Root/
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_supported(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 | /* |
611 | * common helper functions for hstate_next_node_to_{alloc|free}. |
612 | * We may have allocated or freed a huge page based on a different |
613 | * nodes_allowed previously, so h->next_node_to_{alloc|free} might |
614 | * be outside of *nodes_allowed. Ensure that we use an allowed |
615 | * node for alloc or free. |
616 | */ |
617 | static int next_node_allowed(int nid, nodemask_t *nodes_allowed) |
618 | { |
619 | nid = next_node(nid, *nodes_allowed); |
620 | if (nid == MAX_NUMNODES) |
621 | nid = first_node(*nodes_allowed); |
622 | VM_BUG_ON(nid >= MAX_NUMNODES); |
623 | |
624 | return nid; |
625 | } |
626 | |
627 | static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) |
628 | { |
629 | if (!node_isset(nid, *nodes_allowed)) |
630 | nid = next_node_allowed(nid, nodes_allowed); |
631 | return nid; |
632 | } |
633 | |
634 | /* |
635 | * returns the previously saved node ["this node"] from which to |
636 | * allocate a persistent huge page for the pool and advance the |
637 | * next node from which to allocate, handling wrap at end of node |
638 | * mask. |
639 | */ |
640 | static int hstate_next_node_to_alloc(struct hstate *h, |
641 | nodemask_t *nodes_allowed) |
642 | { |
643 | int nid; |
644 | |
645 | VM_BUG_ON(!nodes_allowed); |
646 | |
647 | nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); |
648 | h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); |
649 | |
650 | return nid; |
651 | } |
652 | |
653 | /* |
654 | * helper for free_pool_huge_page() - return the previously saved |
655 | * node ["this node"] from which to free a huge page. Advance the |
656 | * next node id whether or not we find a free huge page to free so |
657 | * that the next attempt to free addresses the next node. |
658 | */ |
659 | static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) |
660 | { |
661 | int nid; |
662 | |
663 | VM_BUG_ON(!nodes_allowed); |
664 | |
665 | nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); |
666 | h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); |
667 | |
668 | return nid; |
669 | } |
670 | |
671 | #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \ |
672 | for (nr_nodes = nodes_weight(*mask); \ |
673 | nr_nodes > 0 && \ |
674 | ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \ |
675 | nr_nodes--) |
676 | |
677 | #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \ |
678 | for (nr_nodes = nodes_weight(*mask); \ |
679 | nr_nodes > 0 && \ |
680 | ((node = hstate_next_node_to_free(hs, mask)) || 1); \ |
681 | nr_nodes--) |
682 | |
683 | #if defined(CONFIG_CMA) && defined(CONFIG_X86_64) |
684 | static void destroy_compound_gigantic_page(struct page *page, |
685 | unsigned long order) |
686 | { |
687 | int i; |
688 | int nr_pages = 1 << order; |
689 | struct page *p = page + 1; |
690 | |
691 | for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { |
692 | __ClearPageTail(p); |
693 | set_page_refcounted(p); |
694 | p->first_page = NULL; |
695 | } |
696 | |
697 | set_compound_order(page, 0); |
698 | __ClearPageHead(page); |
699 | } |
700 | |
701 | static void free_gigantic_page(struct page *page, unsigned order) |
702 | { |
703 | free_contig_range(page_to_pfn(page), 1 << order); |
704 | } |
705 | |
706 | static int __alloc_gigantic_page(unsigned long start_pfn, |
707 | unsigned long nr_pages) |
708 | { |
709 | unsigned long end_pfn = start_pfn + nr_pages; |
710 | return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE); |
711 | } |
712 | |
713 | static bool pfn_range_valid_gigantic(unsigned long start_pfn, |
714 | unsigned long nr_pages) |
715 | { |
716 | unsigned long i, end_pfn = start_pfn + nr_pages; |
717 | struct page *page; |
718 | |
719 | for (i = start_pfn; i < end_pfn; i++) { |
720 | if (!pfn_valid(i)) |
721 | return false; |
722 | |
723 | page = pfn_to_page(i); |
724 | |
725 | if (PageReserved(page)) |
726 | return false; |
727 | |
728 | if (page_count(page) > 0) |
729 | return false; |
730 | |
731 | if (PageHuge(page)) |
732 | return false; |
733 | } |
734 | |
735 | return true; |
736 | } |
737 | |
738 | static bool zone_spans_last_pfn(const struct zone *zone, |
739 | unsigned long start_pfn, unsigned long nr_pages) |
740 | { |
741 | unsigned long last_pfn = start_pfn + nr_pages - 1; |
742 | return zone_spans_pfn(zone, last_pfn); |
743 | } |
744 | |
745 | static struct page *alloc_gigantic_page(int nid, unsigned order) |
746 | { |
747 | unsigned long nr_pages = 1 << order; |
748 | unsigned long ret, pfn, flags; |
749 | struct zone *z; |
750 | |
751 | z = NODE_DATA(nid)->node_zones; |
752 | for (; z - NODE_DATA(nid)->node_zones < MAX_NR_ZONES; z++) { |
753 | spin_lock_irqsave(&z->lock, flags); |
754 | |
755 | pfn = ALIGN(z->zone_start_pfn, nr_pages); |
756 | while (zone_spans_last_pfn(z, pfn, nr_pages)) { |
757 | if (pfn_range_valid_gigantic(pfn, nr_pages)) { |
758 | /* |
759 | * We release the zone lock here because |
760 | * alloc_contig_range() will also lock the zone |
761 | * at some point. If there's an allocation |
762 | * spinning on this lock, it may win the race |
763 | * and cause alloc_contig_range() to fail... |
764 | */ |
765 | spin_unlock_irqrestore(&z->lock, flags); |
766 | ret = __alloc_gigantic_page(pfn, nr_pages); |
767 | if (!ret) |
768 | return pfn_to_page(pfn); |
769 | spin_lock_irqsave(&z->lock, flags); |
770 | } |
771 | pfn += nr_pages; |
772 | } |
773 | |
774 | spin_unlock_irqrestore(&z->lock, flags); |
775 | } |
776 | |
777 | return NULL; |
778 | } |
779 | |
780 | static void prep_new_huge_page(struct hstate *h, struct page *page, int nid); |
781 | static void prep_compound_gigantic_page(struct page *page, unsigned long order); |
782 | |
783 | static struct page *alloc_fresh_gigantic_page_node(struct hstate *h, int nid) |
784 | { |
785 | struct page *page; |
786 | |
787 | page = alloc_gigantic_page(nid, huge_page_order(h)); |
788 | if (page) { |
789 | prep_compound_gigantic_page(page, huge_page_order(h)); |
790 | prep_new_huge_page(h, page, nid); |
791 | } |
792 | |
793 | return page; |
794 | } |
795 | |
796 | static int alloc_fresh_gigantic_page(struct hstate *h, |
797 | nodemask_t *nodes_allowed) |
798 | { |
799 | struct page *page = NULL; |
800 | int nr_nodes, node; |
801 | |
802 | for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { |
803 | page = alloc_fresh_gigantic_page_node(h, node); |
804 | if (page) |
805 | return 1; |
806 | } |
807 | |
808 | return 0; |
809 | } |
810 | |
811 | static inline bool gigantic_page_supported(void) { return true; } |
812 | #else |
813 | static inline bool gigantic_page_supported(void) { return false; } |
814 | static inline void free_gigantic_page(struct page *page, unsigned order) { } |
815 | static inline void destroy_compound_gigantic_page(struct page *page, |
816 | unsigned long order) { } |
817 | static inline int alloc_fresh_gigantic_page(struct hstate *h, |
818 | nodemask_t *nodes_allowed) { return 0; } |
819 | #endif |
820 | |
821 | static void update_and_free_page(struct hstate *h, struct page *page) |
822 | { |
823 | int i; |
824 | |
825 | if (hstate_is_gigantic(h) && !gigantic_page_supported()) |
826 | return; |
827 | |
828 | h->nr_huge_pages--; |
829 | h->nr_huge_pages_node[page_to_nid(page)]--; |
830 | for (i = 0; i < pages_per_huge_page(h); i++) { |
831 | page[i].flags &= ~(1 << PG_locked | 1 << PG_error | |
832 | 1 << PG_referenced | 1 << PG_dirty | |
833 | 1 << PG_active | 1 << PG_private | |
834 | 1 << PG_writeback); |
835 | } |
836 | VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page); |
837 | set_compound_page_dtor(page, NULL); |
838 | set_page_refcounted(page); |
839 | if (hstate_is_gigantic(h)) { |
840 | destroy_compound_gigantic_page(page, huge_page_order(h)); |
841 | free_gigantic_page(page, huge_page_order(h)); |
842 | } else { |
843 | arch_release_hugepage(page); |
844 | __free_pages(page, huge_page_order(h)); |
845 | } |
846 | } |
847 | |
848 | struct hstate *size_to_hstate(unsigned long size) |
849 | { |
850 | struct hstate *h; |
851 | |
852 | for_each_hstate(h) { |
853 | if (huge_page_size(h) == size) |
854 | return h; |
855 | } |
856 | return NULL; |
857 | } |
858 | |
859 | void free_huge_page(struct page *page) |
860 | { |
861 | /* |
862 | * Can't pass hstate in here because it is called from the |
863 | * compound page destructor. |
864 | */ |
865 | struct hstate *h = page_hstate(page); |
866 | int nid = page_to_nid(page); |
867 | struct hugepage_subpool *spool = |
868 | (struct hugepage_subpool *)page_private(page); |
869 | bool restore_reserve; |
870 | |
871 | set_page_private(page, 0); |
872 | page->mapping = NULL; |
873 | BUG_ON(page_count(page)); |
874 | BUG_ON(page_mapcount(page)); |
875 | restore_reserve = PagePrivate(page); |
876 | ClearPagePrivate(page); |
877 | |
878 | spin_lock(&hugetlb_lock); |
879 | hugetlb_cgroup_uncharge_page(hstate_index(h), |
880 | pages_per_huge_page(h), page); |
881 | if (restore_reserve) |
882 | h->resv_huge_pages++; |
883 | |
884 | if (h->surplus_huge_pages_node[nid]) { |
885 | /* remove the page from active list */ |
886 | list_del(&page->lru); |
887 | update_and_free_page(h, page); |
888 | h->surplus_huge_pages--; |
889 | h->surplus_huge_pages_node[nid]--; |
890 | } else { |
891 | arch_clear_hugepage_flags(page); |
892 | enqueue_huge_page(h, page); |
893 | } |
894 | spin_unlock(&hugetlb_lock); |
895 | hugepage_subpool_put_pages(spool, 1); |
896 | } |
897 | |
898 | static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) |
899 | { |
900 | INIT_LIST_HEAD(&page->lru); |
901 | set_compound_page_dtor(page, free_huge_page); |
902 | spin_lock(&hugetlb_lock); |
903 | set_hugetlb_cgroup(page, NULL); |
904 | h->nr_huge_pages++; |
905 | h->nr_huge_pages_node[nid]++; |
906 | spin_unlock(&hugetlb_lock); |
907 | put_page(page); /* free it into the hugepage allocator */ |
908 | } |
909 | |
910 | static void prep_compound_gigantic_page(struct page *page, unsigned long order) |
911 | { |
912 | int i; |
913 | int nr_pages = 1 << order; |
914 | struct page *p = page + 1; |
915 | |
916 | /* we rely on prep_new_huge_page to set the destructor */ |
917 | set_compound_order(page, order); |
918 | __SetPageHead(page); |
919 | __ClearPageReserved(page); |
920 | for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { |
921 | __SetPageTail(p); |
922 | /* |
923 | * For gigantic hugepages allocated through bootmem at |
924 | * boot, it's safer to be consistent with the not-gigantic |
925 | * hugepages and clear the PG_reserved bit from all tail pages |
926 | * too. Otherwse drivers using get_user_pages() to access tail |
927 | * pages may get the reference counting wrong if they see |
928 | * PG_reserved set on a tail page (despite the head page not |
929 | * having PG_reserved set). Enforcing this consistency between |
930 | * head and tail pages allows drivers to optimize away a check |
931 | * on the head page when they need know if put_page() is needed |
932 | * after get_user_pages(). |
933 | */ |
934 | __ClearPageReserved(p); |
935 | set_page_count(p, 0); |
936 | p->first_page = page; |
937 | } |
938 | } |
939 | |
940 | /* |
941 | * PageHuge() only returns true for hugetlbfs pages, but not for normal or |
942 | * transparent huge pages. See the PageTransHuge() documentation for more |
943 | * details. |
944 | */ |
945 | int PageHuge(struct page *page) |
946 | { |
947 | if (!PageCompound(page)) |
948 | return 0; |
949 | |
950 | page = compound_head(page); |
951 | return get_compound_page_dtor(page) == free_huge_page; |
952 | } |
953 | EXPORT_SYMBOL_GPL(PageHuge); |
954 | |
955 | /* |
956 | * PageHeadHuge() only returns true for hugetlbfs head page, but not for |
957 | * normal or transparent huge pages. |
958 | */ |
959 | int PageHeadHuge(struct page *page_head) |
960 | { |
961 | if (!PageHead(page_head)) |
962 | return 0; |
963 | |
964 | return get_compound_page_dtor(page_head) == free_huge_page; |
965 | } |
966 | |
967 | pgoff_t __basepage_index(struct page *page) |
968 | { |
969 | struct page *page_head = compound_head(page); |
970 | pgoff_t index = page_index(page_head); |
971 | unsigned long compound_idx; |
972 | |
973 | if (!PageHuge(page_head)) |
974 | return page_index(page); |
975 | |
976 | if (compound_order(page_head) >= MAX_ORDER) |
977 | compound_idx = page_to_pfn(page) - page_to_pfn(page_head); |
978 | else |
979 | compound_idx = page - page_head; |
980 | |
981 | return (index << compound_order(page_head)) + compound_idx; |
982 | } |
983 | |
984 | static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) |
985 | { |
986 | struct page *page; |
987 | |
988 | page = alloc_pages_exact_node(nid, |
989 | htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE| |
990 | __GFP_REPEAT|__GFP_NOWARN, |
991 | huge_page_order(h)); |
992 | if (page) { |
993 | if (arch_prepare_hugepage(page)) { |
994 | __free_pages(page, huge_page_order(h)); |
995 | return NULL; |
996 | } |
997 | prep_new_huge_page(h, page, nid); |
998 | } |
999 | |
1000 | return page; |
1001 | } |
1002 | |
1003 | static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) |
1004 | { |
1005 | struct page *page; |
1006 | int nr_nodes, node; |
1007 | int ret = 0; |
1008 | |
1009 | for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { |
1010 | page = alloc_fresh_huge_page_node(h, node); |
1011 | if (page) { |
1012 | ret = 1; |
1013 | break; |
1014 | } |
1015 | } |
1016 | |
1017 | if (ret) |
1018 | count_vm_event(HTLB_BUDDY_PGALLOC); |
