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1 | /* |
2 | * Generic hugetlb support. |
3 | * (C) Nadia Yvette Chambers, April 2004 |
4 | */ |
5 | #include <linux/list.h> |
6 | #include <linux/init.h> |
7 | #include <linux/module.h> |
8 | #include <linux/mm.h> |
9 | #include <linux/seq_file.h> |
10 | #include <linux/sysctl.h> |
11 | #include <linux/highmem.h> |
12 | #include <linux/mmu_notifier.h> |
13 | #include <linux/nodemask.h> |
14 | #include <linux/pagemap.h> |
15 | #include <linux/mempolicy.h> |
16 | #include <linux/compiler.h> |
17 | #include <linux/cpuset.h> |
18 | #include <linux/mutex.h> |
19 | #include <linux/bootmem.h> |
20 | #include <linux/sysfs.h> |
21 | #include <linux/slab.h> |
22 | #include <linux/rmap.h> |
23 | #include <linux/swap.h> |
24 | #include <linux/swapops.h> |
25 | #include <linux/page-isolation.h> |
26 | #include <linux/jhash.h> |
27 | |
28 | #include <asm/page.h> |
29 | #include <asm/pgtable.h> |
30 | #include <asm/tlb.h> |
31 | |
32 | #include <linux/io.h> |
33 | #include <linux/hugetlb.h> |
34 | #include <linux/hugetlb_cgroup.h> |
35 | #include <linux/node.h> |
36 | #include "internal.h" |
37 | |
38 | const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; |
39 | unsigned long hugepages_treat_as_movable; |
40 | |
41 | int hugetlb_max_hstate __read_mostly; |
42 | unsigned int default_hstate_idx; |
43 | struct hstate hstates[HUGE_MAX_HSTATE]; |
44 | |
45 | __initdata LIST_HEAD(huge_boot_pages); |
46 | |
47 | /* for command line parsing */ |
48 | static struct hstate * __initdata parsed_hstate; |
49 | static unsigned long __initdata default_hstate_max_huge_pages; |
50 | static unsigned long __initdata default_hstate_size; |
51 | |
52 | /* |
53 | * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages, |
54 | * free_huge_pages, and surplus_huge_pages. |
55 | */ |
56 | DEFINE_SPINLOCK(hugetlb_lock); |
57 | |
58 | /* |
59 | * Serializes faults on the same logical page. This is used to |
60 | * prevent spurious OOMs when the hugepage pool is fully utilized. |
61 | */ |
62 | static int num_fault_mutexes; |
63 | static struct mutex *htlb_fault_mutex_table ____cacheline_aligned_in_smp; |
64 | |
65 | static inline void unlock_or_release_subpool(struct hugepage_subpool *spool) |
66 | { |
67 | bool free = (spool->count == 0) && (spool->used_hpages == 0); |
68 | |
69 | spin_unlock(&spool->lock); |
70 | |
71 | /* If no pages are used, and no other handles to the subpool |
72 | * remain, free the subpool the subpool remain */ |
73 | if (free) |
74 | kfree(spool); |
75 | } |
76 | |
77 | struct hugepage_subpool *hugepage_new_subpool(long nr_blocks) |
78 | { |
79 | struct hugepage_subpool *spool; |
80 | |
81 | spool = kmalloc(sizeof(*spool), GFP_KERNEL); |
82 | if (!spool) |
83 | return NULL; |
84 | |
85 | spin_lock_init(&spool->lock); |
86 | spool->count = 1; |
87 | spool->max_hpages = nr_blocks; |
88 | spool->used_hpages = 0; |
89 | |
90 | return spool; |
91 | } |
92 | |
93 | void hugepage_put_subpool(struct hugepage_subpool *spool) |
94 | { |
95 | spin_lock(&spool->lock); |
96 | BUG_ON(!spool->count); |
97 | spool->count--; |
98 | unlock_or_release_subpool(spool); |
99 | } |
100 | |
101 | static int hugepage_subpool_get_pages(struct hugepage_subpool *spool, |
102 | long delta) |
103 | { |
104 | int ret = 0; |
105 | |
106 | if (!spool) |
107 | return 0; |
108 | |
109 | spin_lock(&spool->lock); |
110 | if ((spool->used_hpages + delta) <= spool->max_hpages) { |
111 | spool->used_hpages += delta; |
112 | } else { |
113 | ret = -ENOMEM; |
114 | } |
115 | spin_unlock(&spool->lock); |
116 | |
117 | return ret; |
118 | } |
119 | |
120 | static void hugepage_subpool_put_pages(struct hugepage_subpool *spool, |
121 | long delta) |
122 | { |
123 | if (!spool) |
124 | return; |
125 | |
126 | spin_lock(&spool->lock); |
127 | spool->used_hpages -= delta; |
128 | /* If hugetlbfs_put_super couldn't free spool due to |
129 | * an outstanding quota reference, free it now. */ |
130 | unlock_or_release_subpool(spool); |
131 | } |
132 | |
133 | static inline struct hugepage_subpool *subpool_inode(struct inode *inode) |
134 | { |
135 | return HUGETLBFS_SB(inode->i_sb)->spool; |
136 | } |
137 | |
138 | static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma) |
139 | { |
140 | return subpool_inode(file_inode(vma->vm_file)); |
141 | } |
142 | |
143 | /* |
144 | * Region tracking -- allows tracking of reservations and instantiated pages |
145 | * across the pages in a mapping. |
146 | * |
147 | * The region data structures are embedded into a resv_map and |
148 | * protected by a resv_map's lock |
149 | */ |
150 | struct file_region { |
151 | struct list_head link; |
152 | long from; |
153 | long to; |
154 | }; |
155 | |
156 | static long region_add(struct resv_map *resv, long f, long t) |
157 | { |
158 | struct list_head *head = &resv->regions; |
159 | struct file_region *rg, *nrg, *trg; |
160 | |
161 | spin_lock(&resv->lock); |
162 | /* Locate the region we are either in or before. */ |
163 | list_for_each_entry(rg, head, link) |
164 | if (f <= rg->to) |
165 | break; |
166 | |
167 | /* Round our left edge to the current segment if it encloses us. */ |
168 | if (f > rg->from) |
169 | f = rg->from; |
170 | |
171 | /* Check for and consume any regions we now overlap with. */ |
172 | nrg = rg; |
173 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { |
174 | if (&rg->link == head) |
175 | break; |
176 | if (rg->from > t) |
177 | break; |
178 | |
179 | /* If this area reaches higher then extend our area to |
180 | * include it completely. If this is not the first area |
181 | * which we intend to reuse, free it. */ |
182 | if (rg->to > t) |
183 | t = rg->to; |
184 | if (rg != nrg) { |
185 | list_del(&rg->link); |
186 | kfree(rg); |
187 | } |
188 | } |
189 | nrg->from = f; |
190 | nrg->to = t; |
191 | spin_unlock(&resv->lock); |
192 | return 0; |
193 | } |
194 | |
195 | static long region_chg(struct resv_map *resv, long f, long t) |
196 | { |
197 | struct list_head *head = &resv->regions; |
198 | struct file_region *rg, *nrg = NULL; |
199 | long chg = 0; |
200 | |
201 | retry: |
202 | spin_lock(&resv->lock); |
203 | /* Locate the region we are before or in. */ |
204 | list_for_each_entry(rg, head, link) |
205 | if (f <= rg->to) |
206 | break; |
207 | |
208 | /* If we are below the current region then a new region is required. |
209 | * Subtle, allocate a new region at the position but make it zero |
210 | * size such that we can guarantee to record the reservation. */ |
211 | if (&rg->link == head || t < rg->from) { |
212 | if (!nrg) { |
213 | spin_unlock(&resv->lock); |
214 | nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); |
215 | if (!nrg) |
216 | return -ENOMEM; |
217 | |
218 | nrg->from = f; |
219 | nrg->to = f; |
220 | INIT_LIST_HEAD(&nrg->link); |
221 | goto retry; |
222 | } |
223 | |
224 | list_add(&nrg->link, rg->link.prev); |
225 | chg = t - f; |
226 | goto out_nrg; |
227 | } |
228 | |
229 | /* Round our left edge to the current segment if it encloses us. */ |
230 | if (f > rg->from) |
231 | f = rg->from; |
232 | chg = t - f; |
233 | |
234 | /* Check for and consume any regions we now overlap with. */ |
235 | list_for_each_entry(rg, rg->link.prev, link) { |
236 | if (&rg->link == head) |
237 | break; |
238 | if (rg->from > t) |
239 | goto out; |
240 | |
241 | /* We overlap with this area, if it extends further than |
242 | * us then we must extend ourselves. Account for its |
243 | * existing reservation. */ |
244 | if (rg->to > t) { |
245 | chg += rg->to - t; |
246 | t = rg->to; |
247 | } |
248 | chg -= rg->to - rg->from; |
249 | } |
250 | |
251 | out: |
252 | spin_unlock(&resv->lock); |
253 | /* We already know we raced and no longer need the new region */ |
254 | kfree(nrg); |
255 | return chg; |
256 | out_nrg: |
257 | spin_unlock(&resv->lock); |
258 | return chg; |
259 | } |
260 | |
261 | static long region_truncate(struct resv_map *resv, long end) |
262 | { |
263 | struct list_head *head = &resv->regions; |
264 | struct file_region *rg, *trg; |
265 | long chg = 0; |
266 | |
267 | spin_lock(&resv->lock); |
268 | /* Locate the region we are either in or before. */ |
269 | list_for_each_entry(rg, head, link) |
270 | if (end <= rg->to) |
271 | break; |
272 | if (&rg->link == head) |
273 | goto out; |
274 | |
275 | /* If we are in the middle of a region then adjust it. */ |
276 | if (end > rg->from) { |
277 | chg = rg->to - end; |
278 | rg->to = end; |
279 | rg = list_entry(rg->link.next, typeof(*rg), link); |
280 | } |
281 | |
282 | /* Drop any remaining regions. */ |
283 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { |
284 | if (&rg->link == head) |
285 | break; |
286 | chg += rg->to - rg->from; |
287 | list_del(&rg->link); |
288 | kfree(rg); |
289 | } |
290 | |
291 | out: |
292 | spin_unlock(&resv->lock); |
293 | return chg; |
294 | } |
295 | |
296 | static long region_count(struct resv_map *resv, long f, long t) |
297 | { |
298 | struct list_head *head = &resv->regions; |
299 | struct file_region *rg; |
300 | long chg = 0; |
301 | |
302 | spin_lock(&resv->lock); |
303 | /* Locate each segment we overlap with, and count that overlap. */ |
304 | list_for_each_entry(rg, head, link) { |
305 | long seg_from; |
306 | long seg_to; |
307 | |
308 | if (rg->to <= f) |
309 | continue; |
310 | if (rg->from >= t) |
311 | break; |
312 | |
313 | seg_from = max(rg->from, f); |
314 | seg_to = min(rg->to, t); |
315 | |
316 | chg += seg_to - seg_from; |
317 | } |
318 | spin_unlock(&resv->lock); |
319 | |
320 | return chg; |
321 | } |
322 | |
323 | /* |
324 | * Convert the address within this vma to the page offset within |
325 | * the mapping, in pagecache page units; huge pages here. |
326 | */ |
327 | static pgoff_t vma_hugecache_offset(struct hstate *h, |
328 | struct vm_area_struct *vma, unsigned long address) |
329 | { |
330 | return ((address - vma->vm_start) >> huge_page_shift(h)) + |
331 | (vma->vm_pgoff >> huge_page_order(h)); |
332 | } |
333 | |
334 | pgoff_t linear_hugepage_index(struct vm_area_struct *vma, |
335 | unsigned long address) |
336 | { |
337 | return vma_hugecache_offset(hstate_vma(vma), vma, address); |
338 | } |
339 | |
340 | /* |
341 | * Return the size of the pages allocated when backing a VMA. In the majority |
342 | * cases this will be same size as used by the page table entries. |
343 | */ |
344 | unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) |
345 | { |
346 | struct hstate *hstate; |
347 | |
348 | if (!is_vm_hugetlb_page(vma)) |
349 | return PAGE_SIZE; |
350 | |
351 | hstate = hstate_vma(vma); |
352 | |
353 | return 1UL << huge_page_shift(hstate); |
354 | } |
355 | EXPORT_SYMBOL_GPL(vma_kernel_pagesize); |
356 | |
357 | /* |
358 | * Return the page size being used by the MMU to back a VMA. In the majority |
359 | * of cases, the page size used by the kernel matches the MMU size. On |
360 | * architectures where it differs, an architecture-specific version of this |
361 | * function is required. |
362 | */ |
363 | #ifndef vma_mmu_pagesize |
364 | unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) |
365 | { |
366 | return vma_kernel_pagesize(vma); |
367 | } |
368 | #endif |
369 | |
370 | /* |
371 | * Flags for MAP_PRIVATE reservations. These are stored in the bottom |
372 | * bits of the reservation map pointer, which are always clear due to |
373 | * alignment. |
374 | */ |
375 | #define HPAGE_RESV_OWNER (1UL << 0) |
376 | #define HPAGE_RESV_UNMAPPED (1UL << 1) |
377 | #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) |
378 | |
379 | /* |
380 | * These helpers are used to track how many pages are reserved for |
381 | * faults in a MAP_PRIVATE mapping. Only the process that called mmap() |
382 | * is guaranteed to have their future faults succeed. |
383 | * |
384 | * With the exception of reset_vma_resv_huge_pages() which is called at fork(), |
385 | * the reserve counters are updated with the hugetlb_lock held. It is safe |
386 | * to reset the VMA at fork() time as it is not in use yet and there is no |
387 | * chance of the global counters getting corrupted as a result of the values. |
388 | * |
389 | * The private mapping reservation is represented in a subtly different |
390 | * manner to a shared mapping. A shared mapping has a region map associated |
391 | * with the underlying file, this region map represents the backing file |
392 | * pages which have ever had a reservation assigned which this persists even |
393 | * after the page is instantiated. A private mapping has a region map |
394 | * associated with the original mmap which is attached to all VMAs which |
395 | * reference it, this region map represents those offsets which have consumed |
396 | * reservation ie. where pages have been instantiated. |
397 | */ |
398 | static unsigned long get_vma_private_data(struct vm_area_struct *vma) |
399 | { |
400 | return (unsigned long)vma->vm_private_data; |
401 | } |
402 | |
403 | static void set_vma_private_data(struct vm_area_struct *vma, |
404 | unsigned long value) |
405 | { |
406 | vma->vm_private_data = (void *)value; |
407 | } |
408 | |
409 | struct resv_map *resv_map_alloc(void) |
410 | { |
411 | struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); |
412 | if (!resv_map) |
413 | return NULL; |
414 | |
415 | kref_init(&resv_map->refs); |
416 | spin_lock_init(&resv_map->lock); |
417 | INIT_LIST_HEAD(&resv_map->regions); |
418 | |
419 | return resv_map; |
420 | } |
421 | |
422 | void resv_map_release(struct kref *ref) |
423 | { |
424 | struct resv_map *resv_map = container_of(ref, struct resv_map, refs); |
425 | |
426 | /* Clear out any active regions before we release the map. */ |
427 | region_truncate(resv_map, 0); |
428 | kfree(resv_map); |
429 | } |
430 | |
431 | static inline struct resv_map *inode_resv_map(struct inode *inode) |
432 | { |
433 | return inode->i_mapping->private_data; |
434 | } |
435 | |
436 | static struct resv_map *vma_resv_map(struct vm_area_struct *vma) |
437 | { |
438 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
439 | if (vma->vm_flags & VM_MAYSHARE) { |
440 | struct address_space *mapping = vma->vm_file->f_mapping; |
441 | struct inode *inode = mapping->host; |
442 | |
443 | return inode_resv_map(inode); |
444 | |
445 | } else { |
446 | return (struct resv_map *)(get_vma_private_data(vma) & |
447 | ~HPAGE_RESV_MASK); |
448 | } |
449 | } |
450 | |
451 | static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) |
452 | { |
453 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
454 | VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); |
455 | |
456 | set_vma_private_data(vma, (get_vma_private_data(vma) & |
457 | HPAGE_RESV_MASK) | (unsigned long)map); |
458 | } |
459 | |
460 | static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) |
461 | { |
462 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
463 | VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); |
464 | |
465 | set_vma_private_data(vma, get_vma_private_data(vma) | flags); |
466 | } |
467 | |
468 | static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) |
469 | { |
470 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
471 | |
472 | return (get_vma_private_data(vma) & flag) != 0; |
473 | } |
474 | |
475 | /* Reset counters to 0 and clear all HPAGE_RESV_* flags */ |
