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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/gfp.h> | |
6 | #include <linux/list.h> | |
7 | #include <linux/init.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/mm.h> | |
10 | #include <linux/sysctl.h> | |
11 | #include <linux/highmem.h> | |
12 | #include <linux/nodemask.h> | |
13 | #include <linux/pagemap.h> | |
14 | #include <linux/mempolicy.h> | |
15 | #include <linux/cpuset.h> | |
16 | #include <linux/mutex.h> | |
17 | #include <linux/bootmem.h> | |
18 | #include <linux/sysfs.h> | |
19 | ||
20 | #include <asm/page.h> | |
21 | #include <asm/pgtable.h> | |
22 | ||
23 | #include <linux/hugetlb.h> | |
24 | #include "internal.h" | |
25 | ||
26 | const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; | |
27 | static gfp_t htlb_alloc_mask = GFP_HIGHUSER; | |
28 | unsigned long hugepages_treat_as_movable; | |
29 | ||
30 | static int max_hstate; | |
31 | unsigned int default_hstate_idx; | |
32 | struct hstate hstates[HUGE_MAX_HSTATE]; | |
33 | ||
34 | __initdata LIST_HEAD(huge_boot_pages); | |
35 | ||
36 | /* for command line parsing */ | |
37 | static struct hstate * __initdata parsed_hstate; | |
38 | static unsigned long __initdata default_hstate_max_huge_pages; | |
39 | static unsigned long __initdata default_hstate_size; | |
40 | ||
41 | #define for_each_hstate(h) \ | |
42 | for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++) | |
43 | ||
44 | /* | |
45 | * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages | |
46 | */ | |
47 | static DEFINE_SPINLOCK(hugetlb_lock); | |
48 | ||
49 | /* | |
50 | * Region tracking -- allows tracking of reservations and instantiated pages | |
51 | * across the pages in a mapping. | |
52 | * | |
53 | * The region data structures are protected by a combination of the mmap_sem | |
54 | * and the hugetlb_instantion_mutex. To access or modify a region the caller | |
55 | * must either hold the mmap_sem for write, or the mmap_sem for read and | |
56 | * the hugetlb_instantiation mutex: | |
57 | * | |
58 | * down_write(&mm->mmap_sem); | |
59 | * or | |
60 | * down_read(&mm->mmap_sem); | |
61 | * mutex_lock(&hugetlb_instantiation_mutex); | |
62 | */ | |
63 | struct file_region { | |
64 | struct list_head link; | |
65 | long from; | |
66 | long to; | |
67 | }; | |
68 | ||
69 | static long region_add(struct list_head *head, long f, long t) | |
70 | { | |
71 | struct file_region *rg, *nrg, *trg; | |
72 | ||
73 | /* Locate the region we are either in or before. */ | |
74 | list_for_each_entry(rg, head, link) | |
75 | if (f <= rg->to) | |
76 | break; | |
77 | ||
78 | /* Round our left edge to the current segment if it encloses us. */ | |
79 | if (f > rg->from) | |
80 | f = rg->from; | |
81 | ||
82 | /* Check for and consume any regions we now overlap with. */ | |
83 | nrg = rg; | |
84 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { | |
85 | if (&rg->link == head) | |
86 | break; | |
87 | if (rg->from > t) | |
88 | break; | |
89 | ||
90 | /* If this area reaches higher then extend our area to | |
91 | * include it completely. If this is not the first area | |
92 | * which we intend to reuse, free it. */ | |
93 | if (rg->to > t) | |
94 | t = rg->to; | |
95 | if (rg != nrg) { | |
96 | list_del(&rg->link); | |
97 | kfree(rg); | |
98 | } | |
99 | } | |
100 | nrg->from = f; | |
101 | nrg->to = t; | |
102 | return 0; | |
103 | } | |
104 | ||
105 | static long region_chg(struct list_head *head, long f, long t) | |
106 | { | |
107 | struct file_region *rg, *nrg; | |
108 | long chg = 0; | |
109 | ||
110 | /* Locate the region we are before or in. */ | |
111 | list_for_each_entry(rg, head, link) | |
112 | if (f <= rg->to) | |
113 | break; | |
114 | ||
115 | /* If we are below the current region then a new region is required. | |
116 | * Subtle, allocate a new region at the position but make it zero | |
117 | * size such that we can guarantee to record the reservation. */ | |
118 | if (&rg->link == head || t < rg->from) { | |
119 | nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); | |
120 | if (!nrg) | |
121 | return -ENOMEM; | |
122 | nrg->from = f; | |
123 | nrg->to = f; | |
124 | INIT_LIST_HEAD(&nrg->link); | |
125 | list_add(&nrg->link, rg->link.prev); | |
126 | ||
127 | return t - f; | |
128 | } | |
129 | ||
130 | /* Round our left edge to the current segment if it encloses us. */ | |
131 | if (f > rg->from) | |
132 | f = rg->from; | |
133 | chg = t - f; | |
134 | ||
135 | /* Check for and consume any regions we now overlap with. */ | |
136 | list_for_each_entry(rg, rg->link.prev, link) { | |
137 | if (&rg->link == head) | |
138 | break; | |
139 | if (rg->from > t) | |
140 | return chg; | |
141 | ||
142 | /* We overlap with this area, if it extends futher than | |
143 | * us then we must extend ourselves. Account for its | |
144 | * existing reservation. */ | |
145 | if (rg->to > t) { | |
146 | chg += rg->to - t; | |
147 | t = rg->to; | |
148 | } | |
149 | chg -= rg->to - rg->from; | |
150 | } | |
151 | return chg; | |
152 | } | |
153 | ||
154 | static long region_truncate(struct list_head *head, long end) | |
155 | { | |
156 | struct file_region *rg, *trg; | |
157 | long chg = 0; | |
158 | ||
159 | /* Locate the region we are either in or before. */ | |
160 | list_for_each_entry(rg, head, link) | |
161 | if (end <= rg->to) | |
162 | break; | |
163 | if (&rg->link == head) | |
164 | return 0; | |
165 | ||
166 | /* If we are in the middle of a region then adjust it. */ | |
167 | if (end > rg->from) { | |
168 | chg = rg->to - end; | |
169 | rg->to = end; | |
170 | rg = list_entry(rg->link.next, typeof(*rg), link); | |
171 | } | |
172 | ||
173 | /* Drop any remaining regions. */ | |
174 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { | |
175 | if (&rg->link == head) | |
176 | break; | |
177 | chg += rg->to - rg->from; | |
178 | list_del(&rg->link); | |
179 | kfree(rg); | |
180 | } | |
181 | return chg; | |
182 | } | |
183 | ||
184 | static long region_count(struct list_head *head, long f, long t) | |
185 | { | |
186 | struct file_region *rg; | |
187 | long chg = 0; | |
188 | ||
189 | /* Locate each segment we overlap with, and count that overlap. */ | |
190 | list_for_each_entry(rg, head, link) { | |
191 | int seg_from; | |
192 | int seg_to; | |
193 | ||
194 | if (rg->to <= f) | |
195 | continue; | |
196 | if (rg->from >= t) | |
197 | break; | |
198 | ||
199 | seg_from = max(rg->from, f); | |
200 | seg_to = min(rg->to, t); | |
201 | ||
202 | chg += seg_to - seg_from; | |
203 | } | |
204 | ||
205 | return chg; | |
206 | } | |
207 | ||
208 | /* | |
209 | * Convert the address within this vma to the page offset within | |
210 | * the mapping, in pagecache page units; huge pages here. | |
211 | */ | |
212 | static pgoff_t vma_hugecache_offset(struct hstate *h, | |
213 | struct vm_area_struct *vma, unsigned long address) | |
214 | { | |
215 | return ((address - vma->vm_start) >> huge_page_shift(h)) + | |
216 | (vma->vm_pgoff >> huge_page_order(h)); | |
217 | } | |
218 | ||
219 | /* | |
220 | * Flags for MAP_PRIVATE reservations. These are stored in the bottom | |
221 | * bits of the reservation map pointer, which are always clear due to | |
222 | * alignment. | |
223 | */ | |
224 | #define HPAGE_RESV_OWNER (1UL << 0) | |
225 | #define HPAGE_RESV_UNMAPPED (1UL << 1) | |
226 | #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) | |
227 | ||
228 | /* | |
229 | * These helpers are used to track how many pages are reserved for | |
230 | * faults in a MAP_PRIVATE mapping. Only the process that called mmap() | |
231 | * is guaranteed to have their future faults succeed. | |
232 | * | |
233 | * With the exception of reset_vma_resv_huge_pages() which is called at fork(), | |
234 | * the reserve counters are updated with the hugetlb_lock held. It is safe | |
235 | * to reset the VMA at fork() time as it is not in use yet and there is no | |
236 | * chance of the global counters getting corrupted as a result of the values. | |
237 | * | |
238 | * The private mapping reservation is represented in a subtly different | |
239 | * manner to a shared mapping. A shared mapping has a region map associated | |
240 | * with the underlying file, this region map represents the backing file | |
241 | * pages which have ever had a reservation assigned which this persists even | |
242 | * after the page is instantiated. A private mapping has a region map | |
243 | * associated with the original mmap which is attached to all VMAs which | |
244 | * reference it, this region map represents those offsets which have consumed | |
245 | * reservation ie. where pages have been instantiated. | |
246 | */ | |
247 | static unsigned long get_vma_private_data(struct vm_area_struct *vma) | |
248 | { | |
249 | return (unsigned long)vma->vm_private_data; | |
250 | } | |
251 | ||
252 | static void set_vma_private_data(struct vm_area_struct *vma, | |
253 | unsigned long value) | |
254 | { | |
255 | vma->vm_private_data = (void *)value; | |
256 | } | |
257 | ||
258 | struct resv_map { | |
259 | struct kref refs; | |
260 | struct list_head regions; | |
261 | }; | |
262 | ||
263 | struct resv_map *resv_map_alloc(void) | |
264 | { | |
265 | struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); | |
266 | if (!resv_map) | |
267 | return NULL; | |
268 | ||
269 | kref_init(&resv_map->refs); | |
270 | INIT_LIST_HEAD(&resv_map->regions); | |
271 | ||
272 | return resv_map; | |
273 | } | |
274 | ||
275 | void resv_map_release(struct kref *ref) | |
276 | { | |
277 | struct resv_map *resv_map = container_of(ref, struct resv_map, refs); | |