1019 | else |
1020 | count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
1021 | |
1022 | return ret; |
1023 | } |
1024 | |
1025 | /* |
1026 | * Free huge page from pool from next node to free. |
1027 | * Attempt to keep persistent huge pages more or less |
1028 | * balanced over allowed nodes. |
1029 | * Called with hugetlb_lock locked. |
1030 | */ |
1031 | static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, |
1032 | bool acct_surplus) |
1033 | { |
1034 | int nr_nodes, node; |
1035 | int ret = 0; |
1036 | |
1037 | for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { |
1038 | /* |
1039 | * If we're returning unused surplus pages, only examine |
1040 | * nodes with surplus pages. |
1041 | */ |
1042 | if ((!acct_surplus || h->surplus_huge_pages_node[node]) && |
1043 | !list_empty(&h->hugepage_freelists[node])) { |
1044 | struct page *page = |
1045 | list_entry(h->hugepage_freelists[node].next, |
1046 | struct page, lru); |
1047 | list_del(&page->lru); |
1048 | h->free_huge_pages--; |
1049 | h->free_huge_pages_node[node]--; |
1050 | if (acct_surplus) { |
1051 | h->surplus_huge_pages--; |
1052 | h->surplus_huge_pages_node[node]--; |
1053 | } |
1054 | update_and_free_page(h, page); |
1055 | ret = 1; |
1056 | break; |
1057 | } |
1058 | } |
1059 | |
1060 | return ret; |
1061 | } |
1062 | |
1063 | /* |
1064 | * Dissolve a given free hugepage into free buddy pages. This function does |
1065 | * nothing for in-use (including surplus) hugepages. |
1066 | */ |
1067 | static void dissolve_free_huge_page(struct page *page) |
1068 | { |
1069 | spin_lock(&hugetlb_lock); |
1070 | if (PageHuge(page) && !page_count(page)) { |
1071 | struct hstate *h = page_hstate(page); |
1072 | int nid = page_to_nid(page); |
1073 | list_del(&page->lru); |
1074 | h->free_huge_pages--; |
1075 | h->free_huge_pages_node[nid]--; |
1076 | update_and_free_page(h, page); |
1077 | } |
1078 | spin_unlock(&hugetlb_lock); |
1079 | } |
1080 | |
1081 | /* |
1082 | * Dissolve free hugepages in a given pfn range. Used by memory hotplug to |
1083 | * make specified memory blocks removable from the system. |
1084 | * Note that start_pfn should aligned with (minimum) hugepage size. |
1085 | */ |
1086 | void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) |
1087 | { |
1088 | unsigned int order = 8 * sizeof(void *); |
1089 | unsigned long pfn; |
1090 | struct hstate *h; |
1091 | |
1092 | /* Set scan step to minimum hugepage size */ |
1093 | for_each_hstate(h) |
1094 | if (order > huge_page_order(h)) |
1095 | order = huge_page_order(h); |
1096 | VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order)); |
1097 | for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) |
1098 | dissolve_free_huge_page(pfn_to_page(pfn)); |
1099 | } |
1100 | |
1101 | static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) |
1102 | { |
1103 | struct page *page; |
1104 | unsigned int r_nid; |
1105 | |
1106 | if (hstate_is_gigantic(h)) |
1107 | return NULL; |
1108 | |
1109 | /* |
1110 | * Assume we will successfully allocate the surplus page to |
1111 | * prevent racing processes from causing the surplus to exceed |
1112 | * overcommit |
1113 | * |
1114 | * This however introduces a different race, where a process B |
1115 | * tries to grow the static hugepage pool while alloc_pages() is |
1116 | * called by process A. B will only examine the per-node |
1117 | * counters in determining if surplus huge pages can be |
1118 | * converted to normal huge pages in adjust_pool_surplus(). A |
1119 | * won't be able to increment the per-node counter, until the |
1120 | * lock is dropped by B, but B doesn't drop hugetlb_lock until |
1121 | * no more huge pages can be converted from surplus to normal |
1122 | * state (and doesn't try to convert again). Thus, we have a |
1123 | * case where a surplus huge page exists, the pool is grown, and |
1124 | * the surplus huge page still exists after, even though it |
1125 | * should just have been converted to a normal huge page. This |
1126 | * does not leak memory, though, as the hugepage will be freed |
1127 | * once it is out of use. It also does not allow the counters to |
1128 | * go out of whack in adjust_pool_surplus() as we don't modify |
1129 | * the node values until we've gotten the hugepage and only the |
1130 | * per-node value is checked there. |
1131 | */ |
1132 | spin_lock(&hugetlb_lock); |
1133 | if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { |
1134 | spin_unlock(&hugetlb_lock); |
1135 | return NULL; |
1136 | } else { |
1137 | h->nr_huge_pages++; |
1138 | h->surplus_huge_pages++; |
1139 | } |
1140 | spin_unlock(&hugetlb_lock); |
1141 | |
1142 | if (nid == NUMA_NO_NODE) |
1143 | page = alloc_pages(htlb_alloc_mask(h)|__GFP_COMP| |
1144 | __GFP_REPEAT|__GFP_NOWARN, |
1145 | huge_page_order(h)); |
1146 | else |
1147 | page = alloc_pages_exact_node(nid, |
1148 | htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE| |
1149 | __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h)); |
1150 | |
1151 | if (page && arch_prepare_hugepage(page)) { |
1152 | __free_pages(page, huge_page_order(h)); |
1153 | page = NULL; |
1154 | } |
1155 | |
1156 | spin_lock(&hugetlb_lock); |
1157 | if (page) { |
1158 | INIT_LIST_HEAD(&page->lru); |
1159 | r_nid = page_to_nid(page); |
1160 | set_compound_page_dtor(page, free_huge_page); |
1161 | set_hugetlb_cgroup(page, NULL); |
1162 | /* |
1163 | * We incremented the global counters already |
1164 | */ |
1165 | h->nr_huge_pages_node[r_nid]++; |
1166 | h->surplus_huge_pages_node[r_nid]++; |
1167 | __count_vm_event(HTLB_BUDDY_PGALLOC); |
1168 | } else { |
1169 | h->nr_huge_pages--; |
1170 | h->surplus_huge_pages--; |
1171 | __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
1172 | } |
1173 | spin_unlock(&hugetlb_lock); |
1174 | |
1175 | return page; |
1176 | } |
1177 | |
1178 | /* |
1179 | * This allocation function is useful in the context where vma is irrelevant. |
1180 | * E.g. soft-offlining uses this function because it only cares physical |
1181 | * address of error page. |
1182 | */ |
1183 | struct page *alloc_huge_page_node(struct hstate *h, int nid) |
1184 | { |
1185 | struct page *page = NULL; |
1186 | |
1187 | spin_lock(&hugetlb_lock); |
1188 | if (h->free_huge_pages - h->resv_huge_pages > 0) |
1189 | page = dequeue_huge_page_node(h, nid); |
1190 | spin_unlock(&hugetlb_lock); |
1191 | |
1192 | if (!page) |
1193 | page = alloc_buddy_huge_page(h, nid); |
1194 | |
1195 | return page; |
1196 | } |
1197 | |
1198 | /* |
1199 | * Increase the hugetlb pool such that it can accommodate a reservation |
1200 | * of size 'delta'. |
1201 | */ |
1202 | static int gather_surplus_pages(struct hstate *h, int delta) |
1203 | { |
1204 | struct list_head surplus_list; |
1205 | struct page *page, *tmp; |
1206 | int ret, i; |
1207 | int needed, allocated; |
1208 | bool alloc_ok = true; |
1209 | |
1210 | needed = (h->resv_huge_pages + delta) - h->free_huge_pages; |
1211 | if (needed <= 0) { |
1212 | h->resv_huge_pages += delta; |
1213 | return 0; |
1214 | } |
1215 | |
1216 | allocated = 0; |
1217 | INIT_LIST_HEAD(&surplus_list); |
1218 | |
1219 | ret = -ENOMEM; |
1220 | retry: |
1221 | spin_unlock(&hugetlb_lock); |
1222 | for (i = 0; i < needed; i++) { |
1223 | page = alloc_buddy_huge_page(h, NUMA_NO_NODE); |
1224 | if (!page) { |
1225 | alloc_ok = false; |
1226 | break; |
1227 | } |
1228 | list_add(&page->lru, &surplus_list); |
1229 | } |
1230 | allocated += i; |
1231 | |
1232 | /* |
1233 | * After retaking hugetlb_lock, we need to recalculate 'needed' |
1234 | * because either resv_huge_pages or free_huge_pages may have changed. |
1235 | */ |
1236 | spin_lock(&hugetlb_lock); |
1237 | needed = (h->resv_huge_pages + delta) - |
1238 | (h->free_huge_pages + allocated); |
1239 | if (needed > 0) { |
1240 | if (alloc_ok) |
1241 | goto retry; |
1242 | /* |
1243 | * We were not able to allocate enough pages to |
1244 | * satisfy the entire reservation so we free what |
1245 | * we've allocated so far. |
1246 | */ |
1247 | goto free; |
1248 | } |
1249 | /* |
1250 | * The surplus_list now contains _at_least_ the number of extra pages |
1251 | * needed to accommodate the reservation. Add the appropriate number |
1252 | * of pages to the hugetlb pool and free the extras back to the buddy |
1253 | * allocator. Commit the entire reservation here to prevent another |
1254 | * process from stealing the pages as they are added to the pool but |
1255 | * before they are reserved. |
1256 | */ |
1257 | needed += allocated; |
1258 | h->resv_huge_pages += delta; |
1259 | ret = 0; |
1260 | |
1261 | /* Free the needed pages to the hugetlb pool */ |
1262 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) { |
1263 | if ((--needed) < 0) |
1264 | break; |
1265 | /* |
1266 | * This page is now managed by the hugetlb allocator and has |
1267 | * no users -- drop the buddy allocator's reference. |
1268 | */ |
1269 | put_page_testzero(page); |
1270 | VM_BUG_ON_PAGE(page_count(page), page); |
1271 | enqueue_huge_page(h, page); |
1272 | } |
1273 | free: |
1274 | spin_unlock(&hugetlb_lock); |
1275 | |
1276 | /* Free unnecessary surplus pages to the buddy allocator */ |
1277 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) |
1278 | put_page(page); |
1279 | spin_lock(&hugetlb_lock); |
1280 | |
1281 | return ret; |
1282 | } |
1283 | |
1284 | /* |
1285 | * When releasing a hugetlb pool reservation, any surplus pages that were |
1286 | * allocated to satisfy the reservation must be explicitly freed if they were |
1287 | * never used. |
1288 | * Called with hugetlb_lock held. |
1289 | */ |
1290 | static void return_unused_surplus_pages(struct hstate *h, |
1291 | unsigned long unused_resv_pages) |
1292 | { |
1293 | unsigned long nr_pages; |
1294 | |
1295 | /* Uncommit the reservation */ |
1296 | h->resv_huge_pages -= unused_resv_pages; |
1297 | |
1298 | /* Cannot return gigantic pages currently */ |
1299 | if (hstate_is_gigantic(h)) |
1300 | return; |
1301 | |
1302 | nr_pages = min(unused_resv_pages, h->surplus_huge_pages); |
1303 | |
1304 | /* |
1305 | * We want to release as many surplus pages as possible, spread |
1306 | * evenly across all nodes with memory. Iterate across these nodes |
1307 | * until we can no longer free unreserved surplus pages. This occurs |
1308 | * when the nodes with surplus pages have no free pages. |
1309 | * free_pool_huge_page() will balance the the freed pages across the |
1310 | * on-line nodes with memory and will handle the hstate accounting. |
1311 | */ |
1312 | while (nr_pages--) { |
1313 | if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1)) |
1314 | break; |
1315 | cond_resched_lock(&hugetlb_lock); |
1316 | } |
1317 | } |
1318 | |
1319 | /* |
1320 | * Determine if the huge page at addr within the vma has an associated |
1321 | * reservation. Where it does not we will need to logically increase |
1322 | * reservation and actually increase subpool usage before an allocation |
1323 | * can occur. Where any new reservation would be required the |
1324 | * reservation change is prepared, but not committed. Once the page |
1325 | * has been allocated from the subpool and instantiated the change should |
1326 | * be committed via vma_commit_reservation. No action is required on |
1327 | * failure. |
1328 | */ |
1329 | static long vma_needs_reservation(struct hstate *h, |
1330 | struct vm_area_struct *vma, unsigned long addr) |
1331 | { |
1332 | struct resv_map *resv; |
1333 | pgoff_t idx; |
1334 | long chg; |
1335 | |
1336 | resv = vma_resv_map(vma); |
1337 | if (!resv) |
1338 | return 1; |
1339 | |
1340 | idx = vma_hugecache_offset(h, vma, addr); |
1341 | chg = region_chg(resv, idx, idx + 1); |
1342 | |
1343 | if (vma->vm_flags & VM_MAYSHARE) |
1344 | return chg; |
1345 | else |
1346 | return chg < 0 ? chg : 0; |
1347 | } |
1348 | static void vma_commit_reservation(struct hstate *h, |
1349 | struct vm_area_struct *vma, unsigned long addr) |
1350 | { |
1351 | struct resv_map *resv; |
1352 | pgoff_t idx; |
1353 | |
1354 | resv = vma_resv_map(vma); |
1355 | if (!resv) |
1356 | return; |
1357 | |
1358 | idx = vma_hugecache_offset(h, vma, addr); |
1359 | region_add(resv, idx, idx + 1); |
1360 | } |
1361 | |
1362 | static struct page *alloc_huge_page(struct vm_area_struct *vma, |
1363 | unsigned long addr, int avoid_reserve) |
1364 | { |
1365 | struct hugepage_subpool *spool = subpool_vma(vma); |
1366 | struct hstate *h = hstate_vma(vma); |
1367 | struct page *page; |
1368 | long chg; |
1369 | int ret, idx; |
1370 | struct hugetlb_cgroup *h_cg; |
1371 | |
1372 | idx = hstate_index(h); |
1373 | /* |
1374 | * Processes that did not create the mapping will have no |
1375 | * reserves and will not have accounted against subpool |
1376 | * limit. Check that the subpool limit can be made before |
1377 | * satisfying the allocation MAP_NORESERVE mappings may also |
1378 | * need pages and subpool limit allocated allocated if no reserve |
1379 | * mapping overlaps. |
1380 | */ |
1381 | chg = vma_needs_reservation(h, vma, addr); |
1382 | if (chg < 0) |
1383 | return ERR_PTR(-ENOMEM); |
1384 | if (chg || avoid_reserve) |
1385 | if (hugepage_subpool_get_pages(spool, 1)) |
1386 | return ERR_PTR(-ENOSPC); |
1387 | |
1388 | ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); |
1389 | if (ret) |
1390 | goto out_subpool_put; |
1391 | |
1392 | spin_lock(&hugetlb_lock); |
1393 | page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg); |
1394 | if (!page) { |
1395 | spin_unlock(&hugetlb_lock); |
