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Commit | Line | Data |
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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); |
27a85ef1 | 119 | |
7893d1d5 | 120 | BUG_ON(page_count(page)); |
27a85ef1 DG |
121 | INIT_LIST_HEAD(&page->lru); |
122 | ||
123 | spin_lock(&hugetlb_lock); | |
7893d1d5 AL |
124 | if (surplus_huge_pages_node[nid]) { |
125 | update_and_free_page(page); | |
126 | surplus_huge_pages--; | |
127 | surplus_huge_pages_node[nid]--; | |
128 | } else { | |
129 | enqueue_huge_page(page); | |
130 | } | |
27a85ef1 DG |
131 | spin_unlock(&hugetlb_lock); |
132 | } | |
133 | ||
7893d1d5 AL |
134 | /* |
135 | * Increment or decrement surplus_huge_pages. Keep node-specific counters | |
136 | * balanced by operating on them in a round-robin fashion. | |
137 | * Returns 1 if an adjustment was made. | |
138 | */ | |
139 | static int adjust_pool_surplus(int delta) | |
140 | { | |
141 | static int prev_nid; | |
142 | int nid = prev_nid; | |
143 | int ret = 0; | |
144 | ||
145 | VM_BUG_ON(delta != -1 && delta != 1); | |
146 | do { | |
147 | nid = next_node(nid, node_online_map); | |
148 | if (nid == MAX_NUMNODES) | |
149 | nid = first_node(node_online_map); | |
150 | ||
151 | /* To shrink on this node, there must be a surplus page */ | |
152 | if (delta < 0 && !surplus_huge_pages_node[nid]) | |
153 | continue; | |
154 | /* Surplus cannot exceed the total number of pages */ | |
155 | if (delta > 0 && surplus_huge_pages_node[nid] >= | |
156 | nr_huge_pages_node[nid]) | |
157 | continue; | |
158 | ||
159 | surplus_huge_pages += delta; | |
160 | surplus_huge_pages_node[nid] += delta; | |
161 | ret = 1; | |
162 | break; | |
163 | } while (nid != prev_nid); | |
164 | ||
165 | prev_nid = nid; | |
166 | return ret; | |
167 | } | |
168 | ||
63b4613c | 169 | static struct page *alloc_fresh_huge_page_node(int nid) |
1da177e4 | 170 | { |
1da177e4 | 171 | struct page *page; |
f96efd58 | 172 | |
63b4613c NA |
173 | page = alloc_pages_node(nid, |
174 | htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|__GFP_NOWARN, | |
175 | HUGETLB_PAGE_ORDER); | |
1da177e4 | 176 | if (page) { |
33f2ef89 | 177 | set_compound_page_dtor(page, free_huge_page); |
0bd0f9fb | 178 | spin_lock(&hugetlb_lock); |
1da177e4 | 179 | nr_huge_pages++; |
63b4613c | 180 | nr_huge_pages_node[nid]++; |
0bd0f9fb | 181 | spin_unlock(&hugetlb_lock); |
a482289d | 182 | put_page(page); /* free it into the hugepage allocator */ |
1da177e4 | 183 | } |
63b4613c NA |
184 | |
185 | return page; | |
186 | } | |
187 | ||
188 | static int alloc_fresh_huge_page(void) | |
189 | { | |
190 | struct page *page; | |
191 | int start_nid; | |
192 | int next_nid; | |
193 | int ret = 0; | |
194 | ||
195 | start_nid = hugetlb_next_nid; | |
196 | ||
197 | do { | |
198 | page = alloc_fresh_huge_page_node(hugetlb_next_nid); | |
199 | if (page) | |
200 | ret = 1; | |
201 | /* | |
202 | * Use a helper variable to find the next node and then | |
203 | * copy it back to hugetlb_next_nid afterwards: | |
204 | * otherwise there's a window in which a racer might | |
205 | * pass invalid nid MAX_NUMNODES to alloc_pages_node. | |
206 | * But we don't need to use a spin_lock here: it really | |
207 | * doesn't matter if occasionally a racer chooses the | |
208 | * same nid as we do. Move nid forward in the mask even | |
