpoison_memory() on it),
4539 * so let it point to itself with list_del_init().
4540 */
4541 list_del_init(&hpage->lru);
4542 set_page_refcounted(hpage);
4543 h->free_huge_pages--;
4544 h->free_huge_pages_node[nid]--;
4545 ret = 0;
4546 }
4547 spin_unlock(&hugetlb_lock);
4548 return ret;
4549}
4550#endif
4551
4552bool isolate_huge_page(struct page *page, struct list_head *list)
4553{
4554 bool ret = true;
4555
4556 VM_BUG_ON_PAGE(!PageHead(page), page);
4557 spin_lock(&hugetlb_lock);
4558 if (!page_huge_active(page) || !get_page_unless_zero(page)) {
4559 ret = false;
4560 goto unlock;
4561 }
4562 clear_page_huge_active(page);
4563 list_move_tail(&page->lru, list);
4564unlock:
4565 spin_unlock(&hugetlb_lock);
4566 return ret;
4567}
4568
4569void putback_active_hugepage(struct page *page)
4570{
4571 VM_BUG_ON_PAGE(!PageHead(page), page);
4572 spin_lock(&hugetlb_lock);
4573 set_page_huge_active(page);
4574 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
4575 spin_unlock(&hugetlb_lock);
4576 put_page(page);
4577}