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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(file_inode(vma->vm_file)); |
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 | pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n", |
1297 | memfmt(buf, huge_page_size(h)), |
1298 | h->free_huge_pages); |
1299 | } |
1300 | } |
1301 | |
1302 | #ifdef CONFIG_HIGHMEM |
1303 | static void try_to_free_low(struct hstate *h, unsigned long count, |
1304 | nodemask_t *nodes_allowed) |
1305 | { |
1306 | int i; |
1307 | |
1308 | if (h->order >= MAX_ORDER) |
1309 | return; |
1310 | |
1311 | for_each_node_mask(i, *nodes_allowed) { |
1312 | struct page *page, *next; |
1313 | struct list_head *freel = &h->hugepage_freelists[i]; |
1314 | list_for_each_entry_safe(page, next, freel, lru) { |
1315 | if (count >= h->nr_huge_pages) |
1316 | return; |
1317 | if (PageHighMem(page)) |
1318 | continue; |
1319 | list_del(&page->lru); |
1320 | update_and_free_page(h, page); |
1321 | h->free_huge_pages--; |
1322 | h->free_huge_pages_node[page_to_nid(page)]--; |
1323 | } |
1324 | } |
1325 | } |
1326 | #else |
1327 | static inline void try_to_free_low(struct hstate *h, unsigned long count, |
1328 | nodemask_t *nodes_allowed) |
1329 | { |
1330 | } |
1331 | #endif |
1332 | |
1333 | /* |
1334 | * Increment or decrement surplus_huge_pages. Keep node-specific counters |
1335 | * balanced by operating on them in a round-robin fashion. |
1336 | * Returns 1 if an adjustment was made. |
1337 | */ |
1338 | static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, |
1339 | int delta) |
1340 | { |
1341 | int start_nid, next_nid; |
1342 | int ret = 0; |
1343 | |
1344 | VM_BUG_ON(delta != -1 && delta != 1); |
1345 | |
1346 | if (delta < 0) |
1347 | start_nid = hstate_next_node_to_alloc(h, nodes_allowed); |
1348 | else |
1349 | start_nid = hstate_next_node_to_free(h, nodes_allowed); |
1350 | next_nid = start_nid; |
1351 | |
1352 | do { |
1353 | int nid = next_nid; |
1354 | if (delta < 0) { |
1355 | /* |
1356 | * To shrink on this node, there must be a surplus page |
1357 | */ |
1358 | if (!h->surplus_huge_pages_node[nid]) { |
1359 | next_nid = hstate_next_node_to_alloc(h, |
1360 | nodes_allowed); |
1361 | continue; |
1362 | } |
1363 | } |
1364 | if (delta > 0) { |
1365 | /* |
1366 | * Surplus cannot exceed the total number of pages |
1367 | */ |
1368 | if (h->surplus_huge_pages_node[nid] >= |
1369 | h->nr_huge_pages_node[nid]) { |
1370 | next_nid = hstate_next_node_to_free(h, |
1371 | nodes_allowed); |
1372 | continue; |
1373 | } |
1374 | } |
1375 | |
1376 | h->surplus_huge_pages += delta; |
1377 | h->surplus_huge_pages_node[nid] += delta; |
1378 | ret = 1; |
1379 | break; |
1380 | } while (next_nid != start_nid); |
1381 | |
1382 | return ret; |
1383 | } |
1384 | |
1385 | #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) |
1386 | static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, |
1387 | nodemask_t *nodes_allowed) |
1388 | { |
1389 | unsigned long min_count, ret; |
1390 | |
1391 | if (h->order >= MAX_ORDER) |
1392 | return h->max_huge_pages; |
1393 | |
1394 | /* |
1395 | * Increase the pool size |
1396 | * First take pages out of surplus state. Then make up the |
1397 | * remaining difference by allocating fresh huge pages. |
1398 | * |
1399 | * We might race with alloc_buddy_huge_page() here and be unable |
1400 | * to convert a surplus huge page to a normal huge page. That is |
1401 | * not critical, though, it just means the overall size of the |
1402 | * pool might be one hugepage larger than it needs to be, but |
1403 | * within all the constraints specified by the sysctls. |
1404 | */ |
1405 | spin_lock(&hugetlb_lock); |
1406 | while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { |
1407 | if (!adjust_pool_surplus(h, nodes_allowed, -1)) |
1408 | break; |
1409 | } |
1410 | |
1411 | while (count > persistent_huge_pages(h)) { |
1412 | /* |
1413 | * If this allocation races such that we no longer need the |
1414 | * page, free_huge_page will handle it by freeing the page |
1415 | * and reducing the surplus. |
1416 | */ |
1417 | spin_unlock(&hugetlb_lock); |
1418 | ret = alloc_fresh_huge_page(h, nodes_allowed); |
1419 | spin_lock(&hugetlb_lock); |
1420 | if (!ret) |
1421 | goto out; |
1422 | |
1423 | /* Bail for signals. Probably ctrl-c from user */ |
1424 | if (signal_pending(current)) |
1425 | goto out; |
1426 | } |
1427 | |
1428 | /* |
1429 | * Decrease the pool size |
1430 | * First return free pages to the buddy allocator (being careful |
1431 | * to keep enough around to satisfy reservations). Then place |
1432 | * pages into surplus state as needed so the pool will shrink |
1433 | * to the desired size as pages become free. |
1434 | * |
1435 | * By placing pages into the surplus state independent of the |
1436 | * overcommit value, we are allowing the surplus pool size to |
1437 | * exceed overcommit. There are few sane options here. Since |
1438 | * alloc_buddy_huge_page() is checking the global counter, |
1439 | * though, we'll note that we're not allowed to exceed surplus |
1440 | * and won't grow the pool anywhere else. Not until one of the |
1441 | * sysctls are changed, or the surplus pages go out of use. |
1442 | */ |
1443 | min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; |
1444 | min_count = max(count, min_count); |
1445 | try_to_free_low(h, min_count, nodes_allowed); |
1446 | while (min_count < persistent_huge_pages(h)) { |
1447 | if (!free_pool_huge_page(h, nodes_allowed, 0)) |
1448 | break; |
1449 | } |
1450 | while (count < persistent_huge_pages(h)) { |
1451 | if (!adjust_pool_surplus(h, nodes_allowed, 1)) |
1452 | break; |
1453 | } |
1454 | out: |
1455 | ret = persistent_huge_pages(h); |
1456 | spin_unlock(&hugetlb_lock); |
1457 | return ret; |
1458 | } |
1459 | |
1460 | #define HSTATE_ATTR_RO(_name) \ |
1461 | static struct kobj_attribute _name##_attr = __ATTR_RO(_name) |
1462 | |
1463 | #define HSTATE_ATTR(_name) \ |
1464 | static struct kobj_attribute _name##_attr = \ |
1465 | __ATTR(_name, 0644, _name##_show, _name##_store) |
1466 | |
1467 | static struct kobject *hugepages_kobj; |
1468 | static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
1469 | |
1470 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); |
1471 | |
1472 | static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) |
1473 | { |
1474 | int i; |
1475 | |
1476 | for (i = 0; i < HUGE_MAX_HSTATE; i++) |
1477 | if (hstate_kobjs[i] == kobj) { |
1478 | if (nidp) |
1479 | *nidp = NUMA_NO_NODE; |
1480 | return &hstates[i]; |
1481 | } |
1482 | |
1483 | return kobj_to_node_hstate(kobj, nidp); |
1484 | } |
1485 | |
1486 | static ssize_t nr_hugepages_show_common(struct kobject *kobj, |
1487 | struct kobj_attribute *attr, char *buf) |
1488 | { |
1489 | struct hstate *h; |
1490 | unsigned long nr_huge_pages; |
1491 | int nid; |
1492 | |
1493 | h = kobj_to_hstate(kobj, &nid); |
1494 | if (nid == NUMA_NO_NODE) |
1495 | nr_huge_pages = h->nr_huge_pages; |
1496 | else |
