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