209 | * if we just successfully allocated a hugepage so that | |
210 | * the next caller gets hugepages on the next node. | |
211 | */ | |
212 | next_nid = next_node(hugetlb_next_nid, node_online_map); | |
213 | if (next_nid == MAX_NUMNODES) | |
214 | next_nid = first_node(node_online_map); | |
215 | hugetlb_next_nid = next_nid; | |
216 | } while (!page && hugetlb_next_nid != start_nid); | |
217 | ||
218 | return ret; | |
1da177e4 LT |
219 | } |
220 | ||
7893d1d5 AL |
221 | static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma, |
222 | unsigned long address) | |
223 | { | |
224 | struct page *page; | |
225 | ||
54f9f80d AL |
226 | /* Check if the dynamic pool is enabled */ |
227 | if (!hugetlb_dynamic_pool) | |
228 | return NULL; | |
229 | ||
7893d1d5 AL |
230 | page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN, |
231 | HUGETLB_PAGE_ORDER); | |
232 | if (page) { | |
233 | set_compound_page_dtor(page, free_huge_page); | |
234 | spin_lock(&hugetlb_lock); | |
235 | nr_huge_pages++; | |
236 | nr_huge_pages_node[page_to_nid(page)]++; | |
237 | surplus_huge_pages++; | |
238 | surplus_huge_pages_node[page_to_nid(page)]++; | |
239 | spin_unlock(&hugetlb_lock); | |
240 | } | |
241 | ||
242 | return page; | |
243 | } | |
244 | ||
e4e574b7 AL |
245 | /* |
246 | * Increase the hugetlb pool such that it can accomodate a reservation | |
247 | * of size 'delta'. | |
248 | */ | |
249 | static int gather_surplus_pages(int delta) | |
250 | { | |
251 | struct list_head surplus_list; | |
252 | struct page *page, *tmp; | |
253 | int ret, i; | |
254 | int needed, allocated; | |
255 | ||
256 | needed = (resv_huge_pages + delta) - free_huge_pages; | |
257 | if (needed <= 0) | |
258 | return 0; | |
259 | ||
260 | allocated = 0; | |
261 | INIT_LIST_HEAD(&surplus_list); | |
262 | ||
263 | ret = -ENOMEM; | |
264 | retry: | |
265 | spin_unlock(&hugetlb_lock); | |
266 | for (i = 0; i < needed; i++) { | |
267 | page = alloc_buddy_huge_page(NULL, 0); | |
268 | if (!page) { | |
269 | /* | |
270 | * We were not able to allocate enough pages to | |
271 | * satisfy the entire reservation so we free what | |
272 | * we've allocated so far. | |
273 | */ | |
274 | spin_lock(&hugetlb_lock); | |
275 | needed = 0; | |
276 | goto free; | |
277 | } | |
278 | ||
279 | list_add(&page->lru, &surplus_list); | |
280 | } | |
281 | allocated += needed; | |
282 | ||
283 | /* | |
284 | * After retaking hugetlb_lock, we need to recalculate 'needed' | |
285 | * because either resv_huge_pages or free_huge_pages may have changed. | |
286 | */ | |
287 | spin_lock(&hugetlb_lock); | |
288 | needed = (resv_huge_pages + delta) - (free_huge_pages + allocated); | |
289 | if (needed > 0) | |
290 | goto retry; | |
291 | ||
292 | /* | |
293 | * The surplus_list now contains _at_least_ the number of extra pages | |
294 | * needed to accomodate the reservation. Add the appropriate number | |
295 | * of pages to the hugetlb pool and free the extras back to the buddy | |
296 | * allocator. | |
297 | */ | |
298 | needed += allocated; | |
299 | ret = 0; | |
300 | free: | |
301 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) { | |
302 | list_del(&page->lru); | |
303 | if ((--needed) >= 0) | |
304 | enqueue_huge_page(page); | |
305 | else | |
306 | update_and_free_page(page); | |
307 | } | |
308 | ||
309 | return ret; | |
310 | } | |
311 | ||
312 | /* | |
313 | * When releasing a hugetlb pool reservation, any surplus pages that were | |
