Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Generic hugetlb support. | |
3 | * (C) William Irwin, April 2004 | |
4 | */ | |
5 | #include <linux/gfp.h> | |
6 | #include <linux/list.h> | |
7 | #include <linux/init.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/mm.h> | |
1da177e4 LT |
10 | #include <linux/sysctl.h> |
11 | #include <linux/highmem.h> | |
12 | #include <linux/nodemask.h> | |
63551ae0 | 13 | #include <linux/pagemap.h> |
5da7ca86 | 14 | #include <linux/mempolicy.h> |
aea47ff3 | 15 | #include <linux/cpuset.h> |
3935baa9 | 16 | #include <linux/mutex.h> |
5da7ca86 | 17 | |
63551ae0 DG |
18 | #include <asm/page.h> |
19 | #include <asm/pgtable.h> | |
20 | ||
21 | #include <linux/hugetlb.h> | |
7835e98b | 22 | #include "internal.h" |
1da177e4 LT |
23 | |
24 | const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; | |
a43a8c39 | 25 | static unsigned long nr_huge_pages, free_huge_pages, resv_huge_pages; |
7893d1d5 | 26 | static unsigned long surplus_huge_pages; |
1da177e4 LT |
27 | unsigned long max_huge_pages; |
28 | static struct list_head hugepage_freelists[MAX_NUMNODES]; | |
29 | static unsigned int nr_huge_pages_node[MAX_NUMNODES]; | |
30 | static unsigned int free_huge_pages_node[MAX_NUMNODES]; | |
7893d1d5 | 31 | static unsigned int surplus_huge_pages_node[MAX_NUMNODES]; |
396faf03 MG |
32 | static gfp_t htlb_alloc_mask = GFP_HIGHUSER; |
33 | unsigned long hugepages_treat_as_movable; | |
54f9f80d | 34 | int hugetlb_dynamic_pool; |
63b4613c | 35 | static int hugetlb_next_nid; |
396faf03 | 36 | |
3935baa9 DG |
37 | /* |
38 | * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages | |
39 | */ | |
40 | static DEFINE_SPINLOCK(hugetlb_lock); | |
0bd0f9fb | 41 | |
79ac6ba4 DG |
42 | static void clear_huge_page(struct page *page, unsigned long addr) |
43 | { | |
44 | int i; | |
45 | ||
46 | might_sleep(); | |
47 | for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); i++) { | |
48 | cond_resched(); | |
281e0e3b | 49 | clear_user_highpage(page + i, addr + i * PAGE_SIZE); |
79ac6ba4 DG |
50 | } |
51 | } | |
52 | ||
53 | static void copy_huge_page(struct page *dst, struct page *src, | |
9de455b2 | 54 | unsigned long addr, struct vm_area_struct *vma) |
79ac6ba4 DG |
55 | { |
56 | int i; | |
57 | ||
58 | might_sleep(); | |
59 | for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++) { | |
60 | cond_resched(); | |
9de455b2 | 61 | copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); |
79ac6ba4 DG |
62 | } |
63 | } | |
64 | ||
1da177e4 LT |
65 | static void enqueue_huge_page(struct page *page) |
66 | { | |
67 | int nid = page_to_nid(page); | |
68 | list_add(&page->lru, &hugepage_freelists[nid]); | |
69 | free_huge_pages++; | |
70 | free_huge_pages_node[nid]++; | |
71 | } | |
72 | ||
5da7ca86 CL |
73 | static struct page *dequeue_huge_page(struct vm_area_struct *vma, |
74 | unsigned long address) | |
1da177e4 | 75 | { |
31a5c6e4 | 76 | int nid; |
1da177e4 | 77 | struct page *page = NULL; |
480eccf9 | 78 | struct mempolicy *mpol; |
396faf03 | 79 | struct zonelist *zonelist = huge_zonelist(vma, address, |
480eccf9 | 80 | htlb_alloc_mask, &mpol); |
96df9333 | 81 | struct zone **z; |
1da177e4 | 82 | |
96df9333 | 83 | for (z = zonelist->zones; *z; z++) { |
89fa3024 | 84 | nid = zone_to_nid(*z); |
396faf03 | 85 | if (cpuset_zone_allowed_softwall(*z, htlb_alloc_mask) && |
3abf7afd AM |
86 | !list_empty(&hugepage_freelists[nid])) { |
87 | page = list_entry(hugepage_freelists[nid].next, | |
88 | struct page, lru); | |
89 | list_del(&page->lru); | |
90 | free_huge_pages--; | |
91 | free_huge_pages_node[nid]--; | |
e4e574b7 AL |
92 | if (vma && vma->vm_flags & VM_MAYSHARE) |
93 | resv_huge_pages--; | |
5ab3ee7b | 94 | break; |
3abf7afd | 95 | } |
1da177e4 | 96 | } |
480eccf9 | 97 | mpol_free(mpol); /* unref if mpol !NULL */ |
1da177e4 LT |
98 | return page; |
99 | } | |
100 | ||
6af2acb6 AL |
101 | static void update_and_free_page(struct page *page) |
102 | { | |
103 | int i; | |
104 | nr_huge_pages--; | |
105 | nr_huge_pages_node[page_to_nid(page)]--; | |
106 | for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) { | |
107 | page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | | |
108 | 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | | |
109 | 1 << PG_private | 1<< PG_writeback); | |
110 | } | |
111 | set_compound_page_dtor(page, NULL); | |
112 | set_page_refcounted(page); | |
113 | __free_pages(page, HUGETLB_PAGE_ORDER); | |
114 | } | |
115 | ||
27a85ef1 DG |
116 | static void free_huge_page(struct page *page) |
117 | { | |
7893d1d5 | 118 | int nid = page_to_nid(page); |
c79fb75e | 119 | struct address_space *mapping; |
27a85ef1 | 120 | |
c79fb75e | 121 | mapping = (struct address_space *) page_private(page); |
7893d1d5 | 122 | BUG_ON(page_count(page)); |
27a85ef1 DG |
123 | INIT_LIST_HEAD(&page->lru); |
124 | ||
125 | spin_lock(&hugetlb_lock); | |
7893d1d5 AL |
126 | if (surplus_huge_pages_node[nid]) { |
127 | update_and_free_page(page); | |
128 | surplus_huge_pages--; | |
129 | surplus_huge_pages_node[nid]--; | |
130 | } else { | |
131 | enqueue_huge_page(page); | |
132 | } | |
27a85ef1 | 133 | spin_unlock(&hugetlb_lock); |
c79fb75e | 134 | if (mapping) |
9a119c05 | 135 | hugetlb_put_quota(mapping, 1); |
c79fb75e | 136 | set_page_private(page, 0); |