278 | ||
279 | /* Clear out any active regions before we release the map. */ | |
280 | region_truncate(&resv_map->regions, 0); | |
281 | kfree(resv_map); | |
282 | } | |
283 | ||
284 | static struct resv_map *vma_resv_map(struct vm_area_struct *vma) | |
285 | { | |
286 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); | |
287 | if (!(vma->vm_flags & VM_SHARED)) | |
288 | return (struct resv_map *)(get_vma_private_data(vma) & | |
289 | ~HPAGE_RESV_MASK); | |
290 | return 0; | |
291 | } | |
292 | ||
293 | static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) | |
294 | { | |
295 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); | |
296 | VM_BUG_ON(vma->vm_flags & VM_SHARED); | |
297 | ||
298 | set_vma_private_data(vma, (get_vma_private_data(vma) & | |
299 | HPAGE_RESV_MASK) | (unsigned long)map); | |
300 | } | |
301 | ||
302 | static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) | |
303 | { | |
304 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); | |
305 | VM_BUG_ON(vma->vm_flags & VM_SHARED); | |
306 | ||
307 | set_vma_private_data(vma, get_vma_private_data(vma) | flags); | |
308 | } | |
309 | ||
310 | static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) | |
311 | { | |
312 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); | |
313 | ||
314 | return (get_vma_private_data(vma) & flag) != 0; | |
315 | } | |
316 | ||
317 | /* Decrement the reserved pages in the hugepage pool by one */ | |
318 | static void decrement_hugepage_resv_vma(struct hstate *h, | |
319 | struct vm_area_struct *vma) | |
320 | { | |
321 | if (vma->vm_flags & VM_NORESERVE) | |
322 | return; | |
323 | ||
324 | if (vma->vm_flags & VM_SHARED) { | |
325 | /* Shared mappings always use reserves */ | |
326 | h->resv_huge_pages--; | |
327 | } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { | |
328 | /* | |
329 | * Only the process that called mmap() has reserves for | |
330 | * private mappings. | |
331 | */ | |
332 | h->resv_huge_pages--; | |
333 | } | |
334 | } | |
335 | ||
336 | /* Reset counters to 0 and clear all HPAGE_RESV_* flags */ | |
337 | void reset_vma_resv_huge_pages(struct vm_area_struct *vma) | |
338 | { | |
339 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); | |
340 | if (!(vma->vm_flags & VM_SHARED)) | |
341 | vma->vm_private_data = (void *)0; | |
342 | } | |
343 | ||
344 | /* Returns true if the VMA has associated reserve pages */ | |
345 | static int vma_has_reserves(struct vm_area_struct *vma) | |
346 | { | |
347 | if (vma->vm_flags & VM_SHARED) | |
348 | return 1; | |
349 | if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) | |
350 | return 1; | |
351 | return 0; | |
352 | } | |
353 | ||
354 | static void clear_huge_page(struct page *page, | |
355 | unsigned long addr, unsigned long sz) | |
356 | { | |
357 | int i; | |
358 | ||
359 | might_sleep(); | |
360 | for (i = 0; i < sz/PAGE_SIZE; i++) { | |
361 | cond_resched(); | |
362 | clear_user_highpage(page + i, addr + i * PAGE_SIZE); | |
363 | } | |
364 | } | |
365 | ||
366 | static void copy_huge_page(struct page *dst, struct page *src, | |
367 | unsigned long addr, struct vm_area_struct *vma) | |
368 | { | |
369 | int i; | |
370 | struct hstate *h = hstate_vma(vma); | |
371 | ||
372 | might_sleep(); | |
373 | for (i = 0; i < pages_per_huge_page(h); i++) { | |
374 | cond_resched(); | |
375 | copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); | |
376 | } | |
377 | } | |
378 | ||
379 | static void enqueue_huge_page(struct hstate *h, struct page *page) | |
380 | { | |
381 | int nid = page_to_nid(page); | |
382 | list_add(&page->lru, &h->hugepage_freelists[nid]); | |
383 | h->free_huge_pages++; | |
384 | h->free_huge_pages_node[nid]++; | |
385 | } | |
386 | ||
387 | static struct page *dequeue_huge_page(struct hstate *h) | |
388 | { | |
389 | int nid; | |
390 | struct page *page = NULL; | |
391 | ||
392 | for (nid = 0; nid < MAX_NUMNODES; ++nid) { | |
393 | if (!list_empty(&h->hugepage_freelists[nid])) { | |
394 | page = list_entry(h->hugepage_freelists[nid].next, | |
395 | struct page, lru); | |
396 | list_del(&page->lru); | |
397 | h->free_huge_pages--; | |
398 | h->free_huge_pages_node[nid]--; | |
399 | break; | |
400 | } | |
401 | } | |
402 | return page; | |
403 | } | |
404 | ||
405 | static struct page *dequeue_huge_page_vma(struct hstate *h, | |
406 | struct vm_area_struct *vma, | |
407 | unsigned long address, int avoid_reserve) | |
408 | { | |
409 | int nid; | |
410 | struct page *page = NULL; | |
411 | struct mempolicy *mpol; | |
412 | nodemask_t *nodemask; | |
413 | struct zonelist *zonelist = huge_zonelist(vma, address, | |
414 | htlb_alloc_mask, &mpol, &nodemask); | |
415 | struct zone *zone; | |
416 | struct zoneref *z; | |
417 | ||
418 | /* | |
419 | * A child process with MAP_PRIVATE mappings created by their parent | |
420 | * have no page reserves. This check ensures that reservations are | |
421 | * not "stolen". The child may still get SIGKILLed | |
422 | */ | |
423 | if (!vma_has_reserves(vma) && | |
424 | h->free_huge_pages - h->resv_huge_pages == 0) | |
425 | return NULL; | |
426 | ||
427 | /* If reserves cannot be used, ensure enough pages are in the pool */ | |
428 | if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) | |
429 | return NULL; | |
430 | ||
431 | for_each_zone_zonelist_nodemask(zone, z, zonelist, | |
432 | MAX_NR_ZONES - 1, nodemask) { | |
433 | nid = zone_to_nid(zone); | |
434 | if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) && | |
435 | !list_empty(&h->hugepage_freelists[nid])) { | |
436 | page = list_entry(h->hugepage_freelists[nid].next, | |
437 | struct page, lru); | |
438 | list_del(&page->lru); | |
439 | h->free_huge_pages--; | |
440 | h->free_huge_pages_node[nid]--; | |
441 | ||
442 | if (!avoid_reserve) | |
443 | decrement_hugepage_resv_vma(h, vma); | |
444 | ||
445 | break; | |
446 | } | |
447 | } | |
448 | mpol_cond_put(mpol); | |
449 | return page; | |
450 | } | |
451 | ||
452 | static void update_and_free_page(struct hstate *h, struct page *page) | |
453 | { | |
454 | int i; | |
455 | ||
456 | h->nr_huge_pages--; | |
457 | h->nr_huge_pages_node[page_to_nid(page)]--; | |
458 | for (i = 0; i < pages_per_huge_page(h); i++) { | |
459 | page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | | |
460 | 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | | |
461 | 1 << PG_private | 1<< PG_writeback); | |
462 | } | |
463 | set_compound_page_dtor(page, NULL); | |
464 | set_page_refcounted(page); | |
465 | arch_release_hugepage(page); | |
466 | __free_pages(page, huge_page_order(h)); | |
467 | } | |
468 | ||
469 | struct hstate *size_to_hstate(unsigned long size) | |
470 | { | |
471 | struct hstate *h; | |
472 | ||
473 | for_each_hstate(h) { | |
474 | if (huge_page_size(h) == size) | |
475 | return h; | |
476 | } | |
477 | return NULL; | |
478 | } | |
479 | ||
480 | static void free_huge_page(struct page *page) | |
481 | { | |
482 | /* | |
483 | * Can't pass hstate in here because it is called from the | |
484 | * compound page destructor. | |
485 | */ | |
486 | struct hstate *h = page_hstate(page); | |
487 | int nid = page_to_nid(page); | |
488 | struct address_space *mapping; | |
489 | ||
490 | mapping = (struct address_space *) page_private(page); | |
491 | set_page_private(page, 0); | |
492 | BUG_ON(page_count(page)); | |
493 | INIT_LIST_HEAD(&page->lru); | |
494 | ||
495 | spin_lock(&hugetlb_lock); | |
496 | if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { | |
497 | update_and_free_page(h, page); | |
498 | h->surplus_huge_pages--; | |
499 | h->surplus_huge_pages_node[nid]--; | |
500 | } else { | |
501 | enqueue_huge_page(h, page); | |
502 | } | |
503 | spin_unlock(&hugetlb_lock); | |
504 | if (mapping) | |
505 | hugetlb_put_quota(mapping, 1); | |
506 | } | |
507 | ||
508 | /* | |
509 | * Increment or decrement surplus_huge_pages. Keep node-specific counters | |
510 | * balanced by operating on them in a round-robin fashion. | |
511 | * Returns 1 if an adjustment was made. | |
512 | */ | |
513 | static int adjust_pool_surplus(struct hstate *h, int delta) | |
514 | { | |
515 | static int prev_nid; | |
516 | int nid = prev_nid; | |
517 | int ret = 0; | |
518 | ||
519 | VM_BUG_ON(delta != -1 && delta != 1); | |
520 | do { | |
521 | nid = next_node(nid, node_online_map); | |
522 | if (nid == MAX_NUMNODES) | |
523 | nid = first_node(node_online_map); | |
524 | ||
525 | /* To shrink on this node, there must be a surplus page */ | |
526 | if (delta < 0 && !h->surplus_huge_pages_node[nid]) | |
527 | continue; | |
528 | /* Surplus cannot exceed the total number of pages */ | |
529 | if (delta > 0 && h->surplus_huge_pages_node[nid] >= | |
530 | h->nr_huge_pages_node[nid]) | |
531 | continue; | |
532 | ||
533 | h->surplus_huge_pages += delta; | |
534 | h->surplus_huge_pages_node[nid] += delta; | |
535 | ret = 1; | |
536 | break; | |
537 | } while (nid != prev_nid); | |
538 | ||
539 | prev_nid = nid; | |
540 | return ret; | |
541 | } | |
542 | ||
543 | static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) | |
544 | { | |
545 | set_compound_page_dtor(page, free_huge_page); | |
546 | spin_lock(&hugetlb_lock); | |
547 | h->nr_huge_pages++; | |
548 | h->nr_huge_pages_node[nid]++; | |
549 | spin_unlock(&hugetlb_lock); | |
550 | put_page(page); /* free it into the hugepage allocator */ | |
551 | } | |
552 | ||
553 | static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) | |
554 | { | |
555 | struct page *page; | |
556 | ||
557 | if (h->order >= MAX_ORDER) | |
558 | return NULL; | |
559 | ||