476 | void reset_vma_resv_huge_pages(struct vm_area_struct *vma) |
477 | { |
478 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
479 | if (!(vma->vm_flags & VM_MAYSHARE)) |
480 | vma->vm_private_data = (void *)0; |
481 | } |
482 | |
483 | /* Returns true if the VMA has associated reserve pages */ |
484 | static int vma_has_reserves(struct vm_area_struct *vma, long chg) |
485 | { |
486 | if (vma->vm_flags & VM_NORESERVE) { |
487 | /* |
488 | * This address is already reserved by other process(chg == 0), |
489 | * so, we should decrement reserved count. Without decrementing, |
490 | * reserve count remains after releasing inode, because this |
491 | * allocated page will go into page cache and is regarded as |
492 | * coming from reserved pool in releasing step. Currently, we |
493 | * don't have any other solution to deal with this situation |
494 | * properly, so add work-around here. |
495 | */ |
496 | if (vma->vm_flags & VM_MAYSHARE && chg == 0) |
497 | return 1; |
498 | else |
499 | return 0; |
500 | } |
501 | |
502 | /* Shared mappings always use reserves */ |
503 | if (vma->vm_flags & VM_MAYSHARE) |
504 | return 1; |
505 | |
506 | /* |
507 | * Only the process that called mmap() has reserves for |
508 | * private mappings. |
509 | */ |
510 | if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
511 | return 1; |
512 | |
513 | return 0; |
514 | } |
515 | |
516 | static void enqueue_huge_page(struct hstate *h, struct page *page) |
517 | { |
518 | int nid = page_to_nid(page); |
519 | list_move(&page->lru, &h->hugepage_freelists[nid]); |
520 | h->free_huge_pages++; |
521 | h->free_huge_pages_node[nid]++; |
522 | } |
523 | |
524 | static struct page *dequeue_huge_page_node(struct hstate *h, int nid) |
525 | { |
526 | struct page *page; |
527 | |
528 | list_for_each_entry(page, &h->hugepage_freelists[nid], lru) |
529 | if (!is_migrate_isolate_page(page)) |
530 | break; |
531 | /* |
532 | * if 'non-isolated free hugepage' not found on the list, |
533 | * the allocation fails. |
534 | */ |
535 | if (&h->hugepage_freelists[nid] == &page->lru) |
536 | return NULL; |
537 | list_move(&page->lru, &h->hugepage_activelist); |
538 | set_page_refcounted(page); |
539 | h->free_huge_pages--; |
540 | h->free_huge_pages_node[nid]--; |
541 | return page; |
542 | } |
543 | |
544 | /* Movability of hugepages depends on migration support. */ |
545 | static inline gfp_t htlb_alloc_mask(struct hstate *h) |
546 | { |
547 | if (hugepages_treat_as_movable || hugepage_migration_support(h)) |
548 | return GFP_HIGHUSER_MOVABLE; |
549 | else |
550 | return GFP_HIGHUSER; |
551 | } |
552 | |
553 | static struct page *dequeue_huge_page_vma(struct hstate *h, |
554 | struct vm_area_struct *vma, |
555 | unsigned long address, int avoid_reserve, |
556 | long chg) |
557 | { |
558 | struct page *page = NULL; |
559 | struct mempolicy *mpol; |
560 | nodemask_t *nodemask; |
561 | struct zonelist *zonelist; |
562 | struct zone *zone; |
563 | struct zoneref *z; |
564 | unsigned int cpuset_mems_cookie; |
565 | |
566 | /* |
567 | * A child process with MAP_PRIVATE mappings created by their parent |
568 | * have no page reserves. This check ensures that reservations are |
569 | * not "stolen". The child may still get SIGKILLed |
570 | */ |
571 | if (!vma_has_reserves(vma, chg) && |
572 | h->free_huge_pages - h->resv_huge_pages == 0) |
573 | goto err; |
574 | |
575 | /* If reserves cannot be used, ensure enough pages are in the pool */ |
576 | if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) |
577 | goto err; |
578 | |
579 | retry_cpuset: |
580 | cpuset_mems_cookie = read_mems_allowed_begin(); |
581 | zonelist = huge_zonelist(vma, address, |
582 | htlb_alloc_mask(h), &mpol, &nodemask); |
583 | |
584 | for_each_zone_zonelist_nodemask(zone, z, zonelist, |
585 | MAX_NR_ZONES - 1, nodemask) { |
586 | if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask(h))) { |
587 | page = dequeue_huge_page_node(h, zone_to_nid(zone)); |
588 | if (page) { |
589 | if (avoid_reserve) |
590 | break; |
591 | if (!vma_has_reserves(vma, chg)) |
592 | break; |
593 | |
594 | SetPagePrivate(page); |
595 | h->resv_huge_pages--; |
596 | break; |
597 | } |
598 | } |
599 | } |
600 | |
601 | mpol_cond_put(mpol); |
602 | if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie))) |
603 | goto retry_cpuset; |
604 | return page; |
605 | |
606 | err: |
607 | return NULL; |
608 | } |
609 | |
610 | static void update_and_free_page(struct hstate *h, struct page *page) |
611 | { |
612 | int i; |
613 | |
614 | VM_BUG_ON(h->order >= MAX_ORDER); |
615 | |
616 | h->nr_huge_pages--; |
617 | h->nr_huge_pages_node[page_to_nid(page)]--; |
618 | for (i = 0; i < pages_per_huge_page(h); i++) { |
619 | page[i].flags &= ~(1 << PG_locked | 1 << PG_error | |
620 | 1 << PG_referenced | 1 << PG_dirty | |
621 | 1 << PG_active | 1 << PG_reserved | |
622 | 1 << PG_private | 1 << PG_writeback); |
623 | } |
624 | VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page); |
625 | set_compound_page_dtor(page, NULL); |
626 | set_page_refcounted(page); |
627 | arch_release_hugepage(page); |
628 | __free_pages(page, huge_page_order(h)); |
629 | } |
630 | |
631 | struct hstate *size_to_hstate(unsigned long size) |
632 | { |
633 | struct hstate *h; |
634 | |
635 | for_each_hstate(h) { |
636 | if (huge_page_size(h) == size) |
637 | return h; |
638 | } |
639 | return NULL; |
640 | } |
641 | |
642 | static void free_huge_page(struct page *page) |
643 | { |
644 | /* |
645 | * Can't pass hstate in here because it is called from the |
646 | * compound page destructor. |
647 | */ |
648 | struct hstate *h = page_hstate(page); |
649 | int nid = page_to_nid(page); |
650 | struct hugepage_subpool *spool = |
651 | (struct hugepage_subpool *)page_private(page); |
652 | bool restore_reserve; |
653 | |
654 | set_page_private(page, 0); |
655 | page->mapping = NULL; |
656 | BUG_ON(page_count(page)); |
657 | BUG_ON(page_mapcount(page)); |
658 | restore_reserve = PagePrivate(page); |
659 | ClearPagePrivate(page); |
660 | |
661 | spin_lock(&hugetlb_lock); |
662 | hugetlb_cgroup_uncharge_page(hstate_index(h), |
663 | pages_per_huge_page(h), page); |
664 | if (restore_reserve) |
665 | h->resv_huge_pages++; |
666 | |
667 | if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { |
668 | /* remove the page from active list */ |
669 | list_del(&page->lru); |
670 | update_and_free_page(h, page); |
671 | h->surplus_huge_pages--; |
672 | h->surplus_huge_pages_node[nid]--; |
673 | } else { |
674 | arch_clear_hugepage_flags(page); |
675 | enqueue_huge_page(h, page); |
676 | } |
677 | spin_unlock(&hugetlb_lock); |
678 | hugepage_subpool_put_pages(spool, 1); |
679 | } |
680 | |
681 | static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) |
682 | { |
683 | INIT_LIST_HEAD(&page->lru); |
684 | set_compound_page_dtor(page, free_huge_page); |
685 | spin_lock(&hugetlb_lock); |
686 | set_hugetlb_cgroup(page, NULL); |
687 | h->nr_huge_pages++; |
688 | h->nr_huge_pages_node[nid]++; |
689 | spin_unlock(&hugetlb_lock); |
690 | put_page(page); /* free it into the hugepage allocator */ |
691 | } |
692 | |
693 | static void __init prep_compound_gigantic_page(struct page *page, |
694 | unsigned long order) |
695 | { |
696 | int i; |
697 | int nr_pages = 1 << order; |
698 | struct page *p = page + 1; |
699 | |
700 | /* we rely on prep_new_huge_page to set the destructor */ |
701 | set_compound_order(page, order); |
702 | __SetPageHead(page); |
703 | __ClearPageReserved(page); |
704 | for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { |
705 | __SetPageTail(p); |
706 | /* |
707 | * For gigantic hugepages allocated through bootmem at |
708 | * boot, it's safer to be consistent with the not-gigantic |
709 | * hugepages and clear the PG_reserved bit from all tail pages |
710 | * too. Otherwse drivers using get_user_pages() to access tail |
711 | * pages may get the reference counting wrong if they see |
712 | * PG_reserved set on a tail page (despite the head page not |
713 | * having PG_reserved set). Enforcing this consistency between |
714 | * head and tail pages allows drivers to optimize away a check |
715 | * on the head page when they need know if put_page() is needed |
716 | * after get_user_pages(). |
717 | */ |
718 | __ClearPageReserved(p); |
719 | set_page_count(p, 0); |
720 | p->first_page = page; |
721 | } |
722 | } |
723 | |
724 | /* |
725 | * PageHuge() only returns true for hugetlbfs pages, but not for normal or |
726 | * transparent huge pages. See the PageTransHuge() documentation for more |
727 | * details. |
728 | */ |
729 | int PageHuge(struct page *page) |
730 | { |
731 | if (!PageCompound(page)) |
732 | return 0; |
733 | |
734 | page = compound_head(page); |
735 | return get_compound_page_dtor(page) == free_huge_page; |
736 | } |
737 | EXPORT_SYMBOL_GPL(PageHuge); |
738 | |
739 | /* |
740 | * PageHeadHuge() only returns true for hugetlbfs head page, but not for |
741 | * normal or transparent huge pages. |
742 | */ |
743 | int PageHeadHuge(struct page *page_head) |
744 | { |
745 | if (!PageHead(page_head)) |
746 | return 0; |
747 | |
748 | return get_compound_page_dtor(page_head) == free_huge_page; |
749 | } |
750 | |
751 | pgoff_t __basepage_index(struct page *page) |
752 | { |
753 | struct page *page_head = compound_head(page); |
754 | pgoff_t index = page_index(page_head); |
755 | unsigned long compound_idx; |
756 | |
757 | if (!PageHuge(page_head)) |
758 | return page_index(page); |
759 | |
760 | if (compound_order(page_head) >= MAX_ORDER) |
761 | compound_idx = page_to_pfn(page) - page_to_pfn(page_head); |
762 | else |
763 | compound_idx = page - page_head; |
764 | |
765 | return (index << compound_order(page_head)) + compound_idx; |
766 | } |
767 | |
768 | static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) |
769 | { |
770 | struct page *page; |
771 | |
772 | if (h->order >= MAX_ORDER) |
773 | return NULL; |
774 | |
775 | page = alloc_pages_exact_node(nid, |
776 | htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE| |
777 | __GFP_REPEAT|__GFP_NOWARN, |
778 | huge_page_order(h)); |
779 | if (page) { |
780 | if (arch_prepare_hugepage(page)) { |
781 | __free_pages(page, huge_page_order(h)); |
782 | return NULL; |
783 | } |
784 | prep_new_huge_page(h, page, nid); |
785 | } |
786 | |
787 | return page; |
788 | } |
789 | |
790 | /* |
791 | * common helper functions for hstate_next_node_to_{alloc|free}. |
792 | * We may have allocated or freed a huge page based on a different |
793 | * nodes_allowed previously, so h->next_node_to_{alloc|free} might |
794 | * be outside of *nodes_allowed. Ensure that we use an allowed |
795 | * node for alloc or free. |
796 | */ |
797 | static int next_node_allowed(int nid, nodemask_t *nodes_allowed) |
798 | { |
799 | nid = next_node(nid, *nodes_allowed); |
800 | if (nid == MAX_NUMNODES) |
801 | nid = first_node(*nodes_allowed); |
802 | VM_BUG_ON(nid >= MAX_NUMNODES); |
803 | |
804 | return nid; |
805 | } |
806 | |
807 | static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) |
808 | { |
809 | if (!node_isset(nid, *nodes_allowed)) |
810 | nid = next_node_allowed(nid, nodes_allowed); |
811 | return nid; |
812 | } |
813 | |
814 | /* |
815 | * returns the previously saved node ["this node"] from which to |
816 | * allocate a persistent huge page for the pool and advance the |
817 | * next node from which to allocate, handling wrap at end of node |
818 | * mask. |
819 | */ |
820 | static int hstate_next_node_to_alloc(struct hstate *h, |
821 | nodemask_t *nodes_allowed) |
822 | { |
823 | int nid; |
824 | |
825 | VM_BUG_ON(!nodes_allowed); |
826 | |
827 | nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); |
828 | h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); |
829 | |
830 | return nid; |
831 | } |
832 | |
833 | /* |
834 | * helper for free_pool_huge_page() - return the previously saved |
835 | * node ["this node"] from which to free a huge page. Advance the |
836 | * next node id whether or not we find a free huge page to free so |
837 | * that the next attempt to free addresses the next node. |
838 | */ |
839 | static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) |
840 | { |
841 | int nid; |
842 | |
843 | VM_BUG_ON(!nodes_allowed); |
844 | |
845 | nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); |
846 | h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); |
847 | |
848 | return nid; |
849 | } |
850 | |
851 | #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \ |
852 | for (nr_nodes = nodes_weight(*mask); \ |
853 | nr_nodes > 0 && \ |
854 | ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \ |
855 | nr_nodes--) |
856 | |
857 | #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \ |
858 | for (nr_nodes = nodes_weight(*mask); \ |
859 | nr_nodes > 0 && \ |
860 | ((node = hstate_next_node_to_free(hs, mask)) || 1); \ |
861 | nr_nodes--) |
862 | |
863 | static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) |
864 | { |
865 | struct page *page; |
866 | int nr_nodes, node; |
867 | int ret = 0; |
868 | |
869 | for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { |
870 | page = alloc_fresh_huge_page_node(h, node); |
871 | if (page) { |
872 | ret = 1; |
873 | break; |
874 | } |
875 | } |
876 | |
877 | if (ret) |
878 | count_vm_event(HTLB_BUDDY_PGALLOC); |
879 | else |
880 | count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
881 | |
882 | return ret; |
883 | } |
884 | |
885 | /* |
886 | * Free huge page from pool from next node to free. |
887 | * Attempt to keep persistent huge pages more or less |
888 | * balanced over allowed nodes. |
889 | * Called with hugetlb_lock locked. |
890 | */ |
891 | static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, |
892 | bool acct_surplus) |
893 | { |
894 | int nr_nodes, node; |
895 | int ret = 0; |
896 | |
897 | for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { |
898 | /* |
899 | * If we're returning unused surplus pages, only examine |
900 | * nodes with surplus pages. |
901 | */ |
902 | if ((!acct_surplus || h->surplus_huge_pages_node[node]) && |
903 | !list_empty(&h->hugepage_freelists[node])) { |
904 | struct page *page = |
905 | list_entry(h->hugepage_freelists[node].next, |
906 | struct page, lru); |
907 | list_del(&page->lru); |
908 | h->free_huge_pages--; |
909 | h->free_huge_pages_node[node]--; |
910 | if (acct_surplus) { |
911 | h->surplus_huge_pages--; |
912 | h->surplus_huge_pages_node[node]--; |
913 | } |
914 | update_and_free_page(h, page); |
915 | ret = 1; |
916 | break; |
917 | } |
918 | } |
919 | |
920 | return ret; |
921 | } |
922 | |
923 | /* |
924 | * Dissolve a given free hugepage into free buddy pages. This function does |
925 | * nothing for in-use (including surplus) hugepages. |
926 | */ |
927 | static void dissolve_free_huge_page(struct page *page) |
928 | { |
929 | spin_lock(&hugetlb_lock); |
930 | if (PageHuge(page) && !page_count(page)) { |
931 | struct hstate *h = page_hstate(page); |
932 | int nid = page_to_nid(page); |
933 | list_del(&page->lru); |
934 | h->free_huge_pages--; |
935 | h->free_huge_pages_node[nid]--; |
936 | update_and_free_page(h, page); |
937 | } |
938 | spin_unlock(&hugetlb_lock); |
939 | } |
940 | |
941 | /* |