1497 | nr_huge_pages = h->nr_huge_pages_node[nid]; |
1498 | |
1499 | return sprintf(buf, "%lu\n", nr_huge_pages); |
1500 | } |
1501 | |
1502 | static ssize_t nr_hugepages_store_common(bool obey_mempolicy, |
1503 | struct kobject *kobj, struct kobj_attribute *attr, |
1504 | const char *buf, size_t len) |
1505 | { |
1506 | int err; |
1507 | int nid; |
1508 | unsigned long count; |
1509 | struct hstate *h; |
1510 | NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); |
1511 | |
1512 | err = strict_strtoul(buf, 10, &count); |
1513 | if (err) |
1514 | goto out; |
1515 | |
1516 | h = kobj_to_hstate(kobj, &nid); |
1517 | if (h->order >= MAX_ORDER) { |
1518 | err = -EINVAL; |
1519 | goto out; |
1520 | } |
1521 | |
1522 | if (nid == NUMA_NO_NODE) { |
1523 | /* |
1524 | * global hstate attribute |
1525 | */ |
1526 | if (!(obey_mempolicy && |
1527 | init_nodemask_of_mempolicy(nodes_allowed))) { |
1528 | NODEMASK_FREE(nodes_allowed); |
1529 | nodes_allowed = &node_states[N_MEMORY]; |
1530 | } |
1531 | } else if (nodes_allowed) { |
1532 | /* |
1533 | * per node hstate attribute: adjust count to global, |
1534 | * but restrict alloc/free to the specified node. |
1535 | */ |
1536 | count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; |
1537 | init_nodemask_of_node(nodes_allowed, nid); |
1538 | } else |
1539 | nodes_allowed = &node_states[N_MEMORY]; |
1540 | |
1541 | h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); |
1542 | |
1543 | if (nodes_allowed != &node_states[N_MEMORY]) |
1544 | NODEMASK_FREE(nodes_allowed); |
1545 | |
1546 | return len; |
1547 | out: |
1548 | NODEMASK_FREE(nodes_allowed); |
1549 | return err; |
1550 | } |
1551 | |
1552 | static ssize_t nr_hugepages_show(struct kobject *kobj, |
1553 | struct kobj_attribute *attr, char *buf) |
1554 | { |
1555 | return nr_hugepages_show_common(kobj, attr, buf); |
1556 | } |
1557 | |
1558 | static ssize_t nr_hugepages_store(struct kobject *kobj, |
1559 | struct kobj_attribute *attr, const char *buf, size_t len) |
1560 | { |
1561 | return nr_hugepages_store_common(false, kobj, attr, buf, len); |
1562 | } |
1563 | HSTATE_ATTR(nr_hugepages); |
1564 | |
1565 | #ifdef CONFIG_NUMA |
1566 | |
1567 | /* |
1568 | * hstate attribute for optionally mempolicy-based constraint on persistent |
1569 | * huge page alloc/free. |
1570 | */ |
1571 | static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, |
1572 | struct kobj_attribute *attr, char *buf) |
1573 | { |
1574 | return nr_hugepages_show_common(kobj, attr, buf); |
1575 | } |
1576 | |
1577 | static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, |
1578 | struct kobj_attribute *attr, const char *buf, size_t len) |
1579 | { |
1580 | return nr_hugepages_store_common(true, kobj, attr, buf, len); |
1581 | } |
1582 | HSTATE_ATTR(nr_hugepages_mempolicy); |
1583 | #endif |
1584 | |
1585 | |
1586 | static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, |
1587 | struct kobj_attribute *attr, char *buf) |
1588 | { |
1589 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
1590 | return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); |
1591 | } |
1592 | |
1593 | static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, |
1594 | struct kobj_attribute *attr, const char *buf, size_t count) |
1595 | { |
1596 | int err; |
1597 | unsigned long input; |
1598 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
1599 | |
1600 | if (h->order >= MAX_ORDER) |
1601 | return -EINVAL; |
1602 | |
1603 | err = strict_strtoul(buf, 10, &input); |
1604 | if (err) |
1605 | return err; |
1606 | |
1607 | spin_lock(&hugetlb_lock); |
1608 | h->nr_overcommit_huge_pages = input; |
1609 | spin_unlock(&hugetlb_lock); |
1610 | |
1611 | return count; |
1612 | } |
1613 | HSTATE_ATTR(nr_overcommit_hugepages); |
1614 | |
1615 | static ssize_t free_hugepages_show(struct kobject *kobj, |
1616 | struct kobj_attribute *attr, char *buf) |
1617 | { |
1618 | struct hstate *h; |
1619 | unsigned long free_huge_pages; |
1620 | int nid; |
1621 | |
1622 | h = kobj_to_hstate(kobj, &nid); |
1623 | if (nid == NUMA_NO_NODE) |
1624 | free_huge_pages = h->free_huge_pages; |
1625 | else |
1626 | free_huge_pages = h->free_huge_pages_node[nid]; |
1627 | |
1628 | return sprintf(buf, "%lu\n", free_huge_pages); |
1629 | } |
1630 | HSTATE_ATTR_RO(free_hugepages); |
1631 | |
1632 | static ssize_t resv_hugepages_show(struct kobject *kobj, |
1633 | struct kobj_attribute *attr, char *buf) |
1634 | { |
1635 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
1636 | return sprintf(buf, "%lu\n", h->resv_huge_pages); |
1637 | } |
1638 | HSTATE_ATTR_RO(resv_hugepages); |
1639 | |
1640 | static ssize_t surplus_hugepages_show(struct kobject *kobj, |
1641 | struct kobj_attribute *attr, char *buf) |
1642 | { |
1643 | struct hstate *h; |
1644 | unsigned long surplus_huge_pages; |
1645 | int nid; |
1646 | |
1647 | h = kobj_to_hstate(kobj, &nid); |
1648 | if (nid == NUMA_NO_NODE) |
1649 | surplus_huge_pages = h->surplus_huge_pages; |
1650 | else |
1651 | surplus_huge_pages = h->surplus_huge_pages_node[nid]; |
1652 | |
1653 | return sprintf(buf, "%lu\n", surplus_huge_pages); |
1654 | } |
1655 | HSTATE_ATTR_RO(surplus_hugepages); |
1656 | |
1657 | static struct attribute *hstate_attrs[] = { |
1658 | &nr_hugepages_attr.attr, |
1659 | &nr_overcommit_hugepages_attr.attr, |
1660 | &free_hugepages_attr.attr, |
1661 | &resv_hugepages_attr.attr, |
1662 | &surplus_hugepages_attr.attr, |
1663 | #ifdef CONFIG_NUMA |
1664 | &nr_hugepages_mempolicy_attr.attr, |
1665 | #endif |
1666 | NULL, |
1667 | }; |
1668 | |
1669 | static struct attribute_group hstate_attr_group = { |
1670 | .attrs = hstate_attrs, |
1671 | }; |
1672 | |
1673 | static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, |
1674 | struct kobject **hstate_kobjs, |
1675 | struct attribute_group *hstate_attr_group) |
1676 | { |
1677 | int retval; |
1678 | int hi = hstate_index(h); |
1679 | |
1680 | hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); |
1681 | if (!hstate_kobjs[hi]) |
1682 | return -ENOMEM; |
1683 | |
1684 | retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); |
1685 | if (retval) |
1686 | kobject_put(hstate_kobjs[hi]); |
1687 | |
1688 | return retval; |
1689 | } |
1690 | |
1691 | static void __init hugetlb_sysfs_init(void) |
1692 | { |
1693 | struct hstate *h; |
1694 | int err; |
1695 | |
1696 | hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); |
1697 | if (!hugepages_kobj) |
1698 | return; |
1699 | |
1700 | for_each_hstate(h) { |
1701 | err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, |
1702 | hstate_kobjs, &hstate_attr_group); |
1703 | if (err) |
1704 | pr_err("Hugetlb: Unable to add hstate %s", h->name); |
1705 | } |
1706 | } |
1707 | |
1708 | #ifdef CONFIG_NUMA |
1709 | |
1710 | /* |
1711 | * node_hstate/s - associate per node hstate attributes, via their kobjects, |
1712 | * with node devices in node_devices[] using a parallel array. The array |
1713 | * index of a node device or _hstate == node id. |
1714 | * This is here to avoid any static dependency of the node device driver, in |