27a85ef1 DG |
137 | } |
138 | ||
7893d1d5 AL |
139 | /* |
140 | * Increment or decrement surplus_huge_pages. Keep node-specific counters | |
141 | * balanced by operating on them in a round-robin fashion. | |
142 | * Returns 1 if an adjustment was made. | |
143 | */ | |
144 | static int adjust_pool_surplus(int delta) | |
145 | { | |
146 | static int prev_nid; | |
147 | int nid = prev_nid; | |
148 | int ret = 0; | |
149 | ||
150 | VM_BUG_ON(delta != -1 && delta != 1); | |
151 | do { | |
152 | nid = next_node(nid, node_online_map); | |
153 | if (nid == MAX_NUMNODES) | |
154 | nid = first_node(node_online_map); | |
155 | ||
156 | /* To shrink on this node, there must be a surplus page */ | |
157 | if (delta < 0 && !surplus_huge_pages_node[nid]) | |
158 | continue; | |
159 | /* Surplus cannot exceed the total number of pages */ | |
160 | if (delta > 0 && surplus_huge_pages_node[nid] >= | |
161 | nr_huge_pages_node[nid]) | |
162 | continue; | |
163 | ||
164 | surplus_huge_pages += delta; | |
165 | surplus_huge_pages_node[nid] += delta; | |
166 | ret = 1; | |
167 | break; | |
168 | } while (nid != prev_nid); | |
169 | ||
170 | prev_nid = nid; | |
171 | return ret; | |
172 | } | |
173 | ||
63b4613c | 174 | static struct page *alloc_fresh_huge_page_node(int nid) |
1da177e4 | 175 | { |
1da177e4 | 176 | struct page *page; |
f96efd58 | 177 | |
63b4613c NA |
178 | page = alloc_pages_node(nid, |
179 | htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|__GFP_NOWARN, | |
180 | HUGETLB_PAGE_ORDER); | |
1da177e4 | 181 | if (page) { |
33f2ef89 | 182 | set_compound_page_dtor(page, free_huge_page); |
0bd0f9fb | 183 | spin_lock(&hugetlb_lock); |
1da177e4 | 184 | nr_huge_pages++; |
63b4613c | 185 | nr_huge_pages_node[nid]++; |
0bd0f9fb | 186 | spin_unlock(&hugetlb_lock); |
a482289d | 187 | put_page(page); /* free it into the hugepage allocator */ |
1da177e4 | 188 | } |
63b4613c NA |
189 | |
190 | return page; | |
191 | } | |
192 | ||
193 | static int alloc_fresh_huge_page(void) | |
194 | { | |
195 | struct page *page; | |
196 | int start_nid; | |
197 | int next_nid; | |
198 | int ret = 0; | |
199 | ||
200 | start_nid = hugetlb_next_nid; | |
201 | ||
202 | do { | |
203 | page = alloc_fresh_huge_page_node(hugetlb_next_nid); | |
204 | if (page) | |
205 | ret = 1; | |
206 | /* | |
207 | * Use a helper variable to find the next node and then | |
208 | * copy it back to hugetlb_next_nid afterwards: | |
209 | * otherwise there's a window in which a racer might | |
210 | * pass invalid nid MAX_NUMNODES to alloc_pages_node. | |
211 | * But we don't need to use a spin_lock here: it really | |
212 | * doesn't matter if occasionally a racer chooses the | |
213 | * same nid as we do. Move nid forward in the mask even | |
214 | * if we just successfully allocated a hugepage so that | |
215 | * the next caller gets hugepages on the next node. | |
216 | */ | |
217 | next_nid = next_node(hugetlb_next_nid, node_online_map); | |
218 | if (next_nid == MAX_NUMNODES) | |
219 | next_nid = first_node(node_online_map); | |
220 | hugetlb_next_nid = next_nid; | |
221 | } while (!page && hugetlb_next_nid != start_nid); | |
222 | ||
223 | return ret; | |
1da177e4 LT |
224 | } |
225 | ||
7893d1d5 AL |
226 | static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma, |
227 | unsigned long address) | |
228 | { | |
229 | struct page *page; | |
230 | ||
54f9f80d AL |
231 | /* Check if the dynamic pool is enabled */ |
232 | if (!hugetlb_dynamic_pool) | |
233 | return NULL; | |
234 | ||
7893d1d5 AL |
235 | page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN, |
236 | HUGETLB_PAGE_ORDER); | |
237 | if (page) { | |
238 | set_compound_page_dtor(page, free_huge_page); | |
239 | spin_lock(&hugetlb_lock); | |
240 | nr_huge_pages++; | |
241 | nr_huge_pages_node[page_to_nid(page)]++; | |
242 | surplus_huge_pages++; | |
243 | surplus_huge_pages_node[page_to_nid(page)]++; | |
244 | spin_unlock(&hugetlb_lock); | |
245 | } | |
246 | ||
247 | return page; | |
248 | } | |
249 | ||
e4e574b7 AL |
250 | /* |
251 | * Increase the hugetlb pool such that it can accomodate a reservation | |
252 | * of size 'delta'. | |
253 | */ | |
254 | static int gather_surplus_pages(int delta) | |
255 | { | |
256 | struct list_head surplus_list; | |
257 | struct page *page, *tmp; | |
258 | int ret, i; | |
259 | int needed, allocated; | |
260 | ||
261 | needed = (resv_huge_pages + delta) - free_huge_pages; | |
262 | if (needed <= 0) | |
263 | return 0; | |
264 | ||
265 | allocated = 0; | |
266 | INIT_LIST_HEAD(&surplus_list); | |
267 | ||
268 | ret = -ENOMEM; | |
269 | retry: | |
270 | spin_unlock(&hugetlb_lock); | |
271 | for (i = 0; i < needed; i++) { | |
272 | page = alloc_buddy_huge_page(NULL, 0); | |
273 | if (!page) { | |
274 | /* | |
275 | * We were not able to allocate enough pages to | |
276 | * satisfy the entire reservation so we free what | |
277 | * we've allocated so far. | |
278 | */ | |
279 | spin_lock(&hugetlb_lock); | |
280 | needed = 0; | |
281 | goto free; | |
282 | } | |
283 | ||
284 | list_add(&page->lru, &surplus_list); | |
285 | } | |
286 | allocated += needed; | |
287 | ||
288 | /* | |
289 | * After retaking hugetlb_lock, we need to recalculate 'needed' | |
290 | * because either resv_huge_pages or free_huge_pages may have changed. | |
291 | */ | |