1396 | page = alloc_buddy_huge_page(h, NUMA_NO_NODE); |
1397 | if (!page) |
1398 | goto out_uncharge_cgroup; |
1399 | |
1400 | spin_lock(&hugetlb_lock); |
1401 | list_move(&page->lru, &h->hugepage_activelist); |
1402 | /* Fall through */ |
1403 | } |
1404 | hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page); |
1405 | spin_unlock(&hugetlb_lock); |
1406 | |
1407 | set_page_private(page, (unsigned long)spool); |
1408 | |
1409 | vma_commit_reservation(h, vma, addr); |
1410 | return page; |
1411 | |
1412 | out_uncharge_cgroup: |
1413 | hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg); |
1414 | out_subpool_put: |
1415 | if (chg || avoid_reserve) |
1416 | hugepage_subpool_put_pages(spool, 1); |
1417 | return ERR_PTR(-ENOSPC); |
1418 | } |
1419 | |
1420 | /* |
1421 | * alloc_huge_page()'s wrapper which simply returns the page if allocation |
1422 | * succeeds, otherwise NULL. This function is called from new_vma_page(), |
1423 | * where no ERR_VALUE is expected to be returned. |
1424 | */ |
1425 | struct page *alloc_huge_page_noerr(struct vm_area_struct *vma, |
1426 | unsigned long addr, int avoid_reserve) |
1427 | { |
1428 | struct page *page = alloc_huge_page(vma, addr, avoid_reserve); |
1429 | if (IS_ERR(page)) |
1430 | page = NULL; |
1431 | return page; |
1432 | } |
1433 | |
1434 | int __weak alloc_bootmem_huge_page(struct hstate *h) |
1435 | { |
1436 | struct huge_bootmem_page *m; |
1437 | int nr_nodes, node; |
1438 | |
1439 | for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) { |
1440 | void *addr; |
1441 | |
1442 | addr = memblock_virt_alloc_try_nid_nopanic( |
1443 | huge_page_size(h), huge_page_size(h), |
1444 | 0, BOOTMEM_ALLOC_ACCESSIBLE, node); |
1445 | if (addr) { |
1446 | /* |
1447 | * Use the beginning of the huge page to store the |
1448 | * huge_bootmem_page struct (until gather_bootmem |
1449 | * puts them into the mem_map). |
1450 | */ |
1451 | m = addr; |
1452 | goto found; |
1453 | } |
1454 | } |
1455 | return 0; |
1456 | |
1457 | found: |
1458 | BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); |
1459 | /* Put them into a private list first because mem_map is not up yet */ |
1460 | list_add(&m->list, &huge_boot_pages); |
1461 | m->hstate = h; |
1462 | return 1; |
1463 | } |
1464 | |
1465 | static void __init prep_compound_huge_page(struct page *page, int order) |
1466 | { |
1467 | if (unlikely(order > (MAX_ORDER - 1))) |
1468 | prep_compound_gigantic_page(page, order); |
1469 | else |
1470 | prep_compound_page(page, order); |
1471 | } |
1472 | |
1473 | /* Put bootmem huge pages into the standard lists after mem_map is up */ |
1474 | static void __init gather_bootmem_prealloc(void) |
1475 | { |
1476 | struct huge_bootmem_page *m; |
1477 | |
1478 | list_for_each_entry(m, &huge_boot_pages, list) { |
1479 | struct hstate *h = m->hstate; |
1480 | struct page *page; |
1481 | |
1482 | #ifdef CONFIG_HIGHMEM |
1483 | page = pfn_to_page(m->phys >> PAGE_SHIFT); |
1484 | memblock_free_late(__pa(m), |
1485 | sizeof(struct huge_bootmem_page)); |
1486 | #else |
1487 | page = virt_to_page(m); |
1488 | #endif |
1489 | WARN_ON(page_count(page) != 1); |
1490 | prep_compound_huge_page(page, h->order); |
1491 | WARN_ON(PageReserved(page)); |
1492 | prep_new_huge_page(h, page, page_to_nid(page)); |
1493 | /* |
1494 | * If we had gigantic hugepages allocated at boot time, we need |
1495 | * to restore the 'stolen' pages to totalram_pages in order to |
1496 | * fix confusing memory reports from free(1) and another |
1497 | * side-effects, like CommitLimit going negative. |
1498 | */ |
1499 | if (hstate_is_gigantic(h)) |
1500 | adjust_managed_page_count(page, 1 << h->order); |
1501 | } |
1502 | } |
1503 | |
1504 | static void __init hugetlb_hstate_alloc_pages(struct hstate *h) |
1505 | { |
1506 | unsigned long i; |
1507 | |
1508 | for (i = 0; i < h->max_huge_pages; ++i) { |
1509 | if (hstate_is_gigantic(h)) { |
1510 | if (!alloc_bootmem_huge_page(h)) |
1511 | break; |
1512 | } else if (!alloc_fresh_huge_page(h, |
1513 | &node_states[N_MEMORY])) |
1514 | break; |
1515 | } |
1516 | h->max_huge_pages = i; |
1517 | } |
1518 | |
1519 | static void __init hugetlb_init_hstates(void) |
1520 | { |
1521 | struct hstate *h; |
1522 | |
1523 | for_each_hstate(h) { |
1524 | /* oversize hugepages were init'ed in early boot */ |
1525 | if (!hstate_is_gigantic(h)) |
1526 | hugetlb_hstate_alloc_pages(h); |
1527 | } |
1528 | } |
1529 | |
1530 | static char * __init memfmt(char *buf, unsigned long n) |
1531 | { |
1532 | if (n >= (1UL << 30)) |
1533 | sprintf(buf, "%lu GB", n >> 30); |
1534 | else if (n >= (1UL << 20)) |
1535 | sprintf(buf, "%lu MB", n >> 20); |
1536 | else |
1537 | sprintf(buf, "%lu KB", n >> 10); |
1538 | return buf; |
1539 | } |
1540 | |
1541 | static void __init report_hugepages(void) |
1542 | { |
1543 | struct hstate *h; |
1544 | |
1545 | for_each_hstate(h) { |
1546 | char buf[32]; |
1547 | pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n", |
1548 | memfmt(buf, huge_page_size(h)), |
1549 | h->free_huge_pages); |
1550 | } |
1551 | } |
1552 | |
1553 | #ifdef CONFIG_HIGHMEM |
1554 | static void try_to_free_low(struct hstate *h, unsigned long count, |
1555 | nodemask_t *nodes_allowed) |
1556 | { |
1557 | int i; |
1558 | |
1559 | if (hstate_is_gigantic(h)) |
1560 | return; |
1561 | |
1562 | for_each_node_mask(i, *nodes_allowed) { |
1563 | struct page *page, *next; |
1564 | struct list_head *freel = &h->hugepage_freelists[i]; |
1565 | list_for_each_entry_safe(page, next, freel, lru) { |
1566 | if (count >= h->nr_huge_pages) |
1567 | return; |
1568 | if (PageHighMem(page)) |
1569 | continue; |
1570 | list_del(&page->lru); |
1571 | update_and_free_page(h, page); |
1572 | h->free_huge_pages--; |
1573 | h->free_huge_pages_node[page_to_nid(page)]--; |
1574 | } |
1575 | } |
1576 | } |
1577 | #else |
1578 | static inline void try_to_free_low(struct hstate *h, unsigned long count, |
1579 | nodemask_t *nodes_allowed) |
1580 | { |
1581 | } |
1582 | #endif |
1583 | |
1584 | /* |
1585 | * Increment or decrement surplus_huge_pages. Keep node-specific counters |
1586 | * balanced by operating on them in a round-robin fashion. |
1587 | * Returns 1 if an adjustment was made. |
1588 | */ |
1589 | static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, |
1590 | int delta) |
1591 | { |
1592 | int nr_nodes, node; |
1593 | |
1594 | VM_BUG_ON(delta != -1 && delta != 1); |
1595 | |
1596 | if (delta < 0) { |
1597 | for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { |
1598 | if (h->surplus_huge_pages_node[node]) |
1599 | goto found; |
1600 | } |
1601 | } else { |
1602 | for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { |
1603 | if (h->surplus_huge_pages_node[node] < |
1604 | h->nr_huge_pages_node[node]) |
1605 | goto found; |
1606 | } |
1607 | } |
1608 | return 0; |
1609 | |
1610 | found: |
1611 | h->surplus_huge_pages += delta; |
1612 | h->surplus_huge_pages_node[node] += delta; |
1613 | return 1; |
1614 | } |
1615 | |
1616 | #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) |
1617 | static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, |
1618 | nodemask_t *nodes_allowed) |
1619 | { |
1620 | unsigned long min_count, ret; |
1621 | |
1622 | if (hstate_is_gigantic(h) && !gigantic_page_supported()) |
1623 | return h->max_huge_pages; |
1624 | |
1625 | /* |
1626 | * Increase the pool size |
1627 | * First take pages out of surplus state. Then make up the |
1628 | * remaining difference by allocating fresh huge pages. |
1629 | * |
1630 | * We might race with alloc_buddy_huge_page() here and be unable |
1631 | * to convert a surplus huge page to a normal huge page. That is |
1632 | * not critical, though, it just means the overall size of the |
1633 | * pool might be one hugepage larger than it needs to be, but |
1634 | * within all the constraints specified by the sysctls. |
1635 | */ |
1636 | spin_lock(&hugetlb_lock); |
1637 | while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { |
1638 | if (!adjust_pool_surplus(h, nodes_allowed, -1)) |
1639 | break; |
1640 | } |
1641 | |
1642 | while (count > persistent_huge_pages(h)) { |
1643 | /* |
1644 | * If this allocation races such that we no longer need the |
1645 | * page, free_huge_page will handle it by freeing the page |
1646 | * and reducing the surplus. |
1647 | */ |
1648 | spin_unlock(&hugetlb_lock); |
1649 | if (hstate_is_gigantic(h)) |
1650 | ret = alloc_fresh_gigantic_page(h, nodes_allowed); |
1651 | else |
1652 | ret = alloc_fresh_huge_page(h, nodes_allowed); |
1653 | spin_lock(&hugetlb_lock); |
1654 | if (!ret) |
1655 | goto out; |
1656 | |
1657 | /* Bail for signals. Probably ctrl-c from user */ |
1658 | if (signal_pending(current)) |
1659 | goto out; |
1660 | } |
1661 | |
1662 | /* |
1663 | * Decrease the pool size |
1664 | * First return free pages to the buddy allocator (being careful |
1665 | * to keep enough around to satisfy reservations). Then place |
1666 | * pages into surplus state as needed so the pool will shrink |
1667 | * to the desired size as pages become free. |
1668 | * |
1669 | * By placing pages into the surplus state independent of the |
1670 | * overcommit value, we are allowing the surplus pool size to |
1671 | * exceed overcommit. There are few sane options here. Since |
1672 | * alloc_buddy_huge_page() is checking the global counter, |
1673 | * though, we'll note that we're not allowed to exceed surplus |
1674 | * and won't grow the pool anywhere else. Not until one of the |
1675 | * sysctls are changed, or the surplus pages go out of use. |
1676 | */ |
1677 | min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; |
1678 | min_count = max(count, min_count); |
1679 | try_to_free_low(h, min_count, nodes_allowed); |
1680 | while (min_count < persistent_huge_pages(h)) { |
1681 | if (!free_pool_huge_page(h, nodes_allowed, 0)) |
1682 | break; |
1683 | cond_resched_lock(&hugetlb_lock); |
1684 | } |
1685 | while (count < persistent_huge_pages(h)) { |
1686 | if (!adjust_pool_surplus(h, nodes_allowed, 1)) |
1687 | break; |
1688 | } |
1689 | out: |
1690 | ret = persistent_huge_pages(h); |
1691 | spin_unlock(&hugetlb_lock); |
1692 | return ret; |
1693 | } |
1694 | |
1695 | #define HSTATE_ATTR_RO(_name) \ |
1696 | static struct kobj_attribute _name##_attr = __ATTR_RO(_name) |
1697 | |
1698 | #define HSTATE_ATTR(_name) \ |
1699 | static struct kobj_attribute _name##_attr = \ |
1700 | __ATTR(_name, 0644, _name##_show, _name##_store) |
1701 | |
1702 | static struct kobject *hugepages_kobj; |
1703 | static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
1704 | |
1705 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); |
1706 | |
1707 | static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) |
1708 | { |
1709 | int i; |
1710 | |
1711 | for (i = 0; i < HUGE_MAX_HSTATE; i++) |
1712 | if (hstate_kobjs[i] == kobj) { |
1713 | if (nidp) |
1714 | *nidp = NUMA_NO_NODE; |
1715 | return &hstates[i]; |
1716 | } |
1717 | |
1718 | return kobj_to_node_hstate(kobj, nidp); |
1719 | } |
1720 | |
1721 | static ssize_t nr_hugepages_show_common(struct kobject *kobj, |
1722 | struct kobj_attribute *attr, char *buf) |
1723 | { |
1724 | struct hstate *h; |
1725 | unsigned long nr_huge_pages; |
1726 | int nid; |
1727 | |
1728 | h = kobj_to_hstate(kobj, &nid); |
1729 | if (nid == NUMA_NO_NODE) |
1730 | nr_huge_pages = h->nr_huge_pages; |
1731 | else |
1732 | nr_huge_pages = h->nr_huge_pages_node[nid]; |
1733 | |
1734 | return sprintf(buf, "%lu\n", nr_huge_pages); |
1735 | } |
1736 | |
1737 | static ssize_t nr_hugepages_store_common(bool obey_mempolicy, |
1738 | struct kobject *kobj, struct kobj_attribute *attr, |
1739 | const char *buf, size_t len) |
1740 | { |
1741 | int err; |
1742 | int nid; |
1743 | unsigned long count; |
1744 | struct hstate *h; |
1745 | NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); |
1746 | |
1747 | err = kstrtoul(buf, 10, &count); |
1748 | if (err) |
1749 | goto out; |
1750 | |
1751 | h = kobj_to_hstate(kobj, &nid); |
1752 | if (hstate_is_gigantic(h) && !gigantic_page_supported()) { |
1753 | err = -EINVAL; |
1754 | goto out; |
1755 | } |
1756 | |
1757 | if (nid == NUMA_NO_NODE) { |
1758 | /* |
1759 | * global hstate attribute |
1760 | */ |
1761 | if (!(obey_mempolicy && |
1762 | init_nodemask_of_mempolicy(nodes_allowed))) { |
1763 | NODEMASK_FREE(nodes_allowed); |
1764 | nodes_allowed = &node_states[N_MEMORY]; |
1765 | } |
1766 | } else if (nodes_allowed) { |
1767 | /* |
1768 | * per node hstate attribute: adjust count to global, |
1769 | * but restrict alloc/free to the specified node. |
1770 | */ |
1771 | count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; |
1772 | init_nodemask_of_node(nodes_allowed, nid); |
1773 | } else |
1774 | nodes_allowed = &node_states[N_MEMORY]; |
1775 | |
1776 | h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); |
1777 | |
1778 | if (nodes_allowed != &node_states[N_MEMORY]) |
1779 | NODEMASK_FREE(nodes_allowed); |
1780 | |
1781 | return len; |
1782 | out: |
1783 | NODEMASK_FREE(nodes_allowed); |
1784 | return err; |
1785 | } |
1786 | |
1787 | static ssize_t nr_hugepages_show(struct kobject *kobj, |
1788 | struct kobj_attribute *attr, char *buf) |
1789 | { |
1790 | return nr_hugepages_show_common(kobj, attr, buf); |
1791 | } |
1792 | |
1793 | static ssize_t nr_hugepages_store(struct kobject *kobj, |
1794 | struct kobj_attribute *attr, const char *buf, size_t len) |
1795 | { |
1796 | return nr_hugepages_store_common(false, kobj, attr, buf, len); |