560 | page = alloc_pages_node(nid, | |
561 | htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| | |
562 | __GFP_REPEAT|__GFP_NOWARN, | |
563 | huge_page_order(h)); | |
564 | if (page) { | |
565 | if (arch_prepare_hugepage(page)) { | |
566 | __free_pages(page, HUGETLB_PAGE_ORDER); | |
567 | return NULL; | |
568 | } | |
569 | prep_new_huge_page(h, page, nid); | |
570 | } | |
571 | ||
572 | return page; | |
573 | } | |
574 | ||
575 | /* | |
576 | * Use a helper variable to find the next node and then | |
577 | * copy it back to hugetlb_next_nid afterwards: | |
578 | * otherwise there's a window in which a racer might | |
579 | * pass invalid nid MAX_NUMNODES to alloc_pages_node. | |
580 | * But we don't need to use a spin_lock here: it really | |
581 | * doesn't matter if occasionally a racer chooses the | |
582 | * same nid as we do. Move nid forward in the mask even | |
583 | * if we just successfully allocated a hugepage so that | |
584 | * the next caller gets hugepages on the next node. | |
585 | */ | |
586 | static int hstate_next_node(struct hstate *h) | |
587 | { | |
588 | int next_nid; | |
589 | next_nid = next_node(h->hugetlb_next_nid, node_online_map); | |
590 | if (next_nid == MAX_NUMNODES) | |
591 | next_nid = first_node(node_online_map); | |
592 | h->hugetlb_next_nid = next_nid; | |
593 | return next_nid; | |
594 | } | |
595 | ||
596 | static int alloc_fresh_huge_page(struct hstate *h) | |
597 | { | |
598 | struct page *page; | |
599 | int start_nid; | |
600 | int next_nid; | |
601 | int ret = 0; | |
602 | ||
603 | start_nid = h->hugetlb_next_nid; | |
604 | ||
605 | do { | |
606 | page = alloc_fresh_huge_page_node(h, h->hugetlb_next_nid); | |
607 | if (page) | |
608 | ret = 1; | |
609 | next_nid = hstate_next_node(h); | |
610 | } while (!page && h->hugetlb_next_nid != start_nid); | |
611 | ||
612 | if (ret) | |
613 | count_vm_event(HTLB_BUDDY_PGALLOC); | |
614 | else | |
615 | count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); | |
616 | ||
617 | return ret; | |
618 | } | |
619 | ||
620 | static struct page *alloc_buddy_huge_page(struct hstate *h, | |
621 | struct vm_area_struct *vma, unsigned long address) | |
622 | { | |
623 | struct page *page; | |
624 | unsigned int nid; | |
625 | ||
626 | if (h->order >= MAX_ORDER) | |
627 | return NULL; | |
628 | ||
629 | /* | |
630 | * Assume we will successfully allocate the surplus page to | |
631 | * prevent racing processes from causing the surplus to exceed | |
632 | * overcommit | |
633 | * | |
634 | * This however introduces a different race, where a process B | |
635 | * tries to grow the static hugepage pool while alloc_pages() is | |
636 | * called by process A. B will only examine the per-node | |
637 | * counters in determining if surplus huge pages can be | |
638 | * converted to normal huge pages in adjust_pool_surplus(). A | |
639 | * won't be able to increment the per-node counter, until the | |
640 | * lock is dropped by B, but B doesn't drop hugetlb_lock until | |
641 | * no more huge pages can be converted from surplus to normal | |
642 | * state (and doesn't try to convert again). Thus, we have a | |
643 | * case where a surplus huge page exists, the pool is grown, and | |
644 | * the surplus huge page still exists after, even though it | |
645 | * should just have been converted to a normal huge page. This | |
646 | * does not leak memory, though, as the hugepage will be freed | |
647 | * once it is out of use. It also does not allow the counters to | |
648 | * go out of whack in adjust_pool_surplus() as we don't modify | |
649 | * the node values until we've gotten the hugepage and only the | |
650 | * per-node value is checked there. | |
651 | */ | |
652 | spin_lock(&hugetlb_lock); | |
653 | if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { | |
654 | spin_unlock(&hugetlb_lock); | |
655 | return NULL; | |
656 | } else { | |
657 | h->nr_huge_pages++; | |
658 | h->surplus_huge_pages++; | |
659 | } | |
660 | spin_unlock(&hugetlb_lock); | |
661 | ||
662 | page = alloc_pages(htlb_alloc_mask|__GFP_COMP| | |
663 | __GFP_REPEAT|__GFP_NOWARN, | |
664 | huge_page_order(h)); | |
665 | ||
666 | spin_lock(&hugetlb_lock); | |
667 | if (page) { | |
668 | /* | |
669 | * This page is now managed by the hugetlb allocator and has | |
670 | * no users -- drop the buddy allocator's reference. | |
671 | */ | |
672 | put_page_testzero(page); | |
673 | VM_BUG_ON(page_count(page)); | |
674 | nid = page_to_nid(page); | |
675 | set_compound_page_dtor(page, free_huge_page); | |
676 | /* | |
677 | * We incremented the global counters already | |
678 | */ | |
679 | h->nr_huge_pages_node[nid]++; | |
680 | h->surplus_huge_pages_node[nid]++; | |
681 | __count_vm_event(HTLB_BUDDY_PGALLOC); | |
682 | } else { | |
683 | h->nr_huge_pages--; | |
684 | h->surplus_huge_pages--; | |
685 | __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); | |
686 | } | |
687 | spin_unlock(&hugetlb_lock); | |
688 | ||
689 | return page; | |
690 | } | |
691 | ||
692 | /* | |
693 | * Increase the hugetlb pool such that it can accomodate a reservation | |
694 | * of size 'delta'. | |
695 | */ | |
696 | static int gather_surplus_pages(struct hstate *h, int delta) | |
697 | { | |
698 | struct list_head surplus_list; | |
699 | struct page *page, *tmp; | |
700 | int ret, i; | |
701 | int needed, allocated; | |
702 | ||
703 | needed = (h->resv_huge_pages + delta) - h->free_huge_pages; | |
704 | if (needed <= 0) { | |
705 | h->resv_huge_pages += delta; | |
706 | return 0; | |
707 | } | |
708 | ||
709 | allocated = 0; | |
710 | INIT_LIST_HEAD(&surplus_list); | |
711 | ||
712 | ret = -ENOMEM; | |
713 | retry: | |
714 | spin_unlock(&hugetlb_lock); | |
715 | for (i = 0; i < needed; i++) { | |
716 | page = alloc_buddy_huge_page(h, NULL, 0); | |
717 | if (!page) { | |
718 | /* | |
719 | * We were not able to allocate enough pages to | |
720 | * satisfy the entire reservation so we free what | |
721 | * we've allocated so far. | |
722 | */ | |
723 | spin_lock(&hugetlb_lock); | |
724 | needed = 0; | |
725 | goto free; | |
726 | } | |
727 | ||
728 | list_add(&page->lru, &surplus_list); | |
729 | } | |
730 | allocated += needed; | |
731 | ||
732 | /* | |
733 | * After retaking hugetlb_lock, we need to recalculate 'needed' | |
734 | * because either resv_huge_pages or free_huge_pages may have changed. | |
735 | */ | |
736 | spin_lock(&hugetlb_lock); | |
737 | needed = (h->resv_huge_pages + delta) - | |
738 | (h->free_huge_pages + allocated); | |
739 | if (needed > 0) | |
740 | goto retry; | |
741 | ||
742 | /* | |
743 | * The surplus_list now contains _at_least_ the number of extra pages | |
744 | * needed to accomodate the reservation. Add the appropriate number | |
745 | * of pages to the hugetlb pool and free the extras back to the buddy | |
746 | * allocator. Commit the entire reservation here to prevent another | |
747 | * process from stealing the pages as they are added to the pool but | |
748 | * before they are reserved. | |
749 | */ | |
750 | needed += allocated; | |
751 | h->resv_huge_pages += delta; | |
752 | ret = 0; | |
753 | free: | |
754 | /* Free the needed pages to the hugetlb pool */ | |
755 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) { | |
756 | if ((--needed) < 0) | |
757 | break; | |
758 | list_del(&page->lru); | |
759 | enqueue_huge_page(h, page); | |
760 | } | |
761 | ||
762 | /* Free unnecessary surplus pages to the buddy allocator */ | |
763 | if (!list_empty(&surplus_list)) { | |
764 | spin_unlock(&hugetlb_lock); | |
765 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) { | |
766 | list_del(&page->lru); | |
767 | /* | |
768 | * The page has a reference count of zero already, so | |
769 | * call free_huge_page directly instead of using | |
770 | * put_page. This must be done with hugetlb_lock | |
771 | * unlocked which is safe because free_huge_page takes | |
772 | * hugetlb_lock before deciding how to free the page. | |
773 | */ | |
774 | free_huge_page(page); | |
775 | } | |
776 | spin_lock(&hugetlb_lock); | |
777 | } | |
778 | ||
779 | return ret; | |
780 | } | |
781 | ||
782 | /* | |
783 | * When releasing a hugetlb pool reservation, any surplus pages that were | |
784 | * allocated to satisfy the reservation must be explicitly freed if they were | |
785 | * never used. | |
786 | */ | |
787 | static void return_unused_surplus_pages(struct hstate *h, | |
788 | unsigned long unused_resv_pages) | |
789 | { | |
790 | static int nid = -1; | |
791 | struct page *page; | |
792 | unsigned long nr_pages; | |
793 | ||
794 | /* | |
795 | * We want to release as many surplus pages as possible, spread | |
796 | * evenly across all nodes. Iterate across all nodes until we | |
797 | * can no longer free unreserved surplus pages. This occurs when | |
798 | * the nodes with surplus pages have no free pages. | |
799 | */ | |
800 | unsigned long remaining_iterations = num_online_nodes(); | |
801 | ||
802 | /* Uncommit the reservation */ | |
803 | h->resv_huge_pages -= unused_resv_pages; | |
804 | ||
805 | /* Cannot return gigantic pages currently */ | |
806 | if (h->order >= MAX_ORDER) | |
807 | return; | |
808 | ||
809 | nr_pages = min(unused_resv_pages, h->surplus_huge_pages); | |
810 | ||
811 | while (remaining_iterations-- && nr_pages) { | |
812 | nid = next_node(nid, node_online_map); | |
813 | if (nid == MAX_NUMNODES) | |
814 | nid = first_node(node_online_map); | |
815 | ||
816 | if (!h->surplus_huge_pages_node[nid]) | |
817 | continue; | |
818 | ||
819 | if (!list_empty(&h->hugepage_freelists[nid])) { | |