292 | spin_lock(&hugetlb_lock); | |
293 | needed = (resv_huge_pages + delta) - (free_huge_pages + allocated); | |
294 | if (needed > 0) | |
295 | goto retry; | |
296 | ||
297 | /* | |
298 | * The surplus_list now contains _at_least_ the number of extra pages | |
299 | * needed to accomodate the reservation. Add the appropriate number | |
300 | * of pages to the hugetlb pool and free the extras back to the buddy | |
301 | * allocator. | |
302 | */ | |
303 | needed += allocated; | |
304 | ret = 0; | |
305 | free: | |
306 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) { | |
307 | list_del(&page->lru); | |
308 | if ((--needed) >= 0) | |
309 | enqueue_huge_page(page); | |
af767cbd AL |
310 | else { |
311 | /* | |
312 | * Decrement the refcount and free the page using its | |
313 | * destructor. This must be done with hugetlb_lock | |
314 | * unlocked which is safe because free_huge_page takes | |
315 | * hugetlb_lock before deciding how to free the page. | |
316 | */ | |
317 | spin_unlock(&hugetlb_lock); | |
318 | put_page(page); | |
319 | spin_lock(&hugetlb_lock); | |
320 | } | |
e4e574b7 AL |
321 | } |
322 | ||
323 | return ret; | |
324 | } | |
325 | ||
326 | /* | |
327 | * When releasing a hugetlb pool reservation, any surplus pages that were | |
328 | * allocated to satisfy the reservation must be explicitly freed if they were | |
329 | * never used. | |
330 | */ | |
8cde045c | 331 | static void return_unused_surplus_pages(unsigned long unused_resv_pages) |
e4e574b7 AL |
332 | { |
333 | static int nid = -1; | |
334 | struct page *page; | |
335 | unsigned long nr_pages; | |
336 | ||
337 | nr_pages = min(unused_resv_pages, surplus_huge_pages); | |
338 | ||
339 | while (nr_pages) { | |
340 | nid = next_node(nid, node_online_map); | |
341 | if (nid == MAX_NUMNODES) | |
342 | nid = first_node(node_online_map); | |
343 | ||
344 | if (!surplus_huge_pages_node[nid]) | |
345 | continue; | |
346 | ||
347 | if (!list_empty(&hugepage_freelists[nid])) { | |
348 | page = list_entry(hugepage_freelists[nid].next, | |
349 | struct page, lru); | |
350 | list_del(&page->lru); | |
351 | update_and_free_page(page); | |
352 | free_huge_pages--; | |
353 | free_huge_pages_node[nid]--; | |
354 | surplus_huge_pages--; | |
355 | surplus_huge_pages_node[nid]--; | |
356 | nr_pages--; | |
357 | } | |
358 | } | |
359 | } | |
360 | ||
348ea204 AL |
361 | |
362 | static struct page *alloc_huge_page_shared(struct vm_area_struct *vma, | |
363 | unsigned long addr) | |
1da177e4 | 364 | { |
348ea204 | 365 | struct page *page; |
1da177e4 LT |
366 | |
367 | spin_lock(&hugetlb_lock); | |
b45b5bd6 | 368 | page = dequeue_huge_page(vma, addr); |
1da177e4 | 369 | spin_unlock(&hugetlb_lock); |
90d8b7e6 | 370 | return page ? page : ERR_PTR(-VM_FAULT_OOM); |
348ea204 | 371 | } |
b45b5bd6 | 372 | |
348ea204 AL |
373 | static struct page *alloc_huge_page_private(struct vm_area_struct *vma, |
374 | unsigned long addr) | |
375 | { | |
376 | struct page *page = NULL; | |
7893d1d5 | 377 | |
90d8b7e6 AL |
378 | if (hugetlb_get_quota(vma->vm_file->f_mapping, 1)) |
379 | return ERR_PTR(-VM_FAULT_SIGBUS); | |
380 | ||
348ea204 AL |
381 | spin_lock(&hugetlb_lock); |
382 | if (free_huge_pages > resv_huge_pages) | |
383 | page = dequeue_huge_page(vma, addr); | |
384 | spin_unlock(&hugetlb_lock); | |
385 | if (!page) | |
7893d1d5 | 386 | page = alloc_buddy_huge_page(vma, addr); |
90d8b7e6 | 387 | return page ? page : ERR_PTR(-VM_FAULT_OOM); |
348ea204 AL |
388 | } |
389 | ||
390 | static struct page *alloc_huge_page(struct vm_area_struct *vma, | |
391 | unsigned long addr) | |
392 | { | |
393 | struct page *page; | |
2fc39cec AL |
394 | struct address_space *mapping = vma->vm_file->f_mapping; |
395 | ||
348ea204 AL |
396 | if (vma->vm_flags & VM_MAYSHARE) |
397 | page = alloc_huge_page_shared(vma, addr); | |
398 | else | |
399 | page = alloc_huge_page_private(vma, addr); | |
90d8b7e6 AL |
400 | |
401 | if (!IS_ERR(page)) { | |
348ea204 | 402 | set_page_refcounted(page); |
2fc39cec | 403 | set_page_private(page, (unsigned long) mapping); |
90d8b7e6 AL |
404 | } |
405 | return page; | |
b45b5bd6 DG |
406 | } |
407 | ||
1da177e4 LT |
408 | static int __init hugetlb_init(void) |
409 | { | |
410 | unsigned long i; | |
1da177e4 | 411 | |
3c726f8d BH |
412 | if (HPAGE_SHIFT == 0) |
413 | return 0; | |
414 | ||
1da177e4 LT |
415 | for (i = 0; i < MAX_NUMNODES; ++i) |
416 | INIT_LIST_HEAD(&hugepage_freelists[i]); | |
417 | ||
63b4613c NA |
418 | hugetlb_next_nid = first_node(node_online_map); |
419 | ||
1da177e4 | 420 | for (i = 0; i < max_huge_pages; ++i) { |
a482289d | 421 | if (!alloc_fresh_huge_page()) |
1da177e4 | 422 | break; |
1da177e4 LT |
423 | } |
424 | max_huge_pages = free_huge_pages = nr_huge_pages = i; | |
425 | printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages); | |
426 | return 0; | |
427 | } | |
428 | module_init(hugetlb_init); | |
429 | ||
430 | static int __init hugetlb_setup(char *s) | |
431 | { | |
432 | if (sscanf(s, "%lu", &max_huge_pages) <= 0) | |
433 | max_huge_pages = 0; | |
434 | return 1; | |
435 | } | |
436 | __setup("hugepages=", hugetlb_setup); | |
437 | ||
8a630112 KC |
438 | static unsigned int cpuset_mems_nr(unsigned int *array) |
439 | { | |
440 | int node; | |
441 | unsigned int nr = 0; | |
442 | ||
