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/memblock.h> |
19 | #include <linux/sysfs.h> |
20 | #include <linux/slab.h> |
21 | #include <linux/mmdebug.h> |
22 | #include <linux/sched/signal.h> |
23 | #include <linux/rmap.h> |
24 | #include <linux/string_helpers.h> |
25 | #include <linux/swap.h> |
26 | #include <linux/swapops.h> |
27 | #include <linux/jhash.h> |
28 | #include <linux/numa.h> |
29 | |
30 | #include <asm/page.h> |
31 | #include <asm/pgtable.h> |
32 | #include <asm/tlb.h> |
33 | |
34 | #include <linux/io.h> |
35 | #include <linux/hugetlb.h> |
36 | #include <linux/hugetlb_cgroup.h> |
37 | #include <linux/node.h> |
38 | #include <linux/userfaultfd_k.h> |
39 | #include <linux/page_owner.h> |
40 | #include "internal.h" |
41 | |
42 | int hugetlb_max_hstate __read_mostly; |
43 | unsigned int default_hstate_idx; |
44 | struct hstate hstates[HUGE_MAX_HSTATE]; |
45 | /* |
46 | * Minimum page order among possible hugepage sizes, set to a proper value |
47 | * at boot time. |
48 | */ |
49 | static unsigned int minimum_order __read_mostly = UINT_MAX; |
50 | |
51 | __initdata LIST_HEAD(huge_boot_pages); |
52 | |
53 | /* for command line parsing */ |
54 | static struct hstate * __initdata parsed_hstate; |
55 | static unsigned long __initdata default_hstate_max_huge_pages; |
56 | static unsigned long __initdata default_hstate_size; |
57 | static bool __initdata parsed_valid_hugepagesz = true; |
58 | |
59 | /* |
60 | * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages, |
61 | * free_huge_pages, and surplus_huge_pages. |
62 | */ |
63 | DEFINE_SPINLOCK(hugetlb_lock); |
64 | |
65 | /* |
66 | * Serializes faults on the same logical page. This is used to |
67 | * prevent spurious OOMs when the hugepage pool is fully utilized. |
68 | */ |
69 | static int num_fault_mutexes; |
70 | struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp; |
71 | |
72 | /* Forward declaration */ |
73 | static int hugetlb_acct_memory(struct hstate *h, long delta); |
74 | |
75 | static inline void unlock_or_release_subpool(struct hugepage_subpool *spool) |
76 | { |
77 | bool free = (spool->count == 0) && (spool->used_hpages == 0); |
78 | |
79 | spin_unlock(&spool->lock); |
80 | |
81 | /* If no pages are used, and no other handles to the subpool |
82 | * remain, give up any reservations mased on minimum size and |
83 | * free the subpool */ |
84 | if (free) { |
85 | if (spool->min_hpages != -1) |
86 | hugetlb_acct_memory(spool->hstate, |
87 | -spool->min_hpages); |
88 | kfree(spool); |
89 | } |
90 | } |
91 | |
92 | struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages, |
93 | long min_hpages) |
94 | { |
95 | struct hugepage_subpool *spool; |
96 | |
97 | spool = kzalloc(sizeof(*spool), GFP_KERNEL); |
98 | if (!spool) |
99 | return NULL; |
100 | |
101 | spin_lock_init(&spool->lock); |
102 | spool->count = 1; |
103 | spool->max_hpages = max_hpages; |
104 | spool->hstate = h; |
105 | spool->min_hpages = min_hpages; |
106 | |
107 | if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) { |
108 | kfree(spool); |
109 | return NULL; |
110 | } |
111 | spool->rsv_hpages = min_hpages; |
112 | |
113 | return spool; |
114 | } |
115 | |
116 | void hugepage_put_subpool(struct hugepage_subpool *spool) |
117 | { |
118 | spin_lock(&spool->lock); |
119 | BUG_ON(!spool->count); |
120 | spool->count--; |
121 | unlock_or_release_subpool(spool); |
122 | } |
123 | |
124 | /* |
125 | * Subpool accounting for allocating and reserving pages. |
126 | * Return -ENOMEM if there are not enough resources to satisfy the |
127 | * the request. Otherwise, return the number of pages by which the |
128 | * global pools must be adjusted (upward). The returned value may |
129 | * only be different than the passed value (delta) in the case where |
130 | * a subpool minimum size must be manitained. |
131 | */ |
132 | static long hugepage_subpool_get_pages(struct hugepage_subpool *spool, |
133 | long delta) |
134 | { |
135 | long ret = delta; |
136 | |
137 | if (!spool) |
138 | return ret; |
139 | |
140 | spin_lock(&spool->lock); |
141 | |
142 | if (spool->max_hpages != -1) { /* maximum size accounting */ |
143 | if ((spool->used_hpages + delta) <= spool->max_hpages) |
144 | spool->used_hpages += delta; |
145 | else { |
146 | ret = -ENOMEM; |
147 | goto unlock_ret; |
148 | } |
149 | } |
150 | |
151 | /* minimum size accounting */ |
152 | if (spool->min_hpages != -1 && spool->rsv_hpages) { |
153 | if (delta > spool->rsv_hpages) { |
154 | /* |
155 | * Asking for more reserves than those already taken on |
156 | * behalf of subpool. Return difference. |
157 | */ |
158 | ret = delta - spool->rsv_hpages; |
159 | spool->rsv_hpages = 0; |
160 | } else { |
161 | ret = 0; /* reserves already accounted for */ |
162 | spool->rsv_hpages -= delta; |
163 | } |
164 | } |
165 | |
166 | unlock_ret: |
167 | spin_unlock(&spool->lock); |
168 | return ret; |
169 | } |
170 | |
171 | /* |
172 | * Subpool accounting for freeing and unreserving pages. |
173 | * Return the number of global page reservations that must be dropped. |
174 | * The return value may only be different than the passed value (delta) |
175 | * in the case where a subpool minimum size must be maintained. |
176 | */ |
177 | static long hugepage_subpool_put_pages(struct hugepage_subpool *spool, |
178 | long delta) |
179 | { |
180 | long ret = delta; |
181 | |
182 | if (!spool) |
183 | return delta; |
184 | |
185 | spin_lock(&spool->lock); |
186 | |
187 | if (spool->max_hpages != -1) /* maximum size accounting */ |
188 | spool->used_hpages -= delta; |
189 | |
190 | /* minimum size accounting */ |
191 | if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) { |
192 | if (spool->rsv_hpages + delta <= spool->min_hpages) |
193 | ret = 0; |
194 | else |
195 | ret = spool->rsv_hpages + delta - spool->min_hpages; |
196 | |
197 | spool->rsv_hpages += delta; |
198 | if (spool->rsv_hpages > spool->min_hpages) |
199 | spool->rsv_hpages = spool->min_hpages; |
200 | } |
201 | |
202 | /* |
203 | * If hugetlbfs_put_super couldn't free spool due to an outstanding |
204 | * quota reference, free it now. |
205 | */ |
206 | unlock_or_release_subpool(spool); |
207 | |
208 | return ret; |
209 | } |
210 | |
211 | static inline struct hugepage_subpool *subpool_inode(struct inode *inode) |
212 | { |
213 | return HUGETLBFS_SB(inode->i_sb)->spool; |
214 | } |
215 | |
216 | static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma) |
217 | { |
218 | return subpool_inode(file_inode(vma->vm_file)); |
219 | } |
220 | |
221 | /* |
222 | * Region tracking -- allows tracking of reservations and instantiated pages |
223 | * across the pages in a mapping. |
224 | * |
225 | * The region data structures are embedded into a resv_map and protected |
226 | * by a resv_map's lock. The set of regions within the resv_map represent |
227 | * reservations for huge pages, or huge pages that have already been |
228 | * instantiated within the map. The from and to elements are huge page |
229 | * indicies into the associated mapping. from indicates the starting index |
230 | * of the region. to represents the first index past the end of the region. |
231 | * |
232 | * For example, a file region structure with from == 0 and to == 4 represents |
233 | * four huge pages in a mapping. It is important to note that the to element |
234 | * represents the first element past the end of the region. This is used in |
235 | * arithmetic as 4(to) - 0(from) = 4 huge pages in the region. |
236 | * |
237 | * Interval notation of the form [from, to) will be used to indicate that |
238 | * the endpoint from is inclusive and to is exclusive. |
239 | */ |
240 | struct file_region { |
241 | struct list_head link; |
242 | long from; |
243 | long to; |
244 | }; |
245 | |
246 | /* |
247 | * Add the huge page range represented by [f, t) to the reserve |
248 | * map. In the normal case, existing regions will be expanded |
249 | * to accommodate the specified range. Sufficient regions should |
250 | * exist for expansion due to the previous call to region_chg |
251 | * with the same range. However, it is possible that region_del |
252 | * could have been called after region_chg and modifed the map |
253 | * in such a way that no region exists to be expanded. In this |
254 | * case, pull a region descriptor from the cache associated with |
255 | * the map and use that for the new range. |
256 | * |
257 | * Return the number of new huge pages added to the map. This |
258 | * number is greater than or equal to zero. |
259 | */ |
260 | static long region_add(struct resv_map *resv, long f, long t) |
261 | { |
262 | struct list_head *head = &resv->regions; |
263 | struct file_region *rg, *nrg, *trg; |
264 | long add = 0; |
265 | |
266 | spin_lock(&resv->lock); |
267 | /* Locate the region we are either in or before. */ |
268 | list_for_each_entry(rg, head, link) |
269 | if (f <= rg->to) |
270 | break; |
271 | |
272 | /* |
273 | * If no region exists which can be expanded to include the |
274 | * specified range, the list must have been modified by an |
275 | * interleving call to region_del(). Pull a region descriptor |
276 | * from the cache and use it for this range. |
277 | */ |
278 | if (&rg->link == head || t < rg->from) { |
279 | VM_BUG_ON(resv->region_cache_count <= 0); |
280 | |
281 | resv->region_cache_count--; |
282 | nrg = list_first_entry(&resv->region_cache, struct file_region, |
283 | link); |
284 | list_del(&nrg->link); |
285 | |
286 | nrg->from = f; |
287 | nrg->to = t; |
288 | list_add(&nrg->link, rg->link.prev); |
289 | |
290 | add += t - f; |
291 | goto out_locked; |
292 | } |
293 | |
294 | /* Round our left edge to the current segment if it encloses us. */ |
295 | if (f > rg->from) |
296 | f = rg->from; |
297 | |
298 | /* Check for and consume any regions we now overlap with. */ |
299 | nrg = rg; |
300 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { |
301 | if (&rg->link == head) |
302 | break; |
303 | if (rg->from > t) |
304 | break; |
305 | |
306 | /* If this area reaches higher then extend our area to |
307 | * include it completely. If this is not the first area |
308 | * which we intend to reuse, free it. */ |
309 | if (rg->to > t) |
310 | t = rg->to; |
311 | if (rg != nrg) { |
312 | /* Decrement return value by the deleted range. |
313 | * Another range will span this area so that by |
314 | * end of routine add will be >= zero |
315 | */ |
316 | add -= (rg->to - rg->from); |
317 | list_del(&rg->link); |
318 | kfree(rg); |
319 | } |
320 | } |
321 | |
322 | add += (nrg->from - f); /* Added to beginning of region */ |
323 | nrg->from = f; |
324 | add += t - nrg->to; /* Added to end of region */ |
325 | nrg->to = t; |
326 | |
327 | out_locked: |
328 | resv->adds_in_progress--; |
329 | spin_unlock(&resv->lock); |
330 | VM_BUG_ON(add < 0); |
331 | return add; |
332 | } |
333 | |
334 | /* |
335 | * Examine the existing reserve map and determine how many |
336 | * huge pages in the specified range [f, t) are NOT currently |
337 | * represented. This routine is called before a subsequent |
338 | * call to region_add that will actually modify the reserve |
339 | * map to add the specified range [f, t). region_chg does |
340 | * not change the number of huge pages represented by the |
341 | * map. However, if the existing regions in the map can not |
342 | * be expanded to represent the new range, a new file_region |
343 | * structure is added to the map as a placeholder. This is |
344 | * so that the subsequent region_add call will have all the |
345 | * regions it needs and will not fail. |
346 | * |
347 | * Upon entry, region_chg will also examine the cache of region descriptors |
348 | * associated with the map. If there are not enough descriptors cached, one |
349 | * will be allocated for the in progress add operation. |
350 | * |
351 | * Returns the number of huge pages that need to be added to the existing |
352 | * reservation map for the range [f, t). This number is greater or equal to |
353 | * zero. -ENOMEM is returned if a new file_region structure or cache entry |
354 | * is needed and can not be allocated. |
355 | */ |
356 | static long region_chg(struct resv_map *resv, long f, long t) |
357 | { |
358 | struct list_head *head = &resv->regions; |
359 | struct file_region *rg, *nrg = NULL; |
360 | long chg = 0; |
361 | |
362 | retry: |
363 | spin_lock(&resv->lock); |
364 | retry_locked: |
365 | resv->adds_in_progress++; |
366 | |
367 | /* |
368 | * Check for sufficient descriptors in the cache to accommodate |
369 | * the number of in progress add operations. |
370 | */ |
371 | if (resv->adds_in_progress > resv->region_cache_count) { |
372 | struct file_region *trg; |
373 | |
374 | VM_BUG_ON(resv->adds_in_progress - resv->region_cache_count > 1); |
375 | /* Must drop lock to allocate a new descriptor. */ |
376 | resv->adds_in_progress--; |
377 | spin_unlock(&resv->lock); |
378 | |
379 | trg = kmalloc(sizeof(*trg), GFP_KERNEL); |
380 | if (!trg) { |
381 | kfree(nrg); |
382 | return -ENOMEM; |
383 | } |
384 | |
385 | spin_lock(&resv->lock); |
386 | list_add(&trg->link, &resv->region_cache); |
387 | resv->region_cache_count++; |
388 | goto retry_locked; |
389 | } |
390 | |
391 | /* Locate the region we are before or in. */ |
392 | list_for_each_entry(rg, head, link) |
393 | if (f <= rg->to) |
394 | break; |
395 | |
396 | /* If we are below the current region then a new region is required. |
397 | * Subtle, allocate a new region at the position but make it zero |
398 | * size such that we can guarantee to record the reservation. */ |
399 | if (&rg->link == head || t < rg->from) { |
400 | if (!nrg) { |
401 | resv->adds_in_progress--; |
402 | spin_unlock(&resv->lock); |
403 | nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); |
404 | if (!nrg) |
405 | return -ENOMEM; |
406 | |
407 | nrg->from = f; |
408 | nrg->to = f; |
409 | INIT_LIST_HEAD(&nrg->link); |
410 | goto retry; |
411 | } |
412 | |
413 | list_add(&nrg->link, rg->link.prev); |
414 | chg = t - f; |
415 | goto out_nrg; |
416 | } |
417 | |
418 | /* Round our left edge to the current segment if it encloses us. */ |
419 | if (f > rg->from) |
420 | f = rg->from; |
421 | chg = t - f; |
422 | |
423 | /* Check for and consume any regions we now overlap with. */ |
424 | list_for_each_entry(rg, rg->link.prev, link) { |
425 | if (&rg->link == head) |
426 | break; |
427 | if (rg->from > t) |
428 | goto out; |
429 | |
430 | /* We overlap with this area, if it extends further than |
431 | * us then we must extend ourselves. Account for its |
432 | * existing reservation. */ |
433 | if (rg->to > t) { |
434 | chg += rg->to - t; |
435 | t = rg->to; |
436 | } |
437 | chg -= rg->to - rg->from; |
438 | } |
439 | |
440 | out: |
441 | spin_unlock(&resv->lock); |
442 | /* We already know we raced and no longer need the new region */ |
443 | kfree(nrg); |
444 | return chg; |
445 | out_nrg: |
446 | spin_unlock(&resv->lock); |
447 | return chg; |
448 | } |
449 | |
450 | /* |
451 | * Abort the in progress add operation. The adds_in_progress field |
452 | * of the resv_map keeps track of the operations in progress between |
453 | * calls to region_chg and region_add. Operations are sometimes |
454 | * aborted after the call to region_chg. In such cases, region_abort |
455 | * is called to decrement the adds_in_progress counter. |
456 | * |
457 | * NOTE: The range arguments [f, t) are not needed or used in this |
458 | * routine. They are kept to make reading the calling code easier as |
459 | * arguments will match the associated region_chg call. |
460 | */ |
461 | static void region_abort(struct resv_map *resv, long f, long t) |
462 | { |
463 | spin_lock(&resv->lock); |
464 | VM_BUG_ON(!resv->region_cache_count); |
465 | resv->adds_in_progress--; |
466 | spin_unlock(&resv->lock); |
467 | } |
468 | |
469 | /* |
470 | * Delete the specified range [f, t) from the reserve map. If the |
471 | * t parameter is LONG_MAX, this indicates that ALL regions after f |
472 | * should be deleted. Locate the regions which intersect [f, t) |
473 | * and either trim, delete or split the existing regions. |
474 | * |
475 | * Returns the number of huge pages deleted from the reserve map. |
476 | * In the normal case, the return value is zero or more. In the |
477 | * case where a region must be split, a new region descriptor must |
478 | * be allocated. If the allocation fails, -ENOMEM will be returned. |
479 | * NOTE: If the parameter t == LONG_MAX, then we will never split |