942 | * Dissolve free hugepages in a given pfn range. Used by memory hotplug to |
943 | * make specified memory blocks removable from the system. |
944 | * Note that start_pfn should aligned with (minimum) hugepage size. |
945 | */ |
946 | void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) |
947 | { |
948 | unsigned int order = 8 * sizeof(void *); |
949 | unsigned long pfn; |
950 | struct hstate *h; |
951 | |
952 | /* Set scan step to minimum hugepage size */ |
953 | for_each_hstate(h) |
954 | if (order > huge_page_order(h)) |
955 | order = huge_page_order(h); |
956 | VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order)); |
957 | for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) |
958 | dissolve_free_huge_page(pfn_to_page(pfn)); |
959 | } |
960 | |
961 | static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) |
962 | { |
963 | struct page *page; |
964 | unsigned int r_nid; |
965 | |
966 | if (h->order >= MAX_ORDER) |
967 | return NULL; |
968 | |
969 | /* |
970 | * Assume we will successfully allocate the surplus page to |
971 | * prevent racing processes from causing the surplus to exceed |
972 | * overcommit |
973 | * |
974 | * This however introduces a different race, where a process B |
975 | * tries to grow the static hugepage pool while alloc_pages() is |
976 | * called by process A. B will only examine the per-node |
977 | * counters in determining if surplus huge pages can be |
978 | * converted to normal huge pages in adjust_pool_surplus(). A |
979 | * won't be able to increment the per-node counter, until the |
980 | * lock is dropped by B, but B doesn't drop hugetlb_lock until |
981 | * no more huge pages can be converted from surplus to normal |
982 | * state (and doesn't try to convert again). Thus, we have a |
983 | * case where a surplus huge page exists, the pool is grown, and |
984 | * the surplus huge page still exists after, even though it |
985 | * should just have been converted to a normal huge page. This |
986 | * does not leak memory, though, as the hugepage will be freed |
987 | * once it is out of use. It also does not allow the counters to |
988 | * go out of whack in adjust_pool_surplus() as we don't modify |
989 | * the node values until we've gotten the hugepage and only the |
990 | * per-node value is checked there. |
991 | */ |
992 | spin_lock(&hugetlb_lock); |
993 | if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { |
994 | spin_unlock(&hugetlb_lock); |
995 | return NULL; |
996 | } else { |
997 | h->nr_huge_pages++; |
998 | h->surplus_huge_pages++; |
999 | } |
1000 | spin_unlock(&hugetlb_lock); |
1001 | |
1002 | if (nid == NUMA_NO_NODE) |
1003 | page = alloc_pages(htlb_alloc_mask(h)|__GFP_COMP| |
1004 | __GFP_REPEAT|__GFP_NOWARN, |
1005 | huge_page_order(h)); |
1006 | else |
1007 | page = alloc_pages_exact_node(nid, |
1008 | htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE| |
1009 | __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h)); |
1010 | |
1011 | if (page && arch_prepare_hugepage(page)) { |
1012 | __free_pages(page, huge_page_order(h)); |
1013 | page = NULL; |
1014 | } |
1015 | |
1016 | spin_lock(&hugetlb_lock); |
1017 | if (page) { |
1018 | INIT_LIST_HEAD(&page->lru); |
1019 | r_nid = page_to_nid(page); |
1020 | set_compound_page_dtor(page, free_huge_page); |
1021 | set_hugetlb_cgroup(page, NULL); |
1022 | /* |
1023 | * We incremented the global counters already |
1024 | */ |
1025 | h->nr_huge_pages_node[r_nid]++; |
1026 | h->surplus_huge_pages_node[r_nid]++; |
1027 | __count_vm_event(HTLB_BUDDY_PGALLOC); |
1028 | } else { |
1029 | h->nr_huge_pages--; |
1030 | h->surplus_huge_pages--; |
1031 | __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
1032 | } |
1033 | spin_unlock(&hugetlb_lock); |
1034 | |
1035 | return page; |
1036 | } |
1037 | |
1038 | /* |
1039 | * This allocation function is useful in the context where vma is irrelevant. |
1040 | * E.g. soft-offlining uses this function because it only cares physical |
1041 | * address of error page. |
1042 | */ |
1043 | struct page *alloc_huge_page_node(struct hstate *h, int nid) |
1044 | { |
1045 | struct page *page = NULL; |
1046 | |
1047 | spin_lock(&hugetlb_lock); |
1048 | if (h->free_huge_pages - h->resv_huge_pages > 0) |
1049 | page = dequeue_huge_page_node(h, nid); |
1050 | spin_unlock(&hugetlb_lock); |
1051 | |
1052 | if (!page) |
1053 | page = alloc_buddy_huge_page(h, nid); |
1054 | |
1055 | return page; |
1056 | } |
1057 | |
1058 | /* |
1059 | * Increase the hugetlb pool such that it can accommodate a reservation |
1060 | * of size 'delta'. |
1061 | */ |
1062 | static int gather_surplus_pages(struct hstate *h, int delta) |
1063 | { |
1064 | struct list_head surplus_list; |
1065 | struct page *page, *tmp; |
1066 | int ret, i; |
1067 | int needed, allocated; |
1068 | bool alloc_ok = true; |
1069 | |
1070 | needed = (h->resv_huge_pages + delta) - h->free_huge_pages; |
1071 | if (needed <= 0) { |
1072 | h->resv_huge_pages += delta; |
1073 | return 0; |
1074 | } |
1075 | |
1076 | allocated = 0; |
1077 | INIT_LIST_HEAD(&surplus_list); |
1078 | |
1079 | ret = -ENOMEM; |
1080 | retry: |
1081 | spin_unlock(&hugetlb_lock); |
1082 | for (i = 0; i < needed; i++) { |
1083 | page = alloc_buddy_huge_page(h, NUMA_NO_NODE); |
1084 | if (!page) { |
1085 | alloc_ok = false; |
1086 | break; |
1087 | } |
1088 | list_add(&page->lru, &surplus_list); |
1089 | } |
1090 | allocated += i; |
1091 | |
1092 | /* |
1093 | * After retaking hugetlb_lock, we need to recalculate 'needed' |
1094 | * because either resv_huge_pages or free_huge_pages may have changed. |
1095 | */ |
1096 | spin_lock(&hugetlb_lock); |
1097 | needed = (h->resv_huge_pages + delta) - |
1098 | (h->free_huge_pages + allocated); |
1099 | if (needed > 0) { |
1100 | if (alloc_ok) |
1101 | goto retry; |
1102 | /* |
1103 | * We were not able to allocate enough pages to |
1104 | * satisfy the entire reservation so we free what |
1105 | * we've allocated so far. |
1106 | */ |
1107 | goto free; |
1108 | } |
1109 | /* |
1110 | * The surplus_list now contains _at_least_ the number of extra pages |
1111 | * needed to accommodate the reservation. Add the appropriate number |
1112 | * of pages to the hugetlb pool and free the extras back to the buddy |
1113 | * allocator. Commit the entire reservation here to prevent another |
1114 | * process from stealing the pages as they are added to the pool but |
1115 | * before they are reserved. |
1116 | */ |
1117 | needed += allocated; |
1118 | h->resv_huge_pages += delta; |
1119 | ret = 0; |
1120 | |
1121 | /* Free the needed pages to the hugetlb pool */ |
1122 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) { |
1123 | if ((--needed) < 0) |
1124 | break; |
1125 | /* |
1126 | * This page is now managed by the hugetlb allocator and has |
1127 | * no users -- drop the buddy allocator's reference. |
1128 | */ |
1129 | put_page_testzero(page); |
1130 | VM_BUG_ON_PAGE(page_count(page), page); |
1131 | enqueue_huge_page(h, page); |
1132 | } |
1133 | free: |
1134 | spin_unlock(&hugetlb_lock); |
1135 | |
1136 | /* Free unnecessary surplus pages to the buddy allocator */ |
1137 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) |
1138 | put_page(page); |
1139 | spin_lock(&hugetlb_lock); |
1140 | |
1141 | return ret; |
1142 | } |
1143 | |
1144 | /* |
1145 | * When releasing a hugetlb pool reservation, any surplus pages that were |
1146 | * allocated to satisfy the reservation must be explicitly freed if they were |
1147 | * never used. |
1148 | * Called with hugetlb_lock held. |
1149 | */ |
1150 | static void return_unused_surplus_pages(struct hstate *h, |
1151 | unsigned long unused_resv_pages) |
1152 | { |
1153 | unsigned long nr_pages; |
1154 | |
1155 | /* Uncommit the reservation */ |
1156 | h->resv_huge_pages -= unused_resv_pages; |
1157 | |
1158 | /* Cannot return gigantic pages currently */ |
1159 | if (h->order >= MAX_ORDER) |
1160 | return; |
1161 | |
1162 | nr_pages = min(unused_resv_pages, h->surplus_huge_pages); |
1163 | |
1164 | /* |
1165 | * We want to release as many surplus pages as possible, spread |
1166 | * evenly across all nodes with memory. Iterate across these nodes |
1167 | * until we can no longer free unreserved surplus pages. This occurs |
1168 | * when the nodes with surplus pages have no free pages. |
1169 | * free_pool_huge_page() will balance the the freed pages across the |
1170 | * on-line nodes with memory and will handle the hstate accounting. |
1171 | */ |
1172 | while (nr_pages--) { |
1173 | if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1)) |
1174 | break; |
1175 | cond_resched_lock(&hugetlb_lock); |
1176 | } |
1177 | } |
1178 | |
1179 | /* |
1180 | * Determine if the huge page at addr within the vma has an associated |
1181 | * reservation. Where it does not we will need to logically increase |
1182 | * reservation and actually increase subpool usage before an allocation |
1183 | * can occur. Where any new reservation would be required the |
1184 | * reservation change is prepared, but not committed. Once the page |
1185 | * has been allocated from the subpool and instantiated the change should |
1186 | * be committed via vma_commit_reservation. No action is required on |
1187 | * failure. |
1188 | */ |
1189 | static long vma_needs_reservation(struct hstate *h, |
1190 | struct vm_area_struct *vma, unsigned long addr) |
1191 | { |
1192 | struct resv_map *resv; |
1193 | pgoff_t idx; |
1194 | long chg; |
1195 | |
1196 | resv = vma_resv_map(vma); |
1197 | if (!resv) |
1198 | return 1; |
1199 | |
1200 | idx = vma_hugecache_offset(h, vma, addr); |
1201 | chg = region_chg(resv, idx, idx + 1); |
1202 | |
1203 | if (vma->vm_flags & VM_MAYSHARE) |
1204 | return chg; |
1205 | else |
1206 | return chg < 0 ? chg : 0; |
1207 | } |
1208 | static void vma_commit_reservation(struct hstate *h, |
1209 | struct vm_area_struct *vma, unsigned long addr) |
1210 | { |
1211 | struct resv_map *resv; |
1212 | pgoff_t idx; |
1213 | |
1214 | resv = vma_resv_map(vma); |
1215 | if (!resv) |
1216 | return; |
1217 | |
1218 | idx = vma_hugecache_offset(h, vma, addr); |
1219 | region_add(resv, idx, idx + 1); |
1220 | } |
1221 | |
1222 | static struct page *alloc_huge_page(struct vm_area_struct *vma, |
1223 | unsigned long addr, int avoid_reserve) |
1224 | { |
1225 | struct hugepage_subpool *spool = subpool_vma(vma); |
1226 | struct hstate *h = hstate_vma(vma); |
1227 | struct page *page; |
1228 | long chg; |
1229 | int ret, idx; |
1230 | struct hugetlb_cgroup *h_cg; |
1231 | |
1232 | idx = hstate_index(h); |
1233 | /* |
1234 | * Processes that did not create the mapping will have no |
1235 | * reserves and will not have accounted against subpool |
1236 | * limit. Check that the subpool limit can be made before |
1237 | * satisfying the allocation MAP_NORESERVE mappings may also |
1238 | * need pages and subpool limit allocated allocated if no reserve |
1239 | * mapping overlaps. |
1240 | */ |
1241 | chg = vma_needs_reservation(h, vma, addr); |
1242 | if (chg < 0) |
1243 | return ERR_PTR(-ENOMEM); |
1244 | if (chg || avoid_reserve) |
1245 | if (hugepage_subpool_get_pages(spool, 1)) |
1246 | return ERR_PTR(-ENOSPC); |
1247 | |
1248 | ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); |
1249 | if (ret) { |
1250 | if (chg || avoid_reserve) |
1251 | hugepage_subpool_put_pages(spool, 1); |
1252 | return ERR_PTR(-ENOSPC); |
1253 | } |
1254 | spin_lock(&hugetlb_lock); |
1255 | page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg); |
1256 | if (!page) { |
1257 | spin_unlock(&hugetlb_lock); |
1258 | page = alloc_buddy_huge_page(h, NUMA_NO_NODE); |
1259 | if (!page) { |
1260 | hugetlb_cgroup_uncharge_cgroup(idx, |
1261 | pages_per_huge_page(h), |
1262 | h_cg); |
1263 | if (chg || avoid_reserve) |
1264 | hugepage_subpool_put_pages(spool, 1); |
1265 | return ERR_PTR(-ENOSPC); |
1266 | } |
1267 | spin_lock(&hugetlb_lock); |
1268 | list_move(&page->lru, &h->hugepage_activelist); |
1269 | /* Fall through */ |
1270 | } |
1271 | hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page); |
1272 | spin_unlock(&hugetlb_lock); |
1273 | |
1274 | set_page_private(page, (unsigned long)spool); |
1275 | |
1276 | vma_commit_reservation(h, vma, addr); |
1277 | return page; |
1278 | } |
1279 | |
1280 | /* |
1281 | * alloc_huge_page()'s wrapper which simply returns the page if allocation |
1282 | * succeeds, otherwise NULL. This function is called from new_vma_page(), |
1283 | * where no ERR_VALUE is expected to be returned. |
1284 | */ |
1285 | struct page *alloc_huge_page_noerr(struct vm_area_struct *vma, |
1286 | unsigned long addr, int avoid_reserve) |
1287 | { |
1288 | struct page *page = alloc_huge_page(vma, addr, avoid_reserve); |
1289 | if (IS_ERR(page)) |
1290 | page = NULL; |
1291 | return page; |
1292 | } |
1293 | |
1294 | int __weak alloc_bootmem_huge_page(struct hstate *h) |
1295 | { |
1296 | struct huge_bootmem_page *m; |
1297 | int nr_nodes, node; |
1298 | |
1299 | for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) { |
1300 | void *addr; |
1301 | |
1302 | addr = memblock_virt_alloc_try_nid_nopanic( |
1303 | huge_page_size(h), huge_page_size(h), |
1304 | 0, BOOTMEM_ALLOC_ACCESSIBLE, node); |
1305 | if (addr) { |
1306 | /* |
1307 | * Use the beginning of the huge page to store the |
1308 | * huge_bootmem_page struct (until gather_bootmem |
1309 | * puts them into the mem_map). |
1310 | */ |
1311 | m = addr; |
1312 | goto found; |
1313 | } |
1314 | } |
1315 | return 0; |
1316 | |
1317 | found: |
1318 | BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); |
1319 | /* Put them into a private list first because mem_map is not up yet */ |
1320 | list_add(&m->list, &huge_boot_pages); |
1321 | m->hstate = h; |
1322 | return 1; |
1323 | } |
1324 | |
1325 | static void __init prep_compound_huge_page(struct page *page, int order) |
1326 | { |
1327 | if (unlikely(order > (MAX_ORDER - 1))) |
1328 | prep_compound_gigantic_page(page, order); |
1329 | else |
1330 | prep_compound_page(page, order); |
1331 | } |
1332 | |
1333 | /* Put bootmem huge pages into the standard lists after mem_map is up */ |
1334 | static void __init gather_bootmem_prealloc(void) |
1335 | { |
1336 | struct huge_bootmem_page *m; |
1337 | |
1338 | list_for_each_entry(m, &huge_boot_pages, list) { |
1339 | struct hstate *h = m->hstate; |
1340 | struct page *page; |
1341 | |
1342 | #ifdef CONFIG_HIGHMEM |
1343 | page = pfn_to_page(m->phys >> PAGE_SHIFT); |
1344 | memblock_free_late(__pa(m), |
1345 | sizeof(struct huge_bootmem_page)); |
1346 | #else |
1347 | page = virt_to_page(m); |
1348 | #endif |
1349 | WARN_ON(page_count(page) != 1); |
1350 | prep_compound_huge_page(page, h->order); |
1351 | WARN_ON(PageReserved(page)); |
1352 | prep_new_huge_page(h, page, page_to_nid(page)); |
1353 | /* |
1354 | * If we had gigantic hugepages allocated at boot time, we need |
1355 | * to restore the 'stolen' pages to totalram_pages in order to |
1356 | * fix confusing memory reports from free(1) and another |
1357 | * side-effects, like CommitLimit going negative. |
1358 | */ |
1359 | if (h->order > (MAX_ORDER - 1)) |
1360 | adjust_managed_page_count(page, 1 << h->order); |
1361 | } |
1362 | } |
1363 | |
1364 | static void __init hugetlb_hstate_alloc_pages(struct hstate *h) |
1365 | { |