443 | for_each_node_mask(node, cpuset_current_mems_allowed) | |
444 | nr += array[node]; | |
445 | ||
446 | return nr; | |
447 | } | |
448 | ||
1da177e4 | 449 | #ifdef CONFIG_SYSCTL |
1da177e4 LT |
450 | #ifdef CONFIG_HIGHMEM |
451 | static void try_to_free_low(unsigned long count) | |
452 | { | |
4415cc8d CL |
453 | int i; |
454 | ||
1da177e4 LT |
455 | for (i = 0; i < MAX_NUMNODES; ++i) { |
456 | struct page *page, *next; | |
457 | list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) { | |
6b0c880d AL |
458 | if (count >= nr_huge_pages) |
459 | return; | |
1da177e4 LT |
460 | if (PageHighMem(page)) |
461 | continue; | |
462 | list_del(&page->lru); | |
463 | update_and_free_page(page); | |
1da177e4 | 464 | free_huge_pages--; |
4415cc8d | 465 | free_huge_pages_node[page_to_nid(page)]--; |
1da177e4 LT |
466 | } |
467 | } | |
468 | } | |
469 | #else | |
470 | static inline void try_to_free_low(unsigned long count) | |
471 | { | |
472 | } | |
473 | #endif | |
474 | ||
7893d1d5 | 475 | #define persistent_huge_pages (nr_huge_pages - surplus_huge_pages) |
1da177e4 LT |
476 | static unsigned long set_max_huge_pages(unsigned long count) |
477 | { | |
7893d1d5 | 478 | unsigned long min_count, ret; |
1da177e4 | 479 | |
7893d1d5 AL |
480 | /* |
481 | * Increase the pool size | |
482 | * First take pages out of surplus state. Then make up the | |
483 | * remaining difference by allocating fresh huge pages. | |
484 | */ | |
1da177e4 | 485 | spin_lock(&hugetlb_lock); |
7893d1d5 AL |
486 | while (surplus_huge_pages && count > persistent_huge_pages) { |
487 | if (!adjust_pool_surplus(-1)) | |
488 | break; | |
489 | } | |
490 | ||
491 | while (count > persistent_huge_pages) { | |
492 | int ret; | |
493 | /* | |
494 | * If this allocation races such that we no longer need the | |
495 | * page, free_huge_page will handle it by freeing the page | |
496 | * and reducing the surplus. | |
497 | */ | |
498 | spin_unlock(&hugetlb_lock); | |
499 | ret = alloc_fresh_huge_page(); | |
500 | spin_lock(&hugetlb_lock); | |
501 | if (!ret) | |
502 | goto out; | |
503 | ||
504 | } | |
7893d1d5 AL |
505 | |
506 | /* | |
507 | * Decrease the pool size | |
508 | * First return free pages to the buddy allocator (being careful | |
509 | * to keep enough around to satisfy reservations). Then place | |
510 | * pages into surplus state as needed so the pool will shrink | |
511 | * to the desired size as pages become free. | |
512 | */ | |
6b0c880d AL |
513 | min_count = resv_huge_pages + nr_huge_pages - free_huge_pages; |
514 | min_count = max(count, min_count); | |
7893d1d5 AL |
515 | try_to_free_low(min_count); |
516 | while (min_count < persistent_huge_pages) { | |
5da7ca86 | 517 | struct page *page = dequeue_huge_page(NULL, 0); |
1da177e4 LT |
518 | if (!page) |
519 | break; | |
520 | update_and_free_page(page); | |
521 | } | |
7893d1d5 AL |
522 | while (count < persistent_huge_pages) { |
523 | if (!adjust_pool_surplus(1)) | |
524 | break; | |
525 | } | |
526 | out: | |
527 | ret = persistent_huge_pages; | |
1da177e4 | 528 | spin_unlock(&hugetlb_lock); |
7893d1d5 | 529 | return ret; |
1da177e4 LT |
530 | } |
531 | ||
532 | int hugetlb_sysctl_handler(struct ctl_table *table, int write, | |
533 | struct file *file, void __user *buffer, | |
534 | size_t *length, loff_t *ppos) | |
535 | { | |
536 | proc_doulongvec_minmax(table, write, file, buffer, length, ppos); | |
537 | max_huge_pages = set_max_huge_pages(max_huge_pages); | |
538 | return 0; | |
539 | } | |
396faf03 MG |
540 | |
541 | int hugetlb_treat_movable_handler(struct ctl_table *table, int write, | |
542 | struct file *file, void __user *buffer, | |
543 | size_t *length, loff_t *ppos) | |
544 | { | |
545 | proc_dointvec(table, write, file, buffer, length, ppos); | |
546 | if (hugepages_treat_as_movable) | |
547 | htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; | |
548 | else | |
549 | htlb_alloc_mask = GFP_HIGHUSER; | |
550 | return 0; | |
551 | } | |
552 | ||
1da177e4 LT |
553 | #endif /* CONFIG_SYSCTL */ |
554 | ||
555 | int hugetlb_report_meminfo(char *buf) | |
556 | { | |
557 | return sprintf(buf, | |
558 | "HugePages_Total: %5lu\n" | |
559 | "HugePages_Free: %5lu\n" | |
a43a8c39 | 560 | "HugePages_Rsvd: %5lu\n" |
7893d1d5 | 561 | "HugePages_Surp: %5lu\n" |
1da177e4 LT |
562 | "Hugepagesize: %5lu kB\n", |
563 | nr_huge_pages, | |
564 | free_huge_pages, | |
a43a8c39 | 565 | resv_huge_pages, |
7893d1d5 | 566 | surplus_huge_pages, |
1da177e4 LT |
567 | HPAGE_SIZE/1024); |
568 | } | |
569 | ||
570 | int hugetlb_report_node_meminfo(int nid, char *buf) | |
571 | { | |
572 | return sprintf(buf, | |
573 | "Node %d HugePages_Total: %5u\n" | |
574 | "Node %d HugePages_Free: %5u\n", | |
575 | nid, nr_huge_pages_node[nid], | |
576 | nid, free_huge_pages_node[nid]); | |
577 | } | |
578 | ||
1da177e4 LT |
579 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
580 | unsigned long hugetlb_total_pages(void) | |
581 | { | |
582 | return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE); | |
583 | } | |
1da177e4 LT |
584 | |
585 | /* | |
586 | * We cannot handle pagefaults against hugetlb pages at all. They cause | |
587 | * handle_mm_fault() to try to instantiate regular-sized pages in the | |
588 | * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get | |
589 | * this far. | |
