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