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