1715 | * the base kernel, on the hugetlb module. |
1716 | */ |
1717 | struct node_hstate { |
1718 | struct kobject *hugepages_kobj; |
1719 | struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
1720 | }; |
1721 | struct node_hstate node_hstates[MAX_NUMNODES]; |
1722 | |
1723 | /* |
1724 | * A subset of global hstate attributes for node devices |
1725 | */ |
1726 | static struct attribute *per_node_hstate_attrs[] = { |
1727 | &nr_hugepages_attr.attr, |
1728 | &free_hugepages_attr.attr, |
1729 | &surplus_hugepages_attr.attr, |
1730 | NULL, |
1731 | }; |
1732 | |
1733 | static struct attribute_group per_node_hstate_attr_group = { |
1734 | .attrs = per_node_hstate_attrs, |
1735 | }; |
1736 | |
1737 | /* |
1738 | * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj. |
1739 | * Returns node id via non-NULL nidp. |
1740 | */ |
1741 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) |
1742 | { |
1743 | int nid; |
1744 | |
1745 | for (nid = 0; nid < nr_node_ids; nid++) { |
1746 | struct node_hstate *nhs = &node_hstates[nid]; |
1747 | int i; |
1748 | for (i = 0; i < HUGE_MAX_HSTATE; i++) |
1749 | if (nhs->hstate_kobjs[i] == kobj) { |
1750 | if (nidp) |
1751 | *nidp = nid; |
1752 | return &hstates[i]; |
1753 | } |
1754 | } |
1755 | |
1756 | BUG(); |
1757 | return NULL; |
1758 | } |
1759 | |
1760 | /* |
1761 | * Unregister hstate attributes from a single node device. |
1762 | * No-op if no hstate attributes attached. |
1763 | */ |
1764 | void hugetlb_unregister_node(struct node *node) |
1765 | { |
1766 | struct hstate *h; |
1767 | struct node_hstate *nhs = &node_hstates[node->dev.id]; |
1768 | |
1769 | if (!nhs->hugepages_kobj) |
1770 | return; /* no hstate attributes */ |
1771 | |
1772 | for_each_hstate(h) { |
1773 | int idx = hstate_index(h); |
1774 | if (nhs->hstate_kobjs[idx]) { |
1775 | kobject_put(nhs->hstate_kobjs[idx]); |
1776 | nhs->hstate_kobjs[idx] = NULL; |
1777 | } |
1778 | } |
1779 | |
1780 | kobject_put(nhs->hugepages_kobj); |
1781 | nhs->hugepages_kobj = NULL; |
1782 | } |
1783 | |
1784 | /* |
1785 | * hugetlb module exit: unregister hstate attributes from node devices |
1786 | * that have them. |
1787 | */ |
1788 | static void hugetlb_unregister_all_nodes(void) |
1789 | { |
1790 | int nid; |
1791 | |
1792 | /* |
1793 | * disable node device registrations. |
1794 | */ |
1795 | register_hugetlbfs_with_node(NULL, NULL); |
1796 | |
1797 | /* |
1798 | * remove hstate attributes from any nodes that have them. |
1799 | */ |
1800 | for (nid = 0; nid < nr_node_ids; nid++) |
1801 | hugetlb_unregister_node(node_devices[nid]); |
1802 | } |
1803 | |
1804 | /* |
1805 | * Register hstate attributes for a single node device. |
1806 | * No-op if attributes already registered. |
1807 | */ |
1808 | void hugetlb_register_node(struct node *node) |
1809 | { |
1810 | struct hstate *h; |
1811 | struct node_hstate *nhs = &node_hstates[node->dev.id]; |
1812 | int err; |
1813 | |
1814 | if (nhs->hugepages_kobj) |
1815 | return; /* already allocated */ |
1816 | |
1817 | nhs->hugepages_kobj = kobject_create_and_add("hugepages", |
1818 | &node->dev.kobj); |
1819 | if (!nhs->hugepages_kobj) |
1820 | return; |
1821 | |
1822 | for_each_hstate(h) { |
1823 | err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, |
1824 | nhs->hstate_kobjs, |
1825 | &per_node_hstate_attr_group); |
1826 | if (err) { |
1827 | pr_err("Hugetlb: Unable to add hstate %s for node %d\n", |
1828 | h->name, node->dev.id); |
1829 | hugetlb_unregister_node(node); |
1830 | break; |
1831 | } |
1832 | } |
1833 | } |
1834 | |
1835 | /* |
1836 | * hugetlb init time: register hstate attributes for all registered node |
1837 | * devices of nodes that have memory. All on-line nodes should have |
1838 | * registered their associated device by this time. |
1839 | */ |
1840 | static void hugetlb_register_all_nodes(void) |
1841 | { |
1842 | int nid; |
1843 | |
1844 | for_each_node_state(nid, N_MEMORY) { |
1845 | struct node *node = node_devices[nid]; |
1846 | if (node->dev.id == nid) |
1847 | hugetlb_register_node(node); |
1848 | } |
1849 | |
1850 | /* |
1851 | * Let the node device driver know we're here so it can |
1852 | * [un]register hstate attributes on node hotplug. |
1853 | */ |
1854 | register_hugetlbfs_with_node(hugetlb_register_node, |
1855 | hugetlb_unregister_node); |
1856 | } |
1857 | #else /* !CONFIG_NUMA */ |
1858 | |
1859 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) |
1860 | { |
1861 | BUG(); |
1862 | if (nidp) |
1863 | *nidp = -1; |
1864 | return NULL; |
1865 | } |
1866 | |
1867 | static void hugetlb_unregister_all_nodes(void) { } |
1868 | |
1869 | static void hugetlb_register_all_nodes(void) { } |
1870 | |
1871 | #endif |
1872 | |
1873 | static void __exit hugetlb_exit(void) |
1874 | { |
1875 | struct hstate *h; |
1876 | |
1877 | hugetlb_unregister_all_nodes(); |
1878 | |
1879 | for_each_hstate(h) { |
1880 | kobject_put(hstate_kobjs[hstate_index(h)]); |
1881 | } |
1882 | |
1883 | kobject_put(hugepages_kobj); |
1884 | } |
1885 | module_exit(hugetlb_exit); |
1886 | |
1887 | static int __init hugetlb_init(void) |
1888 | { |
1889 | /* Some platform decide whether they support huge pages at boot |
1890 | * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when |
1891 | * there is no such support |
1892 | */ |
1893 | if (HPAGE_SHIFT == 0) |
1894 | return 0; |
1895 | |
1896 | if (!size_to_hstate(default_hstate_size)) { |
1897 | default_hstate_size = HPAGE_SIZE; |
1898 | if (!size_to_hstate(default_hstate_size)) |
1899 | hugetlb_add_hstate(HUGETLB_PAGE_ORDER); |
1900 | } |
1901 | default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size)); |
1902 | if (default_hstate_max_huge_pages) |
1903 | default_hstate.max_huge_pages = default_hstate_max_huge_pages; |
1904 | |
1905 | hugetlb_init_hstates(); |
1906 | gather_bootmem_prealloc(); |
1907 | report_hugepages(); |
1908 | |
1909 | hugetlb_sysfs_init(); |
1910 | hugetlb_register_all_nodes(); |
1911 | hugetlb_cgroup_file_init(); |
1912 | |
1913 | return 0; |
1914 | } |
1915 | module_init(hugetlb_init); |
1916 | |
1917 | /* Should be called on processing a hugepagesz=... option */ |
1918 | void __init hugetlb_add_hstate(unsigned order) |
1919 | { |
1920 | struct hstate *h; |
1921 | unsigned long i; |
1922 | |
1923 | if (size_to_hstate(PAGE_SIZE << order)) { |
1924 | pr_warning("hugepagesz= specified twice, ignoring\n"); |
1925 | return; |
1926 | } |
1927 | BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); |
1928 | BUG_ON(order == 0); |
1929 | h = &hstates[hugetlb_max_hstate++]; |
1930 | h->order = order; |
1931 | h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); |
1932 | h->nr_huge_pages = 0; |
1933 | h->free_huge_pages = 0; |
1934 | for (i = 0; i < MAX_NUMNODES; ++i) |
1935 | INIT_LIST_HEAD(&h->hugepage_freelists[i]); |
1936 | INIT_LIST_HEAD(&h->hugepage_activelist); |
1937 | h->next_nid_to_alloc = first_node(node_states[N_MEMORY]); |
1938 | h->next_nid_to_free = first_node(node_states[N_MEMORY]); |
1939 | snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", |