820 | page = list_entry(h->hugepage_freelists[nid].next, | |
821 | struct page, lru); | |
822 | list_del(&page->lru); | |
823 | update_and_free_page(h, page); | |
824 | h->free_huge_pages--; | |
825 | h->free_huge_pages_node[nid]--; | |
826 | h->surplus_huge_pages--; | |
827 | h->surplus_huge_pages_node[nid]--; | |
828 | nr_pages--; | |
829 | remaining_iterations = num_online_nodes(); | |
830 | } | |
831 | } | |
832 | } | |
833 | ||
834 | /* | |
835 | * Determine if the huge page at addr within the vma has an associated | |
836 | * reservation. Where it does not we will need to logically increase | |
837 | * reservation and actually increase quota before an allocation can occur. | |
838 | * Where any new reservation would be required the reservation change is | |
839 | * prepared, but not committed. Once the page has been quota'd allocated | |
840 | * an instantiated the change should be committed via vma_commit_reservation. | |
841 | * No action is required on failure. | |
842 | */ | |
843 | static int vma_needs_reservation(struct hstate *h, | |
844 | struct vm_area_struct *vma, unsigned long addr) | |
845 | { | |
846 | struct address_space *mapping = vma->vm_file->f_mapping; | |
847 | struct inode *inode = mapping->host; | |
848 | ||
849 | if (vma->vm_flags & VM_SHARED) { | |
850 | pgoff_t idx = vma_hugecache_offset(h, vma, addr); | |
851 | return region_chg(&inode->i_mapping->private_list, | |
852 | idx, idx + 1); | |
853 | ||
854 | } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { | |
855 | return 1; | |
856 | ||
857 | } else { | |
858 | int err; | |
859 | pgoff_t idx = vma_hugecache_offset(h, vma, addr); | |
860 | struct resv_map *reservations = vma_resv_map(vma); | |
861 | ||
862 | err = region_chg(&reservations->regions, idx, idx + 1); | |
863 | if (err < 0) | |
864 | return err; | |
865 | return 0; | |
866 | } | |
867 | } | |
868 | static void vma_commit_reservation(struct hstate *h, | |
869 | struct vm_area_struct *vma, unsigned long addr) | |
870 | { | |
871 | struct address_space *mapping = vma->vm_file->f_mapping; | |
872 | struct inode *inode = mapping->host; | |
873 | ||
874 | if (vma->vm_flags & VM_SHARED) { | |
875 | pgoff_t idx = vma_hugecache_offset(h, vma, addr); | |
876 | region_add(&inode->i_mapping->private_list, idx, idx + 1); | |
877 | ||
878 | } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { | |
879 | pgoff_t idx = vma_hugecache_offset(h, vma, addr); | |
880 | struct resv_map *reservations = vma_resv_map(vma); | |
881 | ||
882 | /* Mark this page used in the map. */ | |
883 | region_add(&reservations->regions, idx, idx + 1); | |
884 | } | |
885 | } | |
886 | ||
887 | static struct page *alloc_huge_page(struct vm_area_struct *vma, | |
888 | unsigned long addr, int avoid_reserve) | |
889 | { | |
890 | struct hstate *h = hstate_vma(vma); | |
891 | struct page *page; | |
892 | struct address_space *mapping = vma->vm_file->f_mapping; | |
893 | struct inode *inode = mapping->host; | |
894 | unsigned int chg; | |
895 | ||
896 | /* | |
897 | * Processes that did not create the mapping will have no reserves and | |
898 | * will not have accounted against quota. Check that the quota can be | |
899 | * made before satisfying the allocation | |
900 | * MAP_NORESERVE mappings may also need pages and quota allocated | |
901 | * if no reserve mapping overlaps. | |
902 | */ | |
903 | chg = vma_needs_reservation(h, vma, addr); | |
904 | if (chg < 0) | |
905 | return ERR_PTR(chg); | |
906 | if (chg) | |
907 | if (hugetlb_get_quota(inode->i_mapping, chg)) | |
908 | return ERR_PTR(-ENOSPC); | |
909 | ||
910 | spin_lock(&hugetlb_lock); | |
911 | page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); | |
912 | spin_unlock(&hugetlb_lock); | |
913 | ||
914 | if (!page) { | |
915 | page = alloc_buddy_huge_page(h, vma, addr); | |
916 | if (!page) { | |
917 | hugetlb_put_quota(inode->i_mapping, chg); | |
918 | return ERR_PTR(-VM_FAULT_OOM); | |
919 | } | |
920 | } | |
921 | ||
922 | set_page_refcounted(page); | |
923 | set_page_private(page, (unsigned long) mapping); | |
924 | ||
925 | vma_commit_reservation(h, vma, addr); | |
926 | ||
927 | return page; | |
928 | } | |
929 | ||
930 | __attribute__((weak)) int alloc_bootmem_huge_page(struct hstate *h) | |
931 | { | |
932 | struct huge_bootmem_page *m; | |
933 | int nr_nodes = nodes_weight(node_online_map); | |
934 | ||
935 | while (nr_nodes) { | |
936 | void *addr; | |
937 | ||
938 | addr = __alloc_bootmem_node_nopanic( | |
939 | NODE_DATA(h->hugetlb_next_nid), | |
940 | huge_page_size(h), huge_page_size(h), 0); | |
941 | ||
942 | if (addr) { | |
943 | /* | |
944 | * Use the beginning of the huge page to store the | |
945 | * huge_bootmem_page struct (until gather_bootmem | |
946 | * puts them into the mem_map). | |
947 | */ | |
948 | m = addr; | |
949 | if (m) | |
950 | goto found; | |
951 | } | |
952 | hstate_next_node(h); | |
953 | nr_nodes--; | |
954 | } | |
955 | return 0; | |
956 | ||
957 | found: | |
958 | BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); | |
959 | /* Put them into a private list first because mem_map is not up yet */ | |
960 | list_add(&m->list, &huge_boot_pages); | |
961 | m->hstate = h; | |
962 | return 1; | |
963 | } | |
964 | ||
965 | /* Put bootmem huge pages into the standard lists after mem_map is up */ | |
966 | static void __init gather_bootmem_prealloc(void) | |
967 | { | |
968 | struct huge_bootmem_page *m; | |
969 | ||
970 | list_for_each_entry(m, &huge_boot_pages, list) { | |
971 | struct page *page = virt_to_page(m); | |
972 | struct hstate *h = m->hstate; | |
973 | __ClearPageReserved(page); | |
974 | WARN_ON(page_count(page) != 1); | |
975 | prep_compound_page(page, h->order); | |
976 | prep_new_huge_page(h, page, page_to_nid(page)); | |
977 | } | |
978 | } | |
979 | ||
980 | static void __init hugetlb_hstate_alloc_pages(struct hstate *h) | |
981 | { | |
982 | unsigned long i; | |
983 | ||
984 | for (i = 0; i < h->max_huge_pages; ++i) { | |
985 | if (h->order >= MAX_ORDER) { | |
986 | if (!alloc_bootmem_huge_page(h)) | |
987 | break; | |
988 | } else if (!alloc_fresh_huge_page(h)) | |
989 | break; | |
990 | } | |
991 | h->max_huge_pages = i; | |
992 | } | |
993 | ||
994 | static void __init hugetlb_init_hstates(void) | |
995 | { | |
996 | struct hstate *h; | |
997 | ||
998 | for_each_hstate(h) { | |
999 | /* oversize hugepages were init'ed in early boot */ | |
1000 | if (h->order < MAX_ORDER) | |
1001 | hugetlb_hstate_alloc_pages(h); | |
1002 | } | |
1003 | } | |
1004 | ||
1005 | static char * __init memfmt(char *buf, unsigned long n) | |
1006 | { | |
1007 | if (n >= (1UL << 30)) | |
1008 | sprintf(buf, "%lu GB", n >> 30); | |
1009 | else if (n >= (1UL << 20)) | |
1010 | sprintf(buf, "%lu MB", n >> 20); | |
1011 | else | |
1012 | sprintf(buf, "%lu KB", n >> 10); | |
1013 | return buf; | |
1014 | } | |
1015 | ||
1016 | static void __init report_hugepages(void) | |
1017 | { | |
1018 | struct hstate *h; | |
1019 | ||
1020 | for_each_hstate(h) { | |
1021 | char buf[32]; | |
1022 | printk(KERN_INFO "HugeTLB registered %s page size, " | |
1023 | "pre-allocated %ld pages\n", | |
1024 | memfmt(buf, huge_page_size(h)), | |
1025 | h->free_huge_pages); | |
1026 | } | |
1027 | } | |
1028 | ||
1029 | #ifdef CONFIG_HIGHMEM | |
1030 | static void try_to_free_low(struct hstate *h, unsigned long count) | |
1031 | { | |
1032 | int i; | |
1033 | ||
1034 | if (h->order >= MAX_ORDER) | |
1035 | return; | |
1036 | ||
1037 | for (i = 0; i < MAX_NUMNODES; ++i) { | |
1038 | struct page *page, *next; | |
1039 | struct list_head *freel = &h->hugepage_freelists[i]; | |
1040 | list_for_each_entry_safe(page, next, freel, lru) { | |
1041 | if (count >= h->nr_huge_pages) | |
1042 | return; | |
1043 | if (PageHighMem(page)) | |
1044 | continue; | |
1045 | list_del(&page->lru); | |
1046 | update_and_free_page(h, page); | |
1047 | h->free_huge_pages--; | |
1048 | h->free_huge_pages_node[page_to_nid(page)]--; | |
1049 | } | |
1050 | } | |
1051 | } | |
1052 | #else | |
1053 | static inline void try_to_free_low(struct hstate *h, unsigned long count) | |
1054 | { | |
1055 | } | |
1056 | #endif | |
1057 | ||
1058 | #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) | |
1059 | static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count) | |
1060 | { | |
1061 | unsigned long min_count, ret; | |
1062 | ||
1063 | if (h->order >= MAX_ORDER) | |
1064 | return h->max_huge_pages; | |
1065 | ||
1066 | /* | |
1067 | * Increase the pool size | |
1068 | * First take pages out of surplus state. Then make up the | |
1069 | * remaining difference by allocating fresh huge pages. | |
1070 | * | |
1071 | * We might race with alloc_buddy_huge_page() here and be unable | |
1072 | * to convert a surplus huge page to a normal huge page. That is | |
1073 | * not critical, though, it just means the overall size of the | |
1074 | * pool might be one hugepage larger than it needs to be, but | |
1075 | * within all the constraints specified by the sysctls. | |
1076 | */ | |
1077 | spin_lock(&hugetlb_lock); | |
1078 | while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { | |
1079 | if (!adjust_pool_surplus(h, -1)) | |
1080 | break; | |
1081 | } | |
1082 | ||
1083 | while (count > persistent_huge_pages(h)) { | |
1084 | /* | |
1085 | * If this allocation races such that we no longer need the | |
1086 | * page, free_huge_page will handle it by freeing the page | |
1087 | * and reducing the surplus. | |
1088 | */ | |
1089 | spin_unlock(&hugetlb_lock); | |
1090 | ret = alloc_fresh_huge_page(h); | |
1091 | spin_lock(&hugetlb_lock); | |
1092 | if (!ret) | |