1366 | unsigned long i; |
1367 | |
1368 | for (i = 0; i < h->max_huge_pages; ++i) { |
1369 | if (h->order >= MAX_ORDER) { |
1370 | if (!alloc_bootmem_huge_page(h)) |
1371 | break; |
1372 | } else if (!alloc_fresh_huge_page(h, |
1373 | &node_states[N_MEMORY])) |
1374 | break; |
1375 | } |
1376 | h->max_huge_pages = i; |
1377 | } |
1378 | |
1379 | static void __init hugetlb_init_hstates(void) |
1380 | { |
1381 | struct hstate *h; |
1382 | |
1383 | for_each_hstate(h) { |
1384 | /* oversize hugepages were init'ed in early boot */ |
1385 | if (h->order < MAX_ORDER) |
1386 | hugetlb_hstate_alloc_pages(h); |
1387 | } |
1388 | } |
1389 | |
1390 | static char * __init memfmt(char *buf, unsigned long n) |
1391 | { |
1392 | if (n >= (1UL << 30)) |
1393 | sprintf(buf, "%lu GB", n >> 30); |
1394 | else if (n >= (1UL << 20)) |
1395 | sprintf(buf, "%lu MB", n >> 20); |
1396 | else |
1397 | sprintf(buf, "%lu KB", n >> 10); |
1398 | return buf; |
1399 | } |
1400 | |
1401 | static void __init report_hugepages(void) |
1402 | { |
1403 | struct hstate *h; |
1404 | |
1405 | for_each_hstate(h) { |
1406 | char buf[32]; |
1407 | pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n", |
1408 | memfmt(buf, huge_page_size(h)), |
1409 | h->free_huge_pages); |
1410 | } |
1411 | } |
1412 | |
1413 | #ifdef CONFIG_HIGHMEM |
1414 | static void try_to_free_low(struct hstate *h, unsigned long count, |
1415 | nodemask_t *nodes_allowed) |
1416 | { |
1417 | int i; |
1418 | |
1419 | if (h->order >= MAX_ORDER) |
1420 | return; |
1421 | |
1422 | for_each_node_mask(i, *nodes_allowed) { |
1423 | struct page *page, *next; |
1424 | struct list_head *freel = &h->hugepage_freelists[i]; |
1425 | list_for_each_entry_safe(page, next, freel, lru) { |
1426 | if (count >= h->nr_huge_pages) |
1427 | return; |
1428 | if (PageHighMem(page)) |
1429 | continue; |
1430 | list_del(&page->lru); |
1431 | update_and_free_page(h, page); |
1432 | h->free_huge_pages--; |
1433 | h->free_huge_pages_node[page_to_nid(page)]--; |
1434 | } |
1435 | } |
1436 | } |
1437 | #else |
1438 | static inline void try_to_free_low(struct hstate *h, unsigned long count, |
1439 | nodemask_t *nodes_allowed) |
1440 | { |
1441 | } |
1442 | #endif |
1443 | |
1444 | /* |
1445 | * Increment or decrement surplus_huge_pages. Keep node-specific counters |
1446 | * balanced by operating on them in a round-robin fashion. |
1447 | * Returns 1 if an adjustment was made. |
1448 | */ |
1449 | static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, |
1450 | int delta) |
1451 | { |
1452 | int nr_nodes, node; |
1453 | |
1454 | VM_BUG_ON(delta != -1 && delta != 1); |
1455 | |
1456 | if (delta < 0) { |
1457 | for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { |
1458 | if (h->surplus_huge_pages_node[node]) |
1459 | goto found; |
1460 | } |
1461 | } else { |
1462 | for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { |
1463 | if (h->surplus_huge_pages_node[node] < |
1464 | h->nr_huge_pages_node[node]) |
1465 | goto found; |
1466 | } |
1467 | } |
1468 | return 0; |
1469 | |
1470 | found: |
1471 | h->surplus_huge_pages += delta; |
1472 | h->surplus_huge_pages_node[node] += delta; |
1473 | return 1; |
1474 | } |
1475 | |
1476 | #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) |
1477 | static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, |
1478 | nodemask_t *nodes_allowed) |
1479 | { |
1480 | unsigned long min_count, ret; |
1481 | |
1482 | if (h->order >= MAX_ORDER) |
1483 | return h->max_huge_pages; |
1484 | |
1485 | /* |
1486 | * Increase the pool size |
1487 | * First take pages out of surplus state. Then make up the |
1488 | * remaining difference by allocating fresh huge pages. |
1489 | * |
1490 | * We might race with alloc_buddy_huge_page() here and be unable |
1491 | * to convert a surplus huge page to a normal huge page. That is |
1492 | * not critical, though, it just means the overall size of the |
1493 | * pool might be one hugepage larger than it needs to be, but |
1494 | * within all the constraints specified by the sysctls. |
1495 | */ |
1496 | spin_lock(&hugetlb_lock); |
1497 | while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { |
1498 | if (!adjust_pool_surplus(h, nodes_allowed, -1)) |
1499 | break; |
1500 | } |
1501 | |
1502 | while (count > persistent_huge_pages(h)) { |
1503 | /* |
1504 | * If this allocation races such that we no longer need the |
1505 | * page, free_huge_page will handle it by freeing the page |
1506 | * and reducing the surplus. |
1507 | */ |
1508 | spin_unlock(&hugetlb_lock); |
1509 | ret = alloc_fresh_huge_page(h, nodes_allowed); |
1510 | spin_lock(&hugetlb_lock); |
1511 | if (!ret) |
1512 | goto out; |
1513 | |
1514 | /* Bail for signals. Probably ctrl-c from user */ |
1515 | if (signal_pending(current)) |
1516 | goto out; |
1517 | } |
1518 | |
1519 | /* |
1520 | * Decrease the pool size |
1521 | * First return free pages to the buddy allocator (being careful |
1522 | * to keep enough around to satisfy reservations). Then place |
1523 | * pages into surplus state as needed so the pool will shrink |
1524 | * to the desired size as pages become free. |
1525 | * |
1526 | * By placing pages into the surplus state independent of the |
1527 | * overcommit value, we are allowing the surplus pool size to |
1528 | * exceed overcommit. There are few sane options here. Since |
1529 | * alloc_buddy_huge_page() is checking the global counter, |
1530 | * though, we'll note that we're not allowed to exceed surplus |
1531 | * and won't grow the pool anywhere else. Not until one of the |
1532 | * sysctls are changed, or the surplus pages go out of use. |
1533 | */ |
1534 | min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; |
1535 | min_count = max(count, min_count); |
1536 | try_to_free_low(h, min_count, nodes_allowed); |
1537 | while (min_count < persistent_huge_pages(h)) { |
1538 | if (!free_pool_huge_page(h, nodes_allowed, 0)) |
1539 | break; |
1540 | cond_resched_lock(&hugetlb_lock); |
1541 | } |
1542 | while (count < persistent_huge_pages(h)) { |
1543 | if (!adjust_pool_surplus(h, nodes_allowed, 1)) |
1544 | break; |
1545 | } |
1546 | out: |
1547 | ret = persistent_huge_pages(h); |
1548 | spin_unlock(&hugetlb_lock); |
1549 | return ret; |
1550 | } |
1551 | |
1552 | #define HSTATE_ATTR_RO(_name) \ |
1553 | static struct kobj_attribute _name##_attr = __ATTR_RO(_name) |
1554 | |
1555 | #define HSTATE_ATTR(_name) \ |
1556 | static struct kobj_attribute _name##_attr = \ |
1557 | __ATTR(_name, 0644, _name##_show, _name##_store) |
1558 | |
1559 | static struct kobject *hugepages_kobj; |
1560 | static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
1561 | |
1562 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); |
1563 | |
1564 | static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) |
1565 | { |
1566 | int i; |
1567 | |
1568 | for (i = 0; i < HUGE_MAX_HSTATE; i++) |
1569 | if (hstate_kobjs[i] == kobj) { |
1570 | if (nidp) |
1571 | *nidp = NUMA_NO_NODE; |
1572 | return &hstates[i]; |
1573 | } |
1574 | |
1575 | return kobj_to_node_hstate(kobj, nidp); |
1576 | } |
1577 | |
1578 | static ssize_t nr_hugepages_show_common(struct kobject *kobj, |
1579 | struct kobj_attribute *attr, char *buf) |
1580 | { |
1581 | struct hstate *h; |
1582 | unsigned long nr_huge_pages; |
1583 | int nid; |
1584 | |
1585 | h = kobj_to_hstate(kobj, &nid); |
1586 | if (nid == NUMA_NO_NODE) |
1587 | nr_huge_pages = h->nr_huge_pages; |
1588 | else |
1589 | nr_huge_pages = h->nr_huge_pages_node[nid]; |
1590 | |
1591 | return sprintf(buf, "%lu\n", nr_huge_pages); |
1592 | } |
1593 | |
1594 | static ssize_t nr_hugepages_store_common(bool obey_mempolicy, |
1595 | struct kobject *kobj, struct kobj_attribute *attr, |
1596 | const char *buf, size_t len) |
1597 | { |
1598 | int err; |
1599 | int nid; |
1600 | unsigned long count; |
1601 | struct hstate *h; |
1602 | NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); |
1603 | |
1604 | err = kstrtoul(buf, 10, &count); |
1605 | if (err) |
1606 | goto out; |
1607 | |
1608 | h = kobj_to_hstate(kobj, &nid); |
1609 | if (h->order >= MAX_ORDER) { |
1610 | err = -EINVAL; |
1611 | goto out; |
1612 | } |
1613 | |
1614 | if (nid == NUMA_NO_NODE) { |
1615 | /* |
1616 | * global hstate attribute |
1617 | */ |
1618 | if (!(obey_mempolicy && |
1619 | init_nodemask_of_mempolicy(nodes_allowed))) { |
1620 | NODEMASK_FREE(nodes_allowed); |
1621 | nodes_allowed = &node_states[N_MEMORY]; |
1622 | } |
1623 | } else if (nodes_allowed) { |
1624 | /* |
1625 | * per node hstate attribute: adjust count to global, |
1626 | * but restrict alloc/free to the specified node. |
1627 | */ |
1628 | count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; |
1629 | init_nodemask_of_node(nodes_allowed, nid); |
1630 | } else |
1631 | nodes_allowed = &node_states[N_MEMORY]; |
1632 | |
1633 | h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); |
1634 | |
1635 | if (nodes_allowed != &node_states[N_MEMORY]) |
1636 | NODEMASK_FREE(nodes_allowed); |
1637 | |
1638 | return len; |
1639 | out: |
1640 | NODEMASK_FREE(nodes_allowed); |
1641 | return err; |
1642 | } |
1643 | |
1644 | static ssize_t nr_hugepages_show(struct kobject *kobj, |
1645 | struct kobj_attribute *attr, char *buf) |
1646 | { |
1647 | return nr_hugepages_show_common(kobj, attr, buf); |
1648 | } |
1649 | |
1650 | static ssize_t nr_hugepages_store(struct kobject *kobj, |
1651 | struct kobj_attribute *attr, const char *buf, size_t len) |
1652 | { |
1653 | return nr_hugepages_store_common(false, kobj, attr, buf, len); |
1654 | } |
1655 | HSTATE_ATTR(nr_hugepages); |
1656 | |
1657 | #ifdef CONFIG_NUMA |
1658 | |
1659 | /* |
1660 | * hstate attribute for optionally mempolicy-based constraint on persistent |
1661 | * huge page alloc/free. |
1662 | */ |
1663 | static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, |
1664 | struct kobj_attribute *attr, char *buf) |
1665 | { |
1666 | return nr_hugepages_show_common(kobj, attr, buf); |
1667 | } |
1668 | |
1669 | static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, |
1670 | struct kobj_attribute *attr, const char *buf, size_t len) |
1671 | { |
1672 | return nr_hugepages_store_common(true, kobj, attr, buf, len); |
1673 | } |
1674 | HSTATE_ATTR(nr_hugepages_mempolicy); |
1675 | #endif |
1676 | |
1677 | |
1678 | static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, |
1679 | struct kobj_attribute *attr, char *buf) |
1680 | { |
1681 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
1682 | return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); |
1683 | } |
1684 | |
1685 | static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, |
1686 | struct kobj_attribute *attr, const char *buf, size_t count) |
1687 | { |
1688 | int err; |
1689 | unsigned long input; |
1690 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
1691 | |
1692 | if (h->order >= MAX_ORDER) |
1693 | return -EINVAL; |
1694 | |
1695 | err = kstrtoul(buf, 10, &input); |
1696 | if (err) |
1697 | return err; |
1698 | |
1699 | spin_lock(&hugetlb_lock); |
1700 | h->nr_overcommit_huge_pages = input; |
1701 | spin_unlock(&hugetlb_lock); |
1702 | |
1703 | return count; |
1704 | } |
1705 | HSTATE_ATTR(nr_overcommit_hugepages); |
1706 | |
1707 | static ssize_t free_hugepages_show(struct kobject *kobj, |
1708 | struct kobj_attribute *attr, char *buf) |
1709 | { |
1710 | struct hstate *h; |
1711 | unsigned long free_huge_pages; |
1712 | int nid; |
1713 | |
1714 | h = kobj_to_hstate(kobj, &nid); |
1715 | if (nid == NUMA_NO_NODE) |
1716 | free_huge_pages = h->free_huge_pages; |
1717 | else |
1718 | free_huge_pages = h->free_huge_pages_node[nid]; |
1719 | |
1720 | return sprintf(buf, "%lu\n", free_huge_pages); |
1721 | } |
1722 | HSTATE_ATTR_RO(free_hugepages); |
1723 | |
1724 | static ssize_t resv_hugepages_show(struct kobject *kobj, |
1725 | struct kobj_attribute *attr, char *buf) |
1726 | { |
1727 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
1728 | return sprintf(buf, "%lu\n", h->resv_huge_pages); |
1729 | } |
1730 | HSTATE_ATTR_RO(resv_hugepages); |
1731 | |
1732 | static ssize_t surplus_hugepages_show(struct kobject *kobj, |
1733 | struct kobj_attribute *attr, char *buf) |
1734 | { |
1735 | struct hstate *h; |
1736 | unsigned long surplus_huge_pages; |
1737 | int nid; |
1738 | |
1739 | h = kobj_to_hstate(kobj, &nid); |
1740 | if (nid == NUMA_NO_NODE) |
1741 | surplus_huge_pages = h->surplus_huge_pages; |
1742 | else |
1743 | surplus_huge_pages = h->surplus_huge_pages_node[nid]; |
1744 | |
1745 | return sprintf(buf, "%lu\n", surplus_huge_pages); |
1746 | } |
1747 | HSTATE_ATTR_RO(surplus_hugepages); |
1748 | |
1749 | static struct attribute *hstate_attrs[] = { |
1750 | &nr_hugepages_attr.attr, |
1751 | &nr_overcommit_hugepages_attr.attr, |
1752 | &free_hugepages_attr.attr, |
1753 | &resv_hugepages_attr.attr, |
1754 | &surplus_hugepages_attr.attr, |
1755 | #ifdef CONFIG_NUMA |
1756 | &nr_hugepages_mempolicy_attr.attr, |
1757 | #endif |
1758 | NULL, |
1759 | }; |
1760 | |
1761 | static struct attribute_group hstate_attr_group = { |
1762 | .attrs = hstate_attrs, |
1763 | }; |
1764 | |
1765 | static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, |
1766 | struct kobject **hstate_kobjs, |
1767 | struct attribute_group *hstate_attr_group) |
1768 | { |
1769 | int retval; |
1770 | int hi = hstate_index(h); |
1771 | |
1772 | hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); |
1773 | if (!hstate_kobjs[hi]) |
1774 | return -ENOMEM; |
1775 | |
1776 | retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); |
1777 | if (retval) |
1778 | kobject_put(hstate_kobjs[hi]); |
1779 | |
1780 | return retval; |
1781 | } |
1782 | |
1783 | static void __init hugetlb_sysfs_init(void) |
1784 | { |
1785 | struct hstate *h; |
1786 | int err; |
1787 | |
1788 | hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); |
1789 | if (!hugepages_kobj) |
1790 | return; |
1791 | |
1792 | for_each_hstate(h) { |
1793 | err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, |
1794 | hstate_kobjs, &hstate_attr_group); |
1795 | if (err) |
1796 | pr_err("Hugetlb: Unable to add hstate %s", h->name); |
1797 | } |
1798 | } |
1799 | |
1800 | #ifdef CONFIG_NUMA |
1801 | |
1802 | /* |
1803 | * node_hstate/s - associate per node hstate attributes, via their kobjects, |
1804 | * with node devices in node_devices[] using a parallel array. The array |
1805 | * index of a node device or _hstate == node id. |
1806 | * This is here to avoid any static dependency of the node device driver, in |
1807 | * the base kernel, on the hugetlb module. |
1808 | */ |
1809 | struct node_hstate { |
1810 | struct kobject *hugepages_kobj; |
1811 | struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
1812 | }; |
1813 | struct node_hstate node_hstates[MAX_NUMNODES]; |
1814 | |
1815 | /* |
1816 | * A subset of global hstate attributes for node devices |
1817 | */ |
1818 | static struct attribute *per_node_hstate_attrs[] = { |
1819 | &nr_hugepages_attr.attr, |
1820 | &free_hugepages_attr.attr, |
1821 | &surplus_hugepages_attr.attr, |
1822 | NULL, |
1823 | }; |
1824 | |
1825 | static struct attribute_group per_node_hstate_attr_group = { |
1826 | .attrs = per_node_hstate_attrs, |
1827 | }; |
1828 | |
1829 | /* |
1830 | * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj. |
