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