1940 | huge_page_size(h)/1024); |
1941 | |
1942 | parsed_hstate = h; |
1943 | } |
1944 | |
1945 | static int __init hugetlb_nrpages_setup(char *s) |
1946 | { |
1947 | unsigned long *mhp; |
1948 | static unsigned long *last_mhp; |
1949 | |
1950 | /* |
1951 | * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet, |
1952 | * so this hugepages= parameter goes to the "default hstate". |
1953 | */ |
1954 | if (!hugetlb_max_hstate) |
1955 | mhp = &default_hstate_max_huge_pages; |
1956 | else |
1957 | mhp = &parsed_hstate->max_huge_pages; |
1958 | |
1959 | if (mhp == last_mhp) { |
1960 | pr_warning("hugepages= specified twice without " |
1961 | "interleaving hugepagesz=, ignoring\n"); |
1962 | return 1; |
1963 | } |
1964 | |
1965 | if (sscanf(s, "%lu", mhp) <= 0) |
1966 | *mhp = 0; |
1967 | |
1968 | /* |
1969 | * Global state is always initialized later in hugetlb_init. |
1970 | * But we need to allocate >= MAX_ORDER hstates here early to still |
1971 | * use the bootmem allocator. |
1972 | */ |
1973 | if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER) |
1974 | hugetlb_hstate_alloc_pages(parsed_hstate); |
1975 | |
1976 | last_mhp = mhp; |
1977 | |
1978 | return 1; |
1979 | } |
1980 | __setup("hugepages=", hugetlb_nrpages_setup); |
1981 | |
1982 | static int __init hugetlb_default_setup(char *s) |
1983 | { |
1984 | default_hstate_size = memparse(s, &s); |
1985 | return 1; |
1986 | } |
1987 | __setup("default_hugepagesz=", hugetlb_default_setup); |
1988 | |
1989 | static unsigned int cpuset_mems_nr(unsigned int *array) |
1990 | { |
1991 | int node; |
1992 | unsigned int nr = 0; |
1993 | |
1994 | for_each_node_mask(node, cpuset_current_mems_allowed) |
1995 | nr += array[node]; |
1996 | |
1997 | return nr; |
1998 | } |
1999 | |
2000 | #ifdef CONFIG_SYSCTL |
2001 | static int hugetlb_sysctl_handler_common(bool obey_mempolicy, |
2002 | struct ctl_table *table, int write, |
2003 | void __user *buffer, size_t *length, loff_t *ppos) |
2004 | { |
2005 | struct hstate *h = &default_hstate; |
2006 | unsigned long tmp; |
2007 | int ret; |
2008 | |
2009 | tmp = h->max_huge_pages; |
2010 | |
2011 | if (write && h->order >= MAX_ORDER) |
2012 | return -EINVAL; |
2013 | |
2014 | table->data = &tmp; |
2015 | table->maxlen = sizeof(unsigned long); |
2016 | ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); |
2017 | if (ret) |
2018 | goto out; |
2019 | |
2020 | if (write) { |
2021 | NODEMASK_ALLOC(nodemask_t, nodes_allowed, |
2022 | GFP_KERNEL | __GFP_NORETRY); |
2023 | if (!(obey_mempolicy && |
2024 | init_nodemask_of_mempolicy(nodes_allowed))) { |
2025 | NODEMASK_FREE(nodes_allowed); |
2026 | nodes_allowed = &node_states[N_MEMORY]; |
2027 | } |
2028 | h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); |
2029 | |
2030 | if (nodes_allowed != &node_states[N_MEMORY]) |
2031 | NODEMASK_FREE(nodes_allowed); |
2032 | } |
2033 | out: |
2034 | return ret; |
2035 | } |
2036 | |
2037 | int hugetlb_sysctl_handler(struct ctl_table *table, int write, |
2038 | void __user *buffer, size_t *length, loff_t *ppos) |
2039 | { |
2040 | |
2041 | return hugetlb_sysctl_handler_common(false, table, write, |
2042 | buffer, length, ppos); |
2043 | } |
2044 | |
2045 | #ifdef CONFIG_NUMA |
2046 | int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, |
2047 | void __user *buffer, size_t *length, loff_t *ppos) |
2048 | { |
2049 | return hugetlb_sysctl_handler_common(true, table, write, |
2050 | buffer, length, ppos); |
2051 | } |
2052 | #endif /* CONFIG_NUMA */ |
2053 | |
2054 | int hugetlb_treat_movable_handler(struct ctl_table *table, int write, |
2055 | void __user *buffer, |
2056 | size_t *length, loff_t *ppos) |
2057 | { |
2058 | proc_dointvec(table, write, buffer, length, ppos); |
2059 | if (hugepages_treat_as_movable) |
2060 | htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; |
2061 | else |
2062 | htlb_alloc_mask = GFP_HIGHUSER; |
2063 | return 0; |
2064 | } |
2065 | |
2066 | int hugetlb_overcommit_handler(struct ctl_table *table, int write, |
2067 | void __user *buffer, |
2068 | size_t *length, loff_t *ppos) |
2069 | { |
2070 | struct hstate *h = &default_hstate; |
2071 | unsigned long tmp; |
2072 | int ret; |
2073 | |
2074 | tmp = h->nr_overcommit_huge_pages; |
2075 | |
2076 | if (write && h->order >= MAX_ORDER) |
2077 | return -EINVAL; |
2078 | |
2079 | table->data = &tmp; |
2080 | table->maxlen = sizeof(unsigned long); |
2081 | ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); |
2082 | if (ret) |
2083 | goto out; |
2084 | |
2085 | if (write) { |
2086 | spin_lock(&hugetlb_lock); |
2087 | h->nr_overcommit_huge_pages = tmp; |
2088 | spin_unlock(&hugetlb_lock); |
2089 | } |
2090 | out: |
2091 | return ret; |
2092 | } |
2093 | |
2094 | #endif /* CONFIG_SYSCTL */ |
2095 | |
2096 | void hugetlb_report_meminfo(struct seq_file *m) |
2097 | { |
2098 | struct hstate *h = &default_hstate; |
2099 | seq_printf(m, |
2100 | "HugePages_Total: %5lu\n" |
2101 | "HugePages_Free: %5lu\n" |
2102 | "HugePages_Rsvd: %5lu\n" |
2103 | "HugePages_Surp: %5lu\n" |
2104 | "Hugepagesize: %8lu kB\n", |
2105 | h->nr_huge_pages, |
2106 | h->free_huge_pages, |
2107 | h->resv_huge_pages, |
2108 | h->surplus_huge_pages, |
2109 | 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); |
2110 | } |
2111 | |
2112 | int hugetlb_report_node_meminfo(int nid, char *buf) |
2113 | { |
2114 | struct hstate *h = &default_hstate; |
2115 | return sprintf(buf, |
2116 | "Node %d HugePages_Total: %5u\n" |
2117 | "Node %d HugePages_Free: %5u\n" |
2118 | "Node %d HugePages_Surp: %5u\n", |
2119 | nid, h->nr_huge_pages_node[nid], |
2120 | nid, h->free_huge_pages_node[nid], |
2121 | nid, h->surplus_huge_pages_node[nid]); |
2122 | } |
2123 | |
2124 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
2125 | unsigned long hugetlb_total_pages(void) |
2126 | { |
2127 | struct hstate *h; |
2128 | unsigned long nr_total_pages = 0; |
2129 | |
2130 | for_each_hstate(h) |
2131 | nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h); |
2132 | return nr_total_pages; |
2133 | } |
2134 | |
2135 | static int hugetlb_acct_memory(struct hstate *h, long delta) |
2136 | { |
2137 | int ret = -ENOMEM; |
2138 | |
2139 | spin_lock(&hugetlb_lock); |
2140 | /* |
2141 | * When cpuset is configured, it breaks the strict hugetlb page |
2142 | * reservation as the accounting is done on a global variable. Such |
2143 | * reservation is completely rubbish in the presence of cpuset because |
2144 | * the reservation is not checked against page availability for the |
2145 | * current cpuset. Application can still potentially OOM'ed by kernel |
2146 | * with lack of free htlb page in cpuset that the task is in. |
2147 | * Attempt to enforce strict accounting with cpuset is almost |
2148 | * impossible (or too ugly) because cpuset is too fluid that |
2149 | * task or memory node can be dynamically moved between cpusets. |
2150 | * |
2151 | * The change of semantics for shared hugetlb mapping with cpuset is |
2152 | * undesirable. However, in order to preserve some of the semantics, |