1831 | * Returns node id via non-NULL nidp. |
1832 | */ |
1833 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) |
1834 | { |
1835 | int nid; |
1836 | |
1837 | for (nid = 0; nid < nr_node_ids; nid++) { |
1838 | struct node_hstate *nhs = &node_hstates[nid]; |
1839 | int i; |
1840 | for (i = 0; i < HUGE_MAX_HSTATE; i++) |
1841 | if (nhs->hstate_kobjs[i] == kobj) { |
1842 | if (nidp) |
1843 | *nidp = nid; |
1844 | return &hstates[i]; |
1845 | } |
1846 | } |
1847 | |
1848 | BUG(); |
1849 | return NULL; |
1850 | } |
1851 | |
1852 | /* |
1853 | * Unregister hstate attributes from a single node device. |
1854 | * No-op if no hstate attributes attached. |
1855 | */ |
1856 | static void hugetlb_unregister_node(struct node *node) |
1857 | { |
1858 | struct hstate *h; |
1859 | struct node_hstate *nhs = &node_hstates[node->dev.id]; |
1860 | |
1861 | if (!nhs->hugepages_kobj) |
1862 | return; /* no hstate attributes */ |
1863 | |
1864 | for_each_hstate(h) { |
1865 | int idx = hstate_index(h); |
1866 | if (nhs->hstate_kobjs[idx]) { |
1867 | kobject_put(nhs->hstate_kobjs[idx]); |
1868 | nhs->hstate_kobjs[idx] = NULL; |
1869 | } |
1870 | } |
1871 | |
1872 | kobject_put(nhs->hugepages_kobj); |
1873 | nhs->hugepages_kobj = NULL; |
1874 | } |
1875 | |
1876 | /* |
1877 | * hugetlb module exit: unregister hstate attributes from node devices |
1878 | * that have them. |
1879 | */ |
1880 | static void hugetlb_unregister_all_nodes(void) |
1881 | { |
1882 | int nid; |
1883 | |
1884 | /* |
1885 | * disable node device registrations. |
1886 | */ |
1887 | register_hugetlbfs_with_node(NULL, NULL); |
1888 | |
1889 | /* |
1890 | * remove hstate attributes from any nodes that have them. |
1891 | */ |
1892 | for (nid = 0; nid < nr_node_ids; nid++) |
1893 | hugetlb_unregister_node(node_devices[nid]); |
1894 | } |
1895 | |
1896 | /* |
1897 | * Register hstate attributes for a single node device. |
1898 | * No-op if attributes already registered. |
1899 | */ |
1900 | static void hugetlb_register_node(struct node *node) |
1901 | { |
1902 | struct hstate *h; |
1903 | struct node_hstate *nhs = &node_hstates[node->dev.id]; |
1904 | int err; |
1905 | |
1906 | if (nhs->hugepages_kobj) |
1907 | return; /* already allocated */ |
1908 | |
1909 | nhs->hugepages_kobj = kobject_create_and_add("hugepages", |
1910 | &node->dev.kobj); |
1911 | if (!nhs->hugepages_kobj) |
1912 | return; |
1913 | |
1914 | for_each_hstate(h) { |
1915 | err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, |
1916 | nhs->hstate_kobjs, |
1917 | &per_node_hstate_attr_group); |
1918 | if (err) { |
1919 | pr_err("Hugetlb: Unable to add hstate %s for node %d\n", |
1920 | h->name, node->dev.id); |
1921 | hugetlb_unregister_node(node); |
1922 | break; |
1923 | } |
1924 | } |
1925 | } |
1926 | |
1927 | /* |
1928 | * hugetlb init time: register hstate attributes for all registered node |
1929 | * devices of nodes that have memory. All on-line nodes should have |
1930 | * registered their associated device by this time. |
1931 | */ |
1932 | static void hugetlb_register_all_nodes(void) |
1933 | { |
1934 | int nid; |
1935 | |
1936 | for_each_node_state(nid, N_MEMORY) { |
1937 | struct node *node = node_devices[nid]; |
1938 | if (node->dev.id == nid) |
1939 | hugetlb_register_node(node); |
1940 | } |
1941 | |
1942 | /* |
1943 | * Let the node device driver know we're here so it can |
1944 | * [un]register hstate attributes on node hotplug. |
1945 | */ |
1946 | register_hugetlbfs_with_node(hugetlb_register_node, |
1947 | hugetlb_unregister_node); |
1948 | } |
1949 | #else /* !CONFIG_NUMA */ |
1950 | |
1951 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) |
1952 | { |
1953 | BUG(); |
1954 | if (nidp) |
1955 | *nidp = -1; |
1956 | return NULL; |
1957 | } |
1958 | |
1959 | static void hugetlb_unregister_all_nodes(void) { } |
1960 | |
1961 | static void hugetlb_register_all_nodes(void) { } |
1962 | |
1963 | #endif |
1964 | |
1965 | static void __exit hugetlb_exit(void) |
1966 | { |
1967 | struct hstate *h; |
1968 | |
1969 | hugetlb_unregister_all_nodes(); |
1970 | |
1971 | for_each_hstate(h) { |
1972 | kobject_put(hstate_kobjs[hstate_index(h)]); |
1973 | } |
1974 | |
1975 | kobject_put(hugepages_kobj); |
1976 | kfree(htlb_fault_mutex_table); |
1977 | } |
1978 | module_exit(hugetlb_exit); |
1979 | |
1980 | static int __init hugetlb_init(void) |
1981 | { |
1982 | int i; |
1983 | |
1984 | if (!hugepages_supported()) |
1985 | return 0; |
1986 | |
1987 | if (!size_to_hstate(default_hstate_size)) { |
1988 | default_hstate_size = HPAGE_SIZE; |
1989 | if (!size_to_hstate(default_hstate_size)) |
1990 | hugetlb_add_hstate(HUGETLB_PAGE_ORDER); |
1991 | } |
1992 | default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size)); |
1993 | if (default_hstate_max_huge_pages) |
1994 | default_hstate.max_huge_pages = default_hstate_max_huge_pages; |
1995 | |
1996 | hugetlb_init_hstates(); |
1997 | gather_bootmem_prealloc(); |
1998 | report_hugepages(); |
1999 | |
2000 | hugetlb_sysfs_init(); |
2001 | hugetlb_register_all_nodes(); |
2002 | hugetlb_cgroup_file_init(); |
2003 | |
2004 | #ifdef CONFIG_SMP |
2005 | num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus()); |
2006 | #else |
2007 | num_fault_mutexes = 1; |
2008 | #endif |
2009 | htlb_fault_mutex_table = |
2010 | kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL); |
2011 | BUG_ON(!htlb_fault_mutex_table); |
2012 | |
2013 | for (i = 0; i < num_fault_mutexes; i++) |
2014 | mutex_init(&htlb_fault_mutex_table[i]); |
2015 | return 0; |
2016 | } |
2017 | module_init(hugetlb_init); |
2018 | |
2019 | /* Should be called on processing a hugepagesz=... option */ |
2020 | void __init hugetlb_add_hstate(unsigned order) |
2021 | { |
2022 | struct hstate *h; |
2023 | unsigned long i; |
2024 | |
2025 | if (size_to_hstate(PAGE_SIZE << order)) { |
2026 | pr_warning("hugepagesz= specified twice, ignoring\n"); |
2027 | return; |
2028 | } |
2029 | BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); |
2030 | BUG_ON(order == 0); |
2031 | h = &hstates[hugetlb_max_hstate++]; |
2032 | h->order = order; |
2033 | h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); |
2034 | h->nr_huge_pages = 0; |
2035 | h->free_huge_pages = 0; |
2036 | for (i = 0; i < MAX_NUMNODES; ++i) |
2037 | INIT_LIST_HEAD(&h->hugepage_freelists[i]); |
2038 | INIT_LIST_HEAD(&h->hugepage_activelist); |
2039 | h->next_nid_to_alloc = first_node(node_states[N_MEMORY]); |
2040 | h->next_nid_to_free = first_node(node_states[N_MEMORY]); |
2041 | snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", |
2042 | huge_page_size(h)/1024); |
2043 | |
2044 | parsed_hstate = h; |
2045 | } |
2046 | |
2047 | static int __init hugetlb_nrpages_setup(char *s) |
2048 | { |
2049 | unsigned long *mhp; |
2050 | static unsigned long *last_mhp; |
2051 | |
2052 | /* |
2053 | * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet, |
2054 | * so this hugepages= parameter goes to the "default hstate". |
2055 | */ |
2056 | if (!hugetlb_max_hstate) |
2057 | mhp = &default_hstate_max_huge_pages; |
2058 | else |
2059 | mhp = &parsed_hstate->max_huge_pages; |
2060 | |
2061 | if (mhp == last_mhp) { |
2062 | pr_warning("hugepages= specified twice without " |
2063 | "interleaving hugepagesz=, ignoring\n"); |
2064 | return 1; |
2065 | } |
2066 | |
2067 | if (sscanf(s, "%lu", mhp) <= 0) |
2068 | *mhp = 0; |
2069 | |
2070 | /* |
2071 | * Global state is always initialized later in hugetlb_init. |
2072 | * But we need to allocate >= MAX_ORDER hstates here early to still |
2073 | * use the bootmem allocator. |
2074 | */ |
2075 | if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER) |
2076 | hugetlb_hstate_alloc_pages(parsed_hstate); |
2077 | |
2078 | last_mhp = mhp; |
2079 | |
2080 | return 1; |
2081 | } |
2082 | __setup("hugepages=", hugetlb_nrpages_setup); |
2083 | |
2084 | static int __init hugetlb_default_setup(char *s) |
2085 | { |
2086 | default_hstate_size = memparse(s, &s); |
2087 | return 1; |
2088 | } |
2089 | __setup("default_hugepagesz=", hugetlb_default_setup); |
2090 | |
2091 | static unsigned int cpuset_mems_nr(unsigned int *array) |
2092 | { |
2093 | int node; |
2094 | unsigned int nr = 0; |
2095 | |
2096 | for_each_node_mask(node, cpuset_current_mems_allowed) |
2097 | nr += array[node]; |
2098 | |
2099 | return nr; |
2100 | } |
2101 | |
2102 | #ifdef CONFIG_SYSCTL |
2103 | static int hugetlb_sysctl_handler_common(bool obey_mempolicy, |
2104 | struct ctl_table *table, int write, |
2105 | void __user *buffer, size_t *length, loff_t *ppos) |
2106 | { |
2107 | struct hstate *h = &default_hstate; |
2108 | unsigned long tmp; |
2109 | int ret; |
2110 | |
2111 | if (!hugepages_supported()) |
2112 | return -ENOTSUPP; |
2113 | |
2114 | tmp = h->max_huge_pages; |
2115 | |
2116 | if (write && h->order >= MAX_ORDER) |
2117 | return -EINVAL; |
2118 | |
2119 | table->data = &tmp; |
2120 | table->maxlen = sizeof(unsigned long); |
2121 | ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); |
2122 | if (ret) |
2123 | goto out; |
2124 | |
2125 | if (write) { |
2126 | NODEMASK_ALLOC(nodemask_t, nodes_allowed, |
2127 | GFP_KERNEL | __GFP_NORETRY); |
2128 | if (!(obey_mempolicy && |
2129 | init_nodemask_of_mempolicy(nodes_allowed))) { |
2130 | NODEMASK_FREE(nodes_allowed); |
2131 | nodes_allowed = &node_states[N_MEMORY]; |
2132 | } |
2133 | h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); |
2134 | |
2135 | if (nodes_allowed != &node_states[N_MEMORY]) |
2136 | NODEMASK_FREE(nodes_allowed); |
2137 | } |
2138 | out: |
2139 | return ret; |
2140 | } |
2141 | |
2142 | int hugetlb_sysctl_handler(struct ctl_table *table, int write, |
2143 | void __user *buffer, size_t *length, loff_t *ppos) |
2144 | { |
2145 | |
2146 | return hugetlb_sysctl_handler_common(false, table, write, |
2147 | buffer, length, ppos); |
2148 | } |
2149 | |
2150 | #ifdef CONFIG_NUMA |
2151 | int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, |
2152 | void __user *buffer, size_t *length, loff_t *ppos) |
2153 | { |
2154 | return hugetlb_sysctl_handler_common(true, table, write, |
2155 | buffer, length, ppos); |
2156 | } |
2157 | #endif /* CONFIG_NUMA */ |
2158 | |
2159 | int hugetlb_overcommit_handler(struct ctl_table *table, int write, |
2160 | void __user *buffer, |
2161 | size_t *length, loff_t *ppos) |
2162 | { |
2163 | struct hstate *h = &default_hstate; |
2164 | unsigned long tmp; |
2165 | int ret; |
2166 | |
2167 | if (!hugepages_supported()) |
2168 | return -ENOTSUPP; |
2169 | |
2170 | tmp = h->nr_overcommit_huge_pages; |
2171 | |
2172 | if (write && h->order >= MAX_ORDER) |
2173 | return -EINVAL; |
2174 | |
2175 | table->data = &tmp; |
2176 | table->maxlen = sizeof(unsigned long); |
2177 | ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); |
2178 | if (ret) |
2179 | goto out; |
2180 | |
2181 | if (write) { |
2182 | spin_lock(&hugetlb_lock); |
2183 | h->nr_overcommit_huge_pages = tmp; |
2184 | spin_unlock(&hugetlb_lock); |
2185 | } |
2186 | out: |
2187 | return ret; |
2188 | } |
2189 | |
2190 | #endif /* CONFIG_SYSCTL */ |
2191 | |
2192 | void hugetlb_report_meminfo(struct seq_file *m) |
2193 | { |
2194 | struct hstate *h = &default_hstate; |
2195 | if (!hugepages_supported()) |
2196 | return; |
2197 | seq_printf(m, |
2198 | "HugePages_Total: %5lu\n" |
2199 | "HugePages_Free: %5lu\n" |
2200 | "HugePages_Rsvd: %5lu\n" |
2201 | "HugePages_Surp: %5lu\n" |
2202 | "Hugepagesize: %8lu kB\n", |
2203 | h->nr_huge_pages, |
2204 | h->free_huge_pages, |
2205 | h->resv_huge_pages, |
2206 | h->surplus_huge_pages, |
2207 | 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); |
2208 | } |
2209 | |
2210 | int hugetlb_report_node_meminfo(int nid, char *buf) |
2211 | { |
2212 | struct hstate *h = &default_hstate; |
2213 | if (!hugepages_supported()) |
2214 | return 0; |
2215 | return sprintf(buf, |
2216 | "Node %d HugePages_Total: %5u\n" |
2217 | "Node %d HugePages_Free: %5u\n" |
2218 | "Node %d HugePages_Surp: %5u\n", |
2219 | nid, h->nr_huge_pages_node[nid], |
2220 | nid, h->free_huge_pages_node[nid], |
2221 | nid, h->surplus_huge_pages_node[nid]); |
2222 | } |
2223 | |
2224 | void hugetlb_show_meminfo(void) |
2225 | { |
2226 | struct hstate *h; |
2227 | int nid; |
2228 | |
2229 | if (!hugepages_supported()) |
2230 | return; |
2231 | |
2232 | for_each_node_state(nid, N_MEMORY) |
2233 | for_each_hstate(h) |
2234 | pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n", |
2235 | nid, |
2236 | h->nr_huge_pages_node[nid], |
2237 | h->free_huge_pages_node[nid], |
2238 | h->surplus_huge_pages_node[nid], |
2239 | 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); |
2240 | } |
2241 | |
2242 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
2243 | unsigned long hugetlb_total_pages(void) |
2244 | { |
2245 | struct hstate *h; |
2246 | unsigned long nr_total_pages = 0; |
2247 | |
2248 | for_each_hstate(h) |
2249 | nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h); |
2250 | return nr_total_pages; |
2251 | } |
2252 | |
2253 | static int hugetlb_acct_memory(struct hstate *h, long delta) |
2254 | { |
2255 | int ret = -ENOMEM; |
2256 | |
2257 | spin_lock(&hugetlb_lock); |
2258 | /* |
2259 | * When cpuset is configured, it breaks the strict hugetlb page |
2260 | * reservation as the accounting is done on a global variable. Such |
2261 | * reservation is completely rubbish in the presence of cpuset because |
2262 | * the reservation is not checked against page availability for the |
2263 | * current cpuset. Application can still potentially OOM'ed by kernel |
2264 | * with lack of free htlb page in cpuset that the task is in. |
2265 | * Attempt to enforce strict accounting with cpuset is almost |
2266 | * impossible (or too ugly) because cpuset is too fluid that |
2267 | * task or memory node can be dynamically moved between cpusets. |
2268 | * |
2269 | * The change of semantics for shared hugetlb mapping with cpuset is |
2270 | * undesirable. However, in order to preserve some of the semantics, |
2271 | * we fall back to check against current free page availability as |
2272 | * a best attempt and hopefully to minimize the impact of changing |
2273 | * semantics that cpuset has. |
2274 | */ |
2275 | if (delta > 0) { |
2276 | if (gather_surplus_pages(h, delta) < 0) |
2277 | goto out; |
2278 | |
2279 | if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { |
2280 | return_unused_surplus_pages(h, delta); |
2281 | goto out; |
2282 | } |
2283 | } |
2284 | |
2285 | ret = 0; |
2286 | if (delta < 0) |
2287 | return_unused_surplus_pages(h, (unsigned long) -delta); |
2288 | |
2289 | out: |
2290 | spin_unlock(&hugetlb_lock); |
2291 | return ret; |
2292 | } |
2293 | |
2294 | static void hugetlb_vm_op_open(struct vm_area_struct *vma) |
2295 | { |
2296 | struct resv_map *resv = vma_resv_map(vma); |
2297 | |
2298 | /* |
2299 | * This new VMA should share its siblings reservation map if present. |
2300 | * The VMA will only ever have a valid reservation map pointer where |
2301 | * it is being copied for another still existing VMA. As that VMA |
2302 | * has a reference to the reservation map it cannot disappear until |
2303 | * after this open call completes. It is therefore safe to take a |
2304 | * new reference here without additional locking. |
2305 | */ |