1797 | } |
1798 | HSTATE_ATTR(nr_hugepages); |
1799 | |
1800 | #ifdef CONFIG_NUMA |
1801 | |
1802 | /* |
1803 | * hstate attribute for optionally mempolicy-based constraint on persistent |
1804 | * huge page alloc/free. |
1805 | */ |
1806 | static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, |
1807 | struct kobj_attribute *attr, char *buf) |
1808 | { |
1809 | return nr_hugepages_show_common(kobj, attr, buf); |
1810 | } |
1811 | |
1812 | static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, |
1813 | struct kobj_attribute *attr, const char *buf, size_t len) |
1814 | { |
1815 | return nr_hugepages_store_common(true, kobj, attr, buf, len); |
1816 | } |
1817 | HSTATE_ATTR(nr_hugepages_mempolicy); |
1818 | #endif |
1819 | |
1820 | |
1821 | static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, |
1822 | struct kobj_attribute *attr, char *buf) |
1823 | { |
1824 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
1825 | return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); |
1826 | } |
1827 | |
1828 | static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, |
1829 | struct kobj_attribute *attr, const char *buf, size_t count) |
1830 | { |
1831 | int err; |
1832 | unsigned long input; |
1833 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
1834 | |
1835 | if (hstate_is_gigantic(h)) |
1836 | return -EINVAL; |
1837 | |
1838 | err = kstrtoul(buf, 10, &input); |
1839 | if (err) |
1840 | return err; |
1841 | |
1842 | spin_lock(&hugetlb_lock); |
1843 | h->nr_overcommit_huge_pages = input; |
1844 | spin_unlock(&hugetlb_lock); |
1845 | |
1846 | return count; |
1847 | } |
1848 | HSTATE_ATTR(nr_overcommit_hugepages); |
1849 | |
1850 | static ssize_t free_hugepages_show(struct kobject *kobj, |
1851 | struct kobj_attribute *attr, char *buf) |
1852 | { |
1853 | struct hstate *h; |
1854 | unsigned long free_huge_pages; |
1855 | int nid; |
1856 | |
1857 | h = kobj_to_hstate(kobj, &nid); |
1858 | if (nid == NUMA_NO_NODE) |
1859 | free_huge_pages = h->free_huge_pages; |
1860 | else |
1861 | free_huge_pages = h->free_huge_pages_node[nid]; |
1862 | |
1863 | return sprintf(buf, "%lu\n", free_huge_pages); |
1864 | } |
1865 | HSTATE_ATTR_RO(free_hugepages); |
1866 | |
1867 | static ssize_t resv_hugepages_show(struct kobject *kobj, |
1868 | struct kobj_attribute *attr, char *buf) |
1869 | { |
1870 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
1871 | return sprintf(buf, "%lu\n", h->resv_huge_pages); |
1872 | } |
1873 | HSTATE_ATTR_RO(resv_hugepages); |
1874 | |
1875 | static ssize_t surplus_hugepages_show(struct kobject *kobj, |
1876 | struct kobj_attribute *attr, char *buf) |
1877 | { |
1878 | struct hstate *h; |
1879 | unsigned long surplus_huge_pages; |
1880 | int nid; |
1881 | |
1882 | h = kobj_to_hstate(kobj, &nid); |
1883 | if (nid == NUMA_NO_NODE) |
1884 | surplus_huge_pages = h->surplus_huge_pages; |
1885 | else |
1886 | surplus_huge_pages = h->surplus_huge_pages_node[nid]; |
1887 | |
1888 | return sprintf(buf, "%lu\n", surplus_huge_pages); |
1889 | } |
1890 | HSTATE_ATTR_RO(surplus_hugepages); |
1891 | |
1892 | static struct attribute *hstate_attrs[] = { |
1893 | &nr_hugepages_attr.attr, |
1894 | &nr_overcommit_hugepages_attr.attr, |
1895 | &free_hugepages_attr.attr, |
1896 | &resv_hugepages_attr.attr, |
1897 | &surplus_hugepages_attr.attr, |
1898 | #ifdef CONFIG_NUMA |
1899 | &nr_hugepages_mempolicy_attr.attr, |
1900 | #endif |
1901 | NULL, |
1902 | }; |
1903 | |
1904 | static struct attribute_group hstate_attr_group = { |
1905 | .attrs = hstate_attrs, |
1906 | }; |
1907 | |
1908 | static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, |
1909 | struct kobject **hstate_kobjs, |
1910 | struct attribute_group *hstate_attr_group) |
1911 | { |
1912 | int retval; |
1913 | int hi = hstate_index(h); |
1914 | |
1915 | hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); |
1916 | if (!hstate_kobjs[hi]) |
1917 | return -ENOMEM; |
1918 | |
1919 | retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); |
1920 | if (retval) |
1921 | kobject_put(hstate_kobjs[hi]); |
1922 | |
1923 | return retval; |
1924 | } |
1925 | |
1926 | static void __init hugetlb_sysfs_init(void) |
1927 | { |
1928 | struct hstate *h; |
1929 | int err; |
1930 | |
1931 | hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); |
1932 | if (!hugepages_kobj) |
1933 | return; |
1934 | |
1935 | for_each_hstate(h) { |
1936 | err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, |
1937 | hstate_kobjs, &hstate_attr_group); |
1938 | if (err) |
1939 | pr_err("Hugetlb: Unable to add hstate %s", h->name); |
1940 | } |
1941 | } |
1942 | |
1943 | #ifdef CONFIG_NUMA |
1944 | |
1945 | /* |
1946 | * node_hstate/s - associate per node hstate attributes, via their kobjects, |
1947 | * with node devices in node_devices[] using a parallel array. The array |
1948 | * index of a node device or _hstate == node id. |
1949 | * This is here to avoid any static dependency of the node device driver, in |
1950 | * the base kernel, on the hugetlb module. |
1951 | */ |
1952 | struct node_hstate { |
1953 | struct kobject *hugepages_kobj; |
1954 | struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
1955 | }; |
1956 | struct node_hstate node_hstates[MAX_NUMNODES]; |
1957 | |
1958 | /* |
1959 | * A subset of global hstate attributes for node devices |
1960 | */ |
1961 | static struct attribute *per_node_hstate_attrs[] = { |
1962 | &nr_hugepages_attr.attr, |
1963 | &free_hugepages_attr.attr, |
1964 | &surplus_hugepages_attr.attr, |
1965 | NULL, |
1966 | }; |
1967 | |
1968 | static struct attribute_group per_node_hstate_attr_group = { |
1969 | .attrs = per_node_hstate_attrs, |
1970 | }; |
1971 | |
1972 | /* |
1973 | * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj. |
1974 | * Returns node id via non-NULL nidp. |
1975 | */ |
1976 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) |
1977 | { |
1978 | int nid; |
1979 | |
1980 | for (nid = 0; nid < nr_node_ids; nid++) { |
1981 | struct node_hstate *nhs = &node_hstates[nid]; |
1982 | int i; |
1983 | for (i = 0; i < HUGE_MAX_HSTATE; i++) |
1984 | if (nhs->hstate_kobjs[i] == kobj) { |
1985 | if (nidp) |
1986 | *nidp = nid; |
1987 | return &hstates[i]; |
1988 | } |
1989 | } |
1990 | |
1991 | BUG(); |
1992 | return NULL; |
1993 | } |
1994 | |
1995 | /* |
1996 | * Unregister hstate attributes from a single node device. |
1997 | * No-op if no hstate attributes attached. |
1998 | */ |
1999 | static void hugetlb_unregister_node(struct node *node) |
2000 | { |
2001 | struct hstate *h; |
2002 | struct node_hstate *nhs = &node_hstates[node->dev.id]; |
2003 | |
2004 | if (!nhs->hugepages_kobj) |
2005 | return; /* no hstate attributes */ |
2006 | |
2007 | for_each_hstate(h) { |
2008 | int idx = hstate_index(h); |
2009 | if (nhs->hstate_kobjs[idx]) { |
2010 | kobject_put(nhs->hstate_kobjs[idx]); |
2011 | nhs->hstate_kobjs[idx] = NULL; |
2012 | } |
2013 | } |
2014 | |
2015 | kobject_put(nhs->hugepages_kobj); |
2016 | nhs->hugepages_kobj = NULL; |
2017 | } |
2018 | |
2019 | /* |
2020 | * hugetlb module exit: unregister hstate attributes from node devices |
2021 | * that have them. |
2022 | */ |
2023 | static void hugetlb_unregister_all_nodes(void) |
2024 | { |
2025 | int nid; |
2026 | |
2027 | /* |
2028 | * disable node device registrations. |
2029 | */ |
2030 | register_hugetlbfs_with_node(NULL, NULL); |
2031 | |
2032 | /* |
2033 | * remove hstate attributes from any nodes that have them. |
2034 | */ |
2035 | for (nid = 0; nid < nr_node_ids; nid++) |
2036 | hugetlb_unregister_node(node_devices[nid]); |
2037 | } |
2038 | |
2039 | /* |
2040 | * Register hstate attributes for a single node device. |
2041 | * No-op if attributes already registered. |
2042 | */ |
2043 | static void hugetlb_register_node(struct node *node) |
2044 | { |
2045 | struct hstate *h; |
2046 | struct node_hstate *nhs = &node_hstates[node->dev.id]; |
2047 | int err; |
2048 | |
2049 | if (nhs->hugepages_kobj) |
2050 | return; /* already allocated */ |
2051 | |
2052 | nhs->hugepages_kobj = kobject_create_and_add("hugepages", |
2053 | &node->dev.kobj); |
2054 | if (!nhs->hugepages_kobj) |
2055 | return; |
2056 | |
2057 | for_each_hstate(h) { |
2058 | err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, |
2059 | nhs->hstate_kobjs, |
2060 | &per_node_hstate_attr_group); |
2061 | if (err) { |
2062 | pr_err("Hugetlb: Unable to add hstate %s for node %d\n", |
2063 | h->name, node->dev.id); |
2064 | hugetlb_unregister_node(node); |
2065 | break; |
2066 | } |
2067 | } |
2068 | } |
2069 | |
2070 | /* |
2071 | * hugetlb init time: register hstate attributes for all registered node |
2072 | * devices of nodes that have memory. All on-line nodes should have |
2073 | * registered their associated device by this time. |
2074 | */ |
2075 | static void hugetlb_register_all_nodes(void) |
2076 | { |
2077 | int nid; |
2078 | |
2079 | for_each_node_state(nid, N_MEMORY) { |
2080 | struct node *node = node_devices[nid]; |
2081 | if (node->dev.id == nid) |
2082 | hugetlb_register_node(node); |
2083 | } |
2084 | |
2085 | /* |
2086 | * Let the node device driver know we're here so it can |
2087 | * [un]register hstate attributes on node hotplug. |
2088 | */ |
2089 | register_hugetlbfs_with_node(hugetlb_register_node, |
2090 | hugetlb_unregister_node); |
2091 | } |
2092 | #else /* !CONFIG_NUMA */ |
2093 | |
2094 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) |
2095 | { |
2096 | BUG(); |
2097 | if (nidp) |
2098 | *nidp = -1; |
2099 | return NULL; |
2100 | } |
2101 | |
2102 | static void hugetlb_unregister_all_nodes(void) { } |
2103 | |
2104 | static void hugetlb_register_all_nodes(void) { } |
2105 | |
2106 | #endif |
2107 | |
2108 | static void __exit hugetlb_exit(void) |
2109 | { |
2110 | struct hstate *h; |
2111 | |
2112 | hugetlb_unregister_all_nodes(); |
2113 | |
2114 | for_each_hstate(h) { |
2115 | kobject_put(hstate_kobjs[hstate_index(h)]); |
2116 | } |
2117 | |
2118 | kobject_put(hugepages_kobj); |
2119 | kfree(htlb_fault_mutex_table); |
2120 | } |
2121 | module_exit(hugetlb_exit); |
2122 | |
2123 | static int __init hugetlb_init(void) |
2124 | { |
2125 | int i; |
2126 | |
2127 | if (!hugepages_supported()) |
2128 | return 0; |
2129 | |
2130 | if (!size_to_hstate(default_hstate_size)) { |
2131 | default_hstate_size = HPAGE_SIZE; |
2132 | if (!size_to_hstate(default_hstate_size)) |
2133 | hugetlb_add_hstate(HUGETLB_PAGE_ORDER); |
2134 | } |
2135 | default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size)); |
2136 | if (default_hstate_max_huge_pages) |
2137 | default_hstate.max_huge_pages = default_hstate_max_huge_pages; |
2138 | |
2139 | hugetlb_init_hstates(); |
2140 | gather_bootmem_prealloc(); |
2141 | report_hugepages(); |
2142 | |
2143 | hugetlb_sysfs_init(); |
2144 | hugetlb_register_all_nodes(); |
2145 | hugetlb_cgroup_file_init(); |
2146 | |
2147 | #ifdef CONFIG_SMP |
2148 | num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus()); |
2149 | #else |
2150 | num_fault_mutexes = 1; |
2151 | #endif |
2152 | htlb_fault_mutex_table = |
2153 | kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL); |
2154 | BUG_ON(!htlb_fault_mutex_table); |
2155 | |
2156 | for (i = 0; i < num_fault_mutexes; i++) |
2157 | mutex_init(&htlb_fault_mutex_table[i]); |
2158 | return 0; |
2159 | } |
2160 | module_init(hugetlb_init); |
2161 | |
2162 | /* Should be called on processing a hugepagesz=... option */ |
2163 | void __init hugetlb_add_hstate(unsigned order) |
2164 | { |
2165 | struct hstate *h; |
2166 | unsigned long i; |
2167 | |
2168 | if (size_to_hstate(PAGE_SIZE << order)) { |
2169 | pr_warning("hugepagesz= specified twice, ignoring\n"); |
2170 | return; |
2171 | } |
2172 | BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); |
2173 | BUG_ON(order == 0); |
2174 | h = &hstates[hugetlb_max_hstate++]; |
2175 | h->order = order; |
2176 | h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); |
2177 | h->nr_huge_pages = 0; |
2178 | h->free_huge_pages = 0; |
2179 | for (i = 0; i < MAX_NUMNODES; ++i) |
2180 | INIT_LIST_HEAD(&h->hugepage_freelists[i]); |
2181 | INIT_LIST_HEAD(&h->hugepage_activelist); |
2182 | h->next_nid_to_alloc = first_node(node_states[N_MEMORY]); |
2183 | h->next_nid_to_free = first_node(node_states[N_MEMORY]); |
2184 | snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", |
2185 | huge_page_size(h)/1024); |
2186 | |
2187 | parsed_hstate = h; |
2188 | } |
2189 | |
2190 | static int __init hugetlb_nrpages_setup(char *s) |
2191 | { |
2192 | unsigned long *mhp; |
2193 | static unsigned long *last_mhp; |
2194 | |
2195 | /* |
2196 | * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet, |
2197 | * so this hugepages= parameter goes to the "default hstate". |
2198 | */ |
2199 | if (!hugetlb_max_hstate) |
2200 | mhp = &default_hstate_max_huge_pages; |
2201 | else |
2202 | mhp = &parsed_hstate->max_huge_pages; |
2203 | |
2204 | if (mhp == last_mhp) { |
2205 | pr_warning("hugepages= specified twice without " |
2206 | "interleaving hugepagesz=, ignoring\n"); |
2207 | return 1; |
2208 | } |
2209 | |
2210 | if (sscanf(s, "%lu", mhp) <= 0) |
2211 | *mhp = 0; |
2212 | |
2213 | /* |
2214 | * Global state is always initialized later in hugetlb_init. |
2215 | * But we need to allocate >= MAX_ORDER hstates here early to still |
2216 | * use the bootmem allocator. |
2217 | */ |
2218 | if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER) |
2219 | hugetlb_hstate_alloc_pages(parsed_hstate); |
2220 | |
2221 | last_mhp = mhp; |
2222 | |
