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