2306 | if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
2307 | kref_get(&resv->refs); |
2308 | } |
2309 | |
2310 | static void hugetlb_vm_op_close(struct vm_area_struct *vma) |
2311 | { |
2312 | struct hstate *h = hstate_vma(vma); |
2313 | struct resv_map *resv = vma_resv_map(vma); |
2314 | struct hugepage_subpool *spool = subpool_vma(vma); |
2315 | unsigned long reserve, start, end; |
2316 | |
2317 | if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
2318 | return; |
2319 | |
2320 | start = vma_hugecache_offset(h, vma, vma->vm_start); |
2321 | end = vma_hugecache_offset(h, vma, vma->vm_end); |
2322 | |
2323 | reserve = (end - start) - region_count(resv, start, end); |
2324 | |
2325 | kref_put(&resv->refs, resv_map_release); |
2326 | |
2327 | if (reserve) { |
2328 | hugetlb_acct_memory(h, -reserve); |
2329 | hugepage_subpool_put_pages(spool, reserve); |
2330 | } |
2331 | } |
2332 | |
2333 | /* |
2334 | * We cannot handle pagefaults against hugetlb pages at all. They cause |
2335 | * handle_mm_fault() to try to instantiate regular-sized pages in the |
2336 | * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get |
2337 | * this far. |
2338 | */ |
2339 | static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
2340 | { |
2341 | BUG(); |
2342 | return 0; |
2343 | } |
2344 | |
2345 | const struct vm_operations_struct hugetlb_vm_ops = { |
2346 | .fault = hugetlb_vm_op_fault, |
2347 | .open = hugetlb_vm_op_open, |
2348 | .close = hugetlb_vm_op_close, |
2349 | }; |
2350 | |
2351 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
2352 | int writable) |
2353 | { |
2354 | pte_t entry; |
2355 | |
2356 | if (writable) { |
2357 | entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page, |
2358 | vma->vm_page_prot))); |
2359 | } else { |
2360 | entry = huge_pte_wrprotect(mk_huge_pte(page, |
2361 | vma->vm_page_prot)); |
2362 | } |
2363 | entry = pte_mkyoung(entry); |
2364 | entry = pte_mkhuge(entry); |
2365 | entry = arch_make_huge_pte(entry, vma, page, writable); |
2366 | |
2367 | return entry; |
2368 | } |
2369 | |
2370 | static void set_huge_ptep_writable(struct vm_area_struct *vma, |
2371 | unsigned long address, pte_t *ptep) |
2372 | { |
2373 | pte_t entry; |
2374 | |
2375 | entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep))); |
2376 | if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) |
2377 | update_mmu_cache(vma, address, ptep); |
2378 | } |
2379 | |
2380 | |
2381 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
2382 | struct vm_area_struct *vma) |
2383 | { |
2384 | pte_t *src_pte, *dst_pte, entry; |
2385 | struct page *ptepage; |
2386 | unsigned long addr; |
2387 | int cow; |
2388 | struct hstate *h = hstate_vma(vma); |
2389 | unsigned long sz = huge_page_size(h); |
2390 | unsigned long mmun_start; /* For mmu_notifiers */ |
2391 | unsigned long mmun_end; /* For mmu_notifiers */ |
2392 | int ret = 0; |
2393 | |
2394 | cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; |
2395 | |
2396 | mmun_start = vma->vm_start; |
2397 | mmun_end = vma->vm_end; |
2398 | if (cow) |
2399 | mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end); |
2400 | |
2401 | for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { |
2402 | spinlock_t *src_ptl, *dst_ptl; |
2403 | src_pte = huge_pte_offset(src, addr); |
2404 | if (!src_pte) |
2405 | continue; |
2406 | dst_pte = huge_pte_alloc(dst, addr, sz); |
2407 | if (!dst_pte) { |
2408 | ret = -ENOMEM; |
2409 | break; |
2410 | } |
2411 | |
2412 | /* If the pagetables are shared don't copy or take references */ |
2413 | if (dst_pte == src_pte) |
2414 | continue; |
2415 | |
2416 | dst_ptl = huge_pte_lock(h, dst, dst_pte); |
2417 | src_ptl = huge_pte_lockptr(h, src, src_pte); |
2418 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
2419 | if (!huge_pte_none(huge_ptep_get(src_pte))) { |
2420 | if (cow) |
2421 | huge_ptep_set_wrprotect(src, addr, src_pte); |
2422 | entry = huge_ptep_get(src_pte); |
2423 | ptepage = pte_page(entry); |
2424 | get_page(ptepage); |
2425 | page_dup_rmap(ptepage); |
2426 | set_huge_pte_at(dst, addr, dst_pte, entry); |
2427 | } |
2428 | spin_unlock(src_ptl); |
2429 | spin_unlock(dst_ptl); |
2430 | } |
2431 | |
2432 | if (cow) |
2433 | mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end); |
2434 | |
2435 | return ret; |
2436 | } |
2437 | |
2438 | static int is_hugetlb_entry_migration(pte_t pte) |
2439 | { |
2440 | swp_entry_t swp; |
2441 | |
2442 | if (huge_pte_none(pte) || pte_present(pte)) |
2443 | return 0; |
2444 | swp = pte_to_swp_entry(pte); |
2445 | if (non_swap_entry(swp) && is_migration_entry(swp)) |
2446 | return 1; |
2447 | else |
2448 | return 0; |
2449 | } |
2450 | |
2451 | static int is_hugetlb_entry_hwpoisoned(pte_t pte) |
2452 | { |
2453 | swp_entry_t swp; |
2454 | |
2455 | if (huge_pte_none(pte) || pte_present(pte)) |
2456 | return 0; |
2457 | swp = pte_to_swp_entry(pte); |
2458 | if (non_swap_entry(swp) && is_hwpoison_entry(swp)) |
2459 | return 1; |
2460 | else |
2461 | return 0; |
2462 | } |
2463 | |
2464 | void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, |
2465 | unsigned long start, unsigned long end, |
2466 | struct page *ref_page) |
2467 | { |
2468 | int force_flush = 0; |
2469 | struct mm_struct *mm = vma->vm_mm; |
2470 | unsigned long address; |
2471 | pte_t *ptep; |
2472 | pte_t pte; |
2473 | spinlock_t *ptl; |
2474 | struct page *page; |
2475 | struct hstate *h = hstate_vma(vma); |
2476 | unsigned long sz = huge_page_size(h); |
2477 | const unsigned long mmun_start = start; /* For mmu_notifiers */ |
2478 | const unsigned long mmun_end = end; /* For mmu_notifiers */ |
2479 | |
2480 | WARN_ON(!is_vm_hugetlb_page(vma)); |
2481 | BUG_ON(start & ~huge_page_mask(h)); |
2482 | BUG_ON(end & ~huge_page_mask(h)); |
2483 | |
2484 | tlb_start_vma(tlb, vma); |
2485 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
2486 | again: |
2487 | for (address = start; address < end; address += sz) { |
2488 | ptep = huge_pte_offset(mm, address); |
2489 | if (!ptep) |
2490 | continue; |
2491 | |
2492 | ptl = huge_pte_lock(h, mm, ptep); |
2493 | if (huge_pmd_unshare(mm, &address, ptep)) |
2494 | goto unlock; |
2495 | |
2496 | pte = huge_ptep_get(ptep); |
2497 | if (huge_pte_none(pte)) |
2498 | goto unlock; |
2499 | |
2500 | /* |
2501 | * HWPoisoned hugepage is already unmapped and dropped reference |
2502 | */ |
2503 | if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) { |
2504 | huge_pte_clear(mm, address, ptep); |
2505 | goto unlock; |
2506 | } |
2507 | |
2508 | page = pte_page(pte); |
2509 | /* |
2510 | * If a reference page is supplied, it is because a specific |
2511 | * page is being unmapped, not a range. Ensure the page we |
2512 | * are about to unmap is the actual page of interest. |
2513 | */ |
2514 | if (ref_page) { |
2515 | if (page != ref_page) |
2516 | goto unlock; |
2517 | |
2518 | /* |
2519 | * Mark the VMA as having unmapped its page so that |
2520 | * future faults in this VMA will fail rather than |
2521 | * looking like data was lost |
2522 | */ |
2523 | set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); |
2524 | } |
2525 | |
2526 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
2527 | tlb_remove_tlb_entry(tlb, ptep, address); |
2528 | if (huge_pte_dirty(pte)) |
2529 | set_page_dirty(page); |
2530 | |
2531 | page_remove_rmap(page); |
2532 | force_flush = !__tlb_remove_page(tlb, page); |
2533 | if (force_flush) { |
2534 | spin_unlock(ptl); |
2535 | break; |
2536 | } |
2537 | /* Bail out after unmapping reference page if supplied */ |
2538 | if (ref_page) { |
2539 | spin_unlock(ptl); |
2540 | break; |
2541 | } |
2542 | unlock: |
2543 | spin_unlock(ptl); |
2544 | } |
2545 | /* |
2546 | * mmu_gather ran out of room to batch pages, we break out of |
2547 | * the PTE lock to avoid doing the potential expensive TLB invalidate |
2548 | * and page-free while holding it. |
2549 | */ |
2550 | if (force_flush) { |
2551 | force_flush = 0; |
2552 | tlb_flush_mmu(tlb); |
2553 | if (address < end && !ref_page) |
2554 | goto again; |
2555 | } |
2556 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
2557 | tlb_end_vma(tlb, vma); |
2558 | } |
2559 | |
2560 | void __unmap_hugepage_range_final(struct mmu_gather *tlb, |
2561 | struct vm_area_struct *vma, unsigned long start, |
2562 | unsigned long end, struct page *ref_page) |
2563 | { |
2564 | __unmap_hugepage_range(tlb, vma, start, end, ref_page); |
2565 | |
2566 | /* |
2567 | * Clear this flag so that x86's huge_pmd_share page_table_shareable |
2568 | * test will fail on a vma being torn down, and not grab a page table |
2569 | * on its way out. We're lucky that the flag has such an appropriate |
2570 | * name, and can in fact be safely cleared here. We could clear it |
2571 | * before the __unmap_hugepage_range above, but all that's necessary |
2572 | * is to clear it before releasing the i_mmap_mutex. This works |
2573 | * because in the context this is called, the VMA is about to be |
2574 | * destroyed and the i_mmap_mutex is held. |
2575 | */ |
2576 | vma->vm_flags &= ~VM_MAYSHARE; |
2577 | } |
2578 | |
2579 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
2580 | unsigned long end, struct page *ref_page) |
2581 | { |
2582 | struct mm_struct *mm; |
2583 | struct mmu_gather tlb; |
2584 | |
2585 | mm = vma->vm_mm; |
2586 | |
2587 | tlb_gather_mmu(&tlb, mm, start, end); |
2588 | __unmap_hugepage_range(&tlb, vma, start, end, ref_page); |
2589 | tlb_finish_mmu(&tlb, start, end); |
2590 | } |
2591 | |
2592 | /* |
2593 | * This is called when the original mapper is failing to COW a MAP_PRIVATE |
2594 | * mappping it owns the reserve page for. The intention is to unmap the page |
2595 | * from other VMAs and let the children be SIGKILLed if they are faulting the |
2596 | * same region. |
2597 | */ |
2598 | static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, |
2599 | struct page *page, unsigned long address) |
2600 | { |
2601 | struct hstate *h = hstate_vma(vma); |
2602 | struct vm_area_struct *iter_vma; |
2603 | struct address_space *mapping; |
2604 | pgoff_t pgoff; |
2605 | |
2606 | /* |
2607 | * vm_pgoff is in PAGE_SIZE units, hence the different calculation |
2608 | * from page cache lookup which is in HPAGE_SIZE units. |
2609 | */ |
2610 | address = address & huge_page_mask(h); |
2611 | pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + |
2612 | vma->vm_pgoff; |
2613 | mapping = file_inode(vma->vm_file)->i_mapping; |
2614 | |
2615 | /* |
2616 | * Take the mapping lock for the duration of the table walk. As |
2617 | * this mapping should be shared between all the VMAs, |
2618 | * __unmap_hugepage_range() is called as the lock is already held |
2619 | */ |
2620 | mutex_lock(&mapping->i_mmap_mutex); |
2621 | vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) { |
2622 | /* Do not unmap the current VMA */ |
2623 | if (iter_vma == vma) |
2624 | continue; |
2625 | |
2626 | /* |
2627 | * Unmap the page from other VMAs without their own reserves. |
2628 | * They get marked to be SIGKILLed if they fault in these |
2629 | * areas. This is because a future no-page fault on this VMA |
2630 | * could insert a zeroed page instead of the data existing |
2631 | * from the time of fork. This would look like data corruption |
2632 | */ |
2633 | if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) |
2634 | unmap_hugepage_range(iter_vma, address, |
2635 | address + huge_page_size(h), page); |
2636 | } |
2637 | mutex_unlock(&mapping->i_mmap_mutex); |
2638 | |
2639 | return 1; |
2640 | } |
2641 | |
2642 | /* |
2643 | * Hugetlb_cow() should be called with page lock of the original hugepage held. |
2644 | * Called with hugetlb_instantiation_mutex held and pte_page locked so we |
2645 | * cannot race with other handlers or page migration. |
2646 | * Keep the pte_same checks anyway to make transition from the mutex easier. |
2647 | */ |
2648 | static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
2649 | unsigned long address, pte_t *ptep, pte_t pte, |
2650 | struct page *pagecache_page, spinlock_t *ptl) |
2651 | { |
2652 | struct hstate *h = hstate_vma(vma); |
2653 | struct page *old_page, *new_page; |
2654 | int outside_reserve = 0; |
2655 | unsigned long mmun_start; /* For mmu_notifiers */ |
2656 | unsigned long mmun_end; /* For mmu_notifiers */ |
2657 | |
2658 | old_page = pte_page(pte); |
2659 | |
2660 | retry_avoidcopy: |
2661 | /* If no-one else is actually using this page, avoid the copy |
2662 | * and just make the page writable */ |
2663 | if (page_mapcount(old_page) == 1 && PageAnon(old_page)) { |
2664 | page_move_anon_rmap(old_page, vma, address); |
2665 | set_huge_ptep_writable(vma, address, ptep); |
2666 | return 0; |
2667 | } |
2668 | |
2669 | /* |
2670 | * If the process that created a MAP_PRIVATE mapping is about to |
2671 | * perform a COW due to a shared page count, attempt to satisfy |
2672 | * the allocation without using the existing reserves. The pagecache |
2673 | * page is used to determine if the reserve at this address was |
2674 | * consumed or not. If reserves were used, a partial faulted mapping |
2675 | * at the time of fork() could consume its reserves on COW instead |
2676 | * of the full address range. |
2677 | */ |
2678 | if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && |
2679 | old_page != pagecache_page) |
2680 | outside_reserve = 1; |
2681 | |
2682 | page_cache_get(old_page); |
2683 | |
2684 | /* Drop page table lock as buddy allocator may be called */ |
2685 | spin_unlock(ptl); |
2686 | new_page = alloc_huge_page(vma, address, outside_reserve); |
2687 | |
2688 | if (IS_ERR(new_page)) { |
2689 | long err = PTR_ERR(new_page); |
2690 | page_cache_release(old_page); |
2691 | |
2692 | /* |
2693 | * If a process owning a MAP_PRIVATE mapping fails to COW, |
2694 | * it is due to references held by a child and an insufficient |
2695 | * huge page pool. To guarantee the original mappers |
2696 | * reliability, unmap the page from child processes. The child |
2697 | * may get SIGKILLed if it later faults. |
2698 | */ |
2699 | if (outside_reserve) { |
2700 | BUG_ON(huge_pte_none(pte)); |
2701 | if (unmap_ref_private(mm, vma, old_page, address)) { |
2702 | BUG_ON(huge_pte_none(pte)); |
2703 | spin_lock(ptl); |
2704 | ptep = huge_pte_offset(mm, address & huge_page_mask(h)); |
2705 | if (likely(ptep && |
2706 | pte_same(huge_ptep_get(ptep), pte))) |
2707 | goto retry_avoidcopy; |
2708 | /* |
2709 | * race occurs while re-acquiring page table |
2710 | * lock, and our job is done. |
2711 | */ |
2712 | return 0; |
2713 | } |
2714 | WARN_ON_ONCE(1); |
2715 | } |
2716 | |
2717 | /* Caller expects lock to be held */ |
2718 | spin_lock(ptl); |
2719 | if (err == -ENOMEM) |
2720 | return VM_FAULT_OOM; |
2721 | else |
2722 | return VM_FAULT_SIGBUS; |
2723 | } |
2724 | |
2725 | /* |
2726 | * When the original hugepage is shared one, it does not have |
2727 | * anon_vma prepared. |
2728 | */ |
2729 | if (unlikely(anon_vma_prepare(vma))) { |
2730 | page_cache_release(new_page); |
2731 | page_cache_release(old_page); |
2732 | /* Caller expects lock to be held */ |
2733 | spin_lock(ptl); |
2734 | return VM_FAULT_OOM; |
2735 | } |
2736 | |
2737 | copy_user_huge_page(new_page, old_page, address, vma, |
2738 | pages_per_huge_page(h)); |
2739 | __SetPageUptodate(new_page); |