2223 | return 1; |
2224 | } |
2225 | __setup("hugepages=", hugetlb_nrpages_setup); |
2226 | |
2227 | static int __init hugetlb_default_setup(char *s) |
2228 | { |
2229 | default_hstate_size = memparse(s, &s); |
2230 | return 1; |
2231 | } |
2232 | __setup("default_hugepagesz=", hugetlb_default_setup); |
2233 | |
2234 | static unsigned int cpuset_mems_nr(unsigned int *array) |
2235 | { |
2236 | int node; |
2237 | unsigned int nr = 0; |
2238 | |
2239 | for_each_node_mask(node, cpuset_current_mems_allowed) |
2240 | nr += array[node]; |
2241 | |
2242 | return nr; |
2243 | } |
2244 | |
2245 | #ifdef CONFIG_SYSCTL |
2246 | static int hugetlb_sysctl_handler_common(bool obey_mempolicy, |
2247 | struct ctl_table *table, int write, |
2248 | void __user *buffer, size_t *length, loff_t *ppos) |
2249 | { |
2250 | struct hstate *h = &default_hstate; |
2251 | unsigned long tmp; |
2252 | int ret; |
2253 | |
2254 | if (!hugepages_supported()) |
2255 | return -ENOTSUPP; |
2256 | |
2257 | tmp = h->max_huge_pages; |
2258 | |
2259 | if (write && hstate_is_gigantic(h) && !gigantic_page_supported()) |
2260 | return -EINVAL; |
2261 | |
2262 | table->data = &tmp; |
2263 | table->maxlen = sizeof(unsigned long); |
2264 | ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); |
2265 | if (ret) |
2266 | goto out; |
2267 | |
2268 | if (write) { |
2269 | NODEMASK_ALLOC(nodemask_t, nodes_allowed, |
2270 | GFP_KERNEL | __GFP_NORETRY); |
2271 | if (!(obey_mempolicy && |
2272 | init_nodemask_of_mempolicy(nodes_allowed))) { |
2273 | NODEMASK_FREE(nodes_allowed); |
2274 | nodes_allowed = &node_states[N_MEMORY]; |
2275 | } |
2276 | h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); |
2277 | |
2278 | if (nodes_allowed != &node_states[N_MEMORY]) |
2279 | NODEMASK_FREE(nodes_allowed); |
2280 | } |
2281 | out: |
2282 | return ret; |
2283 | } |
2284 | |
2285 | int hugetlb_sysctl_handler(struct ctl_table *table, int write, |
2286 | void __user *buffer, size_t *length, loff_t *ppos) |
2287 | { |
2288 | |
2289 | return hugetlb_sysctl_handler_common(false, table, write, |
2290 | buffer, length, ppos); |
2291 | } |
2292 | |
2293 | #ifdef CONFIG_NUMA |
2294 | int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, |
2295 | void __user *buffer, size_t *length, loff_t *ppos) |
2296 | { |
2297 | return hugetlb_sysctl_handler_common(true, table, write, |
2298 | buffer, length, ppos); |
2299 | } |
2300 | #endif /* CONFIG_NUMA */ |
2301 | |
2302 | int hugetlb_overcommit_handler(struct ctl_table *table, int write, |
2303 | void __user *buffer, |
2304 | size_t *length, loff_t *ppos) |
2305 | { |
2306 | struct hstate *h = &default_hstate; |
2307 | unsigned long tmp; |
2308 | int ret; |
2309 | |
2310 | if (!hugepages_supported()) |
2311 | return -ENOTSUPP; |
2312 | |
2313 | tmp = h->nr_overcommit_huge_pages; |
2314 | |
2315 | if (write && hstate_is_gigantic(h)) |
2316 | return -EINVAL; |
2317 | |
2318 | table->data = &tmp; |
2319 | table->maxlen = sizeof(unsigned long); |
2320 | ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); |
2321 | if (ret) |
2322 | goto out; |
2323 | |
2324 | if (write) { |
2325 | spin_lock(&hugetlb_lock); |
2326 | h->nr_overcommit_huge_pages = tmp; |
2327 | spin_unlock(&hugetlb_lock); |
2328 | } |
2329 | out: |
2330 | return ret; |
2331 | } |
2332 | |
2333 | #endif /* CONFIG_SYSCTL */ |
2334 | |
2335 | void hugetlb_report_meminfo(struct seq_file *m) |
2336 | { |
2337 | struct hstate *h = &default_hstate; |
2338 | if (!hugepages_supported()) |
2339 | return; |
2340 | seq_printf(m, |
2341 | "HugePages_Total: %5lu\n" |
2342 | "HugePages_Free: %5lu\n" |
2343 | "HugePages_Rsvd: %5lu\n" |
2344 | "HugePages_Surp: %5lu\n" |
2345 | "Hugepagesize: %8lu kB\n", |
2346 | h->nr_huge_pages, |
2347 | h->free_huge_pages, |
2348 | h->resv_huge_pages, |
2349 | h->surplus_huge_pages, |
2350 | 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); |
2351 | } |
2352 | |
2353 | int hugetlb_report_node_meminfo(int nid, char *buf) |
2354 | { |
2355 | struct hstate *h = &default_hstate; |
2356 | if (!hugepages_supported()) |
2357 | return 0; |
2358 | return sprintf(buf, |
2359 | "Node %d HugePages_Total: %5u\n" |
2360 | "Node %d HugePages_Free: %5u\n" |
2361 | "Node %d HugePages_Surp: %5u\n", |
2362 | nid, h->nr_huge_pages_node[nid], |
2363 | nid, h->free_huge_pages_node[nid], |
2364 | nid, h->surplus_huge_pages_node[nid]); |
2365 | } |
2366 | |
2367 | void hugetlb_show_meminfo(void) |
2368 | { |
2369 | struct hstate *h; |
2370 | int nid; |
2371 | |
2372 | if (!hugepages_supported()) |
2373 | return; |
2374 | |
2375 | for_each_node_state(nid, N_MEMORY) |
2376 | for_each_hstate(h) |
2377 | pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n", |
2378 | nid, |
2379 | h->nr_huge_pages_node[nid], |
2380 | h->free_huge_pages_node[nid], |
2381 | h->surplus_huge_pages_node[nid], |
2382 | 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); |
2383 | } |
2384 | |
2385 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
2386 | unsigned long hugetlb_total_pages(void) |
2387 | { |
2388 | struct hstate *h; |
2389 | unsigned long nr_total_pages = 0; |
2390 | |
2391 | for_each_hstate(h) |
2392 | nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h); |
2393 | return nr_total_pages; |
2394 | } |
2395 | |
2396 | static int hugetlb_acct_memory(struct hstate *h, long delta) |
2397 | { |
2398 | int ret = -ENOMEM; |
2399 | |
2400 | spin_lock(&hugetlb_lock); |
2401 | /* |
2402 | * When cpuset is configured, it breaks the strict hugetlb page |
2403 | * reservation as the accounting is done on a global variable. Such |
2404 | * reservation is completely rubbish in the presence of cpuset because |
2405 | * the reservation is not checked against page availability for the |
2406 | * current cpuset. Application can still potentially OOM'ed by kernel |
2407 | * with lack of free htlb page in cpuset that the task is in. |
2408 | * Attempt to enforce strict accounting with cpuset is almost |
2409 | * impossible (or too ugly) because cpuset is too fluid that |
2410 | * task or memory node can be dynamically moved between cpusets. |
2411 | * |
2412 | * The change of semantics for shared hugetlb mapping with cpuset is |
2413 | * undesirable. However, in order to preserve some of the semantics, |
2414 | * we fall back to check against current free page availability as |
2415 | * a best attempt and hopefully to minimize the impact of changing |
2416 | * semantics that cpuset has. |
2417 | */ |
2418 | if (delta > 0) { |
2419 | if (gather_surplus_pages(h, delta) < 0) |
2420 | goto out; |
2421 | |
2422 | if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { |
2423 | return_unused_surplus_pages(h, delta); |
2424 | goto out; |
2425 | } |
2426 | } |
2427 | |
2428 | ret = 0; |
2429 | if (delta < 0) |
2430 | return_unused_surplus_pages(h, (unsigned long) -delta); |
2431 | |
2432 | out: |
2433 | spin_unlock(&hugetlb_lock); |
2434 | return ret; |
2435 | } |
2436 | |
2437 | static void hugetlb_vm_op_open(struct vm_area_struct *vma) |
2438 | { |
2439 | struct resv_map *resv = vma_resv_map(vma); |
2440 | |
2441 | /* |
2442 | * This new VMA should share its siblings reservation map if present. |
2443 | * The VMA will only ever have a valid reservation map pointer where |
2444 | * it is being copied for another still existing VMA. As that VMA |
2445 | * has a reference to the reservation map it cannot disappear until |
2446 | * after this open call completes. It is therefore safe to take a |
2447 | * new reference here without additional locking. |
2448 | */ |
2449 | if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
2450 | kref_get(&resv->refs); |
2451 | } |
2452 | |
2453 | static void hugetlb_vm_op_close(struct vm_area_struct *vma) |
2454 | { |
2455 | struct hstate *h = hstate_vma(vma); |
2456 | struct resv_map *resv = vma_resv_map(vma); |
2457 | struct hugepage_subpool *spool = subpool_vma(vma); |
2458 | unsigned long reserve, start, end; |
2459 | |
2460 | if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
2461 | return; |
2462 | |
2463 | start = vma_hugecache_offset(h, vma, vma->vm_start); |
2464 | end = vma_hugecache_offset(h, vma, vma->vm_end); |
2465 | |
2466 | reserve = (end - start) - region_count(resv, start, end); |
2467 | |
2468 | kref_put(&resv->refs, resv_map_release); |
2469 | |
2470 | if (reserve) { |
2471 | hugetlb_acct_memory(h, -reserve); |
2472 | hugepage_subpool_put_pages(spool, reserve); |
2473 | } |
2474 | } |
2475 | |
2476 | /* |
2477 | * We cannot handle pagefaults against hugetlb pages at all. They cause |
2478 | * handle_mm_fault() to try to instantiate regular-sized pages in the |
2479 | * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get |
2480 | * this far. |
2481 | */ |
2482 | static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
2483 | { |
2484 | BUG(); |
2485 | return 0; |
2486 | } |
2487 | |
2488 | const struct vm_operations_struct hugetlb_vm_ops = { |
2489 | .fault = hugetlb_vm_op_fault, |
2490 | .open = hugetlb_vm_op_open, |
2491 | .close = hugetlb_vm_op_close, |
2492 | }; |
2493 | |
2494 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
2495 | int writable) |
2496 | { |
2497 | pte_t entry; |
2498 | |
2499 | if (writable) { |
2500 | entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page, |
2501 | vma->vm_page_prot))); |
2502 | } else { |
2503 | entry = huge_pte_wrprotect(mk_huge_pte(page, |
2504 | vma->vm_page_prot)); |
2505 | } |
2506 | entry = pte_mkyoung(entry); |
2507 | entry = pte_mkhuge(entry); |
2508 | entry = arch_make_huge_pte(entry, vma, page, writable); |
2509 | |
2510 | return entry; |
2511 | } |
2512 | |
2513 | static void set_huge_ptep_writable(struct vm_area_struct *vma, |
2514 | unsigned long address, pte_t *ptep) |
2515 | { |
2516 | pte_t entry; |
2517 | |
2518 | entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep))); |
2519 | if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) |
2520 | update_mmu_cache(vma, address, ptep); |
2521 | } |
2522 | |
2523 | static int is_hugetlb_entry_migration(pte_t pte) |
2524 | { |
2525 | swp_entry_t swp; |
2526 | |
2527 | if (huge_pte_none(pte) || pte_present(pte)) |
2528 | return 0; |
2529 | swp = pte_to_swp_entry(pte); |
2530 | if (non_swap_entry(swp) && is_migration_entry(swp)) |
2531 | return 1; |
2532 | else |
2533 | return 0; |
2534 | } |
2535 | |
2536 | static int is_hugetlb_entry_hwpoisoned(pte_t pte) |
2537 | { |
2538 | swp_entry_t swp; |
2539 | |
2540 | if (huge_pte_none(pte) || pte_present(pte)) |
2541 | return 0; |
2542 | swp = pte_to_swp_entry(pte); |
2543 | if (non_swap_entry(swp) && is_hwpoison_entry(swp)) |
2544 | return 1; |
2545 | else |
2546 | return 0; |
2547 | } |
2548 | |
2549 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
2550 | struct vm_area_struct *vma) |
2551 | { |
2552 | pte_t *src_pte, *dst_pte, entry; |
2553 | struct page *ptepage; |
2554 | unsigned long addr; |
2555 | int cow; |
2556 | struct hstate *h = hstate_vma(vma); |
2557 | unsigned long sz = huge_page_size(h); |
2558 | unsigned long mmun_start; /* For mmu_notifiers */ |
2559 | unsigned long mmun_end; /* For mmu_notifiers */ |
2560 | int ret = 0; |
2561 | |
2562 | cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; |
2563 | |
2564 | mmun_start = vma->vm_start; |
2565 | mmun_end = vma->vm_end; |
2566 | if (cow) |
2567 | mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end); |
2568 | |
2569 | for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { |
2570 | spinlock_t *src_ptl, *dst_ptl; |
2571 | src_pte = huge_pte_offset(src, addr); |
2572 | if (!src_pte) |
2573 | continue; |
2574 | dst_pte = huge_pte_alloc(dst, addr, sz); |
2575 | if (!dst_pte) { |
2576 | ret = -ENOMEM; |
2577 | break; |
2578 | } |
2579 | |
2580 | /* If the pagetables are shared don't copy or take references */ |
2581 | if (dst_pte == src_pte) |
2582 | continue; |
2583 | |
2584 | dst_ptl = huge_pte_lock(h, dst, dst_pte); |
2585 | src_ptl = huge_pte_lockptr(h, src, src_pte); |
2586 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
2587 | entry = huge_ptep_get(src_pte); |
2588 | if (huge_pte_none(entry)) { /* skip none entry */ |
2589 | ; |
2590 | } else if (unlikely(is_hugetlb_entry_migration(entry) || |
2591 | is_hugetlb_entry_hwpoisoned(entry))) { |
2592 | swp_entry_t swp_entry = pte_to_swp_entry(entry); |
2593 | |
2594 | if (is_write_migration_entry(swp_entry) && cow) { |
2595 | /* |
2596 | * COW mappings require pages in both |
2597 | * parent and child to be set to read. |
2598 | */ |
2599 | make_migration_entry_read(&swp_entry); |
2600 | entry = swp_entry_to_pte(swp_entry); |
2601 | set_huge_pte_at(src, addr, src_pte, entry); |
2602 | } |
2603 | set_huge_pte_at(dst, addr, dst_pte, entry); |
2604 | } else { |
2605 | if (cow) |
2606 | huge_ptep_set_wrprotect(src, addr, src_pte); |
2607 | entry = huge_ptep_get(src_pte); |
2608 | ptepage = pte_page(entry); |
2609 | get_page(ptepage); |
2610 | page_dup_rmap(ptepage); |
2611 | set_huge_pte_at(dst, addr, dst_pte, entry); |
2612 | } |
2613 | spin_unlock(src_ptl); |
2614 | spin_unlock(dst_ptl); |
2615 | } |
2616 | |
2617 | if (cow) |
2618 | mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end); |
2619 | |
2620 | return ret; |
2621 | } |
2622 | |
2623 | void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, |
2624 | unsigned long start, unsigned long end, |
2625 | struct page *ref_page) |
2626 | { |
2627 | int force_flush = 0; |
2628 | struct mm_struct *mm = vma->vm_mm; |
2629 | unsigned long address; |
2630 | pte_t *ptep; |
2631 | pte_t pte; |