2153 | * we fall back to check against current free page availability as |
2154 | * a best attempt and hopefully to minimize the impact of changing |
2155 | * semantics that cpuset has. |
2156 | */ |
2157 | if (delta > 0) { |
2158 | if (gather_surplus_pages(h, delta) < 0) |
2159 | goto out; |
2160 | |
2161 | if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { |
2162 | return_unused_surplus_pages(h, delta); |
2163 | goto out; |
2164 | } |
2165 | } |
2166 | |
2167 | ret = 0; |
2168 | if (delta < 0) |
2169 | return_unused_surplus_pages(h, (unsigned long) -delta); |
2170 | |
2171 | out: |
2172 | spin_unlock(&hugetlb_lock); |
2173 | return ret; |
2174 | } |
2175 | |
2176 | static void hugetlb_vm_op_open(struct vm_area_struct *vma) |
2177 | { |
2178 | struct resv_map *reservations = vma_resv_map(vma); |
2179 | |
2180 | /* |
2181 | * This new VMA should share its siblings reservation map if present. |
2182 | * The VMA will only ever have a valid reservation map pointer where |
2183 | * it is being copied for another still existing VMA. As that VMA |
2184 | * has a reference to the reservation map it cannot disappear until |
2185 | * after this open call completes. It is therefore safe to take a |
2186 | * new reference here without additional locking. |
2187 | */ |
2188 | if (reservations) |
2189 | kref_get(&reservations->refs); |
2190 | } |
2191 | |
2192 | static void resv_map_put(struct vm_area_struct *vma) |
2193 | { |
2194 | struct resv_map *reservations = vma_resv_map(vma); |
2195 | |
2196 | if (!reservations) |
2197 | return; |
2198 | kref_put(&reservations->refs, resv_map_release); |
2199 | } |
2200 | |
2201 | static void hugetlb_vm_op_close(struct vm_area_struct *vma) |
2202 | { |
2203 | struct hstate *h = hstate_vma(vma); |
2204 | struct resv_map *reservations = vma_resv_map(vma); |
2205 | struct hugepage_subpool *spool = subpool_vma(vma); |
2206 | unsigned long reserve; |
2207 | unsigned long start; |
2208 | unsigned long end; |
2209 | |
2210 | if (reservations) { |
2211 | start = vma_hugecache_offset(h, vma, vma->vm_start); |
2212 | end = vma_hugecache_offset(h, vma, vma->vm_end); |
2213 | |
2214 | reserve = (end - start) - |
2215 | region_count(&reservations->regions, start, end); |
2216 | |
2217 | resv_map_put(vma); |
2218 | |
2219 | if (reserve) { |
2220 | hugetlb_acct_memory(h, -reserve); |
2221 | hugepage_subpool_put_pages(spool, reserve); |
2222 | } |
2223 | } |
2224 | } |
2225 | |
2226 | /* |
2227 | * We cannot handle pagefaults against hugetlb pages at all. They cause |
2228 | * handle_mm_fault() to try to instantiate regular-sized pages in the |
2229 | * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get |
2230 | * this far. |
2231 | */ |
2232 | static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
2233 | { |
2234 | BUG(); |
2235 | return 0; |
2236 | } |
2237 | |
2238 | const struct vm_operations_struct hugetlb_vm_ops = { |
2239 | .fault = hugetlb_vm_op_fault, |
2240 | .open = hugetlb_vm_op_open, |
2241 | .close = hugetlb_vm_op_close, |
2242 | }; |
2243 | |
2244 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
2245 | int writable) |
2246 | { |
2247 | pte_t entry; |
2248 | |
2249 | if (writable) { |
2250 | entry = |
2251 | pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); |
2252 | } else { |
2253 | entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); |
2254 | } |
2255 | entry = pte_mkyoung(entry); |
2256 | entry = pte_mkhuge(entry); |
2257 | entry = arch_make_huge_pte(entry, vma, page, writable); |
2258 | |
2259 | return entry; |
2260 | } |
2261 | |
2262 | static void set_huge_ptep_writable(struct vm_area_struct *vma, |
2263 | unsigned long address, pte_t *ptep) |
2264 | { |
2265 | pte_t entry; |
2266 | |
2267 | entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); |
2268 | if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) |
2269 | update_mmu_cache(vma, address, ptep); |
2270 | } |
2271 | |
2272 | |
2273 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
2274 | struct vm_area_struct *vma) |
2275 | { |
2276 | pte_t *src_pte, *dst_pte, entry; |
2277 | struct page *ptepage; |
2278 | unsigned long addr; |
2279 | int cow; |
2280 | struct hstate *h = hstate_vma(vma); |
2281 | unsigned long sz = huge_page_size(h); |
2282 | |
2283 | cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; |
2284 | |
2285 | for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { |
2286 | src_pte = huge_pte_offset(src, addr); |
2287 | if (!src_pte) |
2288 | continue; |
2289 | dst_pte = huge_pte_alloc(dst, addr, sz); |
2290 | if (!dst_pte) |
2291 | goto nomem; |
2292 | |
2293 | /* If the pagetables are shared don't copy or take references */ |
2294 | if (dst_pte == src_pte) |
2295 | continue; |
2296 | |
2297 | spin_lock(&dst->page_table_lock); |
2298 | spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); |
2299 | if (!huge_pte_none(huge_ptep_get(src_pte))) { |
2300 | if (cow) |
2301 | huge_ptep_set_wrprotect(src, addr, src_pte); |
2302 | entry = huge_ptep_get(src_pte); |
2303 | ptepage = pte_page(entry); |
2304 | get_page(ptepage); |
2305 | page_dup_rmap(ptepage); |
2306 | set_huge_pte_at(dst, addr, dst_pte, entry); |
2307 | } |
2308 | spin_unlock(&src->page_table_lock); |
2309 | spin_unlock(&dst->page_table_lock); |
2310 | } |
2311 | return 0; |
2312 | |
2313 | nomem: |
2314 | return -ENOMEM; |
2315 | } |
2316 | |
2317 | static int is_hugetlb_entry_migration(pte_t pte) |
2318 | { |
2319 | swp_entry_t swp; |
2320 | |
2321 | if (huge_pte_none(pte) || pte_present(pte)) |
2322 | return 0; |
2323 | swp = pte_to_swp_entry(pte); |
2324 | if (non_swap_entry(swp) && is_migration_entry(swp)) |
2325 | return 1; |
2326 | else |
2327 | return 0; |
2328 | } |
2329 | |
2330 | static int is_hugetlb_entry_hwpoisoned(pte_t pte) |
2331 | { |
2332 | swp_entry_t swp; |
2333 | |
2334 | if (huge_pte_none(pte) || pte_present(pte)) |
2335 | return 0; |
2336 | swp = pte_to_swp_entry(pte); |
2337 | if (non_swap_entry(swp) && is_hwpoison_entry(swp)) |
2338 | return 1; |
2339 | else |
2340 | return 0; |
2341 | } |
2342 | |
2343 | void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, |
2344 | unsigned long start, unsigned long end, |
2345 | struct page *ref_page) |
2346 | { |
2347 | int force_flush = 0; |
2348 | struct mm_struct *mm = vma->vm_mm; |
2349 | unsigned long address; |
2350 | pte_t *ptep; |
2351 | pte_t pte; |
2352 | struct page *page; |
2353 | struct hstate *h = hstate_vma(vma); |
2354 | unsigned long sz = huge_page_size(h); |
2355 | const unsigned long mmun_start = start; /* For mmu_notifiers */ |
2356 | const unsigned long mmun_end = end; /* For mmu_notifiers */ |
2357 | |
2358 | WARN_ON(!is_vm_hugetlb_page(vma)); |
2359 | BUG_ON(start & ~huge_page_mask(h)); |
2360 | BUG_ON(end & ~huge_page_mask(h)); |
2361 | |
2362 | tlb_start_vma(tlb, vma); |
2363 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
2364 | again: |
2365 | spin_lock(&mm->page_table_lock); |
2366 | for (address = start; address < end; address += sz) { |