480 | * a region and possibly return -ENOMEM. Callers specifying |
481 | * t == LONG_MAX do not need to check for -ENOMEM error. |
482 | */ |
483 | static long region_del(struct resv_map *resv, long f, long t) |
484 | { |
485 | struct list_head *head = &resv->regions; |
486 | struct file_region *rg, *trg; |
487 | struct file_region *nrg = NULL; |
488 | long del = 0; |
489 | |
490 | retry: |
491 | spin_lock(&resv->lock); |
492 | list_for_each_entry_safe(rg, trg, head, link) { |
493 | /* |
494 | * Skip regions before the range to be deleted. file_region |
495 | * ranges are normally of the form [from, to). However, there |
496 | * may be a "placeholder" entry in the map which is of the form |
497 | * (from, to) with from == to. Check for placeholder entries |
498 | * at the beginning of the range to be deleted. |
499 | */ |
500 | if (rg->to <= f && (rg->to != rg->from || rg->to != f)) |
501 | continue; |
502 | |
503 | if (rg->from >= t) |
504 | break; |
505 | |
506 | if (f > rg->from && t < rg->to) { /* Must split region */ |
507 | /* |
508 | * Check for an entry in the cache before dropping |
509 | * lock and attempting allocation. |
510 | */ |
511 | if (!nrg && |
512 | resv->region_cache_count > resv->adds_in_progress) { |
513 | nrg = list_first_entry(&resv->region_cache, |
514 | struct file_region, |
515 | link); |
516 | list_del(&nrg->link); |
517 | resv->region_cache_count--; |
518 | } |
519 | |
520 | if (!nrg) { |
521 | spin_unlock(&resv->lock); |
522 | nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); |
523 | if (!nrg) |
524 | return -ENOMEM; |
525 | goto retry; |
526 | } |
527 | |
528 | del += t - f; |
529 | |
530 | /* New entry for end of split region */ |
531 | nrg->from = t; |
532 | nrg->to = rg->to; |
533 | INIT_LIST_HEAD(&nrg->link); |
534 | |
535 | /* Original entry is trimmed */ |
536 | rg->to = f; |
537 | |
538 | list_add(&nrg->link, &rg->link); |
539 | nrg = NULL; |
540 | break; |
541 | } |
542 | |
543 | if (f <= rg->from && t >= rg->to) { /* Remove entire region */ |
544 | del += rg->to - rg->from; |
545 | list_del(&rg->link); |
546 | kfree(rg); |
547 | continue; |
548 | } |
549 | |
550 | if (f <= rg->from) { /* Trim beginning of region */ |
551 | del += t - rg->from; |
552 | rg->from = t; |
553 | } else { /* Trim end of region */ |
554 | del += rg->to - f; |
555 | rg->to = f; |
556 | } |
557 | } |
558 | |
559 | spin_unlock(&resv->lock); |
560 | kfree(nrg); |
561 | return del; |
562 | } |
563 | |
564 | /* |
565 | * A rare out of memory error was encountered which prevented removal of |
566 | * the reserve map region for a page. The huge page itself was free'ed |
567 | * and removed from the page cache. This routine will adjust the subpool |
568 | * usage count, and the global reserve count if needed. By incrementing |
569 | * these counts, the reserve map entry which could not be deleted will |
570 | * appear as a "reserved" entry instead of simply dangling with incorrect |
571 | * counts. |
572 | */ |
573 | void hugetlb_fix_reserve_counts(struct inode *inode) |
574 | { |
575 | struct hugepage_subpool *spool = subpool_inode(inode); |
576 | long rsv_adjust; |
577 | |
578 | rsv_adjust = hugepage_subpool_get_pages(spool, 1); |
579 | if (rsv_adjust) { |
580 | struct hstate *h = hstate_inode(inode); |
581 | |
582 | hugetlb_acct_memory(h, 1); |
583 | } |
584 | } |
585 | |
586 | /* |
587 | * Count and return the number of huge pages in the reserve map |
588 | * that intersect with the range [f, t). |
589 | */ |
590 | static long region_count(struct resv_map *resv, long f, long t) |
591 | { |
592 | struct list_head *head = &resv->regions; |
593 | struct file_region *rg; |
594 | long chg = 0; |
595 | |
596 | spin_lock(&resv->lock); |
597 | /* Locate each segment we overlap with, and count that overlap. */ |
598 | list_for_each_entry(rg, head, link) { |
599 | long seg_from; |
600 | long seg_to; |
601 | |
602 | if (rg->to <= f) |
603 | continue; |
604 | if (rg->from >= t) |
605 | break; |
606 | |
607 | seg_from = max(rg->from, f); |
608 | seg_to = min(rg->to, t); |
609 | |
610 | chg += seg_to - seg_from; |
611 | } |
612 | spin_unlock(&resv->lock); |
613 | |
614 | return chg; |
615 | } |
616 | |
617 | /* |
618 | * Convert the address within this vma to the page offset within |
619 | * the mapping, in pagecache page units; huge pages here. |
620 | */ |
621 | static pgoff_t vma_hugecache_offset(struct hstate *h, |
622 | struct vm_area_struct *vma, unsigned long address) |
623 | { |
624 | return ((address - vma->vm_start) >> huge_page_shift(h)) + |
625 | (vma->vm_pgoff >> huge_page_order(h)); |
626 | } |
627 | |
628 | pgoff_t linear_hugepage_index(struct vm_area_struct *vma, |
629 | unsigned long address) |
630 | { |
631 | return vma_hugecache_offset(hstate_vma(vma), vma, address); |
632 | } |
633 | EXPORT_SYMBOL_GPL(linear_hugepage_index); |
634 | |
635 | /* |
636 | * Return the size of the pages allocated when backing a VMA. In the majority |
637 | * cases this will be same size as used by the page table entries. |
638 | */ |
639 | unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) |
640 | { |
641 | if (vma->vm_ops && vma->vm_ops->pagesize) |
642 | return vma->vm_ops->pagesize(vma); |
643 | return PAGE_SIZE; |
644 | } |
645 | EXPORT_SYMBOL_GPL(vma_kernel_pagesize); |
646 | |
647 | /* |
648 | * Return the page size being used by the MMU to back a VMA. In the majority |
649 | * of cases, the page size used by the kernel matches the MMU size. On |
650 | * architectures where it differs, an architecture-specific 'strong' |
651 | * version of this symbol is required. |
652 | */ |
653 | __weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) |
654 | { |
655 | return vma_kernel_pagesize(vma); |
656 | } |
657 | |
658 | /* |
659 | * Flags for MAP_PRIVATE reservations. These are stored in the bottom |
660 | * bits of the reservation map pointer, which are always clear due to |
661 | * alignment. |
662 | */ |
663 | #define HPAGE_RESV_OWNER (1UL << 0) |
664 | #define HPAGE_RESV_UNMAPPED (1UL << 1) |
665 | #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) |
666 | |
667 | /* |
668 | * These helpers are used to track how many pages are reserved for |
669 | * faults in a MAP_PRIVATE mapping. Only the process that called mmap() |
670 | * is guaranteed to have their future faults succeed. |
671 | * |
672 | * With the exception of reset_vma_resv_huge_pages() which is called at fork(), |
673 | * the reserve counters are updated with the hugetlb_lock held. It is safe |
674 | * to reset the VMA at fork() time as it is not in use yet and there is no |
675 | * chance of the global counters getting corrupted as a result of the values. |
676 | * |
677 | * The private mapping reservation is represented in a subtly different |
678 | * manner to a shared mapping. A shared mapping has a region map associated |
679 | * with the underlying file, this region map represents the backing file |
680 | * pages which have ever had a reservation assigned which this persists even |
681 | * after the page is instantiated. A private mapping has a region map |
682 | * associated with the original mmap which is attached to all VMAs which |
683 | * reference it, this region map represents those offsets which have consumed |
684 | * reservation ie. where pages have been instantiated. |
685 | */ |
686 | static unsigned long get_vma_private_data(struct vm_area_struct *vma) |
687 | { |
688 | return (unsigned long)vma->vm_private_data; |
689 | } |
690 | |
691 | static void set_vma_private_data(struct vm_area_struct *vma, |
692 | unsigned long value) |
693 | { |
694 | vma->vm_private_data = (void *)value; |
695 | } |
696 | |
697 | struct resv_map *resv_map_alloc(void) |
698 | { |
699 | struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); |
700 | struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL); |
701 | |
702 | if (!resv_map || !rg) { |
703 | kfree(resv_map); |
704 | kfree(rg); |
705 | return NULL; |
706 | } |
707 | |
708 | kref_init(&resv_map->refs); |
709 | spin_lock_init(&resv_map->lock); |
710 | INIT_LIST_HEAD(&resv_map->regions); |
711 | |
712 | resv_map->adds_in_progress = 0; |
713 | |
714 | INIT_LIST_HEAD(&resv_map->region_cache); |
715 | list_add(&rg->link, &resv_map->region_cache); |
716 | resv_map->region_cache_count = 1; |
717 | |
718 | return resv_map; |
719 | } |
720 | |
721 | void resv_map_release(struct kref *ref) |
722 | { |
723 | struct resv_map *resv_map = container_of(ref, struct resv_map, refs); |
724 | struct list_head *head = &resv_map->region_cache; |
725 | struct file_region *rg, *trg; |
726 | |
727 | /* Clear out any active regions before we release the map. */ |
728 | region_del(resv_map, 0, LONG_MAX); |
729 | |
730 | /* ... and any entries left in the cache */ |
731 | list_for_each_entry_safe(rg, trg, head, link) { |
732 | list_del(&rg->link); |
733 | kfree(rg); |
734 | } |
735 | |
736 | VM_BUG_ON(resv_map->adds_in_progress); |
737 | |
738 | kfree(resv_map); |
739 | } |
740 | |
741 | static inline struct resv_map *inode_resv_map(struct inode *inode) |
742 | { |
743 | return inode->i_mapping->private_data; |
744 | } |
745 | |
746 | static struct resv_map *vma_resv_map(struct vm_area_struct *vma) |
747 | { |
748 | VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
749 | if (vma->vm_flags & VM_MAYSHARE) { |
750 | struct address_space *mapping = vma->vm_file->f_mapping; |
751 | struct inode *inode = mapping->host; |
752 | |
753 | return inode_resv_map(inode); |
754 | |
755 | } else { |
756 | return (struct resv_map *)(get_vma_private_data(vma) & |
757 | ~HPAGE_RESV_MASK); |
758 | } |
759 | } |
760 | |
761 | static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) |
762 | { |
763 | VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
764 | VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma); |
765 | |
766 | set_vma_private_data(vma, (get_vma_private_data(vma) & |
767 | HPAGE_RESV_MASK) | (unsigned long)map); |
768 | } |
769 | |
770 | static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) |
771 | { |
772 | VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
773 | VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma); |
774 | |
775 | set_vma_private_data(vma, get_vma_private_data(vma) | flags); |
776 | } |
777 | |
778 | static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) |
779 | { |
780 | VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
781 | |
782 | return (get_vma_private_data(vma) & flag) != 0; |
783 | } |
784 | |
785 | /* Reset counters to 0 and clear all HPAGE_RESV_* flags */ |
786 | void reset_vma_resv_huge_pages(struct vm_area_struct *vma) |
787 | { |
788 | VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
789 | if (!(vma->vm_flags & VM_MAYSHARE)) |
790 | vma->vm_private_data = (void *)0; |
791 | } |
792 | |
793 | /* Returns true if the VMA has associated reserve pages */ |
794 | static bool vma_has_reserves(struct vm_area_struct *vma, long chg) |
795 | { |
796 | if (vma->vm_flags & VM_NORESERVE) { |
797 | /* |
798 | * This address is already reserved by other process(chg == 0), |
799 | * so, we should decrement reserved count. Without decrementing, |
800 | * reserve count remains after releasing inode, because this |
801 | * allocated page will go into page cache and is regarded as |
802 | * coming from reserved pool in releasing step. Currently, we |
803 | * don't have any other solution to deal with this situation |
804 | * properly, so add work-around here. |
805 | */ |
806 | if (vma->vm_flags & VM_MAYSHARE && chg == 0) |
807 | return true; |
808 | else |
809 | return false; |
810 | } |
811 | |
812 | /* Shared mappings always use reserves */ |
813 | if (vma->vm_flags & VM_MAYSHARE) { |
814 | /* |
815 | * We know VM_NORESERVE is not set. Therefore, there SHOULD |
816 | * be a region map for all pages. The only situation where |
817 | * there is no region map is if a hole was punched via |
818 | * fallocate. In this case, there really are no reverves to |
819 | * use. This situation is indicated if chg != 0. |
820 | */ |
821 | if (chg) |
822 | return false; |
823 | else |
824 | return true; |
825 | } |
826 | |
827 | /* |
828 | * Only the process that called mmap() has reserves for |
829 | * private mappings. |
830 | */ |
831 | if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
832 | /* |
833 | * Like the shared case above, a hole punch or truncate |
834 | * could have been performed on the private mapping. |
835 | * Examine the value of chg to determine if reserves |
836 | * actually exist or were previously consumed. |
837 | * Very Subtle - The value of chg comes from a previous |
838 | * call to vma_needs_reserves(). The reserve map for |
839 | * private mappings has different (opposite) semantics |
840 | * than that of shared mappings. vma_needs_reserves() |
841 | * has already taken this difference in semantics into |
842 | * account. Therefore, the meaning of chg is the same |
843 | * as in the shared case above. Code could easily be |
844 | * combined, but keeping it separate draws attention to |
845 | * subtle differences. |
846 | */ |
847 | if (chg) |
848 | return false; |
849 | else |
850 | return true; |
851 | } |
852 | |
853 | return false; |
854 | } |
855 | |
856 | static void enqueue_huge_page(struct hstate *h, struct page *page) |
857 | { |
858 | int nid = page_to_nid(page); |
859 | list_move(&page->lru, &h->hugepage_freelists[nid]); |
860 | h->free_huge_pages++; |
861 | h->free_huge_pages_node[nid]++; |
862 | } |
863 | |
864 | static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid) |
865 | { |
866 | struct page *page; |
867 | |
868 | list_for_each_entry(page, &h->hugepage_freelists[nid], lru) |
869 | if (!PageHWPoison(page)) |
870 | break; |
871 | /* |
872 | * if 'non-isolated free hugepage' not found on the list, |
873 | * the allocation fails. |
874 | */ |
875 | if (&h->hugepage_freelists[nid] == &page->lru) |
876 | return NULL; |
877 | list_move(&page->lru, &h->hugepage_activelist); |
878 | set_page_refcounted(page); |
879 | h->free_huge_pages--; |
880 | h->free_huge_pages_node[nid]--; |
881 | return page; |
882 | } |
883 | |
884 | static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid, |
885 | nodemask_t *nmask) |
886 | { |
887 | unsigned int cpuset_mems_cookie; |
888 | struct zonelist *zonelist; |
889 | struct zone *zone; |
890 | struct zoneref *z; |
891 | int node = NUMA_NO_NODE; |
892 | |
893 | zonelist = node_zonelist(nid, gfp_mask); |
894 | |
895 | retry_cpuset: |
896 | cpuset_mems_cookie = read_mems_allowed_begin(); |
897 | for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) { |
898 | struct page *page; |
899 | |
900 | if (!cpuset_zone_allowed(zone, gfp_mask)) |
901 | continue; |
902 | /* |
903 | * no need to ask again on the same node. Pool is node rather than |
904 | * zone aware |
905 | */ |
906 | if (zone_to_nid(zone) == node) |
907 | continue; |
908 | node = zone_to_nid(zone); |
909 | |
910 | page = dequeue_huge_page_node_exact(h, node); |
911 | if (page) |
912 | return page; |
913 | } |
914 | if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie))) |
915 | goto retry_cpuset; |
916 | |
917 | return NULL; |
918 | } |
919 | |
920 | /* Movability of hugepages depends on migration support. */ |
921 | static inline gfp_t htlb_alloc_mask(struct hstate *h) |
922 | { |
923 | if (hugepage_movable_supported(h)) |
924 | return GFP_HIGHUSER_MOVABLE; |
925 | else |
926 | return GFP_HIGHUSER; |
927 | } |
928 | |
929 | static struct page *dequeue_huge_page_vma(struct hstate *h, |
930 | struct vm_area_struct *vma, |
931 | unsigned long address, int avoid_reserve, |
932 | long chg) |
933 | { |
934 | struct page *page; |
935 | struct mempolicy *mpol; |
936 | gfp_t gfp_mask; |
937 | nodemask_t *nodemask; |
938 | int nid; |
939 | |
940 | /* |
941 | * A child process with MAP_PRIVATE mappings created by their parent |
942 | * have no page reserves. This check ensures that reservations are |
943 | * not "stolen". The child may still get SIGKILLed |
944 | */ |
945 | if (!vma_has_reserves(vma, chg) && |
946 | h->free_huge_pages - h->resv_huge_pages == 0) |
947 | goto err; |
948 | |
949 | /* If reserves cannot be used, ensure enough pages are in the pool */ |
950 | if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) |
951 | goto err; |
952 | |
953 | gfp_mask = htlb_alloc_mask(h); |
954 | nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask); |
955 | page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask); |
956 | if (page && !avoid_reserve && vma_has_reserves(vma, chg)) { |