314 | * allocated to satisfy the reservation must be explicitly freed if they were | |
315 | * never used. | |
316 | */ | |
317 | void return_unused_surplus_pages(unsigned long unused_resv_pages) | |
318 | { | |
319 | static int nid = -1; | |
320 | struct page *page; | |
321 | unsigned long nr_pages; | |
322 | ||
323 | nr_pages = min(unused_resv_pages, surplus_huge_pages); | |
324 | ||
325 | while (nr_pages) { | |
326 | nid = next_node(nid, node_online_map); | |
327 | if (nid == MAX_NUMNODES) | |
328 | nid = first_node(node_online_map); | |
329 | ||
330 | if (!surplus_huge_pages_node[nid]) | |
331 | continue; | |
332 | ||
333 | if (!list_empty(&hugepage_freelists[nid])) { | |
334 | page = list_entry(hugepage_freelists[nid].next, | |
335 | struct page, lru); | |
336 | list_del(&page->lru); | |
337 | update_and_free_page(page); | |
338 | free_huge_pages--; | |
339 | free_huge_pages_node[nid]--; | |
340 | surplus_huge_pages--; | |
341 | surplus_huge_pages_node[nid]--; | |
342 | nr_pages--; | |
343 | } | |
344 | } | |
345 | } | |
346 | ||
27a85ef1 DG |
347 | static struct page *alloc_huge_page(struct vm_area_struct *vma, |
348 | unsigned long addr) | |
1da177e4 | 349 | { |
7893d1d5 | 350 | struct page *page = NULL; |
e4e574b7 | 351 | int use_reserved_page = vma->vm_flags & VM_MAYSHARE; |
1da177e4 LT |
352 | |
353 | spin_lock(&hugetlb_lock); | |
e4e574b7 | 354 | if (!use_reserved_page && (free_huge_pages <= resv_huge_pages)) |
a43a8c39 | 355 | goto fail; |
b45b5bd6 DG |
356 | |
357 | page = dequeue_huge_page(vma, addr); | |
358 | if (!page) | |
359 | goto fail; | |
360 | ||
1da177e4 | 361 | spin_unlock(&hugetlb_lock); |
7835e98b | 362 | set_page_refcounted(page); |
1da177e4 | 363 | return page; |
b45b5bd6 | 364 | |
a43a8c39 | 365 | fail: |
b45b5bd6 | 366 | spin_unlock(&hugetlb_lock); |
7893d1d5 AL |
367 | |
368 | /* | |
369 | * Private mappings do not use reserved huge pages so the allocation | |
370 | * may have failed due to an undersized hugetlb pool. Try to grab a | |
371 | * surplus huge page from the buddy allocator. | |
372 | */ | |
e4e574b7 | 373 | if (!use_reserved_page) |
7893d1d5 AL |
374 | page = alloc_buddy_huge_page(vma, addr); |
375 | ||
376 | return page; | |
b45b5bd6 DG |
377 | } |
378 | ||
1da177e4 LT |
379 | static int __init hugetlb_init(void) |
380 | { | |
381 | unsigned long i; | |
1da177e4 | 382 | |
3c726f8d BH |
383 | if (HPAGE_SHIFT == 0) |
384 | return 0; | |
385 | ||
1da177e4 LT |
386 | for (i = 0; i < MAX_NUMNODES; ++i) |
387 | INIT_LIST_HEAD(&hugepage_freelists[i]); | |
388 | ||
63b4613c NA |
389 | hugetlb_next_nid = first_node(node_online_map); |
390 | ||
1da177e4 | 391 | for (i = 0; i < max_huge_pages; ++i) { |
a482289d | 392 | if (!alloc_fresh_huge_page()) |
1da177e4 | 393 | break; |
1da177e4 LT |
394 | } |
395 | max_huge_pages = free_huge_pages = nr_huge_pages = i; | |
396 | printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages); | |
397 | return 0; | |
398 | } | |
399 | module_init(hugetlb_init); | |
400 | ||
401 | static int __init hugetlb_setup(char *s) | |
402 | { | |
403 | if (sscanf(s, "%lu", &max_huge_pages) <= 0) | |
404 | max_huge_pages = 0; | |
405 | return 1; | |
406 | } | |
407 | __setup("hugepages=", hugetlb_setup); | |
408 | ||
8a630112 KC |
409 | static unsigned int cpuset_mems_nr(unsigned int *array) |
410 | { | |
411 | int node; | |