2367 | ptep = huge_pte_offset(mm, address); |
2368 | if (!ptep) |
2369 | continue; |
2370 | |
2371 | if (huge_pmd_unshare(mm, &address, ptep)) |
2372 | continue; |
2373 | |
2374 | pte = huge_ptep_get(ptep); |
2375 | if (huge_pte_none(pte)) |
2376 | continue; |
2377 | |
2378 | /* |
2379 | * HWPoisoned hugepage is already unmapped and dropped reference |
2380 | */ |
2381 | if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) { |
2382 | pte_clear(mm, address, ptep); |
2383 | continue; |
2384 | } |
2385 | |
2386 | page = pte_page(pte); |
2387 | /* |
2388 | * If a reference page is supplied, it is because a specific |
2389 | * page is being unmapped, not a range. Ensure the page we |
2390 | * are about to unmap is the actual page of interest. |
2391 | */ |
2392 | if (ref_page) { |
2393 | if (page != ref_page) |
2394 | continue; |
2395 | |
2396 | /* |
2397 | * Mark the VMA as having unmapped its page so that |
2398 | * future faults in this VMA will fail rather than |
2399 | * looking like data was lost |
2400 | */ |
2401 | set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); |
2402 | } |
2403 | |
2404 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
2405 | tlb_remove_tlb_entry(tlb, ptep, address); |
2406 | if (pte_dirty(pte)) |
2407 | set_page_dirty(page); |
2408 | |
2409 | page_remove_rmap(page); |
2410 | force_flush = !__tlb_remove_page(tlb, page); |
2411 | if (force_flush) |
2412 | break; |
2413 | /* Bail out after unmapping reference page if supplied */ |
2414 | if (ref_page) |
2415 | break; |
2416 | } |
2417 | spin_unlock(&mm->page_table_lock); |
2418 | /* |
2419 | * mmu_gather ran out of room to batch pages, we break out of |
2420 | * the PTE lock to avoid doing the potential expensive TLB invalidate |
2421 | * and page-free while holding it. |
2422 | */ |
2423 | if (force_flush) { |
2424 | force_flush = 0; |
2425 | tlb_flush_mmu(tlb); |
2426 | if (address < end && !ref_page) |
2427 | goto again; |
2428 | } |
2429 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
2430 | tlb_end_vma(tlb, vma); |
2431 | } |
2432 | |
2433 | void __unmap_hugepage_range_final(struct mmu_gather *tlb, |
2434 | struct vm_area_struct *vma, unsigned long start, |
2435 | unsigned long end, struct page *ref_page) |
2436 | { |
2437 | __unmap_hugepage_range(tlb, vma, start, end, ref_page); |
2438 | |
2439 | /* |
2440 | * Clear this flag so that x86's huge_pmd_share page_table_shareable |
2441 | * test will fail on a vma being torn down, and not grab a page table |
2442 | * on its way out. We're lucky that the flag has such an appropriate |
2443 | * name, and can in fact be safely cleared here. We could clear it |
2444 | * before the __unmap_hugepage_range above, but all that's necessary |
2445 | * is to clear it before releasing the i_mmap_mutex. This works |
2446 | * because in the context this is called, the VMA is about to be |
2447 | * destroyed and the i_mmap_mutex is held. |
2448 | */ |
2449 | vma->vm_flags &= ~VM_MAYSHARE; |
2450 | } |
2451 | |
2452 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
2453 | unsigned long end, struct page *ref_page) |
2454 | { |
2455 | struct mm_struct *mm; |
2456 | struct mmu_gather tlb; |
2457 | |
2458 | mm = vma->vm_mm; |
2459 | |
2460 | tlb_gather_mmu(&tlb, mm, 0); |
2461 | __unmap_hugepage_range(&tlb, vma, start, end, ref_page); |
2462 | tlb_finish_mmu(&tlb, start, end); |
2463 | } |
2464 | |
2465 | /* |
2466 | * This is called when the original mapper is failing to COW a MAP_PRIVATE |
2467 | * mappping it owns the reserve page for. The intention is to unmap the page |
2468 | * from other VMAs and let the children be SIGKILLed if they are faulting the |
2469 | * same region. |
2470 | */ |
2471 | static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, |
2472 | struct page *page, unsigned long address) |
2473 | { |
2474 | struct hstate *h = hstate_vma(vma); |
2475 | struct vm_area_struct *iter_vma; |
2476 | struct address_space *mapping; |
2477 | pgoff_t pgoff; |
2478 | |
2479 | /* |
2480 | * vm_pgoff is in PAGE_SIZE units, hence the different calculation |
2481 | * from page cache lookup which is in HPAGE_SIZE units. |
2482 | */ |
2483 | address = address & huge_page_mask(h); |
2484 | pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + |
2485 | vma->vm_pgoff; |
2486 | mapping = file_inode(vma->vm_file)->i_mapping; |
2487 | |
2488 | /* |
2489 | * Take the mapping lock for the duration of the table walk. As |
2490 | * this mapping should be shared between all the VMAs, |
2491 | * __unmap_hugepage_range() is called as the lock is already held |
2492 | */ |
2493 | mutex_lock(&mapping->i_mmap_mutex); |
2494 | vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) { |
2495 | /* Do not unmap the current VMA */ |
2496 | if (iter_vma == vma) |
2497 | continue; |
2498 | |
2499 | /* |
2500 | * Unmap the page from other VMAs without their own reserves. |
2501 | * They get marked to be SIGKILLed if they fault in these |
2502 | * areas. This is because a future no-page fault on this VMA |
2503 | * could insert a zeroed page instead of the data existing |
2504 | * from the time of fork. This would look like data corruption |
2505 | */ |
2506 | if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) |
2507 | unmap_hugepage_range(iter_vma, address, |
2508 | address + huge_page_size(h), page); |
2509 | } |
2510 | mutex_unlock(&mapping->i_mmap_mutex); |
2511 | |
2512 | return 1; |
2513 | } |
2514 | |
2515 | /* |
2516 | * Hugetlb_cow() should be called with page lock of the original hugepage held. |
2517 | * Called with hugetlb_instantiation_mutex held and pte_page locked so we |
2518 | * cannot race with other handlers or page migration. |
2519 | * Keep the pte_same checks anyway to make transition from the mutex easier. |
2520 | */ |
2521 | static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
2522 | unsigned long address, pte_t *ptep, pte_t pte, |
2523 | struct page *pagecache_page) |
2524 | { |
2525 | struct hstate *h = hstate_vma(vma); |
2526 | struct page *old_page, *new_page; |
2527 | int avoidcopy; |
2528 | int outside_reserve = 0; |
2529 | unsigned long mmun_start; /* For mmu_notifiers */ |
2530 | unsigned long mmun_end; /* For mmu_notifiers */ |
2531 | |
2532 | old_page = pte_page(pte); |
2533 | |
2534 | retry_avoidcopy: |
2535 | /* If no-one else is actually using this page, avoid the copy |
2536 | * and just make the page writable */ |
2537 | avoidcopy = (page_mapcount(old_page) == 1); |
2538 | if (avoidcopy) { |
2539 | if (PageAnon(old_page)) |
2540 | page_move_anon_rmap(old_page, vma, address); |
2541 | set_huge_ptep_writable(vma, address, ptep); |
2542 | return 0; |
2543 | } |
2544 | |
2545 | /* |
2546 | * If the process that created a MAP_PRIVATE mapping is about to |
2547 | * perform a COW due to a shared page count, attempt to satisfy |
2548 | * the allocation without using the existing reserves. The pagecache |
2549 | * page is used to determine if the reserve at this address was |
2550 | * consumed or not. If reserves were used, a partial faulted mapping |