957 | SetPagePrivate(page); |
958 | h->resv_huge_pages--; |
959 | } |
960 | |
961 | mpol_cond_put(mpol); |
962 | return page; |
963 | |
964 | err: |
965 | return NULL; |
966 | } |
967 | |
968 | /* |
969 | * common helper functions for hstate_next_node_to_{alloc|free}. |
970 | * We may have allocated or freed a huge page based on a different |
971 | * nodes_allowed previously, so h->next_node_to_{alloc|free} might |
972 | * be outside of *nodes_allowed. Ensure that we use an allowed |
973 | * node for alloc or free. |
974 | */ |
975 | static int next_node_allowed(int nid, nodemask_t *nodes_allowed) |
976 | { |
977 | nid = next_node_in(nid, *nodes_allowed); |
978 | VM_BUG_ON(nid >= MAX_NUMNODES); |
979 | |
980 | return nid; |
981 | } |
982 | |
983 | static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) |
984 | { |
985 | if (!node_isset(nid, *nodes_allowed)) |
986 | nid = next_node_allowed(nid, nodes_allowed); |
987 | return nid; |
988 | } |
989 | |
990 | /* |
991 | * returns the previously saved node ["this node"] from which to |
992 | * allocate a persistent huge page for the pool and advance the |
993 | * next node from which to allocate, handling wrap at end of node |
994 | * mask. |
995 | */ |
996 | static int hstate_next_node_to_alloc(struct hstate *h, |
997 | nodemask_t *nodes_allowed) |
998 | { |
999 | int nid; |
1000 | |
1001 | VM_BUG_ON(!nodes_allowed); |
1002 | |
1003 | nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); |
1004 | h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); |
1005 | |
1006 | return nid; |
1007 | } |
1008 | |
1009 | /* |
1010 | * helper for free_pool_huge_page() - return the previously saved |
1011 | * node ["this node"] from which to free a huge page. Advance the |
1012 | * next node id whether or not we find a free huge page to free so |
1013 | * that the next attempt to free addresses the next node. |
1014 | */ |
1015 | static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) |
1016 | { |
1017 | int nid; |
1018 | |
1019 | VM_BUG_ON(!nodes_allowed); |
1020 | |
1021 | nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); |
1022 | h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); |
1023 | |
1024 | return nid; |
1025 | } |
1026 | |
1027 | #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \ |
1028 | for (nr_nodes = nodes_weight(*mask); \ |
1029 | nr_nodes > 0 && \ |
1030 | ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \ |
1031 | nr_nodes--) |
1032 | |
1033 | #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \ |
1034 | for (nr_nodes = nodes_weight(*mask); \ |
1035 | nr_nodes > 0 && \ |
1036 | ((node = hstate_next_node_to_free(hs, mask)) || 1); \ |
1037 | nr_nodes--) |
1038 | |
1039 | #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE |
1040 | static void destroy_compound_gigantic_page(struct page *page, |
1041 | unsigned int order) |
1042 | { |
1043 | int i; |
1044 | int nr_pages = 1 << order; |
1045 | struct page *p = page + 1; |
1046 | |
1047 | atomic_set(compound_mapcount_ptr(page), 0); |
1048 | for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { |
1049 | clear_compound_head(p); |
1050 | set_page_refcounted(p); |
1051 | } |
1052 | |
1053 | set_compound_order(page, 0); |
1054 | __ClearPageHead(page); |
1055 | } |
1056 | |
1057 | static void free_gigantic_page(struct page *page, unsigned int order) |
1058 | { |
1059 | free_contig_range(page_to_pfn(page), 1 << order); |
1060 | } |
1061 | |
1062 | static int __alloc_gigantic_page(unsigned long start_pfn, |
1063 | unsigned long nr_pages, gfp_t gfp_mask) |
1064 | { |
1065 | unsigned long end_pfn = start_pfn + nr_pages; |
1066 | return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE, |
1067 | gfp_mask); |
1068 | } |
1069 | |
1070 | static bool pfn_range_valid_gigantic(struct zone *z, |
1071 | unsigned long start_pfn, unsigned long nr_pages) |
1072 | { |
1073 | unsigned long i, end_pfn = start_pfn + nr_pages; |
1074 | struct page *page; |
1075 | |
1076 | for (i = start_pfn; i < end_pfn; i++) { |
1077 | if (!pfn_valid(i)) |
1078 | return false; |
1079 | |
1080 | page = pfn_to_page(i); |
1081 | |
1082 | if (page_zone(page) != z) |
1083 | return false; |
1084 | |
1085 | if (PageReserved(page)) |
1086 | return false; |
1087 | |
1088 | if (page_count(page) > 0) |
1089 | return false; |
1090 | |
1091 | if (PageHuge(page)) |
1092 | return false; |
1093 | } |
1094 | |
1095 | return true; |
1096 | } |
1097 | |
1098 | static bool zone_spans_last_pfn(const struct zone *zone, |
1099 | unsigned long start_pfn, unsigned long nr_pages) |
1100 | { |
1101 | unsigned long last_pfn = start_pfn + nr_pages - 1; |
1102 | return zone_spans_pfn(zone, last_pfn); |
1103 | } |
1104 | |
1105 | static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, |
1106 | int nid, nodemask_t *nodemask) |
1107 | { |
1108 | unsigned int order = huge_page_order(h); |
1109 | unsigned long nr_pages = 1 << order; |
1110 | unsigned long ret, pfn, flags; |
1111 | struct zonelist *zonelist; |
1112 | struct zone *zone; |
1113 | struct zoneref *z; |
1114 | |
1115 | zonelist = node_zonelist(nid, gfp_mask); |
1116 | for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nodemask) { |
1117 | spin_lock_irqsave(&zone->lock, flags); |
1118 | |
1119 | pfn = ALIGN(zone->zone_start_pfn, nr_pages); |
1120 | while (zone_spans_last_pfn(zone, pfn, nr_pages)) { |
1121 | if (pfn_range_valid_gigantic(zone, pfn, nr_pages)) { |
1122 | /* |
1123 | * We release the zone lock here because |
1124 | * alloc_contig_range() will also lock the zone |
1125 | * at some point. If there's an allocation |
1126 | * spinning on this lock, it may win the race |
1127 | * and cause alloc_contig_range() to fail... |
1128 | */ |
1129 | spin_unlock_irqrestore(&zone->lock, flags); |
1130 | ret = __alloc_gigantic_page(pfn, nr_pages, gfp_mask); |
1131 | if (!ret) |
1132 | return pfn_to_page(pfn); |
1133 | spin_lock_irqsave(&zone->lock, flags); |
1134 | } |
1135 | pfn += nr_pages; |
1136 | } |
1137 | |
1138 | spin_unlock_irqrestore(&zone->lock, flags); |
1139 | } |
1140 | |
1141 | return NULL; |
1142 | } |
1143 | |
1144 | static void prep_new_huge_page(struct hstate *h, struct page *page, int nid); |
1145 | static void prep_compound_gigantic_page(struct page *page, unsigned int order); |
1146 | |
1147 | #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */ |
1148 | static inline bool gigantic_page_supported(void) { return false; } |
1149 | static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, |
1150 | int nid, nodemask_t *nodemask) { return NULL; } |
1151 | static inline void free_gigantic_page(struct page *page, unsigned int order) { } |
1152 | static inline void destroy_compound_gigantic_page(struct page *page, |
1153 | unsigned int order) { } |
1154 | #endif |
1155 | |
1156 | static void update_and_free_page(struct hstate *h, struct page *page) |
1157 | { |
1158 | int i; |
1159 | |
1160 | if (hstate_is_gigantic(h) && !gigantic_page_supported()) |
1161 | return; |
1162 | |
1163 | h->nr_huge_pages--; |
1164 | h->nr_huge_pages_node[page_to_nid(page)]--; |
1165 | for (i = 0; i < pages_per_huge_page(h); i++) { |
1166 | page[i].flags &= ~(1 << PG_locked | 1 << PG_error | |
1167 | 1 << PG_referenced | 1 << PG_dirty | |
1168 | 1 << PG_active | 1 << PG_private | |
1169 | 1 << PG_writeback); |
1170 | } |
1171 | VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page); |
1172 | set_compound_page_dtor(page, NULL_COMPOUND_DTOR); |
1173 | set_page_refcounted(page); |
1174 | if (hstate_is_gigantic(h)) { |
1175 | destroy_compound_gigantic_page(page, huge_page_order(h)); |
1176 | free_gigantic_page(page, huge_page_order(h)); |
1177 | } else { |
1178 | __free_pages(page, huge_page_order(h)); |
1179 | } |
1180 | } |
1181 | |
1182 | struct hstate *size_to_hstate(unsigned long size) |
1183 | { |
1184 | struct hstate *h; |
1185 | |
1186 | for_each_hstate(h) { |
1187 | if (huge_page_size(h) == size) |
1188 | return h; |
1189 | } |
1190 | return NULL; |
1191 | } |
1192 | |
1193 | /* |
1194 | * Test to determine whether the hugepage is "active/in-use" (i.e. being linked |
1195 | * to hstate->hugepage_activelist.) |
1196 | * |
1197 | * This function can be called for tail pages, but never returns true for them. |
1198 | */ |
1199 | bool page_huge_active(struct page *page) |
1200 | { |
1201 | VM_BUG_ON_PAGE(!PageHuge(page), page); |
1202 | return PageHead(page) && PagePrivate(&page[1]); |
1203 | } |
1204 | |
1205 | /* never called for tail page */ |
1206 | static void set_page_huge_active(struct page *page) |
1207 | { |
1208 | VM_BUG_ON_PAGE(!PageHeadHuge(page), page); |
1209 | SetPagePrivate(&page[1]); |
1210 | } |
1211 | |
1212 | static void clear_page_huge_active(struct page *page) |
1213 | { |
1214 | VM_BUG_ON_PAGE(!PageHeadHuge(page), page); |
1215 | ClearPagePrivate(&page[1]); |
1216 | } |
1217 | |
1218 | /* |
1219 | * Internal hugetlb specific page flag. Do not use outside of the hugetlb |
1220 | * code |
1221 | */ |
1222 | static inline bool PageHugeTemporary(struct page *page) |
1223 | { |
1224 | if (!PageHuge(page)) |
1225 | return false; |
1226 | |
1227 | return (unsigned long)page[2].mapping == -1U; |
1228 | } |
1229 | |
1230 | static inline void SetPageHugeTemporary(struct page *page) |
1231 | { |
1232 | page[2].mapping = (void *)-1U; |
1233 | } |
1234 | |
1235 | static inline void ClearPageHugeTemporary(struct page *page) |
1236 | { |
1237 | page[2].mapping = NULL; |
1238 | } |
1239 | |
1240 | void free_huge_page(struct page *page) |
1241 | { |
1242 | /* |
1243 | * Can't pass hstate in here because it is called from the |
1244 | * compound page destructor. |
1245 | */ |
1246 | struct hstate *h = page_hstate(page); |
1247 | int nid = page_to_nid(page); |
1248 | struct hugepage_subpool *spool = |
1249 | (struct hugepage_subpool *)page_private(page); |
1250 | bool restore_reserve; |
1251 | |
1252 | VM_BUG_ON_PAGE(page_count(page), page); |
1253 | VM_BUG_ON_PAGE(page_mapcount(page), page); |
1254 | |
1255 | set_page_private(page, 0); |
1256 | page->mapping = NULL; |
1257 | restore_reserve = PagePrivate(page); |
1258 | ClearPagePrivate(page); |
1259 | |
1260 | /* |
1261 | * A return code of zero implies that the subpool will be under its |
1262 | * minimum size if the reservation is not restored after page is free. |
1263 | * Therefore, force restore_reserve operation. |
1264 | */ |
1265 | if (hugepage_subpool_put_pages(spool, 1) == 0) |
1266 | restore_reserve = true; |
1267 | |
1268 | spin_lock(&hugetlb_lock); |
1269 | clear_page_huge_active(page); |
1270 | hugetlb_cgroup_uncharge_page(hstate_index(h), |
1271 | pages_per_huge_page(h), page); |
1272 | if (restore_reserve) |
1273 | h->resv_huge_pages++; |
1274 | |
1275 | if (PageHugeTemporary(page)) { |
1276 | list_del(&page->lru); |
1277 | ClearPageHugeTemporary(page); |
1278 | update_and_free_page(h, page); |
1279 | } else if (h->surplus_huge_pages_node[nid]) { |
1280 | /* remove the page from active list */ |
1281 | list_del(&page->lru); |
1282 | update_and_free_page(h, page); |
1283 | h->surplus_huge_pages--; |
1284 | h->surplus_huge_pages_node[nid]--; |
1285 | } else { |
1286 | arch_clear_hugepage_flags(page); |
1287 | enqueue_huge_page(h, page); |
1288 | } |
1289 | spin_unlock(&hugetlb_lock); |
1290 | } |
1291 | |
1292 | static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) |
1293 | { |
1294 | INIT_LIST_HEAD(&page->lru); |
1295 | set_compound_page_dtor(page, HUGETLB_PAGE_DTOR); |
1296 | spin_lock(&hugetlb_lock); |
1297 | set_hugetlb_cgroup(page, NULL); |
1298 | h->nr_huge_pages++; |
1299 | h->nr_huge_pages_node[nid]++; |
1300 | spin_unlock(&hugetlb_lock); |
1301 | } |
1302 | |
1303 | static void prep_compound_gigantic_page(struct page *page, unsigned int order) |
1304 | { |
1305 | int i; |
1306 | int nr_pages = 1 << order; |
1307 | struct page *p = page + 1; |
1308 | |
1309 | /* we rely on prep_new_huge_page to set the destructor */ |
1310 | set_compound_order(page, order); |
1311 | __ClearPageReserved(page); |
1312 | __SetPageHead(page); |
1313 | for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { |
1314 | /* |
1315 | * For gigantic hugepages allocated through bootmem at |
1316 | * boot, it's safer to be consistent with the not-gigantic |
1317 | * hugepages and clear the PG_reserved bit from all tail pages |
1318 | * too. Otherwse drivers using get_user_pages() to access tail |
1319 | * pages may get the reference counting wrong if they see |
1320 | * PG_reserved set on a tail page (despite the head page not |
1321 | * having PG_reserved set). Enforcing this consistency between |
1322 | * head and tail pages allows drivers to optimize away a check |
1323 | * on the head page when they need know if put_page() is needed |
1324 | * after get_user_pages(). |
1325 | */ |
1326 | __ClearPageReserved(p); |
1327 | set_page_count(p, 0); |
1328 | set_compound_head(p, page); |
1329 | } |
1330 | atomic_set(compound_mapcount_ptr(page), -1); |
1331 | } |
1332 | |
1333 | /* |
1334 | * PageHuge() only returns true for hugetlbfs pages, but not for normal or |
1335 | * transparent huge pages. See the PageTransHuge() documentation for more |
1336 | * details. |
1337 | */ |
1338 | int PageHuge(struct page *page) |
1339 | { |
1340 | if (!PageCompound(page)) |
1341 | return 0; |
1342 | |
1343 | page = compound_head(page); |
1344 | return page[1].compound_dtor == HUGETLB_PAGE_DTOR; |
1345 | } |
1346 | EXPORT_SYMBOL_GPL(PageHuge); |
1347 | |
1348 | /* |
1349 | * PageHeadHuge() only returns true for hugetlbfs head page, but not for |
1350 | * normal or transparent huge pages. |
1351 | */ |
1352 | int PageHeadHuge(struct page *page_head) |
1353 | { |
1354 | if (!PageHead(page_head)) |
1355 | return 0; |
1356 | |
1357 | return get_compound_page_dtor(page_head) == free_huge_page; |
1358 | } |
1359 | |
1360 | pgoff_t __basepage_index(struct page *page) |
1361 | { |
1362 | struct page *page_head = compound_head(page); |
1363 | pgoff_t index = page_index(page_head); |
1364 | unsigned long compound_idx; |
1365 | |
1366 | if (!PageHuge(page_head)) |
1367 | return page_index(page); |
1368 | |
1369 | if (compound_order(page_head) >= MAX_ORDER) |
1370 | compound_idx = page_to_pfn(page) - page_to_pfn(page_head); |
1371 | else |
1372 | compound_idx = page - page_head; |
1373 | |
1374 | return (index << compound_order(page_head)) + compound_idx; |
1375 | } |
1376 | |
1377 | static struct page *alloc_buddy_huge_page(struct hstate *h, |
1378 | gfp_t gfp_mask, int nid, nodemask_t *nmask) |
1379 | { |
1380 | int order = huge_page_order(h); |
1381 | struct page *page; |
1382 | |
1383 | gfp_mask |= __GFP_COMP|__GFP_RETRY_MAYFAIL|__GFP_NOWARN; |
1384 | if (nid == NUMA_NO_NODE) |
1385 | nid = numa_mem_id(); |
1386 | page = __alloc_pages_nodemask(gfp_mask, order, nid, nmask); |
1387 | if (page) |
1388 | __count_vm_event(HTLB_BUDDY_PGALLOC); |
1389 | else |
1390 | __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
1391 | |
1392 | return page; |
1393 | } |
1394 | |
1395 | /* |
1396 | * Common helper to allocate a fresh hugetlb page. All specific allocators |
1397 | * should use this function to get new hugetlb pages |
1398 | */ |
1399 | static struct page *alloc_fresh_huge_page(struct hstate *h, |
1400 | gfp_t gfp_mask, int nid, nodemask_t *nmask) |
1401 | { |
1402 | struct page *page; |
1403 | |
1404 | if (hstate_is_gigantic(h)) |
1405 | page = alloc_gigantic_page(h, gfp_mask, nid, nmask); |
1406 | else |
1407 | page = alloc_buddy_huge_page(h, gfp_mask, |
1408 | nid, nmask); |
1409 | if (!page) |
1410 | return NULL; |
1411 | |
1412 | if (hstate_is_gigantic(h)) |
1413 | prep_compound_gigantic_page(page, huge_page_order(h)); |
1414 | prep_new_huge_page(h, page, page_to_nid(page)); |
1415 | |
1416 | return page; |
1417 | } |
1418 | |
1419 | /* |
1420 | * Allocates a fresh page to the hugetlb allocator pool in the node interleaved |
1421 | * manner. |
1422 | */ |
1423 | static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed) |
1424 | { |
1425 | struct page *page; |
1426 | int nr_nodes, node; |
1427 | gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE; |
1428 | |
1429 | for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { |
1430 | page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed); |
1431 | if (page) |
1432 | break; |
1433 | } |
1434 | |
1435 | if (!page) |
1436 | return 0; |
1437 | |
1438 | put_page(page); /* free it into the hugepage allocator */ |
1439 | |
1440 | return 1; |
1441 | } |
1442 | |
1443 | /* |
1444 | * Free huge page from pool from next node to free. |