2740 | |
2741 | mmun_start = address & huge_page_mask(h); |
2742 | mmun_end = mmun_start + huge_page_size(h); |
2743 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
2744 | /* |
2745 | * Retake the page table lock to check for racing updates |
2746 | * before the page tables are altered |
2747 | */ |
2748 | spin_lock(ptl); |
2749 | ptep = huge_pte_offset(mm, address & huge_page_mask(h)); |
2750 | if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) { |
2751 | ClearPagePrivate(new_page); |
2752 | |
2753 | /* Break COW */ |
2754 | huge_ptep_clear_flush(vma, address, ptep); |
2755 | set_huge_pte_at(mm, address, ptep, |
2756 | make_huge_pte(vma, new_page, 1)); |
2757 | page_remove_rmap(old_page); |
2758 | hugepage_add_new_anon_rmap(new_page, vma, address); |
2759 | /* Make the old page be freed below */ |
2760 | new_page = old_page; |
2761 | } |
2762 | spin_unlock(ptl); |
2763 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
2764 | page_cache_release(new_page); |
2765 | page_cache_release(old_page); |
2766 | |
2767 | /* Caller expects lock to be held */ |
2768 | spin_lock(ptl); |
2769 | return 0; |
2770 | } |
2771 | |
2772 | /* Return the pagecache page at a given address within a VMA */ |
2773 | static struct page *hugetlbfs_pagecache_page(struct hstate *h, |
2774 | struct vm_area_struct *vma, unsigned long address) |
2775 | { |
2776 | struct address_space *mapping; |
2777 | pgoff_t idx; |
2778 | |
2779 | mapping = vma->vm_file->f_mapping; |
2780 | idx = vma_hugecache_offset(h, vma, address); |
2781 | |
2782 | return find_lock_page(mapping, idx); |
2783 | } |
2784 | |
2785 | /* |
2786 | * Return whether there is a pagecache page to back given address within VMA. |
2787 | * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. |
2788 | */ |
2789 | static bool hugetlbfs_pagecache_present(struct hstate *h, |
2790 | struct vm_area_struct *vma, unsigned long address) |
2791 | { |
2792 | struct address_space *mapping; |
2793 | pgoff_t idx; |
2794 | struct page *page; |
2795 | |
2796 | mapping = vma->vm_file->f_mapping; |
2797 | idx = vma_hugecache_offset(h, vma, address); |
2798 | |
2799 | page = find_get_page(mapping, idx); |
2800 | if (page) |
2801 | put_page(page); |
2802 | return page != NULL; |
2803 | } |
2804 | |
2805 | static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2806 | struct address_space *mapping, pgoff_t idx, |
2807 | unsigned long address, pte_t *ptep, unsigned int flags) |
2808 | { |
2809 | struct hstate *h = hstate_vma(vma); |
2810 | int ret = VM_FAULT_SIGBUS; |
2811 | int anon_rmap = 0; |
2812 | unsigned long size; |
2813 | struct page *page; |
2814 | pte_t new_pte; |
2815 | spinlock_t *ptl; |
2816 | |
2817 | /* |
2818 | * Currently, we are forced to kill the process in the event the |
2819 | * original mapper has unmapped pages from the child due to a failed |
2820 | * COW. Warn that such a situation has occurred as it may not be obvious |
2821 | */ |
2822 | if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { |
2823 | pr_warning("PID %d killed due to inadequate hugepage pool\n", |
2824 | current->pid); |
2825 | return ret; |
2826 | } |
2827 | |
2828 | /* |
2829 | * Use page lock to guard against racing truncation |
2830 | * before we get page_table_lock. |
2831 | */ |
2832 | retry: |
2833 | page = find_lock_page(mapping, idx); |
2834 | if (!page) { |
2835 | size = i_size_read(mapping->host) >> huge_page_shift(h); |
2836 | if (idx >= size) |
2837 | goto out; |
2838 | page = alloc_huge_page(vma, address, 0); |
2839 | if (IS_ERR(page)) { |
2840 | ret = PTR_ERR(page); |
2841 | if (ret == -ENOMEM) |
2842 | ret = VM_FAULT_OOM; |
2843 | else |
2844 | ret = VM_FAULT_SIGBUS; |
2845 | goto out; |
2846 | } |
2847 | clear_huge_page(page, address, pages_per_huge_page(h)); |
2848 | __SetPageUptodate(page); |
2849 | |
2850 | if (vma->vm_flags & VM_MAYSHARE) { |
2851 | int err; |
2852 | struct inode *inode = mapping->host; |
2853 | |
2854 | err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); |
2855 | if (err) { |
2856 | put_page(page); |
2857 | if (err == -EEXIST) |
2858 | goto retry; |
2859 | goto out; |
2860 | } |
2861 | ClearPagePrivate(page); |
2862 | |
2863 | spin_lock(&inode->i_lock); |
2864 | inode->i_blocks += blocks_per_huge_page(h); |
2865 | spin_unlock(&inode->i_lock); |
2866 | } else { |
2867 | lock_page(page); |
2868 | if (unlikely(anon_vma_prepare(vma))) { |
2869 | ret = VM_FAULT_OOM; |
2870 | goto backout_unlocked; |
2871 | } |
2872 | anon_rmap = 1; |
2873 | } |
2874 | } else { |
2875 | /* |
2876 | * If memory error occurs between mmap() and fault, some process |
2877 | * don't have hwpoisoned swap entry for errored virtual address. |
2878 | * So we need to block hugepage fault by PG_hwpoison bit check. |
2879 | */ |
2880 | if (unlikely(PageHWPoison(page))) { |
2881 | ret = VM_FAULT_HWPOISON | |
2882 | VM_FAULT_SET_HINDEX(hstate_index(h)); |
2883 | goto backout_unlocked; |
2884 | } |
2885 | } |
2886 | |
2887 | /* |
2888 | * If we are going to COW a private mapping later, we examine the |
2889 | * pending reservations for this page now. This will ensure that |
2890 | * any allocations necessary to record that reservation occur outside |
2891 | * the spinlock. |
2892 | */ |
2893 | if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) |
2894 | if (vma_needs_reservation(h, vma, address) < 0) { |
2895 | ret = VM_FAULT_OOM; |
2896 | goto backout_unlocked; |
2897 | } |
2898 | |
2899 | ptl = huge_pte_lockptr(h, mm, ptep); |
2900 | spin_lock(ptl); |
2901 | size = i_size_read(mapping->host) >> huge_page_shift(h); |
2902 | if (idx >= size) |
2903 | goto backout; |
2904 | |
2905 | ret = 0; |
2906 | if (!huge_pte_none(huge_ptep_get(ptep))) |
2907 | goto backout; |
2908 | |
2909 | if (anon_rmap) { |
2910 | ClearPagePrivate(page); |
2911 | hugepage_add_new_anon_rmap(page, vma, address); |
2912 | } else |
2913 | page_dup_rmap(page); |
2914 | new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) |
2915 | && (vma->vm_flags & VM_SHARED))); |
2916 | set_huge_pte_at(mm, address, ptep, new_pte); |
2917 | |
2918 | if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { |
2919 | /* Optimization, do the COW without a second fault */ |
2920 | ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl); |
2921 | } |
2922 | |
2923 | spin_unlock(ptl); |
2924 | unlock_page(page); |
2925 | out: |
2926 | return ret; |
2927 | |
2928 | backout: |
2929 | spin_unlock(ptl); |
2930 | backout_unlocked: |
2931 | unlock_page(page); |
2932 | put_page(page); |
2933 | goto out; |
2934 | } |
2935 | |
2936 | #ifdef CONFIG_SMP |
2937 | static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm, |
2938 | struct vm_area_struct *vma, |
2939 | struct address_space *mapping, |
2940 | pgoff_t idx, unsigned long address) |
2941 | { |
2942 | unsigned long key[2]; |
2943 | u32 hash; |
2944 | |
2945 | if (vma->vm_flags & VM_SHARED) { |
2946 | key[0] = (unsigned long) mapping; |
2947 | key[1] = idx; |
2948 | } else { |
2949 | key[0] = (unsigned long) mm; |
2950 | key[1] = address >> huge_page_shift(h); |
2951 | } |
2952 | |
2953 | hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0); |
2954 | |
2955 | return hash & (num_fault_mutexes - 1); |
2956 | } |
2957 | #else |
2958 | /* |
2959 | * For uniprocesor systems we always use a single mutex, so just |
2960 | * return 0 and avoid the hashing overhead. |
2961 | */ |
2962 | static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm, |
2963 | struct vm_area_struct *vma, |
2964 | struct address_space *mapping, |
2965 | pgoff_t idx, unsigned long address) |
2966 | { |
2967 | return 0; |
2968 | } |
2969 | #endif |
2970 | |
2971 | int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
2972 | unsigned long address, unsigned int flags) |
2973 | { |
2974 | pte_t *ptep, entry; |
2975 | spinlock_t *ptl; |
2976 | int ret; |
2977 | u32 hash; |
2978 | pgoff_t idx; |
2979 | struct page *page = NULL; |
2980 | struct page *pagecache_page = NULL; |
2981 | struct hstate *h = hstate_vma(vma); |
2982 | struct address_space *mapping; |
2983 | |
2984 | address &= huge_page_mask(h); |
2985 | |
2986 | ptep = huge_pte_offset(mm, address); |
2987 | if (ptep) { |
2988 | entry = huge_ptep_get(ptep); |
2989 | if (unlikely(is_hugetlb_entry_migration(entry))) { |
2990 | migration_entry_wait_huge(vma, mm, ptep); |
2991 | return 0; |
2992 | } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) |
2993 | return VM_FAULT_HWPOISON_LARGE | |
2994 | VM_FAULT_SET_HINDEX(hstate_index(h)); |
2995 | } |
2996 | |
2997 | ptep = huge_pte_alloc(mm, address, huge_page_size(h)); |
2998 | if (!ptep) |
2999 | return VM_FAULT_OOM; |
3000 | |
3001 | mapping = vma->vm_file->f_mapping; |
3002 | idx = vma_hugecache_offset(h, vma, address); |
3003 | |
3004 | /* |
3005 | * Serialize hugepage allocation and instantiation, so that we don't |
3006 | * get spurious allocation failures if two CPUs race to instantiate |
3007 | * the same page in the page cache. |
3008 | */ |
3009 | hash = fault_mutex_hash(h, mm, vma, mapping, idx, address); |
3010 | mutex_lock(&htlb_fault_mutex_table[hash]); |
3011 | |
3012 | entry = huge_ptep_get(ptep); |
3013 | if (huge_pte_none(entry)) { |
3014 | ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags); |
3015 | goto out_mutex; |
3016 | } |
3017 | |
3018 | ret = 0; |
3019 | |
3020 | /* |
3021 | * If we are going to COW the mapping later, we examine the pending |
3022 | * reservations for this page now. This will ensure that any |
3023 | * allocations necessary to record that reservation occur outside the |
3024 | * spinlock. For private mappings, we also lookup the pagecache |
3025 | * page now as it is used to determine if a reservation has been |
3026 | * consumed. |
3027 | */ |
3028 | if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) { |
3029 | if (vma_needs_reservation(h, vma, address) < 0) { |
3030 | ret = VM_FAULT_OOM; |
3031 | goto out_mutex; |
3032 | } |
3033 | |
3034 | if (!(vma->vm_flags & VM_MAYSHARE)) |
3035 | pagecache_page = hugetlbfs_pagecache_page(h, |
3036 | vma, address); |
3037 | } |
3038 | |
3039 | /* |
3040 | * hugetlb_cow() requires page locks of pte_page(entry) and |
3041 | * pagecache_page, so here we need take the former one |
3042 | * when page != pagecache_page or !pagecache_page. |
3043 | * Note that locking order is always pagecache_page -> page, |
3044 | * so no worry about deadlock. |
3045 | */ |
3046 | page = pte_page(entry); |
3047 | get_page(page); |
3048 | if (page != pagecache_page) |
3049 | lock_page(page); |
3050 | |
3051 | ptl = huge_pte_lockptr(h, mm, ptep); |
3052 | spin_lock(ptl); |
3053 | /* Check for a racing update before calling hugetlb_cow */ |
3054 | if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) |
3055 | goto out_ptl; |
3056 | |
3057 | |
3058 | if (flags & FAULT_FLAG_WRITE) { |
3059 | if (!huge_pte_write(entry)) { |
3060 | ret = hugetlb_cow(mm, vma, address, ptep, entry, |
3061 | pagecache_page, ptl); |
3062 | goto out_ptl; |
3063 | } |
3064 | entry = huge_pte_mkdirty(entry); |
3065 | } |
3066 | entry = pte_mkyoung(entry); |
3067 | if (huge_ptep_set_access_flags(vma, address, ptep, entry, |
3068 | flags & FAULT_FLAG_WRITE)) |
3069 | update_mmu_cache(vma, address, ptep); |
3070 | |
3071 | out_ptl: |
3072 | spin_unlock(ptl); |
3073 | |
3074 | if (pagecache_page) { |
3075 | unlock_page(pagecache_page); |
3076 | put_page(pagecache_page); |
3077 | } |
3078 | if (page != pagecache_page) |
3079 | unlock_page(page); |
3080 | put_page(page); |
3081 | |
3082 | out_mutex: |
3083 | mutex_unlock(&htlb_fault_mutex_table[hash]); |
3084 | return ret; |
3085 | } |
3086 | |
3087 | long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, |
3088 | struct page **pages, struct vm_area_struct **vmas, |
3089 | unsigned long *position, unsigned long *nr_pages, |
3090 | long i, unsigned int flags) |
3091 | { |
3092 | unsigned long pfn_offset; |
3093 | unsigned long vaddr = *position; |
3094 | unsigned long remainder = *nr_pages; |
3095 | struct hstate *h = hstate_vma(vma); |
3096 | |
3097 | while (vaddr < vma->vm_end && remainder) { |
3098 | pte_t *pte; |
3099 | spinlock_t *ptl = NULL; |
3100 | int absent; |
3101 | struct page *page; |
3102 | |
3103 | /* |
3104 | * Some archs (sparc64, sh*) have multiple pte_ts to |
3105 | * each hugepage. We have to make sure we get the |
3106 | * first, for the page indexing below to work. |
3107 | * |
3108 | * Note that page table lock is not held when pte is null. |
3109 | */ |
3110 | pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); |
3111 | if (pte) |
3112 | ptl = huge_pte_lock(h, mm, pte); |
3113 | absent = !pte || huge_pte_none(huge_ptep_get(pte)); |
3114 | |
3115 | /* |
3116 | * When coredumping, it suits get_dump_page if we just return |
3117 | * an error where there's an empty slot with no huge pagecache |
3118 | * to back it. This way, we avoid allocating a hugepage, and |
3119 | * the sparse dumpfile avoids allocating disk blocks, but its |
3120 | * huge holes still show up with zeroes where they need to be. |
3121 | */ |
3122 | if (absent && (flags & FOLL_DUMP) && |
3123 | !hugetlbfs_pagecache_present(h, vma, vaddr)) { |
3124 | if (pte) |
3125 | spin_unlock(ptl); |
3126 | remainder = 0; |
3127 | break; |
3128 | } |
3129 | |
3130 | /* |
3131 | * We need call hugetlb_fault for both hugepages under migration |
3132 | * (in which case hugetlb_fault waits for the migration,) and |
3133 | * hwpoisoned hugepages (in which case we need to prevent the |
3134 | * caller from accessing to them.) In order to do this, we use |
3135 | * here is_swap_pte instead of is_hugetlb_entry_migration and |
3136 | * is_hugetlb_entry_hwpoisoned. This is because it simply covers |
3137 | * both cases, and because we can't follow correct pages |
3138 | * directly from any kind of swap entries. |
3139 | */ |
3140 | if (absent || is_swap_pte(huge_ptep_get(pte)) || |
3141 | ((flags & FOLL_WRITE) && |
3142 | !huge_pte_write(huge_ptep_get(pte)))) { |
3143 | int ret; |
3144 | |
3145 | if (pte) |
3146 | spin_unlock(ptl); |
3147 | ret = hugetlb_fault(mm, vma, vaddr, |
3148 | (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); |
3149 | if (!(ret & VM_FAULT_ERROR)) |
3150 | continue; |
3151 | |
3152 | remainder = 0; |
3153 | break; |
3154 | } |
3155 | |
3156 | pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; |
3157 | page = pte_page(huge_ptep_get(pte)); |
3158 | same_page: |
3159 | if (pages) { |
3160 | pages[i] = mem_map_offset(page, pfn_offset); |
3161 | get_page_foll(pages[i]); |
3162 | } |
3163 | |
3164 | if (vmas) |
3165 | vmas[i] = vma; |
3166 | |
3167 | vaddr += PAGE_SIZE; |
3168 | ++pfn_offset; |
3169 | --remainder; |
3170 | ++i; |
3171 | if (vaddr < vma->vm_end && remainder && |
3172 | pfn_offset < pages_per_huge_page(h)) { |
3173 | /* |
3174 | * We use pfn_offset to avoid touching the pageframes |
3175 | * of this compound page. |
3176 | */ |
3177 | goto same_page; |
3178 | } |
3179 | spin_unlock(ptl); |
3180 | } |
3181 | *nr_pages = remainder; |
3182 | *position = vaddr; |
3183 | |
3184 | return i ? i : -EFAULT; |
3185 | } |
3186 | |
3187 | unsigned long hugetlb_change_protection(struct vm_area_struct *vma, |
3188 | unsigned long address, unsigned long end, pgprot_t newprot) |
3189 | { |
3190 | struct mm_struct *mm = vma->vm_mm; |