2551 | * at the time of fork() could consume its reserves on COW instead |
2552 | * of the full address range. |
2553 | */ |
2554 | if (!(vma->vm_flags & VM_MAYSHARE) && |
2555 | is_vma_resv_set(vma, HPAGE_RESV_OWNER) && |
2556 | old_page != pagecache_page) |
2557 | outside_reserve = 1; |
2558 | |
2559 | page_cache_get(old_page); |
2560 | |
2561 | /* Drop page_table_lock as buddy allocator may be called */ |
2562 | spin_unlock(&mm->page_table_lock); |
2563 | new_page = alloc_huge_page(vma, address, outside_reserve); |
2564 | |
2565 | if (IS_ERR(new_page)) { |
2566 | long err = PTR_ERR(new_page); |
2567 | page_cache_release(old_page); |
2568 | |
2569 | /* |
2570 | * If a process owning a MAP_PRIVATE mapping fails to COW, |
2571 | * it is due to references held by a child and an insufficient |
2572 | * huge page pool. To guarantee the original mappers |
2573 | * reliability, unmap the page from child processes. The child |
2574 | * may get SIGKILLed if it later faults. |
2575 | */ |
2576 | if (outside_reserve) { |
2577 | BUG_ON(huge_pte_none(pte)); |
2578 | if (unmap_ref_private(mm, vma, old_page, address)) { |
2579 | BUG_ON(huge_pte_none(pte)); |
2580 | spin_lock(&mm->page_table_lock); |
2581 | ptep = huge_pte_offset(mm, address & huge_page_mask(h)); |
2582 | if (likely(pte_same(huge_ptep_get(ptep), pte))) |
2583 | goto retry_avoidcopy; |
2584 | /* |
2585 | * race occurs while re-acquiring page_table_lock, and |
2586 | * our job is done. |
2587 | */ |
2588 | return 0; |
2589 | } |
2590 | WARN_ON_ONCE(1); |
2591 | } |
2592 | |
2593 | /* Caller expects lock to be held */ |
2594 | spin_lock(&mm->page_table_lock); |
2595 | if (err == -ENOMEM) |
2596 | return VM_FAULT_OOM; |
2597 | else |
2598 | return VM_FAULT_SIGBUS; |
2599 | } |
2600 | |
2601 | /* |
2602 | * When the original hugepage is shared one, it does not have |
2603 | * anon_vma prepared. |
2604 | */ |
2605 | if (unlikely(anon_vma_prepare(vma))) { |
2606 | page_cache_release(new_page); |
2607 | page_cache_release(old_page); |
2608 | /* Caller expects lock to be held */ |
2609 | spin_lock(&mm->page_table_lock); |
2610 | return VM_FAULT_OOM; |
2611 | } |
2612 | |
2613 | copy_user_huge_page(new_page, old_page, address, vma, |
2614 | pages_per_huge_page(h)); |
2615 | __SetPageUptodate(new_page); |
2616 | |
2617 | mmun_start = address & huge_page_mask(h); |
2618 | mmun_end = mmun_start + huge_page_size(h); |
2619 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
2620 | /* |
2621 | * Retake the page_table_lock to check for racing updates |
2622 | * before the page tables are altered |
2623 | */ |
2624 | spin_lock(&mm->page_table_lock); |
2625 | ptep = huge_pte_offset(mm, address & huge_page_mask(h)); |
2626 | if (likely(pte_same(huge_ptep_get(ptep), pte))) { |
2627 | /* Break COW */ |
2628 | huge_ptep_clear_flush(vma, address, ptep); |
2629 | set_huge_pte_at(mm, address, ptep, |
2630 | make_huge_pte(vma, new_page, 1)); |
2631 | page_remove_rmap(old_page); |
2632 | hugepage_add_new_anon_rmap(new_page, vma, address); |
2633 | /* Make the old page be freed below */ |
2634 | new_page = old_page; |
2635 | } |
2636 | spin_unlock(&mm->page_table_lock); |
2637 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
2638 | /* Caller expects lock to be held */ |
2639 | spin_lock(&mm->page_table_lock); |
2640 | page_cache_release(new_page); |
2641 | page_cache_release(old_page); |
2642 | return 0; |
2643 | } |
2644 | |
2645 | /* Return the pagecache page at a given address within a VMA */ |
2646 | static struct page *hugetlbfs_pagecache_page(struct hstate *h, |
2647 | struct vm_area_struct *vma, unsigned long address) |
2648 | { |
2649 | struct address_space *mapping; |
2650 | pgoff_t idx; |
2651 | |
2652 | mapping = vma->vm_file->f_mapping; |
2653 | idx = vma_hugecache_offset(h, vma, address); |
2654 | |
2655 | return find_lock_page(mapping, idx); |
2656 | } |
2657 | |
2658 | /* |
2659 | * Return whether there is a pagecache page to back given address within VMA. |
2660 | * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. |
2661 | */ |
2662 | static bool hugetlbfs_pagecache_present(struct hstate *h, |
2663 | struct vm_area_struct *vma, unsigned long address) |
2664 | { |
2665 | struct address_space *mapping; |
2666 | pgoff_t idx; |
2667 | struct page *page; |
2668 | |
2669 | mapping = vma->vm_file->f_mapping; |
2670 | idx = vma_hugecache_offset(h, vma, address); |
2671 | |
2672 | page = find_get_page(mapping, idx); |
2673 | if (page) |
2674 | put_page(page); |
2675 | return page != NULL; |
2676 | } |
2677 | |
2678 | static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2679 | unsigned long address, pte_t *ptep, unsigned int flags) |
2680 | { |
2681 | struct hstate *h = hstate_vma(vma); |
2682 | int ret = VM_FAULT_SIGBUS; |
2683 | int anon_rmap = 0; |
2684 | pgoff_t idx; |
2685 | unsigned long size; |
2686 | struct page *page; |
2687 | struct address_space *mapping; |
2688 | pte_t new_pte; |
2689 | |
2690 | /* |
2691 | * Currently, we are forced to kill the process in the event the |
2692 | * original mapper has unmapped pages from the child due to a failed |
2693 | * COW. Warn that such a situation has occurred as it may not be obvious |
2694 | */ |
2695 | if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { |
2696 | pr_warning("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 | long 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, unsigned long *nr_pages, |
2930 | long i, unsigned int flags) |
2931 | { |
2932 | unsigned long pfn_offset; |
2933 | unsigned long vaddr = *position; |
2934 | unsigned long remainder = *nr_pages; |
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 | /* |
2965 | * We need call hugetlb_fault for both hugepages under migration |
2966 | * (in which case hugetlb_fault waits for the migration,) and |
2967 | * hwpoisoned hugepages (in which case we need to prevent the |
2968 | * caller from accessing to them.) In order to do this, we use |
2969 | * here is_swap_pte instead of is_hugetlb_entry_migration and |
2970 | * is_hugetlb_entry_hwpoisoned. This is because it simply covers |
2971 | * both cases, and because we can't follow correct pages |
2972 | * directly from any kind of swap entries. |
2973 | */ |
2974 | if (absent || is_swap_pte(huge_ptep_get(pte)) || |
2975 | ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) { |
2976 | int ret; |
2977 | |
2978 | spin_unlock(&mm->page_table_lock); |
2979 | ret = hugetlb_fault(mm, vma, vaddr, |
2980 | (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); |
2981 | spin_lock(&mm->page_table_lock); |
2982 | if (!(ret & VM_FAULT_ERROR)) |
2983 | continue; |
2984 | |
2985 | remainder = 0; |
2986 | break; |
2987 | } |
2988 | |
2989 | pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; |
2990 | page = pte_page(huge_ptep_get(pte)); |
2991 | same_page: |
2992 | if (pages) { |
2993 | pages[i] = mem_map_offset(page, pfn_offset); |
2994 | get_page(pages[i]); |
2995 | } |
2996 | |
2997 | if (vmas) |
2998 | vmas[i] = vma; |
2999 | |