1445 | * Attempt to keep persistent huge pages more or less |
1446 | * balanced over allowed nodes. |
1447 | * Called with hugetlb_lock locked. |
1448 | */ |
1449 | static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, |
1450 | bool acct_surplus) |
1451 | { |
1452 | int nr_nodes, node; |
1453 | int ret = 0; |
1454 | |
1455 | for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { |
1456 | /* |
1457 | * If we're returning unused surplus pages, only examine |
1458 | * nodes with surplus pages. |
1459 | */ |
1460 | if ((!acct_surplus || h->surplus_huge_pages_node[node]) && |
1461 | !list_empty(&h->hugepage_freelists[node])) { |
1462 | struct page *page = |
1463 | list_entry(h->hugepage_freelists[node].next, |
1464 | struct page, lru); |
1465 | list_del(&page->lru); |
1466 | h->free_huge_pages--; |
1467 | h->free_huge_pages_node[node]--; |
1468 | if (acct_surplus) { |
1469 | h->surplus_huge_pages--; |
1470 | h->surplus_huge_pages_node[node]--; |
1471 | } |
1472 | update_and_free_page(h, page); |
1473 | ret = 1; |
1474 | break; |
1475 | } |
1476 | } |
1477 | |
1478 | return ret; |
1479 | } |
1480 | |
1481 | /* |
1482 | * Dissolve a given free hugepage into free buddy pages. This function does |
1483 | * nothing for in-use (including surplus) hugepages. Returns -EBUSY if the |
1484 | * dissolution fails because a give page is not a free hugepage, or because |
1485 | * free hugepages are fully reserved. |
1486 | */ |
1487 | int dissolve_free_huge_page(struct page *page) |
1488 | { |
1489 | int rc = -EBUSY; |
1490 | |
1491 | spin_lock(&hugetlb_lock); |
1492 | if (PageHuge(page) && !page_count(page)) { |
1493 | struct page *head = compound_head(page); |
1494 | struct hstate *h = page_hstate(head); |
1495 | int nid = page_to_nid(head); |
1496 | if (h->free_huge_pages - h->resv_huge_pages == 0) |
1497 | goto out; |
1498 | /* |
1499 | * Move PageHWPoison flag from head page to the raw error page, |
1500 | * which makes any subpages rather than the error page reusable. |
1501 | */ |
1502 | if (PageHWPoison(head) && page != head) { |
1503 | SetPageHWPoison(page); |
1504 | ClearPageHWPoison(head); |
1505 | } |
1506 | list_del(&head->lru); |
1507 | h->free_huge_pages--; |
1508 | h->free_huge_pages_node[nid]--; |
1509 | h->max_huge_pages--; |
1510 | update_and_free_page(h, head); |
1511 | rc = 0; |
1512 | } |
1513 | out: |
1514 | spin_unlock(&hugetlb_lock); |
1515 | return rc; |
1516 | } |
1517 | |
1518 | /* |
1519 | * Dissolve free hugepages in a given pfn range. Used by memory hotplug to |
1520 | * make specified memory blocks removable from the system. |
1521 | * Note that this will dissolve a free gigantic hugepage completely, if any |
1522 | * part of it lies within the given range. |
1523 | * Also note that if dissolve_free_huge_page() returns with an error, all |
1524 | * free hugepages that were dissolved before that error are lost. |
1525 | */ |
1526 | int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) |
1527 | { |
1528 | unsigned long pfn; |
1529 | struct page *page; |
1530 | int rc = 0; |
1531 | |
1532 | if (!hugepages_supported()) |
1533 | return rc; |
1534 | |
1535 | for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) { |
1536 | page = pfn_to_page(pfn); |
1537 | if (PageHuge(page) && !page_count(page)) { |
1538 | rc = dissolve_free_huge_page(page); |
1539 | if (rc) |
1540 | break; |
1541 | } |
1542 | } |
1543 | |
1544 | return rc; |
1545 | } |
1546 | |
1547 | /* |
1548 | * Allocates a fresh surplus page from the page allocator. |
1549 | */ |
1550 | static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask, |
1551 | int nid, nodemask_t *nmask) |
1552 | { |
1553 | struct page *page = NULL; |
1554 | |
1555 | if (hstate_is_gigantic(h)) |
1556 | return NULL; |
1557 | |
1558 | spin_lock(&hugetlb_lock); |
1559 | if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) |
1560 | goto out_unlock; |
1561 | spin_unlock(&hugetlb_lock); |
1562 | |
1563 | page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask); |
1564 | if (!page) |
1565 | return NULL; |
1566 | |
1567 | spin_lock(&hugetlb_lock); |
1568 | /* |
1569 | * We could have raced with the pool size change. |
1570 | * Double check that and simply deallocate the new page |
1571 | * if we would end up overcommiting the surpluses. Abuse |
1572 | * temporary page to workaround the nasty free_huge_page |
1573 | * codeflow |
1574 | */ |
1575 | if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { |
1576 | SetPageHugeTemporary(page); |
1577 | put_page(page); |
1578 | page = NULL; |
1579 | } else { |
1580 | h->surplus_huge_pages++; |
1581 | h->surplus_huge_pages_node[page_to_nid(page)]++; |
1582 | } |
1583 | |
1584 | out_unlock: |
1585 | spin_unlock(&hugetlb_lock); |
1586 | |
1587 | return page; |
1588 | } |
1589 | |
1590 | struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask, |
1591 | int nid, nodemask_t *nmask) |
1592 | { |
1593 | struct page *page; |
1594 | |
1595 | if (hstate_is_gigantic(h)) |
1596 | return NULL; |
1597 | |
1598 | page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask); |
1599 | if (!page) |
1600 | return NULL; |
1601 | |
1602 | /* |
1603 | * We do not account these pages as surplus because they are only |
1604 | * temporary and will be released properly on the last reference |
1605 | */ |
1606 | SetPageHugeTemporary(page); |
1607 | |
1608 | return page; |
1609 | } |
1610 | |
1611 | /* |
1612 | * Use the VMA's mpolicy to allocate a huge page from the buddy. |
1613 | */ |
1614 | static |
1615 | struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h, |
1616 | struct vm_area_struct *vma, unsigned long addr) |
1617 | { |
1618 | struct page *page; |
1619 | struct mempolicy *mpol; |
1620 | gfp_t gfp_mask = htlb_alloc_mask(h); |
1621 | int nid; |
1622 | nodemask_t *nodemask; |
1623 | |
1624 | nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask); |
1625 | page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask); |
1626 | mpol_cond_put(mpol); |
1627 | |
1628 | return page; |
1629 | } |
1630 | |
1631 | /* page migration callback function */ |
1632 | struct page *alloc_huge_page_node(struct hstate *h, int nid) |
1633 | { |
1634 | gfp_t gfp_mask = htlb_alloc_mask(h); |
1635 | struct page *page = NULL; |
1636 | |
1637 | if (nid != NUMA_NO_NODE) |
1638 | gfp_mask |= __GFP_THISNODE; |
1639 | |
1640 | spin_lock(&hugetlb_lock); |
1641 | if (h->free_huge_pages - h->resv_huge_pages > 0) |
1642 | page = dequeue_huge_page_nodemask(h, gfp_mask, nid, NULL); |
1643 | spin_unlock(&hugetlb_lock); |
1644 | |
1645 | if (!page) |
1646 | page = alloc_migrate_huge_page(h, gfp_mask, nid, NULL); |
1647 | |
1648 | return page; |
1649 | } |
1650 | |
1651 | /* page migration callback function */ |
1652 | struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid, |
1653 | nodemask_t *nmask) |
1654 | { |
1655 | gfp_t gfp_mask = htlb_alloc_mask(h); |
1656 | |
1657 | spin_lock(&hugetlb_lock); |
1658 | if (h->free_huge_pages - h->resv_huge_pages > 0) { |
1659 | struct page *page; |
1660 | |
1661 | page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask); |
1662 | if (page) { |
1663 | spin_unlock(&hugetlb_lock); |
1664 | return page; |
1665 | } |
1666 | } |
1667 | spin_unlock(&hugetlb_lock); |
1668 | |
1669 | return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask); |
1670 | } |
1671 | |
1672 | /* mempolicy aware migration callback */ |
1673 | struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma, |
1674 | unsigned long address) |
1675 | { |
1676 | struct mempolicy *mpol; |
1677 | nodemask_t *nodemask; |
1678 | struct page *page; |
1679 | gfp_t gfp_mask; |
1680 | int node; |
1681 | |
1682 | gfp_mask = htlb_alloc_mask(h); |
1683 | node = huge_node(vma, address, gfp_mask, &mpol, &nodemask); |
1684 | page = alloc_huge_page_nodemask(h, node, nodemask); |
1685 | mpol_cond_put(mpol); |
1686 | |
1687 | return page; |
1688 | } |
1689 | |
1690 | /* |
1691 | * Increase the hugetlb pool such that it can accommodate a reservation |
1692 | * of size 'delta'. |
1693 | */ |
1694 | static int gather_surplus_pages(struct hstate *h, int delta) |
1695 | { |
1696 | struct list_head surplus_list; |
1697 | struct page *page, *tmp; |
1698 | int ret, i; |
1699 | int needed, allocated; |
1700 | bool alloc_ok = true; |
1701 | |
1702 | needed = (h->resv_huge_pages + delta) - h->free_huge_pages; |
1703 | if (needed <= 0) { |
1704 | h->resv_huge_pages += delta; |
1705 | return 0; |
1706 | } |
1707 | |
1708 | allocated = 0; |
1709 | INIT_LIST_HEAD(&surplus_list); |
1710 | |
1711 | ret = -ENOMEM; |
1712 | retry: |
1713 | spin_unlock(&hugetlb_lock); |
1714 | for (i = 0; i < needed; i++) { |
1715 | page = alloc_surplus_huge_page(h, htlb_alloc_mask(h), |
1716 | NUMA_NO_NODE, NULL); |
1717 | if (!page) { |
1718 | alloc_ok = false; |
1719 | break; |
1720 | } |
1721 | list_add(&page->lru, &surplus_list); |
1722 | cond_resched(); |
1723 | } |
1724 | allocated += i; |
1725 | |
1726 | /* |
1727 | * After retaking hugetlb_lock, we need to recalculate 'needed' |
1728 | * because either resv_huge_pages or free_huge_pages may have changed. |
1729 | */ |
1730 | spin_lock(&hugetlb_lock); |
1731 | needed = (h->resv_huge_pages + delta) - |
1732 | (h->free_huge_pages + allocated); |
1733 | if (needed > 0) { |
1734 | if (alloc_ok) |
1735 | goto retry; |
1736 | /* |
1737 | * We were not able to allocate enough pages to |
1738 | * satisfy the entire reservation so we free what |
1739 | * we've allocated so far. |
1740 | */ |
1741 | goto free; |
1742 | } |
1743 | /* |
1744 | * The surplus_list now contains _at_least_ the number of extra pages |
1745 | * needed to accommodate the reservation. Add the appropriate number |
1746 | * of pages to the hugetlb pool and free the extras back to the buddy |
1747 | * allocator. Commit the entire reservation here to prevent another |
1748 | * process from stealing the pages as they are added to the pool but |
1749 | * before they are reserved. |
1750 | */ |
1751 | needed += allocated; |
1752 | h->resv_huge_pages += delta; |
1753 | ret = 0; |
1754 | |
1755 | /* Free the needed pages to the hugetlb pool */ |
1756 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) { |
1757 | if ((--needed) < 0) |
1758 | break; |
1759 | /* |
1760 | * This page is now managed by the hugetlb allocator and has |
1761 | * no users -- drop the buddy allocator's reference. |
1762 | */ |
1763 | put_page_testzero(page); |
1764 | VM_BUG_ON_PAGE(page_count(page), page); |
1765 | enqueue_huge_page(h, page); |
1766 | } |
1767 | free: |
1768 | spin_unlock(&hugetlb_lock); |
1769 | |
1770 | /* Free unnecessary surplus pages to the buddy allocator */ |
1771 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) |
1772 | put_page(page); |
1773 | spin_lock(&hugetlb_lock); |
1774 | |
1775 | return ret; |
1776 | } |
1777 | |
1778 | /* |
1779 | * This routine has two main purposes: |
1780 | * 1) Decrement the reservation count (resv_huge_pages) by the value passed |
1781 | * in unused_resv_pages. This corresponds to the prior adjustments made |
1782 | * to the associated reservation map. |
1783 | * 2) Free any unused surplus pages that may have been allocated to satisfy |
1784 | * the reservation. As many as unused_resv_pages may be freed. |
1785 | * |
1786 | * Called with hugetlb_lock held. However, the lock could be dropped (and |
1787 | * reacquired) during calls to cond_resched_lock. Whenever dropping the lock, |
1788 | * we must make sure nobody else can claim pages we are in the process of |
1789 | * freeing. Do this by ensuring resv_huge_page always is greater than the |
1790 | * number of huge pages we plan to free when dropping the lock. |
1791 | */ |
1792 | static void return_unused_surplus_pages(struct hstate *h, |
1793 | unsigned long unused_resv_pages) |
1794 | { |
1795 | unsigned long nr_pages; |
1796 | |
1797 | /* Cannot return gigantic pages currently */ |
1798 | if (hstate_is_gigantic(h)) |
1799 | goto out; |
1800 | |
1801 | /* |
1802 | * Part (or even all) of the reservation could have been backed |
1803 | * by pre-allocated pages. Only free surplus pages. |
1804 | */ |
1805 | nr_pages = min(unused_resv_pages, h->surplus_huge_pages); |
1806 | |
1807 | /* |
1808 | * We want to release as many surplus pages as possible, spread |
1809 | * evenly across all nodes with memory. Iterate across these nodes |
1810 | * until we can no longer free unreserved surplus pages. This occurs |
1811 | * when the nodes with surplus pages have no free pages. |
1812 | * free_pool_huge_page() will balance the the freed pages across the |
1813 | * on-line nodes with memory and will handle the hstate accounting. |
1814 | * |
1815 | * Note that we decrement resv_huge_pages as we free the pages. If |
1816 | * we drop the lock, resv_huge_pages will still be sufficiently large |
1817 | * to cover subsequent pages we may free. |
1818 | */ |
1819 | while (nr_pages--) { |
1820 | h->resv_huge_pages--; |
1821 | unused_resv_pages--; |
1822 | if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1)) |
1823 | goto out; |
1824 | cond_resched_lock(&hugetlb_lock); |
1825 | } |
1826 | |
1827 | out: |
1828 | /* Fully uncommit the reservation */ |
1829 | h->resv_huge_pages -= unused_resv_pages; |
1830 | } |
1831 | |
1832 | |
1833 | /* |
1834 | * vma_needs_reservation, vma_commit_reservation and vma_end_reservation |
1835 | * are used by the huge page allocation routines to manage reservations. |
1836 | * |
1837 | * vma_needs_reservation is called to determine if the huge page at addr |
1838 | * within the vma has an associated reservation. If a reservation is |
1839 | * needed, the value 1 is returned. The caller is then responsible for |
1840 | * managing the global reservation and subpool usage counts. After |
1841 | * the huge page has been allocated, vma_commit_reservation is called |
1842 | * to add the page to the reservation map. If the page allocation fails, |
1843 | * the reservation must be ended instead of committed. vma_end_reservation |
1844 | * is called in such cases. |
1845 | * |
1846 | * In the normal case, vma_commit_reservation returns the same value |
1847 | * as the preceding vma_needs_reservation call. The only time this |
1848 | * is not the case is if a reserve map was changed between calls. It |
1849 | * is the responsibility of the caller to notice the difference and |
1850 | * take appropriate action. |
1851 | * |
1852 | * vma_add_reservation is used in error paths where a reservation must |
1853 | * be restored when a newly allocated huge page must be freed. It is |
1854 | * to be called after calling vma_needs_reservation to determine if a |
1855 | * reservation exists. |
1856 | */ |
1857 | enum vma_resv_mode { |
1858 | VMA_NEEDS_RESV, |
1859 | VMA_COMMIT_RESV, |
1860 | VMA_END_RESV, |
1861 | VMA_ADD_RESV, |
1862 | }; |
1863 | static long __vma_reservation_common(struct hstate *h, |
1864 | struct vm_area_struct *vma, unsigned long addr, |
1865 | enum vma_resv_mode mode) |
1866 | { |
1867 | struct resv_map *resv; |
1868 | pgoff_t idx; |
1869 | long ret; |
1870 | |
1871 | resv = vma_resv_map(vma); |
1872 | if (!resv) |
1873 | return 1; |
1874 | |
1875 | idx = vma_hugecache_offset(h, vma, addr); |
1876 | switch (mode) { |
1877 | case VMA_NEEDS_RESV: |
1878 | ret = region_chg(resv, idx, idx + 1); |
1879 | break; |
1880 | case VMA_COMMIT_RESV: |
1881 | ret = region_add(resv, idx, idx + 1); |
1882 | break; |
1883 | case VMA_END_RESV: |
1884 | region_abort(resv, idx, idx + 1); |
1885 | ret = 0; |
1886 | break; |
1887 | case VMA_ADD_RESV: |
1888 | if (vma->vm_flags & VM_MAYSHARE) |
1889 | ret = region_add(resv, idx, idx + 1); |
1890 | else { |
1891 | region_abort(resv, idx, idx + 1); |
1892 | ret = region_del(resv, idx, idx + 1); |
1893 | } |
1894 | break; |
1895 | default: |
1896 | BUG(); |
1897 | } |
1898 | |
1899 | if (vma->vm_flags & VM_MAYSHARE) |
1900 | return ret; |
1901 | else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) { |
1902 | /* |
1903 | * In most cases, reserves always exist for private mappings. |
1904 | * However, a file associated with mapping could have been |
1905 | * hole punched or truncated after reserves were consumed. |
1906 | * As subsequent fault on such a range will not use reserves. |
1907 | * Subtle - The reserve map for private mappings has the |
1908 | * opposite meaning than that of shared mappings. If NO |
1909 | * entry is in the reserve map, it means a reservation exists. |
1910 | * If an entry exists in the reserve map, it means the |