590 | */ | |
d0217ac0 | 591 | static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 LT |
592 | { |
593 | BUG(); | |
d0217ac0 | 594 | return 0; |
1da177e4 LT |
595 | } |
596 | ||
597 | struct vm_operations_struct hugetlb_vm_ops = { | |
d0217ac0 | 598 | .fault = hugetlb_vm_op_fault, |
1da177e4 LT |
599 | }; |
600 | ||
1e8f889b DG |
601 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
602 | int writable) | |
63551ae0 DG |
603 | { |
604 | pte_t entry; | |
605 | ||
1e8f889b | 606 | if (writable) { |
63551ae0 DG |
607 | entry = |
608 | pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); | |
609 | } else { | |
610 | entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot)); | |
611 | } | |
612 | entry = pte_mkyoung(entry); | |
613 | entry = pte_mkhuge(entry); | |
614 | ||
615 | return entry; | |
616 | } | |
617 | ||
1e8f889b DG |
618 | static void set_huge_ptep_writable(struct vm_area_struct *vma, |
619 | unsigned long address, pte_t *ptep) | |
620 | { | |
621 | pte_t entry; | |
622 | ||
623 | entry = pte_mkwrite(pte_mkdirty(*ptep)); | |
8dab5241 BH |
624 | if (ptep_set_access_flags(vma, address, ptep, entry, 1)) { |
625 | update_mmu_cache(vma, address, entry); | |
8dab5241 | 626 | } |
1e8f889b DG |
627 | } |
628 | ||
629 | ||
63551ae0 DG |
630 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
631 | struct vm_area_struct *vma) | |
632 | { | |
633 | pte_t *src_pte, *dst_pte, entry; | |
634 | struct page *ptepage; | |
1c59827d | 635 | unsigned long addr; |
1e8f889b DG |
636 | int cow; |
637 | ||
638 | cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; | |
63551ae0 | 639 | |
1c59827d | 640 | for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) { |
c74df32c HD |
641 | src_pte = huge_pte_offset(src, addr); |
642 | if (!src_pte) | |
643 | continue; | |
63551ae0 DG |
644 | dst_pte = huge_pte_alloc(dst, addr); |
645 | if (!dst_pte) | |
646 | goto nomem; | |
c74df32c | 647 | spin_lock(&dst->page_table_lock); |
1c59827d | 648 | spin_lock(&src->page_table_lock); |
c74df32c | 649 | if (!pte_none(*src_pte)) { |
1e8f889b DG |
650 | if (cow) |
651 | ptep_set_wrprotect(src, addr, src_pte); | |
1c59827d HD |
652 | entry = *src_pte; |
653 | ptepage = pte_page(entry); | |
654 | get_page(ptepage); | |
1c59827d HD |
655 | set_huge_pte_at(dst, addr, dst_pte, entry); |
656 | } | |
657 | spin_unlock(&src->page_table_lock); | |
c74df32c | 658 | spin_unlock(&dst->page_table_lock); |
63551ae0 DG |
659 | } |
660 | return 0; | |
661 | ||
662 | nomem: | |
663 | return -ENOMEM; | |
664 | } | |
665 | ||
502717f4 CK |
666 | void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
667 | unsigned long end) | |
63551ae0 DG |
668 | { |
669 | struct mm_struct *mm = vma->vm_mm; | |
670 | unsigned long address; | |
c7546f8f | 671 | pte_t *ptep; |
63551ae0 DG |
672 | pte_t pte; |
673 | struct page *page; | |
fe1668ae | 674 | struct page *tmp; |
c0a499c2 CK |
675 | /* |
676 | * A page gathering list, protected by per file i_mmap_lock. The | |
677 | * lock is used to avoid list corruption from multiple unmapping | |
678 | * of the same page since we are using page->lru. | |
679 | */ | |
fe1668ae | 680 | LIST_HEAD(page_list); |
63551ae0 DG |
681 | |
682 | WARN_ON(!is_vm_hugetlb_page(vma)); | |
683 | BUG_ON(start & ~HPAGE_MASK); | |
684 | BUG_ON(end & ~HPAGE_MASK); | |
685 | ||
508034a3 | 686 | spin_lock(&mm->page_table_lock); |
63551ae0 | 687 | for (address = start; address < end; address += HPAGE_SIZE) { |
c7546f8f | 688 | ptep = huge_pte_offset(mm, address); |
4c887265 | 689 | if (!ptep) |
c7546f8f DG |
690 | continue; |
691 | ||
39dde65c CK |
692 | if (huge_pmd_unshare(mm, &address, ptep)) |
693 | continue; | |
694 | ||
c7546f8f | 695 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
63551ae0 DG |
696 | if (pte_none(pte)) |
697 | continue; | |
c7546f8f | 698 | |
63551ae0 | 699 | page = pte_page(pte); |
6649a386 KC |
700 | if (pte_dirty(pte)) |
701 | set_page_dirty(page); | |
fe1668ae | 702 | list_add(&page->lru, &page_list); |
63551ae0 | 703 | } |
1da177e4 | 704 | spin_unlock(&mm->page_table_lock); |
508034a3 | 705 | flush_tlb_range(vma, start, end); |
fe1668ae CK |
706 | list_for_each_entry_safe(page, tmp, &page_list, lru) { |
707 | list_del(&page->lru); | |
708 | put_page(page); | |
709 | } | |
1da177e4 | 710 | } |
63551ae0 | 711 | |
502717f4 CK |
712 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
713 | unsigned long end) | |
714 | { | |
715 | /* | |
716 | * It is undesirable to test vma->vm_file as it should be non-null | |
717 | * for valid hugetlb area. However, vm_file will be NULL in the error | |
718 | * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails, | |
719 | * do_mmap_pgoff() nullifies vma->vm_file before calling this function | |
720 | * to clean up. Since no pte has actually been setup, it is safe to | |
721 | * do nothing in this case. | |
722 | */ | |
723 | if (vma->vm_file) { | |
724 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); | |
725 | __unmap_hugepage_range(vma, start, end); | |
726 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); | |
727 | } | |
728 | } | |
729 | ||
1e8f889b DG |
730 | static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
731 | unsigned long address, pte_t *ptep, pte_t pte) | |
732 | { | |
733 | struct page *old_page, *new_page; | |