3000 | vaddr += PAGE_SIZE; |
3001 | ++pfn_offset; |
3002 | --remainder; |
3003 | ++i; |
3004 | if (vaddr < vma->vm_end && remainder && |
3005 | pfn_offset < pages_per_huge_page(h)) { |
3006 | /* |
3007 | * We use pfn_offset to avoid touching the pageframes |
3008 | * of this compound page. |
3009 | */ |
3010 | goto same_page; |
3011 | } |
3012 | } |
3013 | spin_unlock(&mm->page_table_lock); |
3014 | *nr_pages = remainder; |
3015 | *position = vaddr; |
3016 | |
3017 | return i ? i : -EFAULT; |
3018 | } |
3019 | |
3020 | unsigned long hugetlb_change_protection(struct vm_area_struct *vma, |
3021 | unsigned long address, unsigned long end, pgprot_t newprot) |
3022 | { |
3023 | struct mm_struct *mm = vma->vm_mm; |
3024 | unsigned long start = address; |
3025 | pte_t *ptep; |
3026 | pte_t pte; |
3027 | struct hstate *h = hstate_vma(vma); |
3028 | unsigned long pages = 0; |
3029 | |
3030 | BUG_ON(address >= end); |
3031 | flush_cache_range(vma, address, end); |
3032 | |
3033 | mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); |
3034 | spin_lock(&mm->page_table_lock); |
3035 | for (; address < end; address += huge_page_size(h)) { |
3036 | ptep = huge_pte_offset(mm, address); |
3037 | if (!ptep) |
3038 | continue; |
3039 | if (huge_pmd_unshare(mm, &address, ptep)) { |
3040 | pages++; |
3041 | continue; |
3042 | } |
3043 | if (!huge_pte_none(huge_ptep_get(ptep))) { |
3044 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
3045 | pte = pte_mkhuge(pte_modify(pte, newprot)); |
3046 | pte = arch_make_huge_pte(pte, vma, NULL, 0); |
3047 | set_huge_pte_at(mm, address, ptep, pte); |
3048 | pages++; |
3049 | } |
3050 | } |
3051 | spin_unlock(&mm->page_table_lock); |
3052 | /* |
3053 | * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare |
3054 | * may have cleared our pud entry and done put_page on the page table: |
3055 | * once we release i_mmap_mutex, another task can do the final put_page |
3056 | * and that page table be reused and filled with junk. |
3057 | */ |
3058 | flush_tlb_range(vma, start, end); |
3059 | mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); |
3060 | |
3061 | return pages << h->order; |
3062 | } |
3063 | |
3064 | int hugetlb_reserve_pages(struct inode *inode, |
3065 | long from, long to, |
3066 | struct vm_area_struct *vma, |
3067 | vm_flags_t vm_flags) |
3068 | { |
3069 | long ret, chg; |
3070 | struct hstate *h = hstate_inode(inode); |
3071 | struct hugepage_subpool *spool = subpool_inode(inode); |
3072 | |
3073 | /* |
3074 | * Only apply hugepage reservation if asked. At fault time, an |
3075 | * attempt will be made for VM_NORESERVE to allocate a page |
3076 | * without using reserves |
3077 | */ |
3078 | if (vm_flags & VM_NORESERVE) |
3079 | return 0; |
3080 | |
3081 | /* |
3082 | * Shared mappings base their reservation on the number of pages that |
3083 | * are already allocated on behalf of the file. Private mappings need |
3084 | * to reserve the full area even if read-only as mprotect() may be |
3085 | * called to make the mapping read-write. Assume !vma is a shm mapping |
3086 | */ |
3087 | if (!vma || vma->vm_flags & VM_MAYSHARE) |
3088 | chg = region_chg(&inode->i_mapping->private_list, from, to); |
3089 | else { |
3090 | struct resv_map *resv_map = resv_map_alloc(); |
3091 | if (!resv_map) |
3092 | return -ENOMEM; |
3093 | |
3094 | chg = to - from; |
3095 | |
3096 | set_vma_resv_map(vma, resv_map); |
3097 | set_vma_resv_flags(vma, HPAGE_RESV_OWNER); |
3098 | } |
3099 | |
3100 | if (chg < 0) { |
3101 | ret = chg; |
3102 | goto out_err; |
3103 | } |
3104 | |
3105 | /* There must be enough pages in the subpool for the mapping */ |
3106 | if (hugepage_subpool_get_pages(spool, chg)) { |
3107 | ret = -ENOSPC; |
3108 | goto out_err; |
3109 | } |
3110 | |
3111 | /* |
3112 | * Check enough hugepages are available for the reservation. |
3113 | * Hand the pages back to the subpool if there are not |
3114 | */ |
3115 | ret = hugetlb_acct_memory(h, chg); |
3116 | if (ret < 0) { |
3117 | hugepage_subpool_put_pages(spool, chg); |
3118 | goto out_err; |
3119 | } |
3120 | |
3121 | /* |
3122 | * Account for the reservations made. Shared mappings record regions |
3123 | * that have reservations as they are shared by multiple VMAs. |
3124 | * When the last VMA disappears, the region map says how much |
3125 | * the reservation was and the page cache tells how much of |
3126 | * the reservation was consumed. Private mappings are per-VMA and |
3127 | * only the consumed reservations are tracked. When the VMA |
3128 | * disappears, the original reservation is the VMA size and the |
3129 | * consumed reservations are stored in the map. Hence, nothing |
3130 | * else has to be done for private mappings here |
3131 | */ |
3132 | if (!vma || vma->vm_flags & VM_MAYSHARE) |
3133 | region_add(&inode->i_mapping->private_list, from, to); |
3134 | return 0; |
3135 | out_err: |
3136 | if (vma) |
3137 | resv_map_put(vma); |
3138 | return ret; |
3139 | } |
3140 | |
3141 | void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) |
3142 | { |
3143 | struct hstate *h = hstate_inode(inode); |
3144 | long chg = region_truncate(&inode->i_mapping->private_list, offset); |
3145 | struct hugepage_subpool *spool = subpool_inode(inode); |
3146 | |
3147 | spin_lock(&inode->i_lock); |
3148 | inode->i_blocks -= (blocks_per_huge_page(h) * freed); |
3149 | spin_unlock(&inode->i_lock); |
3150 | |
3151 | hugepage_subpool_put_pages(spool, (chg - freed)); |
3152 | hugetlb_acct_memory(h, -(chg - freed)); |
3153 | } |
3154 | |
3155 | #ifdef CONFIG_MEMORY_FAILURE |
3156 | |
3157 | /* Should be called in hugetlb_lock */ |
3158 | static int is_hugepage_on_freelist(struct page *hpage) |
3159 | { |
3160 | struct page *page; |
3161 | struct page *tmp; |
3162 | struct hstate *h = page_hstate(hpage); |
3163 | int nid = page_to_nid(hpage); |
3164 | |
3165 | list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru) |
3166 | if (page == hpage) |
3167 | return 1; |
3168 | return 0; |
3169 | } |
3170 | |
3171 | /* |
3172 | * This function is called from memory failure code. |
3173 | * Assume the caller holds page lock of the head page. |
3174 | */ |
3175 | int dequeue_hwpoisoned_huge_page(struct page *hpage) |
3176 | { |
3177 | struct hstate *h = page_hstate(hpage); |
3178 | int nid = page_to_nid(hpage); |
3179 | int ret = -EBUSY; |
3180 | |
3181 | spin_lock(&hugetlb_lock); |
3182 | if (is_hugepage_on_freelist(hpage)) { |
3183 | /* |
3184 | * Hwpoisoned hugepage isn't linked to activelist or freelist, |
3185 | * but dangling hpage->lru can trigger list-debug warnings |
3186 | * (this happens when we call unpoison_memory() on it), |
3187 | * so let it point to itself with list_del_init(). |
3188 | */ |
3189 | list_del_init(&hpage->lru); |
3190 | set_page_refcounted(hpage); |
3191 | h->free_huge_pages--; |
3192 | h->free_huge_pages_node[nid]--; |
3193 | ret = 0; |
3194 | } |
3195 | spin_unlock(&hugetlb_lock); |
3196 | return ret; |
3197 | } |
3198 | #endif |
3199 |
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