1911 | * reservation has already been consumed. As a result, the |
1912 | * return value of this routine is the opposite of the |
1913 | * value returned from reserve map manipulation routines above. |
1914 | */ |
1915 | if (ret) |
1916 | return 0; |
1917 | else |
1918 | return 1; |
1919 | } |
1920 | else |
1921 | return ret < 0 ? ret : 0; |
1922 | } |
1923 | |
1924 | static long vma_needs_reservation(struct hstate *h, |
1925 | struct vm_area_struct *vma, unsigned long addr) |
1926 | { |
1927 | return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV); |
1928 | } |
1929 | |
1930 | static long vma_commit_reservation(struct hstate *h, |
1931 | struct vm_area_struct *vma, unsigned long addr) |
1932 | { |
1933 | return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV); |
1934 | } |
1935 | |
1936 | static void vma_end_reservation(struct hstate *h, |
1937 | struct vm_area_struct *vma, unsigned long addr) |
1938 | { |
1939 | (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV); |
1940 | } |
1941 | |
1942 | static long vma_add_reservation(struct hstate *h, |
1943 | struct vm_area_struct *vma, unsigned long addr) |
1944 | { |
1945 | return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV); |
1946 | } |
1947 | |
1948 | /* |
1949 | * This routine is called to restore a reservation on error paths. In the |
1950 | * specific error paths, a huge page was allocated (via alloc_huge_page) |
1951 | * and is about to be freed. If a reservation for the page existed, |
1952 | * alloc_huge_page would have consumed the reservation and set PagePrivate |
1953 | * in the newly allocated page. When the page is freed via free_huge_page, |
1954 | * the global reservation count will be incremented if PagePrivate is set. |
1955 | * However, free_huge_page can not adjust the reserve map. Adjust the |
1956 | * reserve map here to be consistent with global reserve count adjustments |
1957 | * to be made by free_huge_page. |
1958 | */ |
1959 | static void restore_reserve_on_error(struct hstate *h, |
1960 | struct vm_area_struct *vma, unsigned long address, |
1961 | struct page *page) |
1962 | { |
1963 | if (unlikely(PagePrivate(page))) { |
1964 | long rc = vma_needs_reservation(h, vma, address); |
1965 | |
1966 | if (unlikely(rc < 0)) { |
1967 | /* |
1968 | * Rare out of memory condition in reserve map |
1969 | * manipulation. Clear PagePrivate so that |
1970 | * global reserve count will not be incremented |
1971 | * by free_huge_page. This will make it appear |
1972 | * as though the reservation for this page was |
1973 | * consumed. This may prevent the task from |
1974 | * faulting in the page at a later time. This |
1975 | * is better than inconsistent global huge page |
1976 | * accounting of reserve counts. |
1977 | */ |
1978 | ClearPagePrivate(page); |
1979 | } else if (rc) { |
1980 | rc = vma_add_reservation(h, vma, address); |
1981 | if (unlikely(rc < 0)) |
1982 | /* |
1983 | * See above comment about rare out of |
1984 | * memory condition. |
1985 | */ |
1986 | ClearPagePrivate(page); |
1987 | } else |
1988 | vma_end_reservation(h, vma, address); |
1989 | } |
1990 | } |
1991 | |
1992 | struct page *alloc_huge_page(struct vm_area_struct *vma, |
1993 | unsigned long addr, int avoid_reserve) |
1994 | { |
1995 | struct hugepage_subpool *spool = subpool_vma(vma); |
1996 | struct hstate *h = hstate_vma(vma); |
1997 | struct page *page; |
1998 | long map_chg, map_commit; |
1999 | long gbl_chg; |
2000 | int ret, idx; |
2001 | struct hugetlb_cgroup *h_cg; |
2002 | |
2003 | idx = hstate_index(h); |
2004 | /* |
2005 | * Examine the region/reserve map to determine if the process |
2006 | * has a reservation for the page to be allocated. A return |
2007 | * code of zero indicates a reservation exists (no change). |
2008 | */ |
2009 | map_chg = gbl_chg = vma_needs_reservation(h, vma, addr); |
2010 | if (map_chg < 0) |
2011 | return ERR_PTR(-ENOMEM); |
2012 | |
2013 | /* |
2014 | * Processes that did not create the mapping will have no |
2015 | * reserves as indicated by the region/reserve map. Check |
2016 | * that the allocation will not exceed the subpool limit. |
2017 | * Allocations for MAP_NORESERVE mappings also need to be |
2018 | * checked against any subpool limit. |
2019 | */ |
2020 | if (map_chg || avoid_reserve) { |
2021 | gbl_chg = hugepage_subpool_get_pages(spool, 1); |
2022 | if (gbl_chg < 0) { |
2023 | vma_end_reservation(h, vma, addr); |
2024 | return ERR_PTR(-ENOSPC); |
2025 | } |
2026 | |
2027 | /* |
2028 | * Even though there was no reservation in the region/reserve |
2029 | * map, there could be reservations associated with the |
2030 | * subpool that can be used. This would be indicated if the |
2031 | * return value of hugepage_subpool_get_pages() is zero. |
2032 | * However, if avoid_reserve is specified we still avoid even |
2033 | * the subpool reservations. |
2034 | */ |
2035 | if (avoid_reserve) |
2036 | gbl_chg = 1; |
2037 | } |
2038 | |
2039 | ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); |
2040 | if (ret) |
2041 | goto out_subpool_put; |
2042 | |
2043 | spin_lock(&hugetlb_lock); |
2044 | /* |
2045 | * glb_chg is passed to indicate whether or not a page must be taken |
2046 | * from the global free pool (global change). gbl_chg == 0 indicates |
2047 | * a reservation exists for the allocation. |
2048 | */ |
2049 | page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg); |
2050 | if (!page) { |
2051 | spin_unlock(&hugetlb_lock); |
2052 | page = alloc_buddy_huge_page_with_mpol(h, vma, addr); |
2053 | if (!page) |
2054 | goto out_uncharge_cgroup; |
2055 | if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) { |
2056 | SetPagePrivate(page); |
2057 | h->resv_huge_pages--; |
2058 | } |
2059 | spin_lock(&hugetlb_lock); |
2060 | list_move(&page->lru, &h->hugepage_activelist); |
2061 | /* Fall through */ |
2062 | } |
2063 | hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page); |
2064 | spin_unlock(&hugetlb_lock); |
2065 | |
2066 | set_page_private(page, (unsigned long)spool); |
2067 | |
2068 | map_commit = vma_commit_reservation(h, vma, addr); |
2069 | if (unlikely(map_chg > map_commit)) { |
2070 | /* |
2071 | * The page was added to the reservation map between |
2072 | * vma_needs_reservation and vma_commit_reservation. |
2073 | * This indicates a race with hugetlb_reserve_pages. |
2074 | * Adjust for the subpool count incremented above AND |
2075 | * in hugetlb_reserve_pages for the same page. Also, |
2076 | * the reservation count added in hugetlb_reserve_pages |
2077 | * no longer applies. |
2078 | */ |
2079 | long rsv_adjust; |
2080 | |
2081 | rsv_adjust = hugepage_subpool_put_pages(spool, 1); |
2082 | hugetlb_acct_memory(h, -rsv_adjust); |
2083 | } |
2084 | return page; |
2085 | |
2086 | out_uncharge_cgroup: |
2087 | hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg); |
2088 | out_subpool_put: |
2089 | if (map_chg || avoid_reserve) |
2090 | hugepage_subpool_put_pages(spool, 1); |
2091 | vma_end_reservation(h, vma, addr); |
2092 | return ERR_PTR(-ENOSPC); |
2093 | } |
2094 | |
2095 | int alloc_bootmem_huge_page(struct hstate *h) |
2096 | __attribute__ ((weak, alias("__alloc_bootmem_huge_page" ))); |
2097 | int __alloc_bootmem_huge_page(struct hstate *h) |
2098 | { |
2099 | struct huge_bootmem_page *m; |
2100 | int nr_nodes, node; |
2101 | |
2102 | for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) { |
2103 | void *addr; |
2104 | |
2105 | addr = memblock_alloc_try_nid_raw( |
2106 | huge_page_size(h), huge_page_size(h), |
2107 | 0, MEMBLOCK_ALLOC_ACCESSIBLE, node); |
2108 | if (addr) { |
2109 | /* |
2110 | * Use the beginning of the huge page to store the |
2111 | * huge_bootmem_page struct (until gather_bootmem |
2112 | * puts them into the mem_map). |
2113 | */ |
2114 | m = addr; |
2115 | goto found; |
2116 | } |
2117 | } |
2118 | return 0; |
2119 | |
2120 | found: |
2121 | BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h))); |
2122 | /* Put them into a private list first because mem_map is not up yet */ |
2123 | INIT_LIST_HEAD(&m->list); |
2124 | list_add(&m->list, &huge_boot_pages); |
2125 | m->hstate = h; |
2126 | return 1; |
2127 | } |
2128 | |
2129 | static void __init prep_compound_huge_page(struct page *page, |
2130 | unsigned int order) |
2131 | { |
2132 | if (unlikely(order > (MAX_ORDER - 1))) |
2133 | prep_compound_gigantic_page(page, order); |
2134 | else |
2135 | prep_compound_page(page, order); |
2136 | } |
2137 | |
2138 | /* Put bootmem huge pages into the standard lists after mem_map is up */ |
2139 | static void __init gather_bootmem_prealloc(void) |
2140 | { |
2141 | struct huge_bootmem_page *m; |
2142 | |
2143 | list_for_each_entry(m, &huge_boot_pages, list) { |
2144 | struct page *page = virt_to_page(m); |
2145 | struct hstate *h = m->hstate; |
2146 | |
2147 | WARN_ON(page_count(page) != 1); |
2148 | prep_compound_huge_page(page, h->order); |
2149 | WARN_ON(PageReserved(page)); |
2150 | prep_new_huge_page(h, page, page_to_nid(page)); |
2151 | put_page(page); /* free it into the hugepage allocator */ |
2152 | |
2153 | /* |
2154 | * If we had gigantic hugepages allocated at boot time, we need |
2155 | * to restore the 'stolen' pages to totalram_pages in order to |
2156 | * fix confusing memory reports from free(1) and another |
2157 | * side-effects, like CommitLimit going negative. |
2158 | */ |
2159 | if (hstate_is_gigantic(h)) |
2160 | adjust_managed_page_count(page, 1 << h->order); |
2161 | cond_resched(); |
2162 | } |
2163 | } |
2164 | |
2165 | static void __init hugetlb_hstate_alloc_pages(struct hstate *h) |
2166 | { |
2167 | unsigned long i; |
2168 | |
2169 | for (i = 0; i < h->max_huge_pages; ++i) { |
2170 | if (hstate_is_gigantic(h)) { |
2171 | if (!alloc_bootmem_huge_page(h)) |
2172 | break; |
2173 | } else if (!alloc_pool_huge_page(h, |
2174 | &node_states[N_MEMORY])) |
2175 | break; |
2176 | cond_resched(); |
2177 | } |
2178 | if (i < h->max_huge_pages) { |
2179 | char buf[32]; |
2180 | |
2181 | string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32); |
2182 | pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n" , |
2183 | h->max_huge_pages, buf, i); |
2184 | h->max_huge_pages = i; |
2185 | } |
2186 | } |
2187 | |
2188 | static void __init hugetlb_init_hstates(void) |
2189 | { |
2190 | struct hstate *h; |
2191 | |
2192 | for_each_hstate(h) { |
2193 | if (minimum_order > huge_page_order(h)) |
2194 | minimum_order = huge_page_order(h); |
2195 | |
2196 | /* oversize hugepages were init'ed in early boot */ |
2197 | if (!hstate_is_gigantic(h)) |
2198 | hugetlb_hstate_alloc_pages(h); |
2199 | } |
2200 | VM_BUG_ON(minimum_order == UINT_MAX); |
2201 | } |
2202 | |
2203 | static void __init report_hugepages(void) |
2204 | { |
2205 | struct hstate *h; |
2206 | |
2207 | for_each_hstate(h) { |
2208 | char buf[32]; |
2209 | |
2210 | string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32); |
2211 | pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n" , |
2212 | buf, h->free_huge_pages); |
2213 | } |
2214 | } |
2215 | |
2216 | #ifdef CONFIG_HIGHMEM |
2217 | static void try_to_free_low(struct hstate *h, unsigned long count, |
2218 | nodemask_t *nodes_allowed) |
2219 | { |
2220 | int i; |
2221 | |
2222 | if (hstate_is_gigantic(h)) |
2223 | return; |
2224 | |
2225 | for_each_node_mask(i, *nodes_allowed) { |
2226 | struct page *page, *next; |
2227 | struct list_head *freel = &h->hugepage_freelists[i]; |
2228 | list_for_each_entry_safe(page, next, freel, lru) { |
2229 | if (count >= h->nr_huge_pages) |
2230 | return; |
2231 | if (PageHighMem(page)) |
2232 | continue; |
2233 | list_del(&page->lru); |
2234 | update_and_free_page(h, page); |
2235 | h->free_huge_pages--; |
2236 | h->free_huge_pages_node[page_to_nid(page)]--; |
2237 | } |
2238 | } |
2239 | } |
2240 | #else |
2241 | static inline void try_to_free_low(struct hstate *h, unsigned long count, |
2242 | nodemask_t *nodes_allowed) |
2243 | { |
2244 | } |
2245 | #endif |
2246 | |
2247 | /* |
2248 | * Increment or decrement surplus_huge_pages. Keep node-specific counters |
2249 | * balanced by operating on them in a round-robin fashion. |
2250 | * Returns 1 if an adjustment was made. |
2251 | */ |
2252 | static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, |
2253 | int delta) |
2254 | { |
2255 | int nr_nodes, node; |
2256 | |
2257 | VM_BUG_ON(delta != -1 && delta != 1); |
2258 | |
2259 | if (delta < 0) { |
2260 | for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { |
2261 | if (h->surplus_huge_pages_node[node]) |
2262 | goto found; |
2263 | } |
2264 | } else { |
2265 | for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { |
2266 | if (h->surplus_huge_pages_node[node] < |
2267 | h->nr_huge_pages_node[node]) |
2268 | goto found; |
2269 | } |
2270 | } |
2271 | return 0; |
2272 | |
2273 | found: |
2274 | h->surplus_huge_pages += delta; |
2275 | h->surplus_huge_pages_node[node] += delta; |
2276 | return 1; |
2277 | } |
2278 | |
2279 | #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) |
2280 | static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, |
2281 | nodemask_t *nodes_allowed) |
2282 | { |
2283 | unsigned long min_count, ret; |
2284 | |
2285 | if (hstate_is_gigantic(h) && !gigantic_page_supported()) |
2286 | return h->max_huge_pages; |
2287 | |
2288 | /* |
2289 | * Increase the pool size |
2290 | * First take pages out of surplus state. Then make up the |
2291 | * remaining difference by allocating fresh huge pages. |
2292 | * |
2293 | * We might race with alloc_surplus_huge_page() here and be unable |
2294 | * to convert a surplus huge page to a normal huge page. That is |
2295 | * not critical, though, it just means the overall size of the |
2296 | * pool might be one hugepage larger than it needs to be, but |
2297 | * within all the constraints specified by the sysctls. |
2298 | */ |
2299 | spin_lock(&hugetlb_lock); |
2300 | while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { |
2301 | if (!adjust_pool_surplus(h, nodes_allowed, -1)) |
2302 | break; |
2303 | } |
2304 | |
2305 | while (count > persistent_huge_pages(h)) { |
2306 | /* |
2307 | * If this allocation races such that we no longer need the |
2308 | * page, free_huge_page will handle it by freeing the page |
2309 | * and reducing the surplus. |
2310 | */ |
2311 | spin_unlock(&hugetlb_lock); |
2312 | |
2313 | /* yield cpu to avoid soft lockup */ |
2314 | cond_resched(); |
2315 | |
2316 | ret = alloc_pool_huge_page(h, nodes_allowed); |
2317 | spin_lock(&hugetlb_lock); |
2318 | if (!ret) |
2319 | goto out; |
2320 | |
2321 | /* Bail for signals. Probably ctrl-c from user */ |
2322 | if (signal_pending(current)) |
2323 | goto out; |
2324 | } |
2325 | |
2326 | /* |
2327 | * Decrease the pool size |
2328 | * First return free pages to the buddy allocator (being careful |
2329 | * to keep enough around to satisfy reservations). Then place |
2330 | * pages into surplus state as needed so the pool will shrink |
2331 | * to the desired size as pages become free. |
2332 | * |
2333 | * By placing pages into the surplus state independent of the |
2334 | * overcommit value, we are allowing the surplus pool size to |
2335 | * exceed overcommit. There are few sane options here. Since |
2336 | * alloc_surplus_huge_page() is checking the global counter, |
2337 | * though, we'll note that we're not allowed to exceed surplus |
2338 | * and won't grow the pool anywhere else. Not until one of the |
2339 | * sysctls are changed, or the surplus pages go out of use. |
2340 | */ |
2341 | min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; |
2342 | min_count = max(count, min_count); |
2343 | try_to_free_low(h, min_count, nodes_allowed); |
2344 | while (min_count < persistent_huge_pages(h)) { |
2345 | if (!free_pool_huge_page(h, nodes_allowed, 0)) |
2346 | break; |
2347 | cond_resched_lock(&hugetlb_lock); |
2348 | } |
2349 | while (count < persistent_huge_pages(h)) { |
2350 | if (!adjust_pool_surplus(h, nodes_allowed, 1)) |
2351 | break; |
2352 | } |
2353 | out: |
2354 | ret = persistent_huge_pages(h); |
2355 | spin_unlock(&hugetlb_lock); |
2356 | return ret; |
2357 | } |
2358 | |
2359 | #define HSTATE_ATTR_RO(_name) \ |
2360 | static struct kobj_attribute _name##_attr = __ATTR_RO(_name) |
2361 | |
2362 | #define HSTATE_ATTR(_name) \ |
2363 | static struct kobj_attribute _name##_attr = \ |
2364 | __ATTR(_name, 0644, _name##_show, _name##_store) |
2365 | |
2366 | static struct kobject *hugepages_kobj; |
2367 | static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
2368 | |