1093 | goto out; | |
1094 | ||
1095 | } | |
1096 | ||
1097 | /* | |
1098 | * Decrease the pool size | |
1099 | * First return free pages to the buddy allocator (being careful | |
1100 | * to keep enough around to satisfy reservations). Then place | |
1101 | * pages into surplus state as needed so the pool will shrink | |
1102 | * to the desired size as pages become free. | |
1103 | * | |
1104 | * By placing pages into the surplus state independent of the | |
1105 | * overcommit value, we are allowing the surplus pool size to | |
1106 | * exceed overcommit. There are few sane options here. Since | |
1107 | * alloc_buddy_huge_page() is checking the global counter, | |
1108 | * though, we'll note that we're not allowed to exceed surplus | |
1109 | * and won't grow the pool anywhere else. Not until one of the | |
1110 | * sysctls are changed, or the surplus pages go out of use. | |
1111 | */ | |
1112 | min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; | |
1113 | min_count = max(count, min_count); | |
1114 | try_to_free_low(h, min_count); | |
1115 | while (min_count < persistent_huge_pages(h)) { | |
1116 | struct page *page = dequeue_huge_page(h); | |
1117 | if (!page) | |
1118 | break; | |
1119 | update_and_free_page(h, page); | |
1120 | } | |
1121 | while (count < persistent_huge_pages(h)) { | |
1122 | if (!adjust_pool_surplus(h, 1)) | |
1123 | break; | |
1124 | } | |
1125 | out: | |
1126 | ret = persistent_huge_pages(h); | |
1127 | spin_unlock(&hugetlb_lock); | |
1128 | return ret; | |
1129 | } | |
1130 | ||
1131 | #define HSTATE_ATTR_RO(_name) \ | |
1132 | static struct kobj_attribute _name##_attr = __ATTR_RO(_name) | |
1133 | ||
1134 | #define HSTATE_ATTR(_name) \ | |
1135 | static struct kobj_attribute _name##_attr = \ | |
1136 | __ATTR(_name, 0644, _name##_show, _name##_store) | |
1137 | ||
1138 | static struct kobject *hugepages_kobj; | |
1139 | static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; | |
1140 | ||
1141 | static struct hstate *kobj_to_hstate(struct kobject *kobj) | |
1142 | { | |
1143 | int i; | |
1144 | for (i = 0; i < HUGE_MAX_HSTATE; i++) | |
1145 | if (hstate_kobjs[i] == kobj) | |
1146 | return &hstates[i]; | |
1147 | BUG(); | |
1148 | return NULL; | |
1149 | } | |
1150 | ||
1151 | static ssize_t nr_hugepages_show(struct kobject *kobj, | |
1152 | struct kobj_attribute *attr, char *buf) | |
1153 | { | |
1154 | struct hstate *h = kobj_to_hstate(kobj); | |
1155 | return sprintf(buf, "%lu\n", h->nr_huge_pages); | |
1156 | } | |
1157 | static ssize_t nr_hugepages_store(struct kobject *kobj, | |
1158 | struct kobj_attribute *attr, const char *buf, size_t count) | |
1159 | { | |
1160 | int err; | |
1161 | unsigned long input; | |
1162 | struct hstate *h = kobj_to_hstate(kobj); | |
1163 | ||
1164 | err = strict_strtoul(buf, 10, &input); | |
1165 | if (err) | |
1166 | return 0; | |
1167 | ||
1168 | h->max_huge_pages = set_max_huge_pages(h, input); | |
1169 | ||
1170 | return count; | |
1171 | } | |
1172 | HSTATE_ATTR(nr_hugepages); | |
1173 | ||
1174 | static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, | |
1175 | struct kobj_attribute *attr, char *buf) | |
1176 | { | |
1177 | struct hstate *h = kobj_to_hstate(kobj); | |
1178 | return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); | |
1179 | } | |
1180 | static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, | |
1181 | struct kobj_attribute *attr, const char *buf, size_t count) | |
1182 | { | |
1183 | int err; | |
1184 | unsigned long input; | |
1185 | struct hstate *h = kobj_to_hstate(kobj); | |
1186 | ||
1187 | err = strict_strtoul(buf, 10, &input); | |
1188 | if (err) | |
1189 | return 0; | |
1190 | ||
1191 | spin_lock(&hugetlb_lock); | |
1192 | h->nr_overcommit_huge_pages = input; | |
1193 | spin_unlock(&hugetlb_lock); | |
1194 | ||
1195 | return count; | |
1196 | } | |
1197 | HSTATE_ATTR(nr_overcommit_hugepages); | |
1198 | ||
1199 | static ssize_t free_hugepages_show(struct kobject *kobj, | |
1200 | struct kobj_attribute *attr, char *buf) | |
1201 | { | |
1202 | struct hstate *h = kobj_to_hstate(kobj); | |
1203 | return sprintf(buf, "%lu\n", h->free_huge_pages); | |
1204 | } | |
1205 | HSTATE_ATTR_RO(free_hugepages); | |
1206 | ||
1207 | static ssize_t resv_hugepages_show(struct kobject *kobj, | |
1208 | struct kobj_attribute *attr, char *buf) | |
1209 | { | |
1210 | struct hstate *h = kobj_to_hstate(kobj); | |
1211 | return sprintf(buf, "%lu\n", h->resv_huge_pages); | |
1212 | } | |
1213 | HSTATE_ATTR_RO(resv_hugepages); | |
1214 | ||
1215 | static ssize_t surplus_hugepages_show(struct kobject *kobj, | |
1216 | struct kobj_attribute *attr, char *buf) | |
1217 | { | |
1218 | struct hstate *h = kobj_to_hstate(kobj); | |
1219 | return sprintf(buf, "%lu\n", h->surplus_huge_pages); | |
1220 | } | |
1221 | HSTATE_ATTR_RO(surplus_hugepages); | |
1222 | ||
1223 | static struct attribute *hstate_attrs[] = { | |
1224 | &nr_hugepages_attr.attr, | |
1225 | &nr_overcommit_hugepages_attr.attr, | |
1226 | &free_hugepages_attr.attr, | |
1227 | &resv_hugepages_attr.attr, | |
1228 | &surplus_hugepages_attr.attr, | |
1229 | NULL, | |
1230 | }; | |
1231 | ||
1232 | static struct attribute_group hstate_attr_group = { | |
1233 | .attrs = hstate_attrs, | |
1234 | }; | |
1235 | ||
1236 | static int __init hugetlb_sysfs_add_hstate(struct hstate *h) | |
1237 | { | |
1238 | int retval; | |
1239 | ||
1240 | hstate_kobjs[h - hstates] = kobject_create_and_add(h->name, | |
1241 | hugepages_kobj); | |
1242 | if (!hstate_kobjs[h - hstates]) | |
1243 | return -ENOMEM; | |
1244 | ||
1245 | retval = sysfs_create_group(hstate_kobjs[h - hstates], | |
1246 | &hstate_attr_group); | |
1247 | if (retval) | |
1248 | kobject_put(hstate_kobjs[h - hstates]); | |
1249 | ||
1250 | return retval; | |
1251 | } | |
1252 | ||
1253 | static void __init hugetlb_sysfs_init(void) | |
1254 | { | |
1255 | struct hstate *h; | |
1256 | int err; | |
1257 | ||
1258 | hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); | |
1259 | if (!hugepages_kobj) | |
1260 | return; | |
1261 | ||
1262 | for_each_hstate(h) { | |
1263 | err = hugetlb_sysfs_add_hstate(h); | |
1264 | if (err) | |
1265 | printk(KERN_ERR "Hugetlb: Unable to add hstate %s", | |
1266 | h->name); | |
1267 | } | |
1268 | } | |
1269 | ||
1270 | static void __exit hugetlb_exit(void) | |
1271 | { | |
1272 | struct hstate *h; | |
1273 | ||
1274 | for_each_hstate(h) { | |
1275 | kobject_put(hstate_kobjs[h - hstates]); | |
1276 | } | |
1277 | ||
1278 | kobject_put(hugepages_kobj); | |
1279 | } | |
1280 | module_exit(hugetlb_exit); | |
1281 | ||
1282 | static int __init hugetlb_init(void) | |
1283 | { | |
1284 | BUILD_BUG_ON(HPAGE_SHIFT == 0); | |
1285 | ||
1286 | if (!size_to_hstate(default_hstate_size)) { | |
1287 | default_hstate_size = HPAGE_SIZE; | |
1288 | if (!size_to_hstate(default_hstate_size)) | |
1289 | hugetlb_add_hstate(HUGETLB_PAGE_ORDER); | |
1290 | } | |
1291 | default_hstate_idx = size_to_hstate(default_hstate_size) - hstates; | |
1292 | if (default_hstate_max_huge_pages) | |
1293 | default_hstate.max_huge_pages = default_hstate_max_huge_pages; | |
1294 | ||
1295 | hugetlb_init_hstates(); | |
1296 | ||
1297 | gather_bootmem_prealloc(); | |
1298 | ||
1299 | report_hugepages(); | |
1300 | ||
1301 | hugetlb_sysfs_init(); | |
1302 | ||
1303 | return 0; | |
1304 | } | |
1305 | module_init(hugetlb_init); | |
1306 | ||
1307 | /* Should be called on processing a hugepagesz=... option */ | |
1308 | void __init hugetlb_add_hstate(unsigned order) | |
1309 | { | |
1310 | struct hstate *h; | |
1311 | unsigned long i; | |
1312 | ||
1313 | if (size_to_hstate(PAGE_SIZE << order)) { | |
1314 | printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n"); | |
1315 | return; | |
1316 | } | |
1317 | BUG_ON(max_hstate >= HUGE_MAX_HSTATE); | |
1318 | BUG_ON(order == 0); | |
1319 | h = &hstates[max_hstate++]; | |
1320 | h->order = order; | |
1321 | h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); | |
1322 | h->nr_huge_pages = 0; | |
1323 | h->free_huge_pages = 0; | |
1324 | for (i = 0; i < MAX_NUMNODES; ++i) | |
1325 | INIT_LIST_HEAD(&h->hugepage_freelists[i]); | |
1326 | h->hugetlb_next_nid = first_node(node_online_map); | |
1327 | snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", | |
1328 | huge_page_size(h)/1024); | |
1329 | ||
1330 | parsed_hstate = h; | |
1331 | } | |
1332 | ||
1333 | static int __init hugetlb_nrpages_setup(char *s) | |
1334 | { | |
1335 | unsigned long *mhp; | |
1336 | static unsigned long *last_mhp; | |
1337 | ||
1338 | /* | |
1339 | * !max_hstate means we haven't parsed a hugepagesz= parameter yet, | |
1340 | * so this hugepages= parameter goes to the "default hstate". | |
1341 | */ | |
1342 | if (!max_hstate) | |
1343 | mhp = &default_hstate_max_huge_pages; | |
1344 | else | |
1345 | mhp = &parsed_hstate->max_huge_pages; | |
1346 | ||
1347 | if (mhp == last_mhp) { | |
1348 | printk(KERN_WARNING "hugepages= specified twice without " | |
1349 | "interleaving hugepagesz=, ignoring\n"); | |
1350 | return 1; | |
1351 | } | |
1352 | ||
1353 | if (sscanf(s, "%lu", mhp) <= 0) | |
1354 | *mhp = 0; | |
1355 | ||
1356 | /* | |
1357 | * Global state is always initialized later in hugetlb_init. | |
1358 | * But we need to allocate >= MAX_ORDER hstates here early to still | |
1359 | * use the bootmem allocator. | |
1360 | */ | |
1361 | if (max_hstate && parsed_hstate->order >= MAX_ORDER) | |
1362 | hugetlb_hstate_alloc_pages(parsed_hstate); | |
1363 | ||
1364 | last_mhp = mhp; | |
1365 | ||
1366 | return 1; | |
1367 | } | |