79ac6ba4 | 734 | int avoidcopy; |
1e8f889b DG |
735 | |
736 | old_page = pte_page(pte); | |
737 | ||
738 | /* If no-one else is actually using this page, avoid the copy | |
739 | * and just make the page writable */ | |
740 | avoidcopy = (page_count(old_page) == 1); | |
741 | if (avoidcopy) { | |
742 | set_huge_ptep_writable(vma, address, ptep); | |
83c54070 | 743 | return 0; |
1e8f889b DG |
744 | } |
745 | ||
746 | page_cache_get(old_page); | |
5da7ca86 | 747 | new_page = alloc_huge_page(vma, address); |
1e8f889b | 748 | |
2fc39cec | 749 | if (IS_ERR(new_page)) { |
1e8f889b | 750 | page_cache_release(old_page); |
2fc39cec | 751 | return -PTR_ERR(new_page); |
1e8f889b DG |
752 | } |
753 | ||
754 | spin_unlock(&mm->page_table_lock); | |
9de455b2 | 755 | copy_huge_page(new_page, old_page, address, vma); |
1e8f889b DG |
756 | spin_lock(&mm->page_table_lock); |
757 | ||
758 | ptep = huge_pte_offset(mm, address & HPAGE_MASK); | |
759 | if (likely(pte_same(*ptep, pte))) { | |
760 | /* Break COW */ | |
761 | set_huge_pte_at(mm, address, ptep, | |
762 | make_huge_pte(vma, new_page, 1)); | |
763 | /* Make the old page be freed below */ | |
764 | new_page = old_page; | |
765 | } | |
766 | page_cache_release(new_page); | |
767 | page_cache_release(old_page); | |
83c54070 | 768 | return 0; |
1e8f889b DG |
769 | } |
770 | ||
a1ed3dda | 771 | static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1e8f889b | 772 | unsigned long address, pte_t *ptep, int write_access) |
ac9b9c66 HD |
773 | { |
774 | int ret = VM_FAULT_SIGBUS; | |
4c887265 AL |
775 | unsigned long idx; |
776 | unsigned long size; | |
4c887265 AL |
777 | struct page *page; |
778 | struct address_space *mapping; | |
1e8f889b | 779 | pte_t new_pte; |
4c887265 | 780 | |
4c887265 AL |
781 | mapping = vma->vm_file->f_mapping; |
782 | idx = ((address - vma->vm_start) >> HPAGE_SHIFT) | |
783 | + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT)); | |
784 | ||
785 | /* | |
786 | * Use page lock to guard against racing truncation | |
787 | * before we get page_table_lock. | |
788 | */ | |
6bda666a CL |
789 | retry: |
790 | page = find_lock_page(mapping, idx); | |
791 | if (!page) { | |
ebed4bfc HD |
792 | size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
793 | if (idx >= size) | |
794 | goto out; | |
6bda666a | 795 | page = alloc_huge_page(vma, address); |
2fc39cec AL |
796 | if (IS_ERR(page)) { |
797 | ret = -PTR_ERR(page); | |
6bda666a CL |
798 | goto out; |
799 | } | |
79ac6ba4 | 800 | clear_huge_page(page, address); |
ac9b9c66 | 801 | |
6bda666a CL |
802 | if (vma->vm_flags & VM_SHARED) { |
803 | int err; | |
45c682a6 | 804 | struct inode *inode = mapping->host; |
6bda666a CL |
805 | |
806 | err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); | |
807 | if (err) { | |
808 | put_page(page); | |
6bda666a CL |
809 | if (err == -EEXIST) |
810 | goto retry; | |
811 | goto out; | |
812 | } | |
45c682a6 KC |
813 | |
814 | spin_lock(&inode->i_lock); | |
815 | inode->i_blocks += BLOCKS_PER_HUGEPAGE; | |
816 | spin_unlock(&inode->i_lock); | |
6bda666a CL |
817 | } else |
818 | lock_page(page); | |
819 | } | |
1e8f889b | 820 | |
ac9b9c66 | 821 | spin_lock(&mm->page_table_lock); |
4c887265 AL |
822 | size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
823 | if (idx >= size) | |
824 | goto backout; | |
825 | ||
83c54070 | 826 | ret = 0; |
86e5216f | 827 | if (!pte_none(*ptep)) |
4c887265 AL |
828 | goto backout; |
829 | ||
1e8f889b DG |
830 | new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) |
831 | && (vma->vm_flags & VM_SHARED))); | |
832 | set_huge_pte_at(mm, address, ptep, new_pte); | |
833 | ||
834 | if (write_access && !(vma->vm_flags & VM_SHARED)) { | |
835 | /* Optimization, do the COW without a second fault */ | |
836 | ret = hugetlb_cow(mm, vma, address, ptep, new_pte); | |
837 | } | |
838 | ||
ac9b9c66 | 839 | spin_unlock(&mm->page_table_lock); |
4c887265 AL |
840 | unlock_page(page); |
841 | out: | |
ac9b9c66 | 842 | return ret; |
4c887265 AL |
843 | |
844 | backout: | |
845 | spin_unlock(&mm->page_table_lock); | |
4c887265 AL |
846 | unlock_page(page); |
847 | put_page(page); | |
848 | goto out; | |
ac9b9c66 HD |
849 | } |
850 | ||
86e5216f AL |
851 | int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
852 | unsigned long address, int write_access) | |
853 | { | |
854 | pte_t *ptep; | |
855 | pte_t entry; | |
1e8f889b | 856 | int ret; |
3935baa9 | 857 | static DEFINE_MUTEX(hugetlb_instantiation_mutex); |
86e5216f AL |
858 | |
859 | ptep = huge_pte_alloc(mm, address); | |
860 | if (!ptep) | |
861 | return VM_FAULT_OOM; | |
862 | ||
3935baa9 DG |
863 | /* |
864 | * Serialize hugepage allocation and instantiation, so that we don't | |
865 | * get spurious allocation failures if two CPUs race to instantiate | |
866 | * the same page in the page cache. | |
867 | */ | |
868 | mutex_lock(&hugetlb_instantiation_mutex); | |
86e5216f | 869 | entry = *ptep; |
3935baa9 DG |
870 | if (pte_none(entry)) { |
871 | ret = hugetlb_no_page(mm, vma, address, ptep, write_access); | |
872 | mutex_unlock(&hugetlb_instantiation_mutex); | |
873 | return ret; | |
874 | } | |
86e5216f | 875 | |
83c54070 | 876 | ret = 0; |
1e8f889b DG |
877 | |
878 | spin_lock(&mm->page_table_lock); | |