2369 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); |
2370 | |
2371 | static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) |
2372 | { |
2373 | int i; |
2374 | |
2375 | for (i = 0; i < HUGE_MAX_HSTATE; i++) |
2376 | if (hstate_kobjs[i] == kobj) { |
2377 | if (nidp) |
2378 | *nidp = NUMA_NO_NODE; |
2379 | return &hstates[i]; |
2380 | } |
2381 | |
2382 | return kobj_to_node_hstate(kobj, nidp); |
2383 | } |
2384 | |
2385 | static ssize_t nr_hugepages_show_common(struct kobject *kobj, |
2386 | struct kobj_attribute *attr, char *buf) |
2387 | { |
2388 | struct hstate *h; |
2389 | unsigned long nr_huge_pages; |
2390 | int nid; |
2391 | |
2392 | h = kobj_to_hstate(kobj, &nid); |
2393 | if (nid == NUMA_NO_NODE) |
2394 | nr_huge_pages = h->nr_huge_pages; |
2395 | else |
2396 | nr_huge_pages = h->nr_huge_pages_node[nid]; |
2397 | |
2398 | return sprintf(buf, "%lu\n" , nr_huge_pages); |
2399 | } |
2400 | |
2401 | static ssize_t __nr_hugepages_store_common(bool obey_mempolicy, |
2402 | struct hstate *h, int nid, |
2403 | unsigned long count, size_t len) |
2404 | { |
2405 | int err; |
2406 | NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); |
2407 | |
2408 | if (hstate_is_gigantic(h) && !gigantic_page_supported()) { |
2409 | err = -EINVAL; |
2410 | goto out; |
2411 | } |
2412 | |
2413 | if (nid == NUMA_NO_NODE) { |
2414 | /* |
2415 | * global hstate attribute |
2416 | */ |
2417 | if (!(obey_mempolicy && |
2418 | init_nodemask_of_mempolicy(nodes_allowed))) { |
2419 | NODEMASK_FREE(nodes_allowed); |
2420 | nodes_allowed = &node_states[N_MEMORY]; |
2421 | } |
2422 | } else if (nodes_allowed) { |
2423 | /* |
2424 | * per node hstate attribute: adjust count to global, |
2425 | * but restrict alloc/free to the specified node. |
2426 | */ |
2427 | count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; |
2428 | init_nodemask_of_node(nodes_allowed, nid); |
2429 | } else |
2430 | nodes_allowed = &node_states[N_MEMORY]; |
2431 | |
2432 | h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); |
2433 | |
2434 | if (nodes_allowed != &node_states[N_MEMORY]) |
2435 | NODEMASK_FREE(nodes_allowed); |
2436 | |
2437 | return len; |
2438 | out: |
2439 | NODEMASK_FREE(nodes_allowed); |
2440 | return err; |
2441 | } |
2442 | |
2443 | static ssize_t nr_hugepages_store_common(bool obey_mempolicy, |
2444 | struct kobject *kobj, const char *buf, |
2445 | size_t len) |
2446 | { |
2447 | struct hstate *h; |
2448 | unsigned long count; |
2449 | int nid; |
2450 | int err; |
2451 | |
2452 | err = kstrtoul(buf, 10, &count); |
2453 | if (err) |
2454 | return err; |
2455 | |
2456 | h = kobj_to_hstate(kobj, &nid); |
2457 | return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len); |
2458 | } |
2459 | |
2460 | static ssize_t nr_hugepages_show(struct kobject *kobj, |
2461 | struct kobj_attribute *attr, char *buf) |
2462 | { |
2463 | return nr_hugepages_show_common(kobj, attr, buf); |
2464 | } |
2465 | |
2466 | static ssize_t nr_hugepages_store(struct kobject *kobj, |
2467 | struct kobj_attribute *attr, const char *buf, size_t len) |
2468 | { |
2469 | return nr_hugepages_store_common(false, kobj, buf, len); |
2470 | } |
2471 | HSTATE_ATTR(nr_hugepages); |
2472 | |
2473 | #ifdef CONFIG_NUMA |
2474 | |
2475 | /* |
2476 | * hstate attribute for optionally mempolicy-based constraint on persistent |
2477 | * huge page alloc/free. |
2478 | */ |
2479 | static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, |
2480 | struct kobj_attribute *attr, char *buf) |
2481 | { |
2482 | return nr_hugepages_show_common(kobj, attr, buf); |
2483 | } |
2484 | |
2485 | static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, |
2486 | struct kobj_attribute *attr, const char *buf, size_t len) |
2487 | { |
2488 | return nr_hugepages_store_common(true, kobj, buf, len); |
2489 | } |
2490 | HSTATE_ATTR(nr_hugepages_mempolicy); |
2491 | #endif |
2492 | |
2493 | |
2494 | static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, |
2495 | struct kobj_attribute *attr, char *buf) |
2496 | { |
2497 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
2498 | return sprintf(buf, "%lu\n" , h->nr_overcommit_huge_pages); |
2499 | } |
2500 | |
2501 | static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, |
2502 | struct kobj_attribute *attr, const char *buf, size_t count) |
2503 | { |
2504 | int err; |
2505 | unsigned long input; |
2506 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
2507 | |
2508 | if (hstate_is_gigantic(h)) |
2509 | return -EINVAL; |
2510 | |
2511 | err = kstrtoul(buf, 10, &input); |
2512 | if (err) |
2513 | return err; |
2514 | |
2515 | spin_lock(&hugetlb_lock); |
2516 | h->nr_overcommit_huge_pages = input; |
2517 | spin_unlock(&hugetlb_lock); |
2518 | |
2519 | return count; |
2520 | } |
2521 | HSTATE_ATTR(nr_overcommit_hugepages); |
2522 | |
2523 | static ssize_t free_hugepages_show(struct kobject *kobj, |
2524 | struct kobj_attribute *attr, char *buf) |
2525 | { |
2526 | struct hstate *h; |
2527 | unsigned long free_huge_pages; |
2528 | int nid; |
2529 | |
2530 | h = kobj_to_hstate(kobj, &nid); |
2531 | if (nid == NUMA_NO_NODE) |
2532 | free_huge_pages = h->free_huge_pages; |
2533 | else |
2534 | free_huge_pages = h->free_huge_pages_node[nid]; |
2535 | |
2536 | return sprintf(buf, "%lu\n" , free_huge_pages); |
2537 | } |
2538 | HSTATE_ATTR_RO(free_hugepages); |
2539 | |
2540 | static ssize_t resv_hugepages_show(struct kobject *kobj, |
2541 | struct kobj_attribute *attr, char *buf) |
2542 | { |
2543 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
2544 | return sprintf(buf, "%lu\n" , h->resv_huge_pages); |
2545 | } |
2546 | HSTATE_ATTR_RO(resv_hugepages); |
2547 | |
2548 | static ssize_t surplus_hugepages_show(struct kobject *kobj, |
2549 | struct kobj_attribute *attr, char *buf) |
2550 | { |
2551 | struct hstate *h; |
2552 | unsigned long surplus_huge_pages; |
2553 | int nid; |
2554 | |
2555 | h = kobj_to_hstate(kobj, &nid); |
2556 | if (nid == NUMA_NO_NODE) |
2557 | surplus_huge_pages = h->surplus_huge_pages; |
2558 | else |
2559 | surplus_huge_pages = h->surplus_huge_pages_node[nid]; |
2560 | |
2561 | return sprintf(buf, "%lu\n" , surplus_huge_pages); |
2562 | } |
2563 | HSTATE_ATTR_RO(surplus_hugepages); |
2564 | |
2565 | static struct attribute *hstate_attrs[] = { |
2566 | &nr_hugepages_attr.attr, |
2567 | &nr_overcommit_hugepages_attr.attr, |
2568 | &free_hugepages_attr.attr, |
2569 | &resv_hugepages_attr.attr, |
2570 | &surplus_hugepages_attr.attr, |
2571 | #ifdef CONFIG_NUMA |
2572 | &nr_hugepages_mempolicy_attr.attr, |
2573 | #endif |
2574 | NULL, |
2575 | }; |
2576 | |
2577 | static const struct attribute_group hstate_attr_group = { |
2578 | .attrs = hstate_attrs, |
2579 | }; |
2580 | |
2581 | static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, |
2582 | struct kobject **hstate_kobjs, |
2583 | const struct attribute_group *hstate_attr_group) |
2584 | { |
2585 | int retval; |
2586 | int hi = hstate_index(h); |
2587 | |
2588 | hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); |
2589 | if (!hstate_kobjs[hi]) |
2590 | return -ENOMEM; |
2591 | |
2592 | retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); |
2593 | if (retval) |
2594 | kobject_put(hstate_kobjs[hi]); |
2595 | |
2596 | return retval; |
2597 | } |
2598 | |
2599 | static void __init hugetlb_sysfs_init(void) |
2600 | { |
2601 | struct hstate *h; |
2602 | int err; |
2603 | |
2604 | hugepages_kobj = kobject_create_and_add("hugepages" , mm_kobj); |
2605 | if (!hugepages_kobj) |
2606 | return; |
2607 | |
2608 | for_each_hstate(h) { |
2609 | err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, |
2610 | hstate_kobjs, &hstate_attr_group); |
2611 | if (err) |
2612 | pr_err("Hugetlb: Unable to add hstate %s" , h->name); |
2613 | } |
2614 | } |
2615 | |
2616 | #ifdef CONFIG_NUMA |
2617 | |
2618 | /* |
2619 | * node_hstate/s - associate per node hstate attributes, via their kobjects, |
2620 | * with node devices in node_devices[] using a parallel array. The array |
2621 | * index of a node device or _hstate == node id. |
2622 | * This is here to avoid any static dependency of the node device driver, in |
2623 | * the base kernel, on the hugetlb module. |
2624 | */ |
2625 | struct node_hstate { |
2626 | struct kobject *hugepages_kobj; |
2627 | struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
2628 | }; |
2629 | static struct node_hstate node_hstates[MAX_NUMNODES]; |
2630 | |
2631 | /* |
2632 | * A subset of global hstate attributes for node devices |
2633 | */ |
2634 | static struct attribute *per_node_hstate_attrs[] = { |
2635 | &nr_hugepages_attr.attr, |
2636 | &free_hugepages_attr.attr, |
2637 | &surplus_hugepages_attr.attr, |
2638 | NULL, |
2639 | }; |
2640 | |
2641 | static const struct attribute_group per_node_hstate_attr_group = { |
2642 | .attrs = per_node_hstate_attrs, |
2643 | }; |
2644 | |
2645 | /* |
2646 | * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj. |
2647 | * Returns node id via non-NULL nidp. |
2648 | */ |
2649 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) |
2650 | { |
2651 | int nid; |
2652 | |
2653 | for (nid = 0; nid < nr_node_ids; nid++) { |
2654 | struct node_hstate *nhs = &node_hstates[nid]; |
2655 | int i; |
2656 | for (i = 0; i < HUGE_MAX_HSTATE; i++) |
2657 | if (nhs->hstate_kobjs[i] == kobj) { |
2658 | if (nidp) |
2659 | *nidp = nid; |
2660 | return &hstates[i]; |
2661 | } |
2662 | } |
2663 | |
2664 | BUG(); |
2665 | return NULL; |
2666 | } |
2667 | |
2668 | /* |
2669 | * Unregister hstate attributes from a single node device. |
2670 | * No-op if no hstate attributes attached. |
2671 | */ |
2672 | static void hugetlb_unregister_node(struct node *node) |
2673 | { |
2674 | struct hstate *h; |
2675 | struct node_hstate *nhs = &node_hstates[node->dev.id]; |
2676 | |
2677 | if (!nhs->hugepages_kobj) |
2678 | return; /* no hstate attributes */ |
2679 | |
2680 | for_each_hstate(h) { |
2681 | int idx = hstate_index(h); |
2682 | if (nhs->hstate_kobjs[idx]) { |
2683 | kobject_put(nhs->hstate_kobjs[idx]); |
2684 | nhs->hstate_kobjs[idx] = NULL; |
2685 | } |
2686 | } |
2687 | |
2688 | kobject_put(nhs->hugepages_kobj); |
2689 | nhs->hugepages_kobj = NULL; |
2690 | } |
2691 | |
2692 | |
2693 | /* |
2694 | * Register hstate attributes for a single node device. |
2695 | * No-op if attributes already registered. |
2696 | */ |
2697 | static void hugetlb_register_node(struct node *node) |
2698 | { |
2699 | struct hstate *h; |
2700 | struct node_hstate *nhs = &node_hstates[node->dev.id]; |
2701 | int err; |
2702 | |
2703 | if (nhs->hugepages_kobj) |
2704 | return; /* already allocated */ |
2705 | |
2706 | nhs->hugepages_kobj = kobject_create_and_add("hugepages" , |
2707 | &node->dev.kobj); |
2708 | if (!nhs->hugepages_kobj) |
2709 | return; |
2710 | |
2711 | for_each_hstate(h) { |
2712 | err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, |
2713 | nhs->hstate_kobjs, |
2714 | &per_node_hstate_attr_group); |
2715 | if (err) { |
2716 | pr_err("Hugetlb: Unable to add hstate %s for node %d\n" , |
2717 | h->name, node->dev.id); |
2718 | hugetlb_unregister_node(node); |
2719 | break; |
2720 | } |
2721 | } |
2722 | } |
2723 | |
2724 | /* |
2725 | * hugetlb init time: register hstate attributes for all registered node |
2726 | * devices of nodes that have memory. All on-line nodes should have |
2727 | * registered their associated device by this time. |
2728 | */ |
2729 | static void __init hugetlb_register_all_nodes(void) |
2730 | { |
2731 | int nid; |
2732 | |
2733 | for_each_node_state(nid, N_MEMORY) { |
2734 | struct node *node = node_devices[nid]; |
2735 | if (node->dev.id == nid) |
2736 | hugetlb_register_node(node); |
2737 | } |
2738 | |
2739 | /* |
2740 | * Let the node device driver know we're here so it can |
2741 | * [un]register hstate attributes on node hotplug. |
2742 | */ |
2743 | register_hugetlbfs_with_node(hugetlb_register_node, |
2744 | hugetlb_unregister_node); |
2745 | } |
2746 | #else /* !CONFIG_NUMA */ |
2747 | |
2748 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) |
2749 | { |
2750 | BUG(); |
2751 | if (nidp) |
2752 | *nidp = -1; |
2753 | return NULL; |
2754 | } |
2755 | |
2756 | static void hugetlb_register_all_nodes(void) { } |
2757 | |
2758 | #endif |
2759 | |
2760 | static int __init hugetlb_init(void) |
2761 | { |
2762 | int i; |
2763 | |
2764 | if (!hugepages_supported()) |
2765 | return 0; |
2766 | |
2767 | if (!size_to_hstate(default_hstate_size)) { |
2768 | if (default_hstate_size != 0) { |
2769 | pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n" , |
2770 | default_hstate_size, HPAGE_SIZE); |
2771 | } |
2772 | |
2773 | default_hstate_size = HPAGE_SIZE; |
2774 | if (!size_to_hstate(default_hstate_size)) |
2775 | hugetlb_add_hstate(HUGETLB_PAGE_ORDER); |
2776 | } |
2777 | default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size)); |
2778 | if (default_hstate_max_huge_pages) { |
2779 | if (!default_hstate.max_huge_pages) |
2780 | default_hstate.max_huge_pages = default_hstate_max_huge_pages; |
2781 | } |
2782 | |
2783 | hugetlb_init_hstates(); |
2784 | gather_bootmem_prealloc(); |
2785 | report_hugepages(); |
2786 | |
2787 | hugetlb_sysfs_init(); |
2788 | hugetlb_register_all_nodes(); |
2789 | hugetlb_cgroup_file_init(); |
2790 | |
2791 | #ifdef CONFIG_SMP |
2792 | num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus()); |
2793 | #else |
2794 | num_fault_mutexes = 1; |
2795 | #endif |
2796 | hugetlb_fault_mutex_table = |
2797 | kmalloc_array(num_fault_mutexes, sizeof(struct mutex), |
2798 | GFP_KERNEL); |
2799 | BUG_ON(!hugetlb_fault_mutex_table); |
2800 | |
2801 | for (i = 0; i < num_fault_mutexes; i++) |
2802 | mutex_init(&hugetlb_fault_mutex_table[i]); |
2803 | return 0; |
2804 | } |
2805 | subsys_initcall(hugetlb_init); |
2806 | |
2807 | /* Should be called on processing a hugepagesz=... option */ |
2808 | void __init hugetlb_bad_size(void) |
2809 | { |
2810 | parsed_valid_hugepagesz = false; |
2811 | } |
2812 | |
2813 | void __init hugetlb_add_hstate(unsigned int order) |
2814 | { |
2815 | struct hstate *h; |
2816 | unsigned long i; |
2817 | |
2818 | if (size_to_hstate(PAGE_SIZE << order)) { |
2819 | pr_warn("hugepagesz= specified twice, ignoring\n" ); |
2820 | return; |
2821 | } |
2822 | BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); |
2823 | BUG_ON(order == 0); |
2824 | h = &hstates[hugetlb_max_hstate++]; |
2825 | h->order = order; |
2826 | h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); |
2827 | h->nr_huge_pages = 0; |
2828 | h->free_huge_pages = 0; |
2829 | for (i = 0; i < MAX_NUMNODES; ++i) |
2830 | INIT_LIST_HEAD(&h->hugepage_freelists[i]); |
2831 | INIT_LIST_HEAD(&h->hugepage_activelist); |
2832 | h->next_nid_to_alloc = first_memory_node; |
2833 | h->next_nid_to_free = first_memory_node; |
2834 | snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB" , |
2835 | huge_page_size(h)/1024); |
2836 | |
2837 | parsed_hstate = h; |
2838 | } |
2839 | |
2840 | static int __init hugetlb_nrpages_setup(char *s) |
2841 | { |
2842 | unsigned long *mhp; |
2843 | static unsigned long *last_mhp; |
2844 | |
2845 | if (!parsed_valid_hugepagesz) { |
2846 | pr_warn("hugepages = %s preceded by " |
2847 | "an unsupported hugepagesz, ignoring\n" , s); |
2848 | parsed_valid_hugepagesz = true; |
2849 | return 1; |
2850 | } |
2851 | /* |
2852 | * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet, |
2853 | * so this hugepages= parameter goes to the "default hstate". |
2854 | */ |
2855 | else if (!hugetlb_max_hstate) |
2856 | mhp = &default_hstate_max_huge_pages; |
2857 | else |
2858 | mhp = &parsed_hstate->max_huge_pages; |
2859 | |
2860 | if (mhp == last_mhp) { |
2861 | pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n" ); |
2862 | return 1; |
2863 | } |
2864 | |
2865 | if (sscanf(s, "%lu" , mhp) <= 0) |
2866 | *mhp = 0; |
2867 | |
2868 | /* |
2869 | * Global state is always initialized later in hugetlb_init. |
2870 | * But we need to allocate >= MAX_ORDER hstates here early to still |
2871 | * use the bootmem allocator. |
2872 | */ |
2873 | if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER) |
2874 | hugetlb_hstate_alloc_pages(parsed_hstate); |
2875 | |
2876 | last_mhp = mhp; |
2877 | |
2878 | return 1; |
2879 | } |
2880 | __setup("hugepages=" , hugetlb_nrpages_setup); |
2881 | |
2882 | static int __init hugetlb_default_setup(char *s) |
2883 | { |
2884 | default_hstate_size = memparse(s, &s); |
2885 | return 1; |
2886 | } |
2887 | __setup("default_hugepagesz=" , hugetlb_default_setup); |