1368 | __setup("hugepages=", hugetlb_nrpages_setup); | |
1369 | ||
1370 | static int __init hugetlb_default_setup(char *s) | |
1371 | { | |
1372 | default_hstate_size = memparse(s, &s); | |
1373 | return 1; | |
1374 | } | |
1375 | __setup("default_hugepagesz=", hugetlb_default_setup); | |
1376 | ||
1377 | static unsigned int cpuset_mems_nr(unsigned int *array) | |
1378 | { | |
1379 | int node; | |
1380 | unsigned int nr = 0; | |
1381 | ||
1382 | for_each_node_mask(node, cpuset_current_mems_allowed) | |
1383 | nr += array[node]; | |
1384 | ||
1385 | return nr; | |
1386 | } | |
1387 | ||
1388 | #ifdef CONFIG_SYSCTL | |
1389 | int hugetlb_sysctl_handler(struct ctl_table *table, int write, | |
1390 | struct file *file, void __user *buffer, | |
1391 | size_t *length, loff_t *ppos) | |
1392 | { | |
1393 | struct hstate *h = &default_hstate; | |
1394 | unsigned long tmp; | |
1395 | ||
1396 | if (!write) | |
1397 | tmp = h->max_huge_pages; | |
1398 | ||
1399 | table->data = &tmp; | |
1400 | table->maxlen = sizeof(unsigned long); | |
1401 | proc_doulongvec_minmax(table, write, file, buffer, length, ppos); | |
1402 | ||
1403 | if (write) | |
1404 | h->max_huge_pages = set_max_huge_pages(h, tmp); | |
1405 | ||
1406 | return 0; | |
1407 | } | |
1408 | ||
1409 | int hugetlb_treat_movable_handler(struct ctl_table *table, int write, | |
1410 | struct file *file, void __user *buffer, | |
1411 | size_t *length, loff_t *ppos) | |
1412 | { | |
1413 | proc_dointvec(table, write, file, buffer, length, ppos); | |
1414 | if (hugepages_treat_as_movable) | |
1415 | htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; | |
1416 | else | |
1417 | htlb_alloc_mask = GFP_HIGHUSER; | |
1418 | return 0; | |
1419 | } | |
1420 | ||
1421 | int hugetlb_overcommit_handler(struct ctl_table *table, int write, | |
1422 | struct file *file, void __user *buffer, | |
1423 | size_t *length, loff_t *ppos) | |
1424 | { | |
1425 | struct hstate *h = &default_hstate; | |
1426 | unsigned long tmp; | |
1427 | ||
1428 | if (!write) | |
1429 | tmp = h->nr_overcommit_huge_pages; | |
1430 | ||
1431 | table->data = &tmp; | |
1432 | table->maxlen = sizeof(unsigned long); | |
1433 | proc_doulongvec_minmax(table, write, file, buffer, length, ppos); | |
1434 | ||
1435 | if (write) { | |
1436 | spin_lock(&hugetlb_lock); | |
1437 | h->nr_overcommit_huge_pages = tmp; | |
1438 | spin_unlock(&hugetlb_lock); | |
1439 | } | |
1440 | ||
1441 | return 0; | |
1442 | } | |
1443 | ||
1444 | #endif /* CONFIG_SYSCTL */ | |
1445 | ||
1446 | int hugetlb_report_meminfo(char *buf) | |
1447 | { | |
1448 | struct hstate *h = &default_hstate; | |
1449 | return sprintf(buf, | |
1450 | "HugePages_Total: %5lu\n" | |
1451 | "HugePages_Free: %5lu\n" | |
1452 | "HugePages_Rsvd: %5lu\n" | |
1453 | "HugePages_Surp: %5lu\n" | |
1454 | "Hugepagesize: %5lu kB\n", | |
1455 | h->nr_huge_pages, | |
1456 | h->free_huge_pages, | |
1457 | h->resv_huge_pages, | |
1458 | h->surplus_huge_pages, | |
1459 | 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); | |
1460 | } | |
1461 | ||
1462 | int hugetlb_report_node_meminfo(int nid, char *buf) | |
1463 | { | |
1464 | struct hstate *h = &default_hstate; | |
1465 | return sprintf(buf, | |
1466 | "Node %d HugePages_Total: %5u\n" | |
1467 | "Node %d HugePages_Free: %5u\n" | |
1468 | "Node %d HugePages_Surp: %5u\n", | |
1469 | nid, h->nr_huge_pages_node[nid], | |
1470 | nid, h->free_huge_pages_node[nid], | |
1471 | nid, h->surplus_huge_pages_node[nid]); | |
1472 | } | |
1473 | ||
1474 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ | |
1475 | unsigned long hugetlb_total_pages(void) | |
1476 | { | |
1477 | struct hstate *h = &default_hstate; | |
1478 | return h->nr_huge_pages * pages_per_huge_page(h); | |
1479 | } | |
1480 | ||
1481 | static int hugetlb_acct_memory(struct hstate *h, long delta) | |
1482 | { | |
1483 | int ret = -ENOMEM; | |
1484 | ||
1485 | spin_lock(&hugetlb_lock); | |
1486 | /* | |
1487 | * When cpuset is configured, it breaks the strict hugetlb page | |
1488 | * reservation as the accounting is done on a global variable. Such | |
1489 | * reservation is completely rubbish in the presence of cpuset because | |
1490 | * the reservation is not checked against page availability for the | |
1491 | * current cpuset. Application can still potentially OOM'ed by kernel | |
1492 | * with lack of free htlb page in cpuset that the task is in. | |
1493 | * Attempt to enforce strict accounting with cpuset is almost | |
1494 | * impossible (or too ugly) because cpuset is too fluid that | |
1495 | * task or memory node can be dynamically moved between cpusets. | |
1496 | * | |
1497 | * The change of semantics for shared hugetlb mapping with cpuset is | |
1498 | * undesirable. However, in order to preserve some of the semantics, | |
1499 | * we fall back to check against current free page availability as | |
1500 | * a best attempt and hopefully to minimize the impact of changing | |
1501 | * semantics that cpuset has. | |
1502 | */ | |
1503 | if (delta > 0) { | |
1504 | if (gather_surplus_pages(h, delta) < 0) | |
1505 | goto out; | |
1506 | ||
1507 | if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { | |
1508 | return_unused_surplus_pages(h, delta); | |
1509 | goto out; | |
1510 | } | |
1511 | } | |
1512 | ||
1513 | ret = 0; | |
1514 | if (delta < 0) | |
1515 | return_unused_surplus_pages(h, (unsigned long) -delta); | |
1516 | ||
1517 | out: | |
1518 | spin_unlock(&hugetlb_lock); | |
1519 | return ret; | |
1520 | } | |
1521 | ||
1522 | static void hugetlb_vm_op_open(struct vm_area_struct *vma) | |
1523 | { | |
1524 | struct resv_map *reservations = vma_resv_map(vma); | |
1525 | ||
1526 | /* | |
1527 | * This new VMA should share its siblings reservation map if present. | |
1528 | * The VMA will only ever have a valid reservation map pointer where | |
1529 | * it is being copied for another still existing VMA. As that VMA | |
1530 | * has a reference to the reservation map it cannot dissappear until | |
1531 | * after this open call completes. It is therefore safe to take a | |
1532 | * new reference here without additional locking. | |
1533 | */ | |
1534 | if (reservations) | |
1535 | kref_get(&reservations->refs); | |
1536 | } | |
1537 | ||
1538 | static void hugetlb_vm_op_close(struct vm_area_struct *vma) | |
1539 | { | |
1540 | struct hstate *h = hstate_vma(vma); | |
1541 | struct resv_map *reservations = vma_resv_map(vma); | |
1542 | unsigned long reserve; | |
1543 | unsigned long start; | |
1544 | unsigned long end; | |
1545 | ||
1546 | if (reservations) { | |
1547 | start = vma_hugecache_offset(h, vma, vma->vm_start); | |
1548 | end = vma_hugecache_offset(h, vma, vma->vm_end); | |
1549 | ||
1550 | reserve = (end - start) - | |
1551 | region_count(&reservations->regions, start, end); | |
1552 | ||
1553 | kref_put(&reservations->refs, resv_map_release); | |
1554 | ||
1555 | if (reserve) { | |
1556 | hugetlb_acct_memory(h, -reserve); | |
1557 | hugetlb_put_quota(vma->vm_file->f_mapping, reserve); | |
1558 | } | |
1559 | } | |
1560 | } | |
1561 | ||
1562 | /* | |
1563 | * We cannot handle pagefaults against hugetlb pages at all. They cause | |
1564 | * handle_mm_fault() to try to instantiate regular-sized pages in the | |
1565 | * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get | |
1566 | * this far. | |
1567 | */ | |
1568 | static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
1569 | { | |
1570 | BUG(); | |
1571 | return 0; | |
1572 | } | |
1573 | ||
1574 | struct vm_operations_struct hugetlb_vm_ops = { | |
1575 | .fault = hugetlb_vm_op_fault, | |
1576 | .open = hugetlb_vm_op_open, | |
1577 | .close = hugetlb_vm_op_close, | |
1578 | }; | |
1579 | ||
1580 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, | |
1581 | int writable) | |
1582 | { | |
1583 | pte_t entry; | |
1584 | ||
1585 | if (writable) { | |
1586 | entry = | |
1587 | pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); | |
1588 | } else { | |
1589 | entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); | |
1590 | } | |
1591 | entry = pte_mkyoung(entry); | |
1592 | entry = pte_mkhuge(entry); | |
1593 | ||
1594 | return entry; | |
1595 | } | |
1596 | ||
1597 | static void set_huge_ptep_writable(struct vm_area_struct *vma, | |
1598 | unsigned long address, pte_t *ptep) | |
1599 | { | |
1600 | pte_t entry; | |
1601 | ||
1602 | entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); | |
1603 | if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) { | |
1604 | update_mmu_cache(vma, address, entry); | |
1605 | } | |
1606 | } | |
1607 | ||
1608 | ||
1609 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, | |
1610 | struct vm_area_struct *vma) | |
1611 | { | |
1612 | pte_t *src_pte, *dst_pte, entry; | |
1613 | struct page *ptepage; | |
1614 | unsigned long addr; | |
1615 | int cow; | |
1616 | struct hstate *h = hstate_vma(vma); | |
1617 | unsigned long sz = huge_page_size(h); | |
1618 | ||
1619 | cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; | |
1620 | ||
1621 | for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { | |
1622 | src_pte = huge_pte_offset(src, addr); | |
1623 | if (!src_pte) | |
1624 | continue; | |
1625 | dst_pte = huge_pte_alloc(dst, addr, sz); | |
1626 | if (!dst_pte) | |
1627 | goto nomem; | |
1628 | ||
1629 | /* If the pagetables are shared don't copy or take references */ | |
1630 | if (dst_pte == src_pte) | |
1631 | continue; | |
1632 | ||
1633 | spin_lock(&dst->page_table_lock); | |
1634 | spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); | |
1635 | if (!huge_pte_none(huge_ptep_get(src_pte))) { | |