879 | /* Check for a racing update before calling hugetlb_cow */ | |
880 | if (likely(pte_same(entry, *ptep))) | |
881 | if (write_access && !pte_write(entry)) | |
882 | ret = hugetlb_cow(mm, vma, address, ptep, entry); | |
883 | spin_unlock(&mm->page_table_lock); | |
3935baa9 | 884 | mutex_unlock(&hugetlb_instantiation_mutex); |
1e8f889b DG |
885 | |
886 | return ret; | |
86e5216f AL |
887 | } |
888 | ||
63551ae0 DG |
889 | int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, |
890 | struct page **pages, struct vm_area_struct **vmas, | |
5b23dbe8 AL |
891 | unsigned long *position, int *length, int i, |
892 | int write) | |
63551ae0 | 893 | { |
d5d4b0aa CK |
894 | unsigned long pfn_offset; |
895 | unsigned long vaddr = *position; | |
63551ae0 DG |
896 | int remainder = *length; |
897 | ||
1c59827d | 898 | spin_lock(&mm->page_table_lock); |
63551ae0 | 899 | while (vaddr < vma->vm_end && remainder) { |
4c887265 AL |
900 | pte_t *pte; |
901 | struct page *page; | |
63551ae0 | 902 | |
4c887265 AL |
903 | /* |
904 | * Some archs (sparc64, sh*) have multiple pte_ts to | |
905 | * each hugepage. We have to make * sure we get the | |
906 | * first, for the page indexing below to work. | |
907 | */ | |
908 | pte = huge_pte_offset(mm, vaddr & HPAGE_MASK); | |
63551ae0 | 909 | |
4c887265 AL |
910 | if (!pte || pte_none(*pte)) { |
911 | int ret; | |
63551ae0 | 912 | |
4c887265 | 913 | spin_unlock(&mm->page_table_lock); |
5b23dbe8 | 914 | ret = hugetlb_fault(mm, vma, vaddr, write); |
4c887265 | 915 | spin_lock(&mm->page_table_lock); |
a89182c7 | 916 | if (!(ret & VM_FAULT_ERROR)) |
4c887265 | 917 | continue; |
63551ae0 | 918 | |
4c887265 AL |
919 | remainder = 0; |
920 | if (!i) | |
921 | i = -EFAULT; | |
922 | break; | |
923 | } | |
924 | ||
d5d4b0aa CK |
925 | pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT; |
926 | page = pte_page(*pte); | |
927 | same_page: | |
d6692183 CK |
928 | if (pages) { |
929 | get_page(page); | |
d5d4b0aa | 930 | pages[i] = page + pfn_offset; |
d6692183 | 931 | } |
63551ae0 DG |
932 | |
933 | if (vmas) | |
934 | vmas[i] = vma; | |
935 | ||
936 | vaddr += PAGE_SIZE; | |
d5d4b0aa | 937 | ++pfn_offset; |
63551ae0 DG |
938 | --remainder; |
939 | ++i; | |
d5d4b0aa CK |
940 | if (vaddr < vma->vm_end && remainder && |
941 | pfn_offset < HPAGE_SIZE/PAGE_SIZE) { | |
942 | /* | |
943 | * We use pfn_offset to avoid touching the pageframes | |
944 | * of this compound page. | |
945 | */ | |
946 | goto same_page; | |
947 | } | |
63551ae0 | 948 | } |
1c59827d | 949 | spin_unlock(&mm->page_table_lock); |
63551ae0 DG |
950 | *length = remainder; |
951 | *position = vaddr; | |
952 | ||
953 | return i; | |
954 | } | |
8f860591 ZY |
955 | |
956 | void hugetlb_change_protection(struct vm_area_struct *vma, | |
957 | unsigned long address, unsigned long end, pgprot_t newprot) | |
958 | { | |
959 | struct mm_struct *mm = vma->vm_mm; | |
960 | unsigned long start = address; | |
961 | pte_t *ptep; | |
962 | pte_t pte; | |
963 | ||
964 | BUG_ON(address >= end); | |
965 | flush_cache_range(vma, address, end); | |
966 | ||
39dde65c | 967 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); |
8f860591 ZY |
968 | spin_lock(&mm->page_table_lock); |
969 | for (; address < end; address += HPAGE_SIZE) { | |
970 | ptep = huge_pte_offset(mm, address); | |
971 | if (!ptep) | |
972 | continue; | |
39dde65c CK |
973 | if (huge_pmd_unshare(mm, &address, ptep)) |
974 | continue; | |
8f860591 ZY |
975 | if (!pte_none(*ptep)) { |
976 | pte = huge_ptep_get_and_clear(mm, address, ptep); | |
977 | pte = pte_mkhuge(pte_modify(pte, newprot)); | |
978 | set_huge_pte_at(mm, address, ptep, pte); | |
8f860591 ZY |
979 | } |
980 | } | |
981 | spin_unlock(&mm->page_table_lock); | |
39dde65c | 982 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); |
8f860591 ZY |
983 | |
984 | flush_tlb_range(vma, start, end); | |
985 | } | |
986 | ||
a43a8c39 CK |
987 | struct file_region { |
988 | struct list_head link; | |
989 | long from; | |
990 | long to; | |
991 | }; | |
992 | ||
993 | static long region_add(struct list_head *head, long f, long t) | |
994 | { | |
995 | struct file_region *rg, *nrg, *trg; | |
996 | ||
997 | /* Locate the region we are either in or before. */ | |
998 | list_for_each_entry(rg, head, link) | |
999 | if (f <= rg->to) | |
1000 | break; | |
1001 | ||
1002 | /* Round our left edge to the current segment if it encloses us. */ | |
1003 | if (f > rg->from) | |
1004 | f = rg->from; | |
1005 | ||
1006 | /* Check for and consume any regions we now overlap with. */ | |
1007 | nrg = rg; | |
1008 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { | |
1009 | if (&rg->link == head) | |
1010 | break; | |
1011 | if (rg->from > t) | |
1012 | break; | |
1013 | ||
1014 | /* If this area reaches higher then extend our area to | |
1015 | * include it completely. If this is not the first area | |
1016 | * which we intend to reuse, free it. */ | |
1017 | if (rg->to > t) | |
1018 | t = rg->to; | |
1019 | if (rg != nrg) { | |
1020 | list_del(&rg->link); | |
1021 | kfree(rg); | |
1022 | } | |
1023 | } | |
1024 | nrg->from = f; | |
1025 | nrg->to = t; | |
1026 | return 0; | |
1027 | } | |
1028 | ||
1029 | static long region_chg(struct list_head *head, long f, long t) | |
1030 | { | |
1031 | struct file_region *rg, *nrg; | |
1032 | long chg = 0; | |