2632 | spinlock_t *ptl; |
2633 | struct page *page; |
2634 | struct hstate *h = hstate_vma(vma); |
2635 | unsigned long sz = huge_page_size(h); |
2636 | const unsigned long mmun_start = start; /* For mmu_notifiers */ |
2637 | const unsigned long mmun_end = end; /* For mmu_notifiers */ |
2638 | |
2639 | WARN_ON(!is_vm_hugetlb_page(vma)); |
2640 | BUG_ON(start & ~huge_page_mask(h)); |
2641 | BUG_ON(end & ~huge_page_mask(h)); |
2642 | |
2643 | tlb_start_vma(tlb, vma); |
2644 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
2645 | again: |
2646 | for (address = start; address < end; address += sz) { |
2647 | ptep = huge_pte_offset(mm, address); |
2648 | if (!ptep) |
2649 | continue; |
2650 | |
2651 | ptl = huge_pte_lock(h, mm, ptep); |
2652 | if (huge_pmd_unshare(mm, &address, ptep)) |
2653 | goto unlock; |
2654 | |
2655 | pte = huge_ptep_get(ptep); |
2656 | if (huge_pte_none(pte)) |
2657 | goto unlock; |
2658 | |
2659 | /* |
2660 | * HWPoisoned hugepage is already unmapped and dropped reference |
2661 | */ |
2662 | if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) { |
2663 | huge_pte_clear(mm, address, ptep); |
2664 | goto unlock; |
2665 | } |
2666 | |
2667 | page = pte_page(pte); |
2668 | /* |
2669 | * If a reference page is supplied, it is because a specific |
2670 | * page is being unmapped, not a range. Ensure the page we |
2671 | * are about to unmap is the actual page of interest. |
2672 | */ |
2673 | if (ref_page) { |
2674 | if (page != ref_page) |
2675 | goto unlock; |
2676 | |
2677 | /* |
2678 | * Mark the VMA as having unmapped its page so that |
2679 | * future faults in this VMA will fail rather than |
2680 | * looking like data was lost |
2681 | */ |
2682 | set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); |
2683 | } |
2684 | |
2685 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
2686 | tlb_remove_tlb_entry(tlb, ptep, address); |
2687 | if (huge_pte_dirty(pte)) |
2688 | set_page_dirty(page); |
2689 | |
2690 | page_remove_rmap(page); |
2691 | force_flush = !__tlb_remove_page(tlb, page); |
2692 | if (force_flush) { |
2693 | spin_unlock(ptl); |
2694 | break; |
2695 | } |
2696 | /* Bail out after unmapping reference page if supplied */ |
2697 | if (ref_page) { |
2698 | spin_unlock(ptl); |
2699 | break; |
2700 | } |
2701 | unlock: |
2702 | spin_unlock(ptl); |
2703 | } |
2704 | /* |
2705 | * mmu_gather ran out of room to batch pages, we break out of |
2706 | * the PTE lock to avoid doing the potential expensive TLB invalidate |
2707 | * and page-free while holding it. |
2708 | */ |
2709 | if (force_flush) { |
2710 | force_flush = 0; |
2711 | tlb_flush_mmu(tlb); |
2712 | if (address < end && !ref_page) |
2713 | goto again; |
2714 | } |
2715 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
2716 | tlb_end_vma(tlb, vma); |
2717 | } |
2718 | |
2719 | void __unmap_hugepage_range_final(struct mmu_gather *tlb, |
2720 | struct vm_area_struct *vma, unsigned long start, |
2721 | unsigned long end, struct page *ref_page) |
2722 | { |
2723 | __unmap_hugepage_range(tlb, vma, start, end, ref_page); |
2724 | |
2725 | /* |
2726 | * Clear this flag so that x86's huge_pmd_share page_table_shareable |
2727 | * test will fail on a vma being torn down, and not grab a page table |
2728 | * on its way out. We're lucky that the flag has such an appropriate |
2729 | * name, and can in fact be safely cleared here. We could clear it |
2730 | * before the __unmap_hugepage_range above, but all that's necessary |
2731 | * is to clear it before releasing the i_mmap_mutex. This works |
2732 | * because in the context this is called, the VMA is about to be |
2733 | * destroyed and the i_mmap_mutex is held. |
2734 | */ |
2735 | vma->vm_flags &= ~VM_MAYSHARE; |
2736 | } |
2737 | |
2738 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
2739 | unsigned long end, struct page *ref_page) |
2740 | { |
2741 | struct mm_struct *mm; |
2742 | struct mmu_gather tlb; |
2743 | |
2744 | mm = vma->vm_mm; |
2745 | |
2746 | tlb_gather_mmu(&tlb, mm, start, end); |
2747 | __unmap_hugepage_range(&tlb, vma, start, end, ref_page); |
2748 | tlb_finish_mmu(&tlb, start, end); |
2749 | } |
2750 | |
2751 | /* |
2752 | * This is called when the original mapper is failing to COW a MAP_PRIVATE |
2753 | * mappping it owns the reserve page for. The intention is to unmap the page |
2754 | * from other VMAs and let the children be SIGKILLed if they are faulting the |
2755 | * same region. |
2756 | */ |
2757 | static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, |
2758 | struct page *page, unsigned long address) |
2759 | { |
2760 | struct hstate *h = hstate_vma(vma); |
2761 | struct vm_area_struct *iter_vma; |
2762 | struct address_space *mapping; |
2763 | pgoff_t pgoff; |
2764 | |
2765 | /* |
2766 | * vm_pgoff is in PAGE_SIZE units, hence the different calculation |
2767 | * from page cache lookup which is in HPAGE_SIZE units. |
2768 | */ |
2769 | address = address & huge_page_mask(h); |
2770 | pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + |
2771 | vma->vm_pgoff; |
2772 | mapping = file_inode(vma->vm_file)->i_mapping; |
2773 | |
2774 | /* |
2775 | * Take the mapping lock for the duration of the table walk. As |
2776 | * this mapping should be shared between all the VMAs, |
2777 | * __unmap_hugepage_range() is called as the lock is already held |
2778 | */ |
2779 | mutex_lock(&mapping->i_mmap_mutex); |
2780 | vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) { |
2781 | /* Do not unmap the current VMA */ |
2782 | if (iter_vma == vma) |
2783 | continue; |
2784 | |
2785 | /* |
2786 | * Unmap the page from other VMAs without their own reserves. |
2787 | * They get marked to be SIGKILLed if they fault in these |
2788 | * areas. This is because a future no-page fault on this VMA |
2789 | * could insert a zeroed page instead of the data existing |
2790 | * from the time of fork. This would look like data corruption |
2791 | */ |
2792 | if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) |
2793 | unmap_hugepage_range(iter_vma, address, |
2794 | address + huge_page_size(h), page); |
2795 | } |
2796 | mutex_unlock(&mapping->i_mmap_mutex); |
2797 | |
2798 | return 1; |
2799 | } |
2800 | |
2801 | /* |
2802 | * Hugetlb_cow() should be called with page lock of the original hugepage held. |
2803 | * Called with hugetlb_instantiation_mutex held and pte_page locked so we |
2804 | * cannot race with other handlers or page migration. |
2805 | * Keep the pte_same checks anyway to make transition from the mutex easier. |
2806 | */ |
2807 | static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
2808 | unsigned long address, pte_t *ptep, pte_t pte, |
2809 | struct page *pagecache_page, spinlock_t *ptl) |
2810 | { |
2811 | struct hstate *h = hstate_vma(vma); |
2812 | struct page *old_page, *new_page; |
2813 | int outside_reserve = 0; |
2814 | unsigned long mmun_start; /* For mmu_notifiers */ |
2815 | unsigned long mmun_end; /* For mmu_notifiers */ |
2816 | |
2817 | old_page = pte_page(pte); |
2818 | |
2819 | retry_avoidcopy: |
2820 | /* If no-one else is actually using this page, avoid the copy |
2821 | * and just make the page writable */ |
2822 | if (page_mapcount(old_page) == 1 && PageAnon(old_page)) { |
2823 | page_move_anon_rmap(old_page, vma, address); |
2824 | set_huge_ptep_writable(vma, address, ptep); |
2825 | return 0; |
2826 | } |
2827 | |
2828 | /* |
2829 | * If the process that created a MAP_PRIVATE mapping is about to |
2830 | * perform a COW due to a shared page count, attempt to satisfy |
2831 | * the allocation without using the existing reserves. The pagecache |
2832 | * page is used to determine if the reserve at this address was |
2833 | * consumed or not. If reserves were used, a partial faulted mapping |
2834 | * at the time of fork() could consume its reserves on COW instead |
2835 | * of the full address range. |
2836 | */ |
2837 | if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && |
2838 | old_page != pagecache_page) |
2839 | outside_reserve = 1; |
2840 | |
2841 | page_cache_get(old_page); |
2842 | |
2843 | /* Drop page table lock as buddy allocator may be called */ |
2844 | spin_unlock(ptl); |
2845 | new_page = alloc_huge_page(vma, address, outside_reserve); |
2846 | |
2847 | if (IS_ERR(new_page)) { |
2848 | long err = PTR_ERR(new_page); |
2849 | page_cache_release(old_page); |
2850 | |
2851 | /* |
2852 | * If a process owning a MAP_PRIVATE mapping fails to COW, |
2853 | * it is due to references held by a child and an insufficient |
2854 | * huge page pool. To guarantee the original mappers |
2855 | * reliability, unmap the page from child processes. The child |
2856 | * may get SIGKILLed if it later faults. |
2857 | */ |
2858 | if (outside_reserve) { |
2859 | BUG_ON(huge_pte_none(pte)); |
2860 | if (unmap_ref_private(mm, vma, old_page, address)) { |
2861 | BUG_ON(huge_pte_none(pte)); |
2862 | spin_lock(ptl); |
2863 | ptep = huge_pte_offset(mm, address & huge_page_mask(h)); |
2864 | if (likely(ptep && |
2865 | pte_same(huge_ptep_get(ptep), pte))) |
2866 | goto retry_avoidcopy; |
2867 | /* |
2868 | * race occurs while re-acquiring page table |
2869 | * lock, and our job is done. |
2870 | */ |
2871 | return 0; |
2872 | } |
2873 | WARN_ON_ONCE(1); |
2874 | } |
2875 | |
2876 | /* Caller expects lock to be held */ |
2877 | spin_lock(ptl); |
2878 | if (err == -ENOMEM) |
2879 | return VM_FAULT_OOM; |
2880 | else |
2881 | return VM_FAULT_SIGBUS; |
2882 | } |
2883 | |
2884 | /* |
2885 | * When the original hugepage is shared one, it does not have |
2886 | * anon_vma prepared. |
2887 | */ |
2888 | if (unlikely(anon_vma_prepare(vma))) { |
2889 | page_cache_release(new_page); |
2890 | page_cache_release(old_page); |
2891 | /* Caller expects lock to be held */ |
2892 | spin_lock(ptl); |
2893 | return VM_FAULT_OOM; |
2894 | } |
2895 | |
2896 | copy_user_huge_page(new_page, old_page, address, vma, |
2897 | pages_per_huge_page(h)); |
2898 | __SetPageUptodate(new_page); |
2899 | |
2900 | mmun_start = address & huge_page_mask(h); |
2901 | mmun_end = mmun_start + huge_page_size(h); |
2902 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
2903 | /* |
2904 | * Retake the page table lock to check for racing updates |
2905 | * before the page tables are altered |
2906 | */ |
2907 | spin_lock(ptl); |
2908 | ptep = huge_pte_offset(mm, address & huge_page_mask(h)); |
2909 | if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) { |
2910 | ClearPagePrivate(new_page); |
2911 | |
2912 | /* Break COW */ |
2913 | huge_ptep_clear_flush(vma, address, ptep); |
2914 | set_huge_pte_at(mm, address, ptep, |
2915 | make_huge_pte(vma, new_page, 1)); |
2916 | page_remove_rmap(old_page); |
2917 | hugepage_add_new_anon_rmap(new_page, vma, address); |
2918 | /* Make the old page be freed below */ |
2919 | new_page = old_page; |
2920 | } |
2921 | spin_unlock(ptl); |
2922 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
2923 | page_cache_release(new_page); |
2924 | page_cache_release(old_page); |
2925 | |
2926 | /* Caller expects lock to be held */ |
2927 | spin_lock(ptl); |
2928 | return 0; |
2929 | } |
2930 | |
2931 | /* Return the pagecache page at a given address within a VMA */ |
2932 | static struct page *hugetlbfs_pagecache_page(struct hstate *h, |
2933 | struct vm_area_struct *vma, unsigned long address) |
2934 | { |
2935 | struct address_space *mapping; |
2936 | pgoff_t idx; |
2937 | |
2938 | mapping = vma->vm_file->f_mapping; |
2939 | idx = vma_hugecache_offset(h, vma, address); |
2940 | |
2941 | return find_lock_page(mapping, idx); |
2942 | } |
2943 | |
2944 | /* |
2945 | * Return whether there is a pagecache page to back given address within VMA. |
2946 | * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. |
2947 | */ |
2948 | static bool hugetlbfs_pagecache_present(struct hstate *h, |
2949 | struct vm_area_struct *vma, unsigned long address) |
2950 | { |
2951 | struct address_space *mapping; |
2952 | pgoff_t idx; |
2953 | struct page *page; |
2954 | |
2955 | mapping = vma->vm_file->f_mapping; |
2956 | idx = vma_hugecache_offset(h, vma, address); |
2957 | |
2958 | page = find_get_page(mapping, idx); |
2959 | if (page) |
2960 | put_page(page); |
2961 | return page != NULL; |
2962 | } |
2963 | |
2964 | static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2965 | struct address_space *mapping, pgoff_t idx, |
2966 | unsigned long address, pte_t *ptep, unsigned int flags) |
2967 | { |
2968 | struct hstate *h = hstate_vma(vma); |
2969 | int ret = VM_FAULT_SIGBUS; |
2970 | int anon_rmap = 0; |
2971 | unsigned long size; |
2972 | struct page *page; |
2973 | pte_t new_pte; |
2974 | spinlock_t *ptl; |
2975 | |
2976 | /* |
2977 | * Currently, we are forced to kill the process in the event the |
2978 | * original mapper has unmapped pages from the child due to a failed |
2979 | * COW. Warn that such a situation has occurred as it may not be obvious |
2980 | */ |
2981 | if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { |
2982 | pr_warning("PID %d killed due to inadequate hugepage pool\n", |
2983 | current->pid); |
2984 | return ret; |
2985 | } |
2986 | |
2987 | /* |
2988 | * Use page lock to guard against racing truncation |
2989 | * before we get page_table_lock. |
2990 | */ |
2991 | retry: |
2992 | page = find_lock_page(mapping, idx); |
2993 | if (!page) { |
2994 | size = i_size_read(mapping->host) >> huge_page_shift(h); |
2995 | if (idx >= size) |
2996 | goto out; |
2997 | page = alloc_huge_page(vma, address, 0); |