2888 | |
2889 | static unsigned int cpuset_mems_nr(unsigned int *array) |
2890 | { |
2891 | int node; |
2892 | unsigned int nr = 0; |
2893 | |
2894 | for_each_node_mask(node, cpuset_current_mems_allowed) |
2895 | nr += array[node]; |
2896 | |
2897 | return nr; |
2898 | } |
2899 | |
2900 | #ifdef CONFIG_SYSCTL |
2901 | static int hugetlb_sysctl_handler_common(bool obey_mempolicy, |
2902 | struct ctl_table *table, int write, |
2903 | void __user *buffer, size_t *length, loff_t *ppos) |
2904 | { |
2905 | struct hstate *h = &default_hstate; |
2906 | unsigned long tmp = h->max_huge_pages; |
2907 | int ret; |
2908 | |
2909 | if (!hugepages_supported()) |
2910 | return -EOPNOTSUPP; |
2911 | |
2912 | table->data = &tmp; |
2913 | table->maxlen = sizeof(unsigned long); |
2914 | ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); |
2915 | if (ret) |
2916 | goto out; |
2917 | |
2918 | if (write) |
2919 | ret = __nr_hugepages_store_common(obey_mempolicy, h, |
2920 | NUMA_NO_NODE, tmp, *length); |
2921 | out: |
2922 | return ret; |
2923 | } |
2924 | |
2925 | int hugetlb_sysctl_handler(struct ctl_table *table, int write, |
2926 | void __user *buffer, size_t *length, loff_t *ppos) |
2927 | { |
2928 | |
2929 | return hugetlb_sysctl_handler_common(false, table, write, |
2930 | buffer, length, ppos); |
2931 | } |
2932 | |
2933 | #ifdef CONFIG_NUMA |
2934 | int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, |
2935 | void __user *buffer, size_t *length, loff_t *ppos) |
2936 | { |
2937 | return hugetlb_sysctl_handler_common(true, table, write, |
2938 | buffer, length, ppos); |
2939 | } |
2940 | #endif /* CONFIG_NUMA */ |
2941 | |
2942 | int hugetlb_overcommit_handler(struct ctl_table *table, int write, |
2943 | void __user *buffer, |
2944 | size_t *length, loff_t *ppos) |
2945 | { |
2946 | struct hstate *h = &default_hstate; |
2947 | unsigned long tmp; |
2948 | int ret; |
2949 | |
2950 | if (!hugepages_supported()) |
2951 | return -EOPNOTSUPP; |
2952 | |
2953 | tmp = h->nr_overcommit_huge_pages; |
2954 | |
2955 | if (write && hstate_is_gigantic(h)) |
2956 | return -EINVAL; |
2957 | |
2958 | table->data = &tmp; |
2959 | table->maxlen = sizeof(unsigned long); |
2960 | ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); |
2961 | if (ret) |
2962 | goto out; |
2963 | |
2964 | if (write) { |
2965 | spin_lock(&hugetlb_lock); |
2966 | h->nr_overcommit_huge_pages = tmp; |
2967 | spin_unlock(&hugetlb_lock); |
2968 | } |
2969 | out: |
2970 | return ret; |
2971 | } |
2972 | |
2973 | #endif /* CONFIG_SYSCTL */ |
2974 | |
2975 | void hugetlb_report_meminfo(struct seq_file *m) |
2976 | { |
2977 | struct hstate *h; |
2978 | unsigned long total = 0; |
2979 | |
2980 | if (!hugepages_supported()) |
2981 | return; |
2982 | |
2983 | for_each_hstate(h) { |
2984 | unsigned long count = h->nr_huge_pages; |
2985 | |
2986 | total += (PAGE_SIZE << huge_page_order(h)) * count; |
2987 | |
2988 | if (h == &default_hstate) |
2989 | seq_printf(m, |
2990 | "HugePages_Total: %5lu\n" |
2991 | "HugePages_Free: %5lu\n" |
2992 | "HugePages_Rsvd: %5lu\n" |
2993 | "HugePages_Surp: %5lu\n" |
2994 | "Hugepagesize: %8lu kB\n" , |
2995 | count, |
2996 | h->free_huge_pages, |
2997 | h->resv_huge_pages, |
2998 | h->surplus_huge_pages, |
2999 | (PAGE_SIZE << huge_page_order(h)) / 1024); |
3000 | } |
3001 | |
3002 | seq_printf(m, "Hugetlb: %8lu kB\n" , total / 1024); |
3003 | } |
3004 | |
3005 | int hugetlb_report_node_meminfo(int nid, char *buf) |
3006 | { |
3007 | struct hstate *h = &default_hstate; |
3008 | if (!hugepages_supported()) |
3009 | return 0; |
3010 | return sprintf(buf, |
3011 | "Node %d HugePages_Total: %5u\n" |
3012 | "Node %d HugePages_Free: %5u\n" |
3013 | "Node %d HugePages_Surp: %5u\n" , |
3014 | nid, h->nr_huge_pages_node[nid], |
3015 | nid, h->free_huge_pages_node[nid], |
3016 | nid, h->surplus_huge_pages_node[nid]); |
3017 | } |
3018 | |
3019 | void hugetlb_show_meminfo(void) |
3020 | { |
3021 | struct hstate *h; |
3022 | int nid; |
3023 | |
3024 | if (!hugepages_supported()) |
3025 | return; |
3026 | |
3027 | for_each_node_state(nid, N_MEMORY) |
3028 | for_each_hstate(h) |
3029 | pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n" , |
3030 | nid, |
3031 | h->nr_huge_pages_node[nid], |
3032 | h->free_huge_pages_node[nid], |
3033 | h->surplus_huge_pages_node[nid], |
3034 | 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); |
3035 | } |
3036 | |
3037 | void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm) |
3038 | { |
3039 | seq_printf(m, "HugetlbPages:\t%8lu kB\n" , |
3040 | atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10)); |
3041 | } |
3042 | |
3043 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
3044 | unsigned long hugetlb_total_pages(void) |
3045 | { |
3046 | struct hstate *h; |
3047 | unsigned long nr_total_pages = 0; |
3048 | |
3049 | for_each_hstate(h) |
3050 | nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h); |
3051 | return nr_total_pages; |
3052 | } |
3053 | |
3054 | static int hugetlb_acct_memory(struct hstate *h, long delta) |
3055 | { |
3056 | int ret = -ENOMEM; |
3057 | |
3058 | spin_lock(&hugetlb_lock); |
3059 | /* |
3060 | * When cpuset is configured, it breaks the strict hugetlb page |
3061 | * reservation as the accounting is done on a global variable. Such |
3062 | * reservation is completely rubbish in the presence of cpuset because |
3063 | * the reservation is not checked against page availability for the |
3064 | * current cpuset. Application can still potentially OOM'ed by kernel |
3065 | * with lack of free htlb page in cpuset that the task is in. |
3066 | * Attempt to enforce strict accounting with cpuset is almost |
3067 | * impossible (or too ugly) because cpuset is too fluid that |
3068 | * task or memory node can be dynamically moved between cpusets. |
3069 | * |
3070 | * The change of semantics for shared hugetlb mapping with cpuset is |
3071 | * undesirable. However, in order to preserve some of the semantics, |
3072 | * we fall back to check against current free page availability as |
3073 | * a best attempt and hopefully to minimize the impact of changing |
3074 | * semantics that cpuset has. |
3075 | */ |
3076 | if (delta > 0) { |
3077 | if (gather_surplus_pages(h, delta) < 0) |
3078 | goto out; |
3079 | |
3080 | if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { |
3081 | return_unused_surplus_pages(h, delta); |
3082 | goto out; |
3083 | } |
3084 | } |
3085 | |
3086 | ret = 0; |
3087 | if (delta < 0) |
3088 | return_unused_surplus_pages(h, (unsigned long) -delta); |
3089 | |
3090 | out: |
3091 | spin_unlock(&hugetlb_lock); |
3092 | return ret; |
3093 | } |
3094 | |
3095 | static void hugetlb_vm_op_open(struct vm_area_struct *vma) |
3096 | { |
3097 | struct resv_map *resv = vma_resv_map(vma); |
3098 | |
3099 | /* |
3100 | * This new VMA should share its siblings reservation map if present. |
3101 | * The VMA will only ever have a valid reservation map pointer where |
3102 | * it is being copied for another still existing VMA. As that VMA |
3103 | * has a reference to the reservation map it cannot disappear until |
3104 | * after this open call completes. It is therefore safe to take a |
3105 | * new reference here without additional locking. |
3106 | */ |
3107 | if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
3108 | kref_get(&resv->refs); |
3109 | } |
3110 | |
3111 | static void hugetlb_vm_op_close(struct vm_area_struct *vma) |
3112 | { |
3113 | struct hstate *h = hstate_vma(vma); |
3114 | struct resv_map *resv = vma_resv_map(vma); |
3115 | struct hugepage_subpool *spool = subpool_vma(vma); |
3116 | unsigned long reserve, start, end; |
3117 | long gbl_reserve; |
3118 | |
3119 | if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
3120 | return; |
3121 | |
3122 | start = vma_hugecache_offset(h, vma, vma->vm_start); |
3123 | end = vma_hugecache_offset(h, vma, vma->vm_end); |
3124 | |
3125 | reserve = (end - start) - region_count(resv, start, end); |
3126 | |
3127 | kref_put(&resv->refs, resv_map_release); |
3128 | |
3129 | if (reserve) { |
3130 | /* |
3131 | * Decrement reserve counts. The global reserve count may be |
3132 | * adjusted if the subpool has a minimum size. |
3133 | */ |
3134 | gbl_reserve = hugepage_subpool_put_pages(spool, reserve); |
3135 | hugetlb_acct_memory(h, -gbl_reserve); |
3136 | } |
3137 | } |
3138 | |
3139 | static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr) |
3140 | { |
3141 | if (addr & ~(huge_page_mask(hstate_vma(vma)))) |
3142 | return -EINVAL; |
3143 | return 0; |
3144 | } |
3145 | |
3146 | static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma) |
3147 | { |
3148 | struct hstate *hstate = hstate_vma(vma); |
3149 | |
3150 | return 1UL << huge_page_shift(hstate); |
3151 | } |
3152 | |
3153 | /* |
3154 | * We cannot handle pagefaults against hugetlb pages at all. They cause |
3155 | * handle_mm_fault() to try to instantiate regular-sized pages in the |
3156 | * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get |
3157 | * this far. |
3158 | */ |
3159 | static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf) |
3160 | { |
3161 | BUG(); |
3162 | return 0; |
3163 | } |
3164 | |
3165 | /* |
3166 | * When a new function is introduced to vm_operations_struct and added |
3167 | * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops. |
3168 | * This is because under System V memory model, mappings created via |
3169 | * shmget/shmat with "huge page" specified are backed by hugetlbfs files, |
3170 | * their original vm_ops are overwritten with shm_vm_ops. |
3171 | */ |
3172 | const struct vm_operations_struct hugetlb_vm_ops = { |
3173 | .fault = hugetlb_vm_op_fault, |
3174 | .open = hugetlb_vm_op_open, |
3175 | .close = hugetlb_vm_op_close, |
3176 | .split = hugetlb_vm_op_split, |
3177 | .pagesize = hugetlb_vm_op_pagesize, |
3178 | }; |
3179 | |
3180 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
3181 | int writable) |
3182 | { |
3183 | pte_t entry; |
3184 | |
3185 | if (writable) { |
3186 | entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page, |
3187 | vma->vm_page_prot))); |
3188 | } else { |
3189 | entry = huge_pte_wrprotect(mk_huge_pte(page, |
3190 | vma->vm_page_prot)); |
3191 | } |
3192 | entry = pte_mkyoung(entry); |
3193 | entry = pte_mkhuge(entry); |
3194 | entry = arch_make_huge_pte(entry, vma, page, writable); |
3195 | |
3196 | return entry; |
3197 | } |
3198 | |
3199 | static void set_huge_ptep_writable(struct vm_area_struct *vma, |
3200 | unsigned long address, pte_t *ptep) |
3201 | { |
3202 | pte_t entry; |
3203 | |
3204 | entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep))); |
3205 | if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) |
3206 | update_mmu_cache(vma, address, ptep); |
3207 | } |
3208 | |
3209 | bool is_hugetlb_entry_migration(pte_t pte) |
3210 | { |
3211 | swp_entry_t swp; |
3212 | |
3213 | if (huge_pte_none(pte) || pte_present(pte)) |
3214 | return false; |
3215 | swp = pte_to_swp_entry(pte); |
3216 | if (non_swap_entry(swp) && is_migration_entry(swp)) |
3217 | return true; |
3218 | else |
3219 | return false; |
3220 | } |
3221 | |
3222 | static int is_hugetlb_entry_hwpoisoned(pte_t pte) |
3223 | { |
3224 | swp_entry_t swp; |
3225 | |
3226 | if (huge_pte_none(pte) || pte_present(pte)) |
3227 | return 0; |
3228 | swp = pte_to_swp_entry(pte); |
3229 | if (non_swap_entry(swp) && is_hwpoison_entry(swp)) |
3230 | return 1; |
3231 | else |
3232 | return 0; |
3233 | } |
3234 | |
3235 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
3236 | struct vm_area_struct *vma) |
3237 | { |
3238 | pte_t *src_pte, *dst_pte, entry, dst_entry; |
3239 | struct page *ptepage; |
3240 | unsigned long addr; |
3241 | int cow; |
3242 | struct hstate *h = hstate_vma(vma); |
3243 | unsigned long sz = huge_page_size(h); |
3244 | struct mmu_notifier_range range; |
3245 | int ret = 0; |
3246 | |
3247 | cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; |
3248 | |
3249 | if (cow) { |
3250 | mmu_notifier_range_init(&range, src, vma->vm_start, |
3251 | vma->vm_end); |
3252 | mmu_notifier_invalidate_range_start(&range); |
3253 | } |
3254 | |
3255 | for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { |
3256 | spinlock_t *src_ptl, *dst_ptl; |
3257 | src_pte = huge_pte_offset(src, addr, sz); |
3258 | if (!src_pte) |
3259 | continue; |
3260 | dst_pte = huge_pte_alloc(dst, addr, sz); |
3261 | if (!dst_pte) { |
3262 | ret = -ENOMEM; |
3263 | break; |
3264 | } |
3265 | |
3266 | /* |
3267 | * If the pagetables are shared don't copy or take references. |
3268 | * dst_pte == src_pte is the common case of src/dest sharing. |
3269 | * |
3270 | * However, src could have 'unshared' and dst shares with |
3271 | * another vma. If dst_pte !none, this implies sharing. |
3272 | * Check here before taking page table lock, and once again |
3273 | * after taking the lock below. |
3274 | */ |
3275 | dst_entry = huge_ptep_get(dst_pte); |
3276 | if ((dst_pte == src_pte) || !huge_pte_none(dst_entry)) |
3277 | continue; |
3278 | |
3279 | dst_ptl = huge_pte_lock(h, dst, dst_pte); |
3280 | src_ptl = huge_pte_lockptr(h, src, src_pte); |
3281 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
3282 | entry = huge_ptep_get(src_pte); |
3283 | dst_entry = huge_ptep_get(dst_pte); |
3284 | if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) { |
3285 | /* |
3286 | * Skip if src entry none. Also, skip in the |
3287 | * unlikely case dst entry !none as this implies |
3288 | * sharing with another vma. |
3289 | */ |
3290 | ; |
3291 | } else if (unlikely(is_hugetlb_entry_migration(entry) || |
3292 | is_hugetlb_entry_hwpoisoned(entry))) { |
3293 | swp_entry_t swp_entry = pte_to_swp_entry(entry); |
3294 | |
3295 | if (is_write_migration_entry(swp_entry) && cow) { |
3296 | /* |
3297 | * COW mappings require pages in both |
3298 | * parent and child to be set to read. |
3299 | */ |
3300 | make_migration_entry_read(&swp_entry); |
3301 | entry = swp_entry_to_pte(swp_entry); |
3302 | set_huge_swap_pte_at(src, addr, src_pte, |
3303 | entry, sz); |
3304 | } |
3305 | set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz); |
3306 | } else { |
3307 | if (cow) { |
3308 | /* |
3309 | * No need to notify as we are downgrading page |
3310 | * table protection not changing it to point |
3311 | * to a new page. |
3312 | * |
3313 | * See Documentation/vm/mmu_notifier.rst |
3314 | */ |
3315 | huge_ptep_set_wrprotect(src, addr, src_pte); |
3316 | } |
3317 | entry = huge_ptep_get(src_pte); |
3318 | ptepage = pte_page(entry); |
3319 | get_page(ptepage); |
3320 | page_dup_rmap(ptepage, true); |
3321 | set_huge_pte_at(dst, addr, dst_pte, entry); |
3322 | hugetlb_count_add(pages_per_huge_page(h), dst); |
3323 | } |
3324 | spin_unlock(src_ptl); |
3325 | spin_unlock(dst_ptl); |
3326 | } |
3327 | |
3328 | if (cow) |
3329 | mmu_notifier_invalidate_range_end(&range); |
3330 | |
3331 | return ret; |
3332 | } |
3333 | |
3334 | void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, |
3335 | unsigned long start, unsigned long end, |
3336 | struct page *ref_page) |
3337 | { |
3338 | struct mm_struct *mm = vma->vm_mm; |
3339 | unsigned long address; |
3340 | pte_t *ptep; |
3341 | pte_t pte; |
3342 | spinlock_t *ptl; |
3343 | struct page *page; |
3344 | struct hstate *h = hstate_vma(vma); |
3345 | unsigned long sz = huge_page_size(h); |
3346 | struct mmu_notifier_range range; |
3347 | |
3348 | WARN_ON(!is_vm_hugetlb_page(vma)); |
3349 | BUG_ON(start & ~huge_page_mask(h)); |
3350 | BUG_ON(end & ~huge_page_mask(h)); |
3351 | |
3352 | /* |
3353 | * This is a hugetlb vma, all the pte entries should point |
3354 | * to huge page. |
3355 | */ |
3356 | tlb_remove_check_page_size_change(tlb, sz); |
3357 | tlb_start_vma(tlb, vma); |
3358 | |
3359 | /* |
3360 | * If sharing possible, alert mmu notifiers of worst case. |
3361 | */ |
3362 | mmu_notifier_range_init(&range, mm, start, end); |
3363 | adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end); |
3364 | mmu_notifier_invalidate_range_start(&range); |
3365 | address = start; |
3366 | for (; address < end; address += sz) { |
3367 | ptep = huge_pte_offset(mm, address, sz); |
3368 | if (!ptep) |
3369 | continue; |
3370 | |
3371 | ptl = huge_pte_lock(h, mm, ptep); |
3372 | if (huge_pmd_unshare(mm, &address, ptep)) { |
3373 | spin_unlock(ptl); |
3374 | /* |
3375 | * We just unmapped a page of PMDs by clearing a PUD. |
3376 | * The caller's TLB flush range should cover this area. |
3377 | */ |
3378 | continue; |
3379 | } |
3380 | |