1033 | ||
1034 | /* Locate the region we are before or in. */ | |
1035 | list_for_each_entry(rg, head, link) | |
1036 | if (f <= rg->to) | |
1037 | break; | |
1038 | ||
1039 | /* If we are below the current region then a new region is required. | |
1040 | * Subtle, allocate a new region at the position but make it zero | |
183ff22b | 1041 | * size such that we can guarantee to record the reservation. */ |
a43a8c39 CK |
1042 | if (&rg->link == head || t < rg->from) { |
1043 | nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); | |
c80544dc | 1044 | if (!nrg) |
a43a8c39 CK |
1045 | return -ENOMEM; |
1046 | nrg->from = f; | |
1047 | nrg->to = f; | |
1048 | INIT_LIST_HEAD(&nrg->link); | |
1049 | list_add(&nrg->link, rg->link.prev); | |
1050 | ||
1051 | return t - f; | |
1052 | } | |
1053 | ||
1054 | /* Round our left edge to the current segment if it encloses us. */ | |
1055 | if (f > rg->from) | |
1056 | f = rg->from; | |
1057 | chg = t - f; | |
1058 | ||
1059 | /* Check for and consume any regions we now overlap with. */ | |
1060 | list_for_each_entry(rg, rg->link.prev, link) { | |
1061 | if (&rg->link == head) | |
1062 | break; | |
1063 | if (rg->from > t) | |
1064 | return chg; | |
1065 | ||
1066 | /* We overlap with this area, if it extends futher than | |
1067 | * us then we must extend ourselves. Account for its | |
1068 | * existing reservation. */ | |
1069 | if (rg->to > t) { | |
1070 | chg += rg->to - t; | |
1071 | t = rg->to; | |
1072 | } | |
1073 | chg -= rg->to - rg->from; | |
1074 | } | |
1075 | return chg; | |
1076 | } | |
1077 | ||
1078 | static long region_truncate(struct list_head *head, long end) | |
1079 | { | |
1080 | struct file_region *rg, *trg; | |
1081 | long chg = 0; | |
1082 | ||
1083 | /* Locate the region we are either in or before. */ | |
1084 | list_for_each_entry(rg, head, link) | |
1085 | if (end <= rg->to) | |
1086 | break; | |
1087 | if (&rg->link == head) | |
1088 | return 0; | |
1089 | ||
1090 | /* If we are in the middle of a region then adjust it. */ | |
1091 | if (end > rg->from) { | |
1092 | chg = rg->to - end; | |
1093 | rg->to = end; | |
1094 | rg = list_entry(rg->link.next, typeof(*rg), link); | |
1095 | } | |
1096 | ||
1097 | /* Drop any remaining regions. */ | |
1098 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { | |
1099 | if (&rg->link == head) | |
1100 | break; | |
1101 | chg += rg->to - rg->from; | |
1102 | list_del(&rg->link); | |
1103 | kfree(rg); | |
1104 | } | |
1105 | return chg; | |
1106 | } | |
1107 | ||
1108 | static int hugetlb_acct_memory(long delta) | |
1109 | { | |
1110 | int ret = -ENOMEM; | |
1111 | ||
1112 | spin_lock(&hugetlb_lock); | |
8a630112 KC |
1113 | /* |
1114 | * When cpuset is configured, it breaks the strict hugetlb page | |
1115 | * reservation as the accounting is done on a global variable. Such | |
1116 | * reservation is completely rubbish in the presence of cpuset because | |
1117 | * the reservation is not checked against page availability for the | |
1118 | * current cpuset. Application can still potentially OOM'ed by kernel | |
1119 | * with lack of free htlb page in cpuset that the task is in. | |
1120 | * Attempt to enforce strict accounting with cpuset is almost | |
1121 | * impossible (or too ugly) because cpuset is too fluid that | |
1122 | * task or memory node can be dynamically moved between cpusets. | |
1123 | * | |
1124 | * The change of semantics for shared hugetlb mapping with cpuset is | |
1125 | * undesirable. However, in order to preserve some of the semantics, | |
1126 | * we fall back to check against current free page availability as | |
1127 | * a best attempt and hopefully to minimize the impact of changing | |
1128 | * semantics that cpuset has. | |
1129 | */ | |
e4e574b7 AL |
1130 | if (delta > 0) { |
1131 | if (gather_surplus_pages(delta) < 0) | |
1132 | goto out; | |
1133 | ||
1134 | if (delta > cpuset_mems_nr(free_huge_pages_node)) | |
1135 | goto out; | |
1136 | } | |
1137 | ||
1138 | ret = 0; | |
1139 | resv_huge_pages += delta; | |
1140 | if (delta < 0) | |
1141 | return_unused_surplus_pages((unsigned long) -delta); | |
1142 | ||
1143 | out: | |
1144 | spin_unlock(&hugetlb_lock); | |
1145 | return ret; | |
1146 | } | |
1147 | ||
1148 | int hugetlb_reserve_pages(struct inode *inode, long from, long to) | |
1149 | { | |
1150 | long ret, chg; | |
1151 | ||
1152 | chg = region_chg(&inode->i_mapping->private_list, from, to); | |
1153 | if (chg < 0) | |
1154 | return chg; | |
8a630112 | 1155 | |
90d8b7e6 AL |
1156 | if (hugetlb_get_quota(inode->i_mapping, chg)) |
1157 | return -ENOSPC; | |
a43a8c39 CK |
1158 | ret = hugetlb_acct_memory(chg); |
1159 | if (ret < 0) | |
1160 | return ret; | |
1161 | region_add(&inode->i_mapping->private_list, from, to); | |
1162 | return 0; | |
1163 | } | |
1164 | ||
1165 | void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) | |
1166 | { | |
1167 | long chg = region_truncate(&inode->i_mapping->private_list, offset); | |
45c682a6 KC |
1168 | |
1169 | spin_lock(&inode->i_lock); | |
1170 | inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed; | |
1171 | spin_unlock(&inode->i_lock); | |
1172 | ||
90d8b7e6 AL |
1173 | hugetlb_put_quota(inode->i_mapping, (chg - freed)); |
1174 | hugetlb_acct_memory(-(chg - freed)); | |
a43a8c39 | 1175 | } |