2998 | if (IS_ERR(page)) { |
2999 | ret = PTR_ERR(page); |
3000 | if (ret == -ENOMEM) |
3001 | ret = VM_FAULT_OOM; |
3002 | else |
3003 | ret = VM_FAULT_SIGBUS; |
3004 | goto out; |
3005 | } |
3006 | clear_huge_page(page, address, pages_per_huge_page(h)); |
3007 | __SetPageUptodate(page); |
3008 | |
3009 | if (vma->vm_flags & VM_MAYSHARE) { |
3010 | int err; |
3011 | struct inode *inode = mapping->host; |
3012 | |
3013 | err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); |
3014 | if (err) { |
3015 | put_page(page); |
3016 | if (err == -EEXIST) |
3017 | goto retry; |
3018 | goto out; |
3019 | } |
3020 | ClearPagePrivate(page); |
3021 | |
3022 | spin_lock(&inode->i_lock); |
3023 | inode->i_blocks += blocks_per_huge_page(h); |
3024 | spin_unlock(&inode->i_lock); |
3025 | } else { |
3026 | lock_page(page); |
3027 | if (unlikely(anon_vma_prepare(vma))) { |
3028 | ret = VM_FAULT_OOM; |
3029 | goto backout_unlocked; |
3030 | } |
3031 | anon_rmap = 1; |
3032 | } |
3033 | } else { |
3034 | /* |
3035 | * If memory error occurs between mmap() and fault, some process |
3036 | * don't have hwpoisoned swap entry for errored virtual address. |
3037 | * So we need to block hugepage fault by PG_hwpoison bit check. |
3038 | */ |
3039 | if (unlikely(PageHWPoison(page))) { |
3040 | ret = VM_FAULT_HWPOISON | |
3041 | VM_FAULT_SET_HINDEX(hstate_index(h)); |
3042 | goto backout_unlocked; |
3043 | } |
3044 | } |
3045 | |
3046 | /* |
3047 | * If we are going to COW a private mapping later, we examine the |
3048 | * pending reservations for this page now. This will ensure that |
3049 | * any allocations necessary to record that reservation occur outside |
3050 | * the spinlock. |
3051 | */ |
3052 | if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) |
3053 | if (vma_needs_reservation(h, vma, address) < 0) { |
3054 | ret = VM_FAULT_OOM; |
3055 | goto backout_unlocked; |
3056 | } |
3057 | |
3058 | ptl = huge_pte_lockptr(h, mm, ptep); |
3059 | spin_lock(ptl); |
3060 | size = i_size_read(mapping->host) >> huge_page_shift(h); |
3061 | if (idx >= size) |
3062 | goto backout; |
3063 | |
3064 | ret = 0; |
3065 | if (!huge_pte_none(huge_ptep_get(ptep))) |
3066 | goto backout; |
3067 | |
3068 | if (anon_rmap) { |
3069 | ClearPagePrivate(page); |
3070 | hugepage_add_new_anon_rmap(page, vma, address); |
3071 | } else |
3072 | page_dup_rmap(page); |
3073 | new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) |
3074 | && (vma->vm_flags & VM_SHARED))); |
3075 | set_huge_pte_at(mm, address, ptep, new_pte); |
3076 | |
3077 | if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { |
3078 | /* Optimization, do the COW without a second fault */ |
3079 | ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl); |
3080 | } |
3081 | |
3082 | spin_unlock(ptl); |
3083 | unlock_page(page); |
3084 | out: |
3085 | return ret; |
3086 | |
3087 | backout: |
3088 | spin_unlock(ptl); |
3089 | backout_unlocked: |
3090 | unlock_page(page); |
3091 | put_page(page); |
3092 | goto out; |
3093 | } |
3094 | |
3095 | #ifdef CONFIG_SMP |
3096 | static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm, |
3097 | struct vm_area_struct *vma, |
3098 | struct address_space *mapping, |
3099 | pgoff_t idx, unsigned long address) |
3100 | { |
3101 | unsigned long key[2]; |
3102 | u32 hash; |
3103 | |
3104 | if (vma->vm_flags & VM_SHARED) { |
3105 | key[0] = (unsigned long) mapping; |
3106 | key[1] = idx; |
3107 | } else { |
3108 | key[0] = (unsigned long) mm; |
3109 | key[1] = address >> huge_page_shift(h); |
3110 | } |
3111 | |
3112 | hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0); |
3113 | |
3114 | return hash & (num_fault_mutexes - 1); |
3115 | } |
3116 | #else |
3117 | /* |
3118 | * For uniprocesor systems we always use a single mutex, so just |
3119 | * return 0 and avoid the hashing overhead. |
3120 | */ |
3121 | static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm, |
3122 | struct vm_area_struct *vma, |
3123 | struct address_space *mapping, |
3124 | pgoff_t idx, unsigned long address) |
3125 | { |
3126 | return 0; |
3127 | } |
3128 | #endif |
3129 | |
3130 | int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
3131 | unsigned long address, unsigned int flags) |
3132 | { |
3133 | pte_t *ptep, entry; |
3134 | spinlock_t *ptl; |
3135 | int ret; |
3136 | u32 hash; |
3137 | pgoff_t idx; |
3138 | struct page *page = NULL; |
3139 | struct page *pagecache_page = NULL; |
3140 | struct hstate *h = hstate_vma(vma); |
3141 | struct address_space *mapping; |
3142 | |
3143 | address &= huge_page_mask(h); |
3144 | |
3145 | ptep = huge_pte_offset(mm, address); |
3146 | if (ptep) { |
3147 | entry = huge_ptep_get(ptep); |
3148 | if (unlikely(is_hugetlb_entry_migration(entry))) { |
3149 | migration_entry_wait_huge(vma, mm, ptep); |
3150 | return 0; |
3151 | } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) |
3152 | return VM_FAULT_HWPOISON_LARGE | |
3153 | VM_FAULT_SET_HINDEX(hstate_index(h)); |
3154 | } |
3155 | |
3156 | ptep = huge_pte_alloc(mm, address, huge_page_size(h)); |
3157 | if (!ptep) |
3158 | return VM_FAULT_OOM; |
3159 | |
3160 | mapping = vma->vm_file->f_mapping; |
3161 | idx = vma_hugecache_offset(h, vma, address); |
3162 | |
3163 | /* |
3164 | * Serialize hugepage allocation and instantiation, so that we don't |
3165 | * get spurious allocation failures if two CPUs race to instantiate |
3166 | * the same page in the page cache. |
3167 | */ |
3168 | hash = fault_mutex_hash(h, mm, vma, mapping, idx, address); |
3169 | mutex_lock(&htlb_fault_mutex_table[hash]); |
3170 | |
3171 | entry = huge_ptep_get(ptep); |
3172 | if (huge_pte_none(entry)) { |
3173 | ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags); |
3174 | goto out_mutex; |
3175 | } |
3176 | |
3177 | ret = 0; |
3178 | |
3179 | /* |
3180 | * If we are going to COW the mapping later, we examine the pending |
3181 | * reservations for this page now. This will ensure that any |
3182 | * allocations necessary to record that reservation occur outside the |
3183 | * spinlock. For private mappings, we also lookup the pagecache |
3184 | * page now as it is used to determine if a reservation has been |
3185 | * consumed. |
3186 | */ |
3187 | if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) { |
3188 | if (vma_needs_reservation(h, vma, address) < 0) { |
3189 | ret = VM_FAULT_OOM; |
3190 | goto out_mutex; |
3191 | } |
3192 | |
3193 | if (!(vma->vm_flags & VM_MAYSHARE)) |
3194 | pagecache_page = hugetlbfs_pagecache_page(h, |
3195 | vma, address); |
3196 | } |
3197 | |
3198 | /* |
3199 | * hugetlb_cow() requires page locks of pte_page(entry) and |
3200 | * pagecache_page, so here we need take the former one |
3201 | * when page != pagecache_page or !pagecache_page. |
3202 | * Note that locking order is always pagecache_page -> page, |
3203 | * so no worry about deadlock. |
3204 | */ |
3205 | page = pte_page(entry); |
3206 | get_page(page); |
3207 | if (page != pagecache_page) |
3208 | lock_page(page); |
3209 | |
3210 | ptl = huge_pte_lockptr(h, mm, ptep); |
3211 | spin_lock(ptl); |
3212 | /* Check for a racing update before calling hugetlb_cow */ |
3213 | if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) |
3214 | goto out_ptl; |
3215 | |
3216 | |
3217 | if (flags & FAULT_FLAG_WRITE) { |
3218 | if (!huge_pte_write(entry)) { |
3219 | ret = hugetlb_cow(mm, vma, address, ptep, entry, |
3220 | pagecache_page, ptl); |
3221 | goto out_ptl; |
3222 | } |
3223 | entry = huge_pte_mkdirty(entry); |
3224 | } |
3225 | entry = pte_mkyoung(entry); |
3226 | if (huge_ptep_set_access_flags(vma, address, ptep, entry, |
3227 | flags & FAULT_FLAG_WRITE)) |
3228 | update_mmu_cache(vma, address, ptep); |
3229 | |
3230 | out_ptl: |
3231 | spin_unlock(ptl); |
3232 | |
3233 | if (pagecache_page) { |
3234 | unlock_page(pagecache_page); |
3235 | put_page(pagecache_page); |
3236 | } |
3237 | if (page != pagecache_page) |
3238 | unlock_page(page); |
3239 | put_page(page); |
3240 | |
3241 | out_mutex: |
3242 | mutex_unlock(&htlb_fault_mutex_table[hash]); |
3243 | return ret; |
3244 | } |
3245 | |
3246 | long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, |
3247 | struct page **pages, struct vm_area_struct **vmas, |
3248 | unsigned long *position, unsigned long *nr_pages, |
3249 | long i, unsigned int flags) |
3250 | { |
3251 | unsigned long pfn_offset; |
3252 | unsigned long vaddr = *position; |
3253 | unsigned long remainder = *nr_pages; |
3254 | struct hstate *h = hstate_vma(vma); |
3255 | |
3256 | while (vaddr < vma->vm_end && remainder) { |
3257 | pte_t *pte; |
3258 | spinlock_t *ptl = NULL; |
3259 | int absent; |
3260 | struct page *page; |
3261 | |
3262 | /* |
3263 | * Some archs (sparc64, sh*) have multiple pte_ts to |
3264 | * each hugepage. We have to make sure we get the |
3265 | * first, for the page indexing below to work. |
3266 | * |
3267 | * Note that page table lock is not held when pte is null. |
3268 | */ |
3269 | pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); |
3270 | if (pte) |
3271 | ptl = huge_pte_lock(h, mm, pte); |
3272 | absent = !pte || huge_pte_none(huge_ptep_get(pte)); |
3273 | |
3274 | /* |
3275 | * When coredumping, it suits get_dump_page if we just return |
3276 | * an error where there's an empty slot with no huge pagecache |
3277 | * to back it. This way, we avoid allocating a hugepage, and |
3278 | * the sparse dumpfile avoids allocating disk blocks, but its |
3279 | * huge holes still show up with zeroes where they need to be. |
3280 | */ |
3281 | if (absent && (flags & FOLL_DUMP) && |
3282 | !hugetlbfs_pagecache_present(h, vma, vaddr)) { |
3283 | if (pte) |
3284 | spin_unlock(ptl); |
3285 | remainder = 0; |
3286 | break; |
3287 | } |
3288 | |
3289 | /* |
3290 | * We need call hugetlb_fault for both hugepages under migration |
3291 | * (in which case hugetlb_fault waits for the migration,) and |
3292 | * hwpoisoned hugepages (in which case we need to prevent the |
3293 | * caller from accessing to them.) In order to do this, we use |
3294 | * here is_swap_pte instead of is_hugetlb_entry_migration and |
3295 | * is_hugetlb_entry_hwpoisoned. This is because it simply covers |
3296 | * both cases, and because we can't follow correct pages |
3297 | * directly from any kind of swap entries. |
3298 | */ |
3299 | if (absent || is_swap_pte(huge_ptep_get(pte)) || |
3300 | ((flags & FOLL_WRITE) && |
3301 | !huge_pte_write(huge_ptep_get(pte)))) { |
3302 | int ret; |
3303 | |
3304 | if (pte) |
3305 | spin_unlock(ptl); |
3306 | ret = hugetlb_fault(mm, vma, vaddr, |
3307 | (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); |
3308 | if (!(ret & VM_FAULT_ERROR)) |
3309 | continue; |
3310 | |
3311 | remainder = 0; |
3312 | break; |
3313 | } |
3314 | |
3315 | pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; |
3316 | page = pte_page(huge_ptep_get(pte)); |
3317 | same_page: |
3318 | if (pages) { |
3319 | pages[i] = mem_map_offset(page, pfn_offset); |
3320 | get_page_foll(pages[i]); |
3321 | } |
3322 | |
3323 | if (vmas) |
3324 | vmas[i] = vma; |
3325 | |
3326 | vaddr += PAGE_SIZE; |
3327 | ++pfn_offset; |
3328 | --remainder; |
3329 | ++i; |
3330 | if (vaddr < vma->vm_end && remainder && |
3331 | pfn_offset < pages_per_huge_page(h)) { |
3332 | /* |
3333 | * We use pfn_offset to avoid touching the pageframes |
3334 | * of this compound page. |
3335 | */ |
3336 | goto same_page; |
3337 | } |
3338 | spin_unlock(ptl); |
3339 | } |
3340 | *nr_pages = remainder; |
3341 | *position = vaddr; |
3342 | |
3343 | return i ? i : -EFAULT; |
3344 | } |
3345 | |
3346 | unsigned long hugetlb_change_protection(struct vm_area_struct *vma, |
3347 | unsigned long address, unsigned long end, pgprot_t newprot) |
3348 | { |
3349 | struct mm_struct *mm = vma->vm_mm; |
3350 | unsigned long start = address; |
3351 | pte_t *ptep; |
3352 | pte_t pte; |
3353 | struct hstate *h = hstate_vma(vma); |
3354 | unsigned long pages = 0; |
3355 | |
3356 | BUG_ON(address >= end); |
3357 | flush_cache_range(vma, address, end); |
3358 | |
3359 | mmu_notifier_invalidate_range_start(mm, start, end); |
3360 | mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); |
3361 | for (; address < end; address += huge_page_size(h)) { |
3362 | spinlock_t *ptl; |
3363 | ptep = huge_pte_offset(mm, address); |
3364 | if (!ptep) |
3365 | continue; |
3366 | ptl = huge_pte_lock(h, mm, ptep); |
3367 | if (huge_pmd_unshare(mm, &address, ptep)) { |
3368 | pages++; |
3369 | spin_unlock(ptl); |
3370 | continue; |
3371 | } |
3372 | if (!huge_pte_none(huge_ptep_get(ptep))) { |
3373 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
3374 | pte = pte_mkhuge(huge_pte_modify(pte, newprot)); |
3375 | pte = arch_make_huge_pte(pte, vma, NULL, 0); |
3376 | set_huge_pte_at(mm, address, ptep, pte); |
3377 | pages++; |
3378 | } |
3379 | spin_unlock(ptl); |
3380 | } |
3381 | /* |
3382 | * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare |
3383 | * may have cleared our pud entry and done put_page on the page table: |
3384 | * once we release i_mmap_mutex, another task can do the final put_page |
3385 | * and that page table be reused and filled with junk. |
3386 | */ |
3387 | flush_tlb_range(vma, start, end); |
3388 | mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); |
3389 | mmu_notifier_invalidate_range_end(mm, start, end); |
3390 | |
3391 | return pages << h->order; |
3392 | } |
3393 | |
3394 | int hugetlb_reserve_pages(struct inode *inode, |
3395 | long from, long to, |
3396 | struct vm_area_struct *vma, |
3397 | vm_flags_t vm_flags) |