3381 | pte = huge_ptep_get(ptep); |
3382 | if (huge_pte_none(pte)) { |
3383 | spin_unlock(ptl); |
3384 | continue; |
3385 | } |
3386 | |
3387 | /* |
3388 | * Migrating hugepage or HWPoisoned hugepage is already |
3389 | * unmapped and its refcount is dropped, so just clear pte here. |
3390 | */ |
3391 | if (unlikely(!pte_present(pte))) { |
3392 | huge_pte_clear(mm, address, ptep, sz); |
3393 | spin_unlock(ptl); |
3394 | continue; |
3395 | } |
3396 | |
3397 | page = pte_page(pte); |
3398 | /* |
3399 | * If a reference page is supplied, it is because a specific |
3400 | * page is being unmapped, not a range. Ensure the page we |
3401 | * are about to unmap is the actual page of interest. |
3402 | */ |
3403 | if (ref_page) { |
3404 | if (page != ref_page) { |
3405 | spin_unlock(ptl); |
3406 | continue; |
3407 | } |
3408 | /* |
3409 | * Mark the VMA as having unmapped its page so that |
3410 | * future faults in this VMA will fail rather than |
3411 | * looking like data was lost |
3412 | */ |
3413 | set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); |
3414 | } |
3415 | |
3416 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
3417 | tlb_remove_huge_tlb_entry(h, tlb, ptep, address); |
3418 | if (huge_pte_dirty(pte)) |
3419 | set_page_dirty(page); |
3420 | |
3421 | hugetlb_count_sub(pages_per_huge_page(h), mm); |
3422 | page_remove_rmap(page, true); |
3423 | |
3424 | spin_unlock(ptl); |
3425 | tlb_remove_page_size(tlb, page, huge_page_size(h)); |
3426 | /* |
3427 | * Bail out after unmapping reference page if supplied |
3428 | */ |
3429 | if (ref_page) |
3430 | break; |
3431 | } |
3432 | mmu_notifier_invalidate_range_end(&range); |
3433 | tlb_end_vma(tlb, vma); |
3434 | } |
3435 | |
3436 | void __unmap_hugepage_range_final(struct mmu_gather *tlb, |
3437 | struct vm_area_struct *vma, unsigned long start, |
3438 | unsigned long end, struct page *ref_page) |
3439 | { |
3440 | __unmap_hugepage_range(tlb, vma, start, end, ref_page); |
3441 | |
3442 | /* |
3443 | * Clear this flag so that x86's huge_pmd_share page_table_shareable |
3444 | * test will fail on a vma being torn down, and not grab a page table |
3445 | * on its way out. We're lucky that the flag has such an appropriate |
3446 | * name, and can in fact be safely cleared here. We could clear it |
3447 | * before the __unmap_hugepage_range above, but all that's necessary |
3448 | * is to clear it before releasing the i_mmap_rwsem. This works |
3449 | * because in the context this is called, the VMA is about to be |
3450 | * destroyed and the i_mmap_rwsem is held. |
3451 | */ |
3452 | vma->vm_flags &= ~VM_MAYSHARE; |
3453 | } |
3454 | |
3455 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
3456 | unsigned long end, struct page *ref_page) |
3457 | { |
3458 | struct mm_struct *mm; |
3459 | struct mmu_gather tlb; |
3460 | unsigned long tlb_start = start; |
3461 | unsigned long tlb_end = end; |
3462 | |
3463 | /* |
3464 | * If shared PMDs were possibly used within this vma range, adjust |
3465 | * start/end for worst case tlb flushing. |
3466 | * Note that we can not be sure if PMDs are shared until we try to |
3467 | * unmap pages. However, we want to make sure TLB flushing covers |
3468 | * the largest possible range. |
3469 | */ |
3470 | adjust_range_if_pmd_sharing_possible(vma, &tlb_start, &tlb_end); |
3471 | |
3472 | mm = vma->vm_mm; |
3473 | |
3474 | tlb_gather_mmu(&tlb, mm, tlb_start, tlb_end); |
3475 | __unmap_hugepage_range(&tlb, vma, start, end, ref_page); |
3476 | tlb_finish_mmu(&tlb, tlb_start, tlb_end); |
3477 | } |
3478 | |
3479 | /* |
3480 | * This is called when the original mapper is failing to COW a MAP_PRIVATE |
3481 | * mappping it owns the reserve page for. The intention is to unmap the page |
3482 | * from other VMAs and let the children be SIGKILLed if they are faulting the |
3483 | * same region. |
3484 | */ |
3485 | static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, |
3486 | struct page *page, unsigned long address) |
3487 | { |
3488 | struct hstate *h = hstate_vma(vma); |
3489 | struct vm_area_struct *iter_vma; |
3490 | struct address_space *mapping; |
3491 | pgoff_t pgoff; |
3492 | |
3493 | /* |
3494 | * vm_pgoff is in PAGE_SIZE units, hence the different calculation |
3495 | * from page cache lookup which is in HPAGE_SIZE units. |
3496 | */ |
3497 | address = address & huge_page_mask(h); |
3498 | pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + |
3499 | vma->vm_pgoff; |
3500 | mapping = vma->vm_file->f_mapping; |
3501 | |
3502 | /* |
3503 | * Take the mapping lock for the duration of the table walk. As |
3504 | * this mapping should be shared between all the VMAs, |
3505 | * __unmap_hugepage_range() is called as the lock is already held |
3506 | */ |
3507 | i_mmap_lock_write(mapping); |
3508 | vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) { |
3509 | /* Do not unmap the current VMA */ |
3510 | if (iter_vma == vma) |
3511 | continue; |
3512 | |
3513 | /* |
3514 | * Shared VMAs have their own reserves and do not affect |
3515 | * MAP_PRIVATE accounting but it is possible that a shared |
3516 | * VMA is using the same page so check and skip such VMAs. |
3517 | */ |
3518 | if (iter_vma->vm_flags & VM_MAYSHARE) |
3519 | continue; |
3520 | |
3521 | /* |
3522 | * Unmap the page from other VMAs without their own reserves. |
3523 | * They get marked to be SIGKILLed if they fault in these |
3524 | * areas. This is because a future no-page fault on this VMA |
3525 | * could insert a zeroed page instead of the data existing |
3526 | * from the time of fork. This would look like data corruption |
3527 | */ |
3528 | if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) |
3529 | unmap_hugepage_range(iter_vma, address, |
3530 | address + huge_page_size(h), page); |
3531 | } |
3532 | i_mmap_unlock_write(mapping); |
3533 | } |
3534 | |
3535 | /* |
3536 | * Hugetlb_cow() should be called with page lock of the original hugepage held. |
3537 | * Called with hugetlb_instantiation_mutex held and pte_page locked so we |
3538 | * cannot race with other handlers or page migration. |
3539 | * Keep the pte_same checks anyway to make transition from the mutex easier. |
3540 | */ |
3541 | static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
3542 | unsigned long address, pte_t *ptep, |
3543 | struct page *pagecache_page, spinlock_t *ptl) |
3544 | { |
3545 | pte_t pte; |
3546 | struct hstate *h = hstate_vma(vma); |
3547 | struct page *old_page, *new_page; |
3548 | int outside_reserve = 0; |
3549 | vm_fault_t ret = 0; |
3550 | unsigned long haddr = address & huge_page_mask(h); |
3551 | struct mmu_notifier_range range; |
3552 | |
3553 | pte = huge_ptep_get(ptep); |
3554 | old_page = pte_page(pte); |
3555 | |
3556 | retry_avoidcopy: |
3557 | /* If no-one else is actually using this page, avoid the copy |
3558 | * and just make the page writable */ |
3559 | if (page_mapcount(old_page) == 1 && PageAnon(old_page)) { |
3560 | page_move_anon_rmap(old_page, vma); |
3561 | set_huge_ptep_writable(vma, haddr, ptep); |
3562 | return 0; |
3563 | } |
3564 | |
3565 | /* |
3566 | * If the process that created a MAP_PRIVATE mapping is about to |
3567 | * perform a COW due to a shared page count, attempt to satisfy |
3568 | * the allocation without using the existing reserves. The pagecache |
3569 | * page is used to determine if the reserve at this address was |
3570 | * consumed or not. If reserves were used, a partial faulted mapping |
3571 | * at the time of fork() could consume its reserves on COW instead |
3572 | * of the full address range. |
3573 | */ |
3574 | if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && |
3575 | old_page != pagecache_page) |
3576 | outside_reserve = 1; |
3577 | |
3578 | get_page(old_page); |
3579 | |
3580 | /* |
3581 | * Drop page table lock as buddy allocator may be called. It will |
3582 | * be acquired again before returning to the caller, as expected. |
3583 | */ |
3584 | spin_unlock(ptl); |
3585 | new_page = alloc_huge_page(vma, haddr, outside_reserve); |
3586 | |
3587 | if (IS_ERR(new_page)) { |
3588 | /* |
3589 | * If a process owning a MAP_PRIVATE mapping fails to COW, |
3590 | * it is due to references held by a child and an insufficient |
3591 | * huge page pool. To guarantee the original mappers |
3592 | * reliability, unmap the page from child processes. The child |
3593 | * may get SIGKILLed if it later faults. |
3594 | */ |
3595 | if (outside_reserve) { |
3596 | put_page(old_page); |
3597 | BUG_ON(huge_pte_none(pte)); |
3598 | unmap_ref_private(mm, vma, old_page, haddr); |
3599 | BUG_ON(huge_pte_none(pte)); |
3600 | spin_lock(ptl); |
3601 | ptep = huge_pte_offset(mm, haddr, huge_page_size(h)); |
3602 | if (likely(ptep && |
3603 | pte_same(huge_ptep_get(ptep), pte))) |
3604 | goto retry_avoidcopy; |
3605 | /* |
3606 | * race occurs while re-acquiring page table |
3607 | * lock, and our job is done. |
3608 | */ |
3609 | return 0; |
3610 | } |
3611 | |
3612 | ret = vmf_error(PTR_ERR(new_page)); |
3613 | goto out_release_old; |
3614 | } |
3615 | |
3616 | /* |
3617 | * When the original hugepage is shared one, it does not have |
3618 | * anon_vma prepared. |
3619 | */ |
3620 | if (unlikely(anon_vma_prepare(vma))) { |
3621 | ret = VM_FAULT_OOM; |
3622 | goto out_release_all; |
3623 | } |
3624 | |
3625 | copy_user_huge_page(new_page, old_page, address, vma, |
3626 | pages_per_huge_page(h)); |
3627 | __SetPageUptodate(new_page); |
3628 | |
3629 | mmu_notifier_range_init(&range, mm, haddr, haddr + huge_page_size(h)); |
3630 | mmu_notifier_invalidate_range_start(&range); |
3631 | |
3632 | /* |
3633 | * Retake the page table lock to check for racing updates |
3634 | * before the page tables are altered |
3635 | */ |
3636 | spin_lock(ptl); |
3637 | ptep = huge_pte_offset(mm, haddr, huge_page_size(h)); |
3638 | if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) { |
3639 | ClearPagePrivate(new_page); |
3640 | |
3641 | /* Break COW */ |
3642 | huge_ptep_clear_flush(vma, haddr, ptep); |
3643 | mmu_notifier_invalidate_range(mm, range.start, range.end); |
3644 | set_huge_pte_at(mm, haddr, ptep, |
3645 | make_huge_pte(vma, new_page, 1)); |
3646 | page_remove_rmap(old_page, true); |
3647 | hugepage_add_new_anon_rmap(new_page, vma, haddr); |
3648 | set_page_huge_active(new_page); |
3649 | /* Make the old page be freed below */ |
3650 | new_page = old_page; |
3651 | } |
3652 | spin_unlock(ptl); |
3653 | mmu_notifier_invalidate_range_end(&range); |
3654 | out_release_all: |
3655 | restore_reserve_on_error(h, vma, haddr, new_page); |
3656 | put_page(new_page); |
3657 | out_release_old: |
3658 | put_page(old_page); |
3659 | |
3660 | spin_lock(ptl); /* Caller expects lock to be held */ |
3661 | return ret; |
3662 | } |
3663 | |
3664 | /* Return the pagecache page at a given address within a VMA */ |
3665 | static struct page *hugetlbfs_pagecache_page(struct hstate *h, |
3666 | struct vm_area_struct *vma, unsigned long address) |
3667 | { |
3668 | struct address_space *mapping; |
3669 | pgoff_t idx; |
3670 | |
3671 | mapping = vma->vm_file->f_mapping; |
3672 | idx = vma_hugecache_offset(h, vma, address); |
3673 | |
3674 | return find_lock_page(mapping, idx); |
3675 | } |
3676 | |
3677 | /* |
3678 | * Return whether there is a pagecache page to back given address within VMA. |
3679 | * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. |
3680 | */ |
3681 | static bool hugetlbfs_pagecache_present(struct hstate *h, |
3682 | struct vm_area_struct *vma, unsigned long address) |
3683 | { |
3684 | struct address_space *mapping; |
3685 | pgoff_t idx; |
3686 | struct page *page; |
3687 | |
3688 | mapping = vma->vm_file->f_mapping; |
3689 | idx = vma_hugecache_offset(h, vma, address); |
3690 | |
3691 | page = find_get_page(mapping, idx); |
3692 | if (page) |
3693 | put_page(page); |
3694 | return page != NULL; |
3695 | } |
3696 | |
3697 | int huge_add_to_page_cache(struct page *page, struct address_space *mapping, |
3698 | pgoff_t idx) |
3699 | { |
3700 | struct inode *inode = mapping->host; |
3701 | struct hstate *h = hstate_inode(inode); |
3702 | int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); |
3703 | |
3704 | if (err) |
3705 | return err; |
3706 | ClearPagePrivate(page); |
3707 | |
3708 | /* |
3709 | * set page dirty so that it will not be removed from cache/file |
3710 | * by non-hugetlbfs specific code paths. |
3711 | */ |
3712 | set_page_dirty(page); |
3713 | |
3714 | spin_lock(&inode->i_lock); |
3715 | inode->i_blocks += blocks_per_huge_page(h); |
3716 | spin_unlock(&inode->i_lock); |
3717 | return 0; |
3718 | } |
3719 | |
3720 | static vm_fault_t hugetlb_no_page(struct mm_struct *mm, |
3721 | struct vm_area_struct *vma, |
3722 | struct address_space *mapping, pgoff_t idx, |
3723 | unsigned long address, pte_t *ptep, unsigned int flags) |
3724 | { |
3725 | struct hstate *h = hstate_vma(vma); |
3726 | vm_fault_t ret = VM_FAULT_SIGBUS; |
3727 | int anon_rmap = 0; |
3728 | unsigned long size; |
3729 | struct page *page; |
3730 | pte_t new_pte; |
3731 | spinlock_t *ptl; |
3732 | unsigned long haddr = address & huge_page_mask(h); |
3733 | bool new_page = false; |
3734 | |
3735 | /* |
3736 | * Currently, we are forced to kill the process in the event the |
3737 | * original mapper has unmapped pages from the child due to a failed |
3738 | * COW. Warn that such a situation has occurred as it may not be obvious |
3739 | */ |
3740 | if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { |
3741 | pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n" , |
3742 | current->pid); |
3743 | return ret; |
3744 | } |
3745 | |
3746 | /* |
3747 | * Use page lock to guard against racing truncation |
3748 | * before we get page_table_lock. |
3749 | */ |
3750 | retry: |
3751 | page = find_lock_page(mapping, idx); |
3752 | if (!page) { |
3753 | size = i_size_read(mapping->host) >> huge_page_shift(h); |
3754 | if (idx >= size) |
3755 | goto out; |
3756 | |
3757 | /* |
3758 | * Check for page in userfault range |
3759 | */ |
3760 | if (userfaultfd_missing(vma)) { |
3761 | u32 hash; |
3762 | struct vm_fault vmf = { |
3763 | .vma = vma, |
3764 | .address = haddr, |
3765 | .flags = flags, |
3766 | /* |
3767 | * Hard to debug if it ends up being |
3768 | * used by a callee that assumes |
3769 | * something about the other |
3770 | * uninitialized fields... same as in |
3771 | * memory.c |
3772 | */ |
3773 | }; |
3774 | |
3775 | /* |
3776 | * hugetlb_fault_mutex must be dropped before |
3777 | * handling userfault. Reacquire after handling |
3778 | * fault to make calling code simpler. |
3779 | */ |
3780 | hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping, |
3781 | idx, haddr); |
3782 | mutex_unlock(&hugetlb_fault_mutex_table[hash]); |
3783 | ret = handle_userfault(&vmf, VM_UFFD_MISSING); |
3784 | mutex_lock(&hugetlb_fault_mutex_table[hash]); |
3785 | goto out; |
3786 | } |
3787 | |
3788 | page = alloc_huge_page(vma, haddr, 0); |
3789 | if (IS_ERR(page)) { |
3790 | ret = vmf_error(PTR_ERR(page)); |
3791 | goto out; |
3792 | } |
3793 | clear_huge_page(page, address, pages_per_huge_page(h)); |
3794 | __SetPageUptodate(page); |
3795 | new_page = true; |
3796 | |
3797 | if (vma->vm_flags & VM_MAYSHARE) { |
3798 | int err = huge_add_to_page_cache(page, mapping, idx); |
3799 | if (err) { |
3800 | put_page(page); |
3801 | if (err == -EEXIST) |
3802 | goto retry; |
3803 | goto out; |
3804 | } |
3805 | } else { |
3806 | lock_page(page); |
3807 | if (unlikely(anon_vma_prepare(vma))) { |
3808 | ret = VM_FAULT_OOM; |
3809 | goto backout_unlocked; |
3810 | } |
3811 | anon_rmap = 1; |
3812 | } |
3813 | } else { |
3814 | /* |
3815 | * If memory error occurs between mmap() and fault, some process |
3816 | * don't have hwpoisoned swap entry for errored virtual address. |
3817 | * So we need to block hugepage fault by PG_hwpoison bit check. |
3818 | */ |
3819 | if (unlikely(PageHWPoison(page))) { |
3820 | ret = VM_FAULT_HWPOISON | |
3821 | VM_FAULT_SET_HINDEX(hstate_index(h)); |
3822 | goto backout_unlocked; |
3823 | } |
3824 | } |
3825 | |
3826 | /* |
3827 | * If we are going to COW a private mapping later, we examine the |
3828 | * pending reservations for this page now. This will ensure that |
3829 | * any allocations necessary to record that reservation occur outside |
3830 | * the spinlock. |
3831 | */ |
3832 | if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { |
3833 | if (vma_needs_reservation(h, vma, haddr) < 0) { |
3834 | ret = VM_FAULT_OOM; |
3835 | goto |
---|