412 | unsigned int nr = 0; | |
413 | ||
414 | for_each_node_mask(node, cpuset_current_mems_allowed) | |
415 | nr += array[node]; | |
416 | ||
417 | return nr; | |
418 | } | |
419 | ||
1da177e4 | 420 | #ifdef CONFIG_SYSCTL |
1da177e4 LT |
421 | #ifdef CONFIG_HIGHMEM |
422 | static void try_to_free_low(unsigned long count) | |
423 | { | |
4415cc8d CL |
424 | int i; |
425 | ||
1da177e4 LT |
426 | for (i = 0; i < MAX_NUMNODES; ++i) { |
427 | struct page *page, *next; | |
428 | list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) { | |
6b0c880d AL |
429 | if (count >= nr_huge_pages) |
430 | return; | |
1da177e4 LT |
431 | if (PageHighMem(page)) |
432 | continue; | |
433 | list_del(&page->lru); | |
434 | update_and_free_page(page); | |
1da177e4 | 435 | free_huge_pages--; |
4415cc8d | 436 | free_huge_pages_node[page_to_nid(page)]--; |
1da177e4 LT |
437 | } |
438 | } | |
439 | } | |
440 | #else | |
441 | static inline void try_to_free_low(unsigned long count) | |
442 | { | |
443 | } | |
444 | #endif | |
445 | ||
7893d1d5 | 446 | #define persistent_huge_pages (nr_huge_pages - surplus_huge_pages) |
1da177e4 LT |
447 | static unsigned long set_max_huge_pages(unsigned long count) |
448 | { | |
7893d1d5 | 449 | unsigned long min_count, ret; |
1da177e4 | 450 | |
7893d1d5 AL |
451 | /* |
452 | * Increase the pool size | |
453 | * First take pages out of surplus state. Then make up the | |
454 | * remaining difference by allocating fresh huge pages. | |
455 | */ | |
1da177e4 | 456 | spin_lock(&hugetlb_lock); |
7893d1d5 AL |
457 | while (surplus_huge_pages && count > persistent_huge_pages) { |
458 | if (!adjust_pool_surplus(-1)) | |
459 | break; | |
460 | } | |
461 | ||
462 | while (count > persistent_huge_pages) { | |
463 | int ret; | |
464 | /* | |
465 | * If this allocation races such that we no longer need the | |
466 | * page, free_huge_page will handle it by freeing the page | |
467 | * and reducing the surplus. | |
468 | */ | |
469 | spin_unlock(&hugetlb_lock); | |
470 | ret = alloc_fresh_huge_page(); | |
471 | spin_lock(&hugetlb_lock); | |
472 | if (!ret) | |
473 | goto out; | |
474 | ||
475 | } | |
7893d1d5 AL |
476 | |
477 | /* | |
478 | * Decrease the pool size | |
479 | * First return free pages to the buddy allocator (being careful | |
480 | * to keep enough around to satisfy reservations). Then place | |
481 | * pages into surplus state as needed so the pool will shrink | |
482 | * to the desired size as pages become free. | |
483 | */ | |
6b0c880d AL |
484 | min_count = resv_huge_pages + nr_huge_pages - free_huge_pages; |
485 | min_count = max(count, min_count); | |
7893d1d5 AL |
486 | try_to_free_low(min_count); |
487 | while (min_count < persistent_huge_pages) { | |
5da7ca86 | 488 | struct page *page = dequeue_huge_page(NULL, 0); |
1da177e4 LT |
489 | if (!page) |
490 | break; | |
491 | update_and_free_page(page); | |
492 | } | |
7893d1d5 AL |
493 | while (count < persistent_huge_pages) { |
494 | if (!adjust_pool_surplus(1)) | |
495 | break; | |
496 | } | |
497 | out: | |
498 | ret = persistent_huge_pages; | |
1da177e4 | 499 | spin_unlock(&hugetlb_lock); |
7893d1d5 | 500 | return ret; |
1da177e4 LT |
501 | } |
502 | ||
503 | int hugetlb_sysctl_handler(struct ctl_table *table, int write, | |
504 | struct file *file, void __user *buffer, | |
505 | size_t *length, loff_t *ppos) | |
506 | { | |