3398 | { |
3399 | long ret, chg; |
3400 | struct hstate *h = hstate_inode(inode); |
3401 | struct hugepage_subpool *spool = subpool_inode(inode); |
3402 | struct resv_map *resv_map; |
3403 | |
3404 | /* |
3405 | * Only apply hugepage reservation if asked. At fault time, an |
3406 | * attempt will be made for VM_NORESERVE to allocate a page |
3407 | * without using reserves |
3408 | */ |
3409 | if (vm_flags & VM_NORESERVE) |
3410 | return 0; |
3411 | |
3412 | /* |
3413 | * Shared mappings base their reservation on the number of pages that |
3414 | * are already allocated on behalf of the file. Private mappings need |
3415 | * to reserve the full area even if read-only as mprotect() may be |
3416 | * called to make the mapping read-write. Assume !vma is a shm mapping |
3417 | */ |
3418 | if (!vma || vma->vm_flags & VM_MAYSHARE) { |
3419 | resv_map = inode_resv_map(inode); |
3420 | |
3421 | chg = region_chg(resv_map, from, to); |
3422 | |
3423 | } else { |
3424 | resv_map = resv_map_alloc(); |
3425 | if (!resv_map) |
3426 | return -ENOMEM; |
3427 | |
3428 | chg = to - from; |
3429 | |
3430 | set_vma_resv_map(vma, resv_map); |
3431 | set_vma_resv_flags(vma, HPAGE_RESV_OWNER); |
3432 | } |
3433 | |
3434 | if (chg < 0) { |
3435 | ret = chg; |
3436 | goto out_err; |
3437 | } |
3438 | |
3439 | /* There must be enough pages in the subpool for the mapping */ |
3440 | if (hugepage_subpool_get_pages(spool, chg)) { |
3441 | ret = -ENOSPC; |
3442 | goto out_err; |
3443 | } |
3444 | |
3445 | /* |
3446 | * Check enough hugepages are available for the reservation. |
3447 | * Hand the pages back to the subpool if there are not |
3448 | */ |
3449 | ret = hugetlb_acct_memory(h, chg); |
3450 | if (ret < 0) { |
3451 | hugepage_subpool_put_pages(spool, chg); |
3452 | goto out_err; |
3453 | } |
3454 | |
3455 | /* |
3456 | * Account for the reservations made. Shared mappings record regions |
3457 | * that have reservations as they are shared by multiple VMAs. |
3458 | * When the last VMA disappears, the region map says how much |
3459 | * the reservation was and the page cache tells how much of |
3460 | * the reservation was consumed. Private mappings are per-VMA and |
3461 | * only the consumed reservations are tracked. When the VMA |
3462 | * disappears, the original reservation is the VMA size and the |
3463 | * consumed reservations are stored in the map. Hence, nothing |
3464 | * else has to be done for private mappings here |
3465 | */ |
3466 | if (!vma || vma->vm_flags & VM_MAYSHARE) |
3467 | region_add(resv_map, from, to); |
3468 | return 0; |
3469 | out_err: |
3470 | if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
3471 | kref_put(&resv_map->refs, resv_map_release); |
3472 | return ret; |
3473 | } |
3474 | |
3475 | void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) |
3476 | { |
3477 | struct hstate *h = hstate_inode(inode); |
3478 | struct resv_map *resv_map = inode_resv_map(inode); |
3479 | long chg = 0; |
3480 | struct hugepage_subpool *spool = subpool_inode(inode); |
3481 | |
3482 | if (resv_map) |
3483 | chg = region_truncate(resv_map, offset); |
3484 | spin_lock(&inode->i_lock); |
3485 | inode->i_blocks -= (blocks_per_huge_page(h) * freed); |
3486 | spin_unlock(&inode->i_lock); |
3487 | |
3488 | hugepage_subpool_put_pages(spool, (chg - freed)); |
3489 | hugetlb_acct_memory(h, -(chg - freed)); |
3490 | } |
3491 | |
3492 | #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE |
3493 | static unsigned long page_table_shareable(struct vm_area_struct *svma, |
3494 | struct vm_area_struct *vma, |
3495 | unsigned long addr, pgoff_t idx) |
3496 | { |
3497 | unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) + |
3498 | svma->vm_start; |
3499 | unsigned long sbase = saddr & PUD_MASK; |
3500 | unsigned long s_end = sbase + PUD_SIZE; |
3501 | |
3502 | /* Allow segments to share if only one is marked locked */ |
3503 | unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED; |
3504 | unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED; |
3505 | |
3506 | /* |
3507 | * match the virtual addresses, permission and the alignment of the |
3508 | * page table page. |
3509 | */ |
3510 | if (pmd_index(addr) != pmd_index(saddr) || |
3511 | vm_flags != svm_flags || |
3512 | sbase < svma->vm_start || svma->vm_end < s_end) |
3513 | return 0; |
3514 | |
3515 | return saddr; |
3516 | } |
3517 | |
3518 | static int vma_shareable(struct vm_area_struct *vma, unsigned long addr) |
3519 | { |
3520 | unsigned long base = addr & PUD_MASK; |
3521 | unsigned long end = base + PUD_SIZE; |
3522 | |
3523 | /* |
3524 | * check on proper vm_flags and page table alignment |
3525 | */ |
3526 | if (vma->vm_flags & VM_MAYSHARE && |
3527 | vma->vm_start <= base && end <= vma->vm_end) |
3528 | return 1; |
3529 | return 0; |
3530 | } |
3531 | |
3532 | /* |
3533 | * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc() |
3534 | * and returns the corresponding pte. While this is not necessary for the |
3535 | * !shared pmd case because we can allocate the pmd later as well, it makes the |
3536 | * code much cleaner. pmd allocation is essential for the shared case because |
3537 | * pud has to be populated inside the same i_mmap_mutex section - otherwise |
3538 | * racing tasks could either miss the sharing (see huge_pte_offset) or select a |
3539 | * bad pmd for sharing. |
3540 | */ |
3541 | pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) |
3542 | { |
3543 | struct vm_area_struct *vma = find_vma(mm, addr); |
3544 | struct address_space *mapping = vma->vm_file->f_mapping; |
3545 | pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + |
3546 | vma->vm_pgoff; |
3547 | struct vm_area_struct *svma; |
3548 | unsigned long saddr; |
3549 | pte_t *spte = NULL; |
3550 | pte_t *pte; |
3551 | spinlock_t *ptl; |
3552 | |
3553 | if (!vma_shareable(vma, addr)) |
3554 | return (pte_t *)pmd_alloc(mm, pud, addr); |
3555 | |
3556 | mutex_lock(&mapping->i_mmap_mutex); |
3557 | vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) { |
3558 | if (svma == vma) |
3559 | continue; |
3560 | |
3561 | saddr = page_table_shareable(svma, vma, addr, idx); |
3562 | if (saddr) { |
3563 | spte = huge_pte_offset(svma->vm_mm, saddr); |
3564 | if (spte) { |
3565 | get_page(virt_to_page(spte)); |
3566 | break; |
3567 | } |
3568 | } |
3569 | } |
3570 | |
3571 | if (!spte) |
3572 | goto out; |
3573 | |
3574 | ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte); |
3575 | spin_lock(ptl); |
3576 | if (pud_none(*pud)) |
3577 | pud_populate(mm, pud, |
3578 | (pmd_t *)((unsigned long)spte & PAGE_MASK)); |
3579 | else |
3580 | put_page(virt_to_page(spte)); |
3581 | spin_unlock(ptl); |
3582 | out: |
3583 | pte = (pte_t *)pmd_alloc(mm, pud, addr); |
3584 | mutex_unlock(&mapping->i_mmap_mutex); |
3585 | return pte; |
3586 | } |
3587 | |
3588 | /* |
3589 | * unmap huge page backed by shared pte. |
3590 | * |
3591 | * Hugetlb pte page is ref counted at the time of mapping. If pte is shared |
3592 | * indicated by page_count > 1, unmap is achieved by clearing pud and |
3593 | * decrementing the ref count. If count == 1, the pte page is not shared. |
3594 | * |
3595 | * called with page table lock held. |
3596 | * |
3597 | * returns: 1 successfully unmapped a shared pte page |
3598 | * 0 the underlying pte page is not shared, or it is the last user |
3599 | */ |
3600 | int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) |
3601 | { |
3602 | pgd_t *pgd = pgd_offset(mm, *addr); |
3603 | pud_t *pud = pud_offset(pgd, *addr); |
3604 | |
3605 | BUG_ON(page_count(virt_to_page(ptep)) == 0); |
3606 | if (page_count(virt_to_page(ptep)) == 1) |
3607 | return 0; |
3608 | |
3609 | pud_clear(pud); |
3610 | put_page(virt_to_page(ptep)); |
3611 | *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE; |
3612 | return 1; |
3613 | } |
3614 | #define want_pmd_share() (1) |
3615 | #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ |
3616 | pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) |
3617 | { |
3618 | return NULL; |
3619 | } |
3620 | #define want_pmd_share() (0) |
3621 | #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ |
3622 | |
3623 | #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB |
3624 | pte_t *huge_pte_alloc(struct mm_struct *mm, |
3625 | unsigned long addr, unsigned long sz) |
3626 | { |
3627 | pgd_t *pgd; |
3628 | pud_t *pud; |
3629 | pte_t *pte = NULL; |
3630 | |
3631 | pgd = pgd_offset(mm, addr); |
3632 | pud = pud_alloc(mm, pgd, addr); |
3633 | if (pud) { |
3634 | if (sz == PUD_SIZE) { |
3635 | pte = (pte_t *)pud; |
3636 | } else { |
3637 | BUG_ON(sz != PMD_SIZE); |
3638 | if (want_pmd_share() && pud_none(*pud)) |
3639 | pte = huge_pmd_share(mm, addr, pud); |
3640 | else |
3641 | pte = (pte_t *)pmd_alloc(mm, pud, addr); |
3642 | } |
3643 | } |
3644 | BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte)); |
3645 | |
3646 | return pte; |
3647 | } |
3648 | |
3649 | pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) |
3650 | { |
3651 | pgd_t *pgd; |
3652 | pud_t *pud; |
3653 | pmd_t *pmd = NULL; |
3654 | |
3655 | pgd = pgd_offset(mm, addr); |
3656 | if (pgd_present(*pgd)) { |
3657 | pud = pud_offset(pgd, addr); |
3658 | if (pud_present(*pud)) { |
3659 | if (pud_huge(*pud)) |
3660 | return (pte_t *)pud; |
3661 | pmd = pmd_offset(pud, addr); |
3662 | } |
3663 | } |
3664 | return (pte_t *) pmd; |
3665 | } |
3666 | |
3667 | struct page * |
3668 | follow_huge_pmd(struct mm_struct *mm, unsigned long address, |
3669 | pmd_t *pmd, int write) |
3670 | { |
3671 | struct page *page; |
3672 | |
3673 | page = pte_page(*(pte_t *)pmd); |
3674 | if (page) |
3675 | page += ((address & ~PMD_MASK) >> PAGE_SHIFT); |
3676 | return page; |
3677 | } |
3678 | |
3679 | struct page * |
3680 | follow_huge_pud(struct mm_struct *mm, unsigned long address, |
3681 | pud_t *pud, int write) |
3682 | { |
3683 | struct page *page; |
3684 | |
3685 | page = pte_page(*(pte_t *)pud); |
3686 | if (page) |
3687 | page += ((address & ~PUD_MASK) >> PAGE_SHIFT); |
3688 | return page; |
3689 | } |
3690 | |
3691 | #else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */ |
3692 | |
3693 | /* Can be overriden by architectures */ |
3694 | struct page * __weak |
3695 | follow_huge_pud(struct mm_struct *mm, unsigned long address, |
3696 | pud_t *pud, int write) |
3697 | { |
3698 | BUG(); |
3699 | return NULL; |
3700 | } |
3701 | |
3702 | #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ |
3703 | |
3704 | #ifdef CONFIG_MEMORY_FAILURE |
3705 | |
3706 | /* Should be called in hugetlb_lock */ |
3707 | static int is_hugepage_on_freelist(struct page *hpage) |
3708 | { |
3709 | struct page *page; |
3710 | struct page *tmp; |
3711 | struct hstate *h = page_hstate(hpage); |
3712 | int nid = page_to_nid(hpage); |
3713 | |
3714 | list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru) |
3715 | if (page == hpage) |
3716 | return 1; |
3717 | return 0; |
3718 | } |
3719 | |
3720 | /* |
3721 | * This function is called from memory failure code. |
3722 | * Assume the caller holds page lock of the head page. |
3723 | */ |
3724 | int dequeue_hwpoisoned_huge_page(struct page *hpage) |
3725 | { |
3726 | struct hstate *h = page_hstate(hpage); |
3727 | int nid = page_to_nid(hpage); |
3728 | int ret = -EBUSY; |
3729 | |
3730 | spin_lock(&hugetlb_lock); |
3731 | if (is_hugepage_on_freelist(hpage)) { |
3732 | /* |
3733 | * Hwpoisoned hugepage isn't linked to activelist or freelist, |
3734 | * but dangling hpage->lru can trigger list-debug warnings |
3735 | * (this happens when we call unpoison_memory() on it), |
3736 | * so let it point to itself with list_del_init(). |
3737 | */ |
3738 | list_del_init(&hpage->lru); |
3739 | set_page_refcounted(hpage); |
3740 | h->free_huge_pages--; |
3741 | h->free_huge_pages_node[nid]--; |
3742 | ret = 0; |
3743 | } |
3744 | spin_unlock(&hugetlb_lock); |
3745 | return ret; |
3746 | } |
3747 | #endif |
3748 | |
3749 | bool isolate_huge_page(struct page *page, struct list_head *list) |
3750 | { |
3751 | VM_BUG_ON_PAGE(!PageHead(page), page); |
3752 | if (!get_page_unless_zero(page)) |
3753 | return false; |
3754 | spin_lock(&hugetlb_lock); |
3755 | list_move_tail(&page->lru, list); |
3756 | spin_unlock(&hugetlb_lock); |
3757 | return true; |
3758 | } |
3759 | |
3760 | void putback_active_hugepage(struct page *page) |
3761 | { |
3762 | VM_BUG_ON_PAGE(!PageHead(page), page); |
3763 | spin_lock(&hugetlb_lock); |
3764 | list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist); |
3765 | spin_unlock(&hugetlb_lock); |
3766 | put_page(page); |
3767 | } |
3768 | |
3769 | bool is_hugepage_active(struct page *page) |
3770 | { |
3771 | VM_BUG_ON_PAGE(!PageHuge(page), page); |
3772 | /* |
3773 | * This function can be called for a tail page because the caller, |
3774 | * scan_movable_pages, scans through a given pfn-range which typically |
3775 | * covers one memory block. In systems using gigantic hugepage (1GB |
3776 | * for x86_64,) a hugepage is larger than a memory block, and we don't |
3777 | * support migrating such large hugepages for now, so return false |
3778 | * when called for tail pages. |
3779 | */ |
3780 | if (PageTail(page)) |
3781 | return false; |
3782 | /* |
3783 | * Refcount of a hwpoisoned hugepages is 1, but they are not active, |
3784 | * so we should return false for them. |
3785 | */ |
3786 | if (unlikely(PageHWPoison(page))) |
3787 | return false; |
3788 | return page_count(page) > 0; |
3789 | } |
3790 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9