1636 | if (cow) | |
1637 | huge_ptep_set_wrprotect(src, addr, src_pte); | |
1638 | entry = huge_ptep_get(src_pte); | |
1639 | ptepage = pte_page(entry); | |
1640 | get_page(ptepage); | |
1641 | set_huge_pte_at(dst, addr, dst_pte, entry); | |
1642 | } | |
1643 | spin_unlock(&src->page_table_lock); | |
1644 | spin_unlock(&dst->page_table_lock); | |
1645 | } | |
1646 | return 0; | |
1647 | ||
1648 | nomem: | |
1649 | return -ENOMEM; | |
1650 | } | |
1651 | ||
1652 | void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, | |
1653 | unsigned long end, struct page *ref_page) | |
1654 | { | |
1655 | struct mm_struct *mm = vma->vm_mm; | |
1656 | unsigned long address; | |
1657 | pte_t *ptep; | |
1658 | pte_t pte; | |
1659 | struct page *page; | |
1660 | struct page *tmp; | |
1661 | struct hstate *h = hstate_vma(vma); | |
1662 | unsigned long sz = huge_page_size(h); | |
1663 | ||
1664 | /* | |
1665 | * A page gathering list, protected by per file i_mmap_lock. The | |
1666 | * lock is used to avoid list corruption from multiple unmapping | |
1667 | * of the same page since we are using page->lru. | |
1668 | */ | |
1669 | LIST_HEAD(page_list); | |
1670 | ||
1671 | WARN_ON(!is_vm_hugetlb_page(vma)); | |
1672 | BUG_ON(start & ~huge_page_mask(h)); | |
1673 | BUG_ON(end & ~huge_page_mask(h)); | |
1674 | ||
1675 | spin_lock(&mm->page_table_lock); | |
1676 | for (address = start; address < end; address += sz) { | |
1677 | ptep = huge_pte_offset(mm, address); | |
1678 | if (!ptep) | |
1679 | continue; | |
1680 | ||
1681 | if (huge_pmd_unshare(mm, &address, ptep)) | |
1682 | continue; | |
1683 | ||
1684 | /* | |
1685 | * If a reference page is supplied, it is because a specific | |
1686 | * page is being unmapped, not a range. Ensure the page we | |
1687 | * are about to unmap is the actual page of interest. | |
1688 | */ | |
1689 | if (ref_page) { | |
1690 | pte = huge_ptep_get(ptep); | |
1691 | if (huge_pte_none(pte)) | |
1692 | continue; | |
1693 | page = pte_page(pte); | |
1694 | if (page != ref_page) | |
1695 | continue; | |
1696 | ||
1697 | /* | |
1698 | * Mark the VMA as having unmapped its page so that | |
1699 | * future faults in this VMA will fail rather than | |
1700 | * looking like data was lost | |
1701 | */ | |
1702 | set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); | |
1703 | } | |
1704 | ||
1705 | pte = huge_ptep_get_and_clear(mm, address, ptep); | |
1706 | if (huge_pte_none(pte)) | |
1707 | continue; | |
1708 | ||
1709 | page = pte_page(pte); | |
1710 | if (pte_dirty(pte)) | |
1711 | set_page_dirty(page); | |
1712 | list_add(&page->lru, &page_list); | |
1713 | } | |
1714 | spin_unlock(&mm->page_table_lock); | |
1715 | flush_tlb_range(vma, start, end); | |
1716 | list_for_each_entry_safe(page, tmp, &page_list, lru) { | |
1717 | list_del(&page->lru); | |
1718 | put_page(page); | |
1719 | } | |
1720 | } | |
1721 | ||
1722 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, | |
1723 | unsigned long end, struct page *ref_page) | |
1724 | { | |
1725 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); | |
1726 | __unmap_hugepage_range(vma, start, end, ref_page); | |
1727 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); | |
1728 | } | |
1729 | ||
1730 | /* | |
1731 | * This is called when the original mapper is failing to COW a MAP_PRIVATE | |
1732 | * mappping it owns the reserve page for. The intention is to unmap the page | |
1733 | * from other VMAs and let the children be SIGKILLed if they are faulting the | |
1734 | * same region. | |
1735 | */ | |
1736 | int unmap_ref_private(struct mm_struct *mm, | |
1737 | struct vm_area_struct *vma, | |
1738 | struct page *page, | |
1739 | unsigned long address) | |
1740 | { | |
1741 | struct vm_area_struct *iter_vma; | |
1742 | struct address_space *mapping; | |
1743 | struct prio_tree_iter iter; | |
1744 | pgoff_t pgoff; | |
1745 | ||
1746 | /* | |
1747 | * vm_pgoff is in PAGE_SIZE units, hence the different calculation | |
1748 | * from page cache lookup which is in HPAGE_SIZE units. | |
1749 | */ | |
1750 | address = address & huge_page_mask(hstate_vma(vma)); | |
1751 | pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) | |
1752 | + (vma->vm_pgoff >> PAGE_SHIFT); | |
1753 | mapping = (struct address_space *)page_private(page); | |
1754 | ||
1755 | vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) { | |
1756 | /* Do not unmap the current VMA */ | |
1757 | if (iter_vma == vma) | |
1758 | continue; | |
1759 | ||
1760 | /* | |
1761 | * Unmap the page from other VMAs without their own reserves. | |
1762 | * They get marked to be SIGKILLed if they fault in these | |
1763 | * areas. This is because a future no-page fault on this VMA | |
1764 | * could insert a zeroed page instead of the data existing | |
1765 | * from the time of fork. This would look like data corruption | |
1766 | */ | |
1767 | if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) | |
1768 | unmap_hugepage_range(iter_vma, | |
1769 | address, address + HPAGE_SIZE, | |
1770 | page); | |
1771 | } | |
1772 | ||
1773 | return 1; | |
1774 | } | |
1775 | ||
1776 | static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, | |
1777 | unsigned long address, pte_t *ptep, pte_t pte, | |
1778 | struct page *pagecache_page) | |
1779 | { | |
1780 | struct hstate *h = hstate_vma(vma); | |
1781 | struct page *old_page, *new_page; | |
1782 | int avoidcopy; | |
1783 | int outside_reserve = 0; | |
1784 | ||
1785 | old_page = pte_page(pte); | |
1786 | ||
1787 | retry_avoidcopy: | |
1788 | /* If no-one else is actually using this page, avoid the copy | |
1789 | * and just make the page writable */ | |
1790 | avoidcopy = (page_count(old_page) == 1); | |
1791 | if (avoidcopy) { | |
1792 | set_huge_ptep_writable(vma, address, ptep); | |
1793 | return 0; | |
1794 | } | |
1795 | ||
1796 | /* | |
1797 | * If the process that created a MAP_PRIVATE mapping is about to | |
1798 | * perform a COW due to a shared page count, attempt to satisfy | |
1799 | * the allocation without using the existing reserves. The pagecache | |
1800 | * page is used to determine if the reserve at this address was | |
1801 | * consumed or not. If reserves were used, a partial faulted mapping | |
1802 | * at the time of fork() could consume its reserves on COW instead | |
1803 | * of the full address range. | |
1804 | */ | |
1805 | if (!(vma->vm_flags & VM_SHARED) && | |
1806 | is_vma_resv_set(vma, HPAGE_RESV_OWNER) && | |
1807 | old_page != pagecache_page) | |
1808 | outside_reserve = 1; | |
1809 | ||
1810 | page_cache_get(old_page); | |
1811 | new_page = alloc_huge_page(vma, address, outside_reserve); | |
1812 | ||
1813 | if (IS_ERR(new_page)) { | |
1814 | page_cache_release(old_page); | |
1815 | ||
1816 | /* | |
1817 | * If a process owning a MAP_PRIVATE mapping fails to COW, | |
1818 | * it is due to references held by a child and an insufficient | |
1819 | * huge page pool. To guarantee the original mappers | |
1820 | * reliability, unmap the page from child processes. The child | |
1821 | * may get SIGKILLed if it later faults. | |
1822 | */ | |
1823 | if (outside_reserve) { | |
1824 | BUG_ON(huge_pte_none(pte)); | |
1825 | if (unmap_ref_private(mm, vma, old_page, address)) { | |
1826 | BUG_ON(page_count(old_page) != 1); | |
1827 | BUG_ON(huge_pte_none(pte)); | |
1828 | goto retry_avoidcopy; | |
1829 | } | |
1830 | WARN_ON_ONCE(1); | |
1831 | } | |
1832 | ||
1833 | return -PTR_ERR(new_page); | |
1834 | } | |
1835 | ||
1836 | spin_unlock(&mm->page_table_lock); | |
1837 | copy_huge_page(new_page, old_page, address, vma); | |
1838 | __SetPageUptodate(new_page); | |
1839 | spin_lock(&mm->page_table_lock); | |
1840 | ||
1841 | ptep = huge_pte_offset(mm, address & huge_page_mask(h)); | |
1842 | if (likely(pte_same(huge_ptep_get(ptep), pte))) { | |
1843 | /* Break COW */ | |
1844 | huge_ptep_clear_flush(vma, address, ptep); | |
1845 | set_huge_pte_at(mm, address, ptep, | |
1846 | make_huge_pte(vma, new_page, 1)); | |
1847 | /* Make the old page be freed below */ | |
1848 | new_page = old_page; | |
1849 | } | |
1850 | page_cache_release(new_page); | |
1851 | page_cache_release(old_page); | |
1852 | return 0; | |
1853 | } | |
1854 | ||
1855 | /* Return the pagecache page at a given address within a VMA */ | |
1856 | static struct page *hugetlbfs_pagecache_page(struct hstate *h, | |
1857 | struct vm_area_struct *vma, unsigned long address) | |
1858 | { | |
1859 | struct address_space *mapping; | |
1860 | pgoff_t idx; | |
1861 | ||
1862 | mapping = vma->vm_file->f_mapping; | |
1863 | idx = vma_hugecache_offset(h, vma, address); | |
1864 | ||
1865 | return find_lock_page(mapping, idx); | |
1866 | } | |
1867 | ||
1868 | static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, | |
1869 | unsigned long address, pte_t *ptep, int write_access) | |
1870 | { | |
1871 | struct hstate *h = hstate_vma(vma); | |
1872 | int ret = VM_FAULT_SIGBUS; | |
1873 | pgoff_t idx; | |
1874 | unsigned long size; | |
1875 | struct page *page; | |
1876 | struct address_space *mapping; | |
1877 | pte_t new_pte; | |
1878 | ||
1879 | /* | |
1880 | * Currently, we are forced to kill the process in the event the | |
1881 | * original mapper has unmapped pages from the child due to a failed | |
1882 | * COW. Warn that such a situation has occured as it may not be obvious | |
1883 | */ | |
1884 | if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { | |
1885 | printk(KERN_WARNING | |
1886 | "PID %d killed due to inadequate hugepage pool\n", | |
1887 | current->pid); | |
1888 | return ret; | |
1889 | } | |
1890 | ||