3191 | unsigned long start = address; |
3192 | pte_t *ptep; |
3193 | pte_t pte; |
3194 | struct hstate *h = hstate_vma(vma); |
3195 | unsigned long pages = 0; |
3196 | |
3197 | BUG_ON(address >= end); |
3198 | flush_cache_range(vma, address, end); |
3199 | |
3200 | mmu_notifier_invalidate_range_start(mm, start, end); |
3201 | mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); |
3202 | for (; address < end; address += huge_page_size(h)) { |
3203 | spinlock_t *ptl; |
3204 | ptep = huge_pte_offset(mm, address); |
3205 | if (!ptep) |
3206 | continue; |
3207 | ptl = huge_pte_lock(h, mm, ptep); |
3208 | if (huge_pmd_unshare(mm, &address, ptep)) { |
3209 | pages++; |
3210 | spin_unlock(ptl); |
3211 | continue; |
3212 | } |
3213 | if (!huge_pte_none(huge_ptep_get(ptep))) { |
3214 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
3215 | pte = pte_mkhuge(huge_pte_modify(pte, newprot)); |
3216 | pte = arch_make_huge_pte(pte, vma, NULL, 0); |
3217 | set_huge_pte_at(mm, address, ptep, pte); |
3218 | pages++; |
3219 | } |
3220 | spin_unlock(ptl); |
3221 | } |
3222 | /* |
3223 | * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare |
3224 | * may have cleared our pud entry and done put_page on the page table: |
3225 | * once we release i_mmap_mutex, another task can do the final put_page |
3226 | * and that page table be reused and filled with junk. |
3227 | */ |
3228 | flush_tlb_range(vma, start, end); |
3229 | mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); |
3230 | mmu_notifier_invalidate_range_end(mm, start, end); |
3231 | |
3232 | return pages << h->order; |
3233 | } |
3234 | |
3235 | int hugetlb_reserve_pages(struct inode *inode, |
3236 | long from, long to, |
3237 | struct vm_area_struct *vma, |
3238 | vm_flags_t vm_flags) |
3239 | { |
3240 | long ret, chg; |
3241 | struct hstate *h = hstate_inode(inode); |
3242 | struct hugepage_subpool *spool = subpool_inode(inode); |
3243 | struct resv_map *resv_map; |
3244 | |
3245 | /* |
3246 | * Only apply hugepage reservation if asked. At fault time, an |
3247 | * attempt will be made for VM_NORESERVE to allocate a page |
3248 | * without using reserves |
3249 | */ |
3250 | if (vm_flags & VM_NORESERVE) |
3251 | return 0; |
3252 | |
3253 | /* |
3254 | * Shared mappings base their reservation on the number of pages that |
3255 | * are already allocated on behalf of the file. Private mappings need |
3256 | * to reserve the full area even if read-only as mprotect() may be |
3257 | * called to make the mapping read-write. Assume !vma is a shm mapping |
3258 | */ |
3259 | if (!vma || vma->vm_flags & VM_MAYSHARE) { |
3260 | resv_map = inode_resv_map(inode); |
3261 | |
3262 | chg = region_chg(resv_map, from, to); |
3263 | |
3264 | } else { |
3265 | resv_map = resv_map_alloc(); |
3266 | if (!resv_map) |
3267 | return -ENOMEM; |
3268 | |
3269 | chg = to - from; |
3270 | |
3271 | set_vma_resv_map(vma, resv_map); |
3272 | set_vma_resv_flags(vma, HPAGE_RESV_OWNER); |
3273 | } |
3274 | |
3275 | if (chg < 0) { |
3276 | ret = chg; |
3277 | goto out_err; |
3278 | } |
3279 | |
3280 | /* There must be enough pages in the subpool for the mapping */ |
3281 | if (hugepage_subpool_get_pages(spool, chg)) { |
3282 | ret = -ENOSPC; |
3283 | goto out_err; |
3284 | } |
3285 | |
3286 | /* |
3287 | * Check enough hugepages are available for the reservation. |
3288 | * Hand the pages back to the subpool if there are not |
3289 | */ |
3290 | ret = hugetlb_acct_memory(h, chg); |
3291 | if (ret < 0) { |
3292 | hugepage_subpool_put_pages(spool, chg); |
3293 | goto out_err; |
3294 | } |
3295 | |
3296 | /* |
3297 | * Account for the reservations made. Shared mappings record regions |
3298 | * that have reservations as they are shared by multiple VMAs. |
3299 | * When the last VMA disappears, the region map says how much |
3300 | * the reservation was and the page cache tells how much of |
3301 | * the reservation was consumed. Private mappings are per-VMA and |
3302 | * only the consumed reservations are tracked. When the VMA |
3303 | * disappears, the original reservation is the VMA size and the |
3304 | * consumed reservations are stored in the map. Hence, nothing |
3305 | * else has to be done for private mappings here |
3306 | */ |
3307 | if (!vma || vma->vm_flags & VM_MAYSHARE) |
3308 | region_add(resv_map, from, to); |
3309 | return 0; |
3310 | out_err: |
3311 | if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
3312 | kref_put(&resv_map->refs, resv_map_release); |
3313 | return ret; |
3314 | } |
3315 | |
3316 | void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) |
3317 | { |
3318 | struct hstate *h = hstate_inode(inode); |
3319 | struct resv_map *resv_map = inode_resv_map(inode); |
3320 | long chg = 0; |
3321 | struct hugepage_subpool *spool = subpool_inode(inode); |
3322 | |
3323 | if (resv_map) |
3324 | chg = region_truncate(resv_map, offset); |
3325 | spin_lock(&inode->i_lock); |
3326 | inode->i_blocks -= (blocks_per_huge_page(h) * freed); |
3327 | spin_unlock(&inode->i_lock); |
3328 | |
3329 | hugepage_subpool_put_pages(spool, (chg - freed)); |
3330 | hugetlb_acct_memory(h, -(chg - freed)); |
3331 | } |
3332 | |
3333 | #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE |
3334 | static unsigned long page_table_shareable(struct vm_area_struct *svma, |
3335 | struct vm_area_struct *vma, |
3336 | unsigned long addr, pgoff_t idx) |
3337 | { |
3338 | unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) + |
3339 | svma->vm_start; |
3340 | unsigned long sbase = saddr & PUD_MASK; |
3341 | unsigned long s_end = sbase + PUD_SIZE; |
3342 | |
3343 | /* Allow segments to share if only one is marked locked */ |
3344 | unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED; |
3345 | unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED; |
3346 | |
3347 | /* |
3348 | * match the virtual addresses, permission and the alignment of the |
3349 | * page table page. |
3350 | */ |
3351 | if (pmd_index(addr) != pmd_index(saddr) || |
3352 | vm_flags != svm_flags || |
3353 | sbase < svma->vm_start || svma->vm_end < s_end) |
3354 | return 0; |
3355 | |
3356 | return saddr; |
3357 | } |
3358 | |
3359 | static int vma_shareable(struct vm_area_struct *vma, unsigned long addr) |
3360 | { |
3361 | unsigned long base = addr & PUD_MASK; |
3362 | unsigned long end = base + PUD_SIZE; |
3363 | |
3364 | /* |
3365 | * check on proper vm_flags and page table alignment |
3366 | */ |
3367 | if (vma->vm_flags & VM_MAYSHARE && |
3368 | vma->vm_start <= base && end <= vma->vm_end) |
3369 | return 1; |
3370 | return 0; |
3371 | } |
3372 | |
3373 | /* |
3374 | * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc() |
3375 | * and returns the corresponding pte. While this is not necessary for the |
3376 | * !shared pmd case because we can allocate the pmd later as well, it makes the |
3377 | * code much cleaner. pmd allocation is essential for the shared case because |
3378 | * pud has to be populated inside the same i_mmap_mutex section - otherwise |
3379 | * racing tasks could either miss the sharing (see huge_pte_offset) or select a |
3380 | * bad pmd for sharing. |
3381 | */ |
3382 | pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) |
3383 | { |
3384 | struct vm_area_struct *vma = find_vma(mm, addr); |
3385 | struct address_space *mapping = vma->vm_file->f_mapping; |
3386 | pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + |
3387 | vma->vm_pgoff; |
3388 | struct vm_area_struct *svma; |
3389 | unsigned long saddr; |
3390 | pte_t *spte = NULL; |
3391 | pte_t *pte; |
3392 | spinlock_t *ptl; |
3393 | |
3394 | if (!vma_shareable(vma, addr)) |
3395 | return (pte_t *)pmd_alloc(mm, pud, addr); |
3396 | |
3397 | mutex_lock(&mapping->i_mmap_mutex); |
3398 | vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) { |
3399 | if (svma == vma) |
3400 | continue; |
3401 | |
3402 | saddr = page_table_shareable(svma, vma, addr, idx); |
3403 | if (saddr) { |
3404 | spte = huge_pte_offset(svma->vm_mm, saddr); |
3405 | if (spte) { |
3406 | get_page(virt_to_page(spte)); |
3407 | break; |
3408 | } |
3409 | } |
3410 | } |
3411 | |
3412 | if (!spte) |
3413 | goto out; |
3414 | |
3415 | ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte); |
3416 | spin_lock(ptl); |
3417 | if (pud_none(*pud)) |
3418 | pud_populate(mm, pud, |
3419 | (pmd_t *)((unsigned long)spte & PAGE_MASK)); |
3420 | else |
3421 | put_page(virt_to_page(spte)); |
3422 | spin_unlock(ptl); |
3423 | out: |
3424 | pte = (pte_t *)pmd_alloc(mm, pud, addr); |
3425 | mutex_unlock(&mapping->i_mmap_mutex); |
3426 | return pte; |
3427 | } |
3428 | |
3429 | /* |
3430 | * unmap huge page backed by shared pte. |
3431 | * |
3432 | * Hugetlb pte page is ref counted at the time of mapping. If pte is shared |
3433 | * indicated by page_count > 1, unmap is achieved by clearing pud and |
3434 | * decrementing the ref count. If count == 1, the pte page is not shared. |
3435 | * |
3436 | * called with page table lock held. |
3437 | * |
3438 | * returns: 1 successfully unmapped a shared pte page |
3439 | * 0 the underlying pte page is not shared, or it is the last user |
3440 | */ |
3441 | int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) |
3442 | { |
3443 | pgd_t *pgd = pgd_offset(mm, *addr); |
3444 | pud_t *pud = pud_offset(pgd, *addr); |
3445 | |
3446 | BUG_ON(page_count(virt_to_page(ptep)) == 0); |
3447 | if (page_count(virt_to_page(ptep)) == 1) |
3448 | return 0; |
3449 | |
3450 | pud_clear(pud); |
3451 | put_page(virt_to_page(ptep)); |
3452 | *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE; |
3453 | return 1; |
3454 | } |
3455 | #define want_pmd_share() (1) |
3456 | #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ |
3457 | pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) |
3458 | { |
3459 | return NULL; |
3460 | } |
3461 | #define want_pmd_share() (0) |
3462 | #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ |
3463 | |
3464 | #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB |
3465 | pte_t *huge_pte_alloc(struct mm_struct *mm, |
3466 | unsigned long addr, unsigned long sz) |
3467 | { |
3468 | pgd_t *pgd; |
3469 | pud_t *pud; |
3470 | pte_t *pte = NULL; |
3471 | |
3472 | pgd = pgd_offset(mm, addr); |
3473 | pud = pud_alloc(mm, pgd, addr); |
3474 | if (pud) { |
3475 | if (sz == PUD_SIZE) { |
3476 | pte = (pte_t *)pud; |
3477 | } else { |
3478 | BUG_ON(sz != PMD_SIZE); |
3479 | if (want_pmd_share() && pud_none(*pud)) |
3480 | pte = huge_pmd_share(mm, addr, pud); |
3481 | else |
3482 | pte = (pte_t *)pmd_alloc(mm, pud, addr); |
3483 | } |
3484 | } |
3485 | BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte)); |
3486 | |
3487 | return pte; |
3488 | } |
3489 | |
3490 | pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) |
3491 | { |
3492 | pgd_t *pgd; |
3493 | pud_t *pud; |
3494 | pmd_t *pmd = NULL; |
3495 | |
3496 | pgd = pgd_offset(mm, addr); |
3497 | if (pgd_present(*pgd)) { |
3498 | pud = pud_offset(pgd, addr); |
3499 | if (pud_present(*pud)) { |
3500 | if (pud_huge(*pud)) |
3501 | return (pte_t *)pud; |
3502 | pmd = pmd_offset(pud, addr); |
3503 | } |
3504 | } |
3505 | return (pte_t *) pmd; |
3506 | } |
3507 | |
3508 | struct page * |
3509 | follow_huge_pmd(struct mm_struct *mm, unsigned long address, |
3510 | pmd_t *pmd, int write) |
3511 | { |
3512 | struct page *page; |
3513 | |
3514 | page = pte_page(*(pte_t *)pmd); |
3515 | if (page) |
3516 | page += ((address & ~PMD_MASK) >> PAGE_SHIFT); |
3517 | return page; |
3518 | } |
3519 | |
3520 | struct page * |
3521 | follow_huge_pud(struct mm_struct *mm, unsigned long address, |
3522 | pud_t *pud, int write) |
3523 | { |
3524 | struct page *page; |
3525 | |
3526 | page = pte_page(*(pte_t *)pud); |
3527 | if (page) |
3528 | page += ((address & ~PUD_MASK) >> PAGE_SHIFT); |
3529 | return page; |
3530 | } |
3531 | |
3532 | #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */ |
3533 | |
3534 | /* Can be overriden by architectures */ |
3535 | struct page * __weak |
3536 | follow_huge_pud(struct mm_struct *mm, unsigned long address, |
3537 | pud_t *pud, int write) |
3538 | { |
3539 | BUG(); |
3540 | return NULL; |
3541 | } |
3542 | |
3543 | #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ |
3544 | |
3545 | #ifdef CONFIG_MEMORY_FAILURE |
3546 | |
3547 | /* Should be called in hugetlb_lock */ |
3548 | static int is_hugepage_on_freelist(struct page *hpage) |
3549 | { |
3550 | struct page *page; |
3551 | struct page *tmp; |
3552 | struct hstate *h = page_hstate(hpage); |
3553 | int nid = page_to_nid(hpage); |
3554 | |
3555 | list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru) |
3556 | if (page == hpage) |
3557 | return 1; |
3558 | return 0; |
3559 | } |
3560 | |
3561 | /* |
3562 | * This function is called from memory failure code. |
3563 | * Assume the caller holds page lock of the head page. |
3564 | */ |
3565 | int dequeue_hwpoisoned_huge_page(struct page *hpage) |
3566 | { |
3567 | struct hstate *h = page_hstate(hpage); |
3568 | int nid = page_to_nid(hpage); |
3569 | int ret = -EBUSY; |
3570 | |
3571 | spin_lock(&hugetlb_lock); |
3572 | if (is_hugepage_on_freelist(hpage)) { |
3573 | /* |
3574 | * Hwpoisoned hugepage isn't linked to activelist or freelist, |
3575 | * but dangling hpage->lru can trigger list-debug warnings |
3576 | * (this happens when we call unpoison_memory() on it), |
3577 | * so let it point to itself with list_del_init(). |
3578 | */ |
3579 | list_del_init(&hpage->lru); |
3580 | set_page_refcounted(hpage); |
3581 | h->free_huge_pages--; |
3582 | h->free_huge_pages_node[nid]--; |
3583 | ret = 0; |
3584 | } |
3585 | spin_unlock(&hugetlb_lock); |
3586 | return ret; |
3587 | } |
3588 | #endif |
3589 | |
3590 | bool isolate_huge_page(struct page *page, struct list_head *list) |
3591 | { |
3592 | VM_BUG_ON_PAGE(!PageHead(page), page); |
3593 | if (!get_page_unless_zero(page)) |
3594 | return false; |
3595 | spin_lock(&hugetlb_lock); |
3596 | list_move_tail(&page->lru, list); |
3597 | spin_unlock(&hugetlb_lock); |
3598 | return true; |
3599 | } |
3600 | |
3601 | void putback_active_hugepage(struct page *page) |
3602 | { |
3603 | VM_BUG_ON_PAGE(!PageHead(page), page); |
3604 | spin_lock(&hugetlb_lock); |
3605 | list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist); |
3606 | spin_unlock(&hugetlb_lock); |
3607 | put_page(page); |
3608 | } |
3609 | |
3610 | bool is_hugepage_active(struct page *page) |
3611 | { |
3612 | VM_BUG_ON_PAGE(!PageHuge(page), page); |
3613 | /* |
3614 | * This function can be called for a tail page because the caller, |
3615 | * scan_movable_pages, scans through a given pfn-range which typically |
3616 | * covers one memory block. In systems using gigantic hugepage (1GB |
3617 | * for x86_64,) a hugepage is larger than a memory block, and we don't |
3618 | * support migrating such large hugepages for now, so return false |
3619 | * when called for tail pages. |
3620 | */ |
3621 | if (PageTail(page)) |
3622 | return false; |
3623 | /* |
3624 | * Refcount of a hwpoisoned hugepages is 1, but they are not active, |
3625 | * so we should return false for them. |
3626 | */ |
3627 | if (unlikely(PageHWPoison(page))) |
3628 | return false; |
3629 | return page_count(page) > 0; |
3630 | } |
3631 |
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