507 | proc_doulongvec_minmax(table, write, file, buffer, length, ppos); | |
508 | max_huge_pages = set_max_huge_pages(max_huge_pages); | |
509 | return 0; | |
510 | } | |
396faf03 MG |
511 | |
512 | int hugetlb_treat_movable_handler(struct ctl_table *table, int write, | |
513 | struct file *file, void __user *buffer, | |
514 | size_t *length, loff_t *ppos) | |
515 | { | |
516 | proc_dointvec(table, write, file, buffer, length, ppos); | |
517 | if (hugepages_treat_as_movable) | |
518 | htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; | |
519 | else | |
520 | htlb_alloc_mask = GFP_HIGHUSER; | |
521 | return 0; | |
522 | } | |
523 | ||
1da177e4 LT |
524 | #endif /* CONFIG_SYSCTL */ |
525 | ||
526 | int hugetlb_report_meminfo(char *buf) | |
527 | { | |
528 | return sprintf(buf, | |
529 | "HugePages_Total: %5lu\n" | |
530 | "HugePages_Free: %5lu\n" | |
a43a8c39 | 531 | "HugePages_Rsvd: %5lu\n" |
7893d1d5 | 532 | "HugePages_Surp: %5lu\n" |
1da177e4 LT |
533 | "Hugepagesize: %5lu kB\n", |
534 | nr_huge_pages, | |
535 | free_huge_pages, | |
a43a8c39 | 536 | resv_huge_pages, |
7893d1d5 | 537 | surplus_huge_pages, |
1da177e4 LT |
538 | HPAGE_SIZE/1024); |
539 | } | |
540 | ||
541 | int hugetlb_report_node_meminfo(int nid, char *buf) | |
542 | { | |
543 | return sprintf(buf, | |
544 | "Node %d HugePages_Total: %5u\n" | |
545 | "Node %d HugePages_Free: %5u\n", | |
546 | nid, nr_huge_pages_node[nid], | |
547 | nid, free_huge_pages_node[nid]); | |
548 | } | |
549 | ||
1da177e4 LT |
550 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
551 | unsigned long hugetlb_total_pages(void) | |
552 | { | |
553 | return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE); | |
554 | } | |
1da177e4 LT |
555 | |
556 | /* | |
557 | * We cannot handle pagefaults against hugetlb pages at all. They cause | |
558 | * handle_mm_fault() to try to instantiate regular-sized pages in the | |
559 | * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get | |
560 | * this far. | |
561 | */ | |
d0217ac0 | 562 | static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 LT |
563 | { |
564 | BUG(); | |
d0217ac0 | 565 | return 0; |
1da177e4 LT |
566 | } |
567 | ||
568 | struct vm_operations_struct hugetlb_vm_ops = { | |
d0217ac0 | 569 | .fault = hugetlb_vm_op_fault, |
1da177e4 LT |
570 | }; |
571 | ||
1e8f889b DG |
572 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
573 | int writable) | |
63551ae0 DG |
574 | { |
575 | pte_t entry; | |
576 | ||
1e8f889b | 577 | if (writable) { |
63551ae0 DG |
578 | entry = |
579 | pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); | |
580 | } else { | |
581 | entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot)); | |
582 | } | |
583 | entry = pte_mkyoung(entry); | |
584 | entry = pte_mkhuge(entry); | |
585 | ||
586 | return entry; | |
587 | } | |
588 | ||
1e8f889b DG |
589 | static void set_huge_ptep_writable(struct vm_area_struct *vma, |
590 | unsigned long address, pte_t *ptep) | |
591 | { | |
592 | pte_t entry; | |
593 | ||
594 | entry = pte_mkwrite(pte_mkdirty(*ptep)); | |
8dab5241 BH |
595 | if (ptep_set_access_flags(vma, address, ptep, entry, 1)) { |
596 | update_mmu_cache(vma, address, entry); | |
8dab5241 | 597 | } |
1e8f889b DG |
598 | } |
599 | ||
600 | ||
63551ae0 DG |
601 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
602 | struct vm_area_struct *vma) | |
603 | { | |
604 | pte_t *src_pte, *dst_pte, entry; | |