1891 | mapping = vma->vm_file->f_mapping; | |
1892 | idx = vma_hugecache_offset(h, vma, address); | |
1893 | ||
1894 | /* | |
1895 | * Use page lock to guard against racing truncation | |
1896 | * before we get page_table_lock. | |
1897 | */ | |
1898 | retry: | |
1899 | page = find_lock_page(mapping, idx); | |
1900 | if (!page) { | |
1901 | size = i_size_read(mapping->host) >> huge_page_shift(h); | |
1902 | if (idx >= size) | |
1903 | goto out; | |
1904 | page = alloc_huge_page(vma, address, 0); | |
1905 | if (IS_ERR(page)) { | |
1906 | ret = -PTR_ERR(page); | |
1907 | goto out; | |
1908 | } | |
1909 | clear_huge_page(page, address, huge_page_size(h)); | |
1910 | __SetPageUptodate(page); | |
1911 | ||
1912 | if (vma->vm_flags & VM_SHARED) { | |
1913 | int err; | |
1914 | struct inode *inode = mapping->host; | |
1915 | ||
1916 | err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); | |
1917 | if (err) { | |
1918 | put_page(page); | |
1919 | if (err == -EEXIST) | |
1920 | goto retry; | |
1921 | goto out; | |
1922 | } | |
1923 | ||
1924 | spin_lock(&inode->i_lock); | |
1925 | inode->i_blocks += blocks_per_huge_page(h); | |
1926 | spin_unlock(&inode->i_lock); | |
1927 | } else | |
1928 | lock_page(page); | |
1929 | } | |
1930 | ||
1931 | spin_lock(&mm->page_table_lock); | |
1932 | size = i_size_read(mapping->host) >> huge_page_shift(h); | |
1933 | if (idx >= size) | |
1934 | goto backout; | |
1935 | ||
1936 | ret = 0; | |
1937 | if (!huge_pte_none(huge_ptep_get(ptep))) | |
1938 | goto backout; | |
1939 | ||
1940 | new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) | |
1941 | && (vma->vm_flags & VM_SHARED))); | |
1942 | set_huge_pte_at(mm, address, ptep, new_pte); | |
1943 | ||
1944 | if (write_access && !(vma->vm_flags & VM_SHARED)) { | |
1945 | /* Optimization, do the COW without a second fault */ | |
1946 | ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); | |
1947 | } | |
1948 | ||
1949 | spin_unlock(&mm->page_table_lock); | |
1950 | unlock_page(page); | |
1951 | out: | |
1952 | return ret; | |
1953 | ||
1954 | backout: | |
1955 | spin_unlock(&mm->page_table_lock); | |
1956 | unlock_page(page); | |
1957 | put_page(page); | |
1958 | goto out; | |
1959 | } | |
1960 | ||
1961 | int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, | |
1962 | unsigned long address, int write_access) | |
1963 | { | |
1964 | pte_t *ptep; | |
1965 | pte_t entry; | |
1966 | int ret; | |
1967 | static DEFINE_MUTEX(hugetlb_instantiation_mutex); | |
1968 | struct hstate *h = hstate_vma(vma); | |
1969 | ||
1970 | ptep = huge_pte_alloc(mm, address, huge_page_size(h)); | |
1971 | if (!ptep) | |
1972 | return VM_FAULT_OOM; | |
1973 | ||
1974 | /* | |
1975 | * Serialize hugepage allocation and instantiation, so that we don't | |
1976 | * get spurious allocation failures if two CPUs race to instantiate | |
1977 | * the same page in the page cache. | |
1978 | */ | |
1979 | mutex_lock(&hugetlb_instantiation_mutex); | |
1980 | entry = huge_ptep_get(ptep); | |
1981 | if (huge_pte_none(entry)) { | |
1982 | ret = hugetlb_no_page(mm, vma, address, ptep, write_access); | |
1983 | mutex_unlock(&hugetlb_instantiation_mutex); | |
1984 | return ret; | |
1985 | } | |
1986 | ||
1987 | ret = 0; | |
1988 | ||
1989 | spin_lock(&mm->page_table_lock); | |
1990 | /* Check for a racing update before calling hugetlb_cow */ | |
1991 | if (likely(pte_same(entry, huge_ptep_get(ptep)))) | |
1992 | if (write_access && !pte_write(entry)) { | |
1993 | struct page *page; | |
1994 | page = hugetlbfs_pagecache_page(h, vma, address); | |
1995 | ret = hugetlb_cow(mm, vma, address, ptep, entry, page); | |
1996 | if (page) { | |
1997 | unlock_page(page); | |
1998 | put_page(page); | |
1999 | } | |
2000 | } | |
2001 | spin_unlock(&mm->page_table_lock); | |
2002 | mutex_unlock(&hugetlb_instantiation_mutex); | |
2003 | ||
2004 | return ret; | |
2005 | } | |
2006 | ||
2007 | /* Can be overriden by architectures */ | |
2008 | __attribute__((weak)) struct page * | |
2009 | follow_huge_pud(struct mm_struct *mm, unsigned long address, | |
2010 | pud_t *pud, int write) | |
2011 | { | |
2012 | BUG(); | |
2013 | return NULL; | |
2014 | } | |
2015 | ||
2016 | int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, | |
2017 | struct page **pages, struct vm_area_struct **vmas, | |
2018 | unsigned long *position, int *length, int i, | |
2019 | int write) | |
2020 | { | |
2021 | unsigned long pfn_offset; | |
2022 | unsigned long vaddr = *position; | |
2023 | int remainder = *length; | |
2024 | struct hstate *h = hstate_vma(vma); | |
2025 | ||
2026 | spin_lock(&mm->page_table_lock); | |
2027 | while (vaddr < vma->vm_end && remainder) { | |
2028 | pte_t *pte; | |
2029 | struct page *page; | |
2030 | ||
2031 | /* | |
2032 | * Some archs (sparc64, sh*) have multiple pte_ts to | |
2033 | * each hugepage. We have to make * sure we get the | |
2034 | * first, for the page indexing below to work. | |
2035 | */ | |
2036 | pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); | |
2037 | ||
2038 | if (!pte || huge_pte_none(huge_ptep_get(pte)) || | |
2039 | (write && !pte_write(huge_ptep_get(pte)))) { | |
2040 | int ret; | |
2041 | ||
2042 | spin_unlock(&mm->page_table_lock); | |
2043 | ret = hugetlb_fault(mm, vma, vaddr, write); | |
2044 | spin_lock(&mm->page_table_lock); | |
2045 | if (!(ret & VM_FAULT_ERROR)) | |
2046 | continue; | |
2047 | ||
2048 | remainder = 0; | |
2049 | if (!i) | |
2050 | i = -EFAULT; | |
2051 | break; | |
2052 | } | |
2053 | ||
2054 | pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; | |
2055 | page = pte_page(huge_ptep_get(pte)); | |
2056 | same_page: | |
2057 | if (pages) { | |
2058 | get_page(page); | |
2059 | pages[i] = page + pfn_offset; | |
2060 | } | |
2061 | ||
2062 | if (vmas) | |
2063 | vmas[i] = vma; | |
2064 | ||
2065 | vaddr += PAGE_SIZE; | |
2066 | ++pfn_offset; | |
2067 | --remainder; | |
2068 | ++i; | |
2069 | if (vaddr < vma->vm_end && remainder && | |
2070 | pfn_offset < pages_per_huge_page(h)) { | |
2071 | /* | |
2072 | * We use pfn_offset to avoid touching the pageframes | |
2073 | * of this compound page. | |
2074 | */ | |
2075 | goto same_page; | |
2076 | } | |
2077 | } | |
2078 | spin_unlock(&mm->page_table_lock); | |
2079 | *length = remainder; | |
2080 | *position = vaddr; | |
2081 | ||
2082 | return i; | |
2083 | } | |
2084 | ||
2085 | void hugetlb_change_protection(struct vm_area_struct *vma, | |
2086 | unsigned long address, unsigned long end, pgprot_t newprot) | |
2087 | { | |
2088 | struct mm_struct *mm = vma->vm_mm; | |
2089 | unsigned long start = address; | |
2090 | pte_t *ptep; | |
2091 | pte_t pte; | |
2092 | struct hstate *h = hstate_vma(vma); | |
2093 | ||
2094 | BUG_ON(address >= end); | |
2095 | flush_cache_range(vma, address, end); | |
2096 | ||
2097 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); | |
2098 | spin_lock(&mm->page_table_lock); | |
2099 | for (; address < end; address += huge_page_size(h)) { | |
2100 | ptep = huge_pte_offset(mm, address); | |
2101 | if (!ptep) | |
2102 | continue; | |
2103 | if (huge_pmd_unshare(mm, &address, ptep)) | |
2104 | continue; | |
2105 | if (!huge_pte_none(huge_ptep_get(ptep))) { | |
2106 | pte = huge_ptep_get_and_clear(mm, address, ptep); | |
2107 | pte = pte_mkhuge(pte_modify(pte, newprot)); | |
2108 | set_huge_pte_at(mm, address, ptep, pte); | |
2109 | } | |
2110 | } | |
2111 | spin_unlock(&mm->page_table_lock); | |
2112 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); | |
2113 | ||
2114 | flush_tlb_range(vma, start, end); | |
2115 | } | |
2116 | ||
2117 | int hugetlb_reserve_pages(struct inode *inode, | |
2118 | long from, long to, | |
2119 | struct vm_area_struct *vma) | |
2120 | { | |
2121 | long ret, chg; | |
2122 | struct hstate *h = hstate_inode(inode); | |
2123 | ||
2124 | if (vma && vma->vm_flags & VM_NORESERVE) | |
2125 | return 0; | |
2126 | ||
2127 | /* | |
2128 | * Shared mappings base their reservation on the number of pages that | |
2129 | * are already allocated on behalf of the file. Private mappings need | |
2130 | * to reserve the full area even if read-only as mprotect() may be | |
2131 | * called to make the mapping read-write. Assume !vma is a shm mapping | |
2132 | */ | |
2133 | if (!vma || vma->vm_flags & VM_SHARED) | |
2134 | chg = region_chg(&inode->i_mapping->private_list, from, to); | |
2135 | else { | |
2136 | struct resv_map *resv_map = resv_map_alloc(); | |
2137 | if (!resv_map) | |
2138 | return -ENOMEM; | |
2139 | ||
2140 | chg = to - from; | |
2141 | ||
2142 | set_vma_resv_map(vma, resv_map); | |
2143 | set_vma_resv_flags(vma, HPAGE_RESV_OWNER); | |
2144 | } | |
2145 | ||
2146 | if (chg < 0) | |
2147 | return chg; | |
2148 | ||
2149 | if (hugetlb_get_quota(inode->i_mapping, chg)) | |
2150 | return -ENOSPC; | |
2151 | ret = hugetlb_acct_memory(h, chg); | |
2152 | if (ret < 0) { | |
2153 | hugetlb_put_quota(inode->i_mapping, chg); | |
2154 | return ret; | |
2155 | } | |
2156 | if (!vma || vma->vm_flags & VM_SHARED) | |
2157 | region_add(&inode->i_mapping->private_list, from, to); | |
2158 | return 0; | |
2159 | } | |
2160 | ||
2161 | void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) | |
2162 | { | |
2163 | struct hstate *h = hstate_inode(inode); | |
2164 | long chg = region_truncate(&inode->i_mapping->private_list, offset); | |
2165 | ||
2166 | spin_lock(&inode->i_lock); | |
2167 | inode->i_blocks -= blocks_per_huge_page(h); | |
2168 | spin_unlock(&inode->i_lock); | |
2169 | ||
2170 | hugetlb_put_quota(inode->i_mapping, (chg - freed)); | |
2171 | hugetlb_acct_memory(h, -(chg - freed)); | |
2172 | } |