605 | struct page *ptepage; | |
1c59827d | 606 | unsigned long addr; |
1e8f889b DG |
607 | int cow; |
608 | ||
609 | cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; | |
63551ae0 | 610 | |
1c59827d | 611 | for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) { |
c74df32c HD |
612 | src_pte = huge_pte_offset(src, addr); |
613 | if (!src_pte) | |
614 | continue; | |
63551ae0 DG |
615 | dst_pte = huge_pte_alloc(dst, addr); |
616 | if (!dst_pte) | |
617 | goto nomem; | |
c74df32c | 618 | spin_lock(&dst->page_table_lock); |
1c59827d | 619 | spin_lock(&src->page_table_lock); |
c74df32c | 620 | if (!pte_none(*src_pte)) { |
1e8f889b DG |
621 | if (cow) |
622 | ptep_set_wrprotect(src, addr, src_pte); | |
1c59827d HD |
623 | entry = *src_pte; |
624 | ptepage = pte_page(entry); | |
625 | get_page(ptepage); | |
1c59827d HD |
626 | set_huge_pte_at(dst, addr, dst_pte, entry); |
627 | } | |
628 | spin_unlock(&src->page_table_lock); | |
c74df32c | 629 | spin_unlock(&dst->page_table_lock); |
63551ae0 DG |
630 | } |
631 | return 0; | |
632 | ||
633 | nomem: | |
634 | return -ENOMEM; | |
635 | } | |
636 | ||
502717f4 KC |
637 | void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
638 | unsigned long end) | |
63551ae0 DG |
639 | { |
640 | struct mm_struct *mm = vma->vm_mm; | |
641 | unsigned long address; | |
c7546f8f | 642 | pte_t *ptep; |
63551ae0 DG |
643 | pte_t pte; |
644 | struct page *page; | |
fe1668ae | 645 | struct page *tmp; |
c0a499c2 KC |
646 | /* |
647 | * A page gathering list, protected by per file i_mmap_lock. The | |
648 | * lock is used to avoid list corruption from multiple unmapping | |
649 | * of the same page since we are using page->lru. | |
650 | */ | |
fe1668ae | 651 | LIST_HEAD(page_list); |
63551ae0 DG |
652 | |
653 | WARN_ON(!is_vm_hugetlb_page(vma)); | |
654 | BUG_ON(start & ~HPAGE_MASK); | |
655 | BUG_ON(end & ~HPAGE_MASK); | |
656 | ||
508034a3 | 657 | spin_lock(&mm->page_table_lock); |
63551ae0 | 658 | for (address = start; address < end; address += HPAGE_SIZE) { |
c7546f8f | 659 | ptep = huge_pte_offset(mm, address); |
4c887265 | 660 | if (!ptep) |
c7546f8f DG |
661 | continue; |
662 | ||
39dde65c KC |
663 | if (huge_pmd_unshare(mm, &address, ptep)) |
664 | continue; | |
665 | ||
c7546f8f | 666 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
63551ae0 DG |
667 | if (pte_none(pte)) |
668 | continue; | |
c7546f8f | 669 | |
63551ae0 | 670 | page = pte_page(pte); |
6649a386 KC |
671 | if (pte_dirty(pte)) |
672 | set_page_dirty(page); | |
fe1668ae | 673 | list_add(&page->lru, &page_list); |
63551ae0 | 674 | } |
1da177e4 | 675 | spin_unlock(&mm->page_table_lock); |
508034a3 | 676 | flush_tlb_range(vma, start, end); |
fe1668ae KC |
677 | list_for_each_entry_safe(page, tmp, &page_list, lru) { |
678 | list_del(&page->lru); | |
679 | put_page(page); | |
680 | } | |
1da177e4 | 681 | } |
63551ae0 | 682 | |
502717f4 KC |
683 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
684 | unsigned long end) | |
685 | { | |
686 | /* | |
687 | * It is undesirable to test vma->vm_file as it should be non-null | |
688 | * for valid hugetlb area. However, vm_file will be NULL in the error | |
689 | * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails, | |
690 | * do_mmap_pgoff() nullifies vma->vm_file before calling this function | |
691 | * to clean up. Since no pte has actually been setup, it is safe to | |
692 | * do nothing in this case. | |
693 | */ | |
694 | if (vma->vm_file) { | |
695 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); | |
696 | __unmap_hugepage_range(vma, start, end); | |
697 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); | |
698 | } | |
699 | } | |
700 | ||
1e8f889b DG |
701 | static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
702 | unsigned long address, pte_t *ptep, pte_t pte) | |
703 | { | |
704 | struct page *old_page, *new_page; | |
79ac6ba4 | 705 | int avoidcopy; |
1e8f889b DG |
706 | |
707 | old_page = pte_page(pte); | |
708 | ||
709 | /* If no-one else is actually using this page, avoid the copy | |
710 | * and just make the page writable */ | |
711 | avoidcopy = (page_count(old_page) == 1); | |
712 | if (avoidcopy) { | |
713 | set_huge_ptep_writable(vma, address, ptep); | |
83c54070 | 714 | return 0; |
1e8f889b DG |
715 | } |
716 | ||
717 | page_cache_get(old_page); | |
5da7ca86 | 718 | new_page = alloc_huge_page(vma, address); |
1e8f889b DG |
719 | |
720 | if (!new_page) { | |
721 | page_cache_release(old_page); | |
0df420d8 | 722 | return VM_FAULT_OOM; |
1e8f889b DG |
723 | } |
724 | ||
725 | spin_unlock(&mm->page_table_lock); | |
9de455b2 | 726 | copy_huge_page(new_page, old_page, address, vma); |
1e8f889b DG |
727 | spin_lock(&mm->page_table_lock); |
728 | ||
729 | ptep = huge_pte_offset(mm, address & HPAGE_MASK); | |
730 | if (likely(pte_same(*ptep, pte))) { | |
731 | /* Break COW */ | |
732 | set_huge_pte_at(mm, address, ptep, | |
733 | make_huge_pte(vma, new_page, 1)); | |
734 | /* Make the old page be freed below */ | |
735 | new_page = old_page; | |
736 | } | |
737 | page_cache_release(new_page); | |
738 | page_cache_release(old_page); | |
83c54070 | 739 | return 0; |
1e8f889b DG |
740 | } |
741 | ||
a1ed3dda | 742 | static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1e8f889b | 743 | unsigned long address, pte_t *ptep, int write_access) |
ac9b9c66 HD |
744 | { |
745 | int ret = VM_FAULT_SIGBUS; | |
4c887265 AL |
746 | unsigned long idx; |
747 | unsigned long size; | |
4c887265 AL |
748 | struct page *page; |
749 | struct address_space *mapping; | |
1e8f889b | 750 | pte_t new_pte; |
4c887265 | 751 | |
4c887265 AL |
752 | mapping = vma->vm_file->f_mapping; |
753 | idx = ((address - vma->vm_start) >> HPAGE_SHIFT) | |
754 | + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT)); | |
755 | ||
756 | /* | |
757 | * Use page lock to guard against racing truncation | |
758 | * before we get page_table_lock. | |
759 | */ | |
6bda666a CL |
760 | retry: |
761 | page = find_lock_page(mapping, idx); | |
762 | if (!page) { | |
ebed4bfc HD |
763 | size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
764 | if (idx >= size) | |
765 | goto out; | |
6bda666a CL |
766 | if (hugetlb_get_quota(mapping)) |
767 | goto out; | |
768 | page = alloc_huge_page(vma, address); | |
769 | if (!page) { | |
770 | hugetlb_put_quota(mapping); | |
0df420d8 | 771 | ret = VM_FAULT_OOM; |
6bda666a CL |
772 | goto out; |
773 | } | |
79ac6ba4 | 774 | clear_huge_page(page, address); |
ac9b9c66 | 775 | |
6bda666a CL |
776 | if (vma->vm_flags & VM_SHARED) { |
777 | int err; | |
778 | ||
779 | err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); | |
780 | if (err) { | |
781 | put_page(page); | |
782 | hugetlb_put_quota(mapping); | |
783 | if (err == -EEXIST) | |
784 | goto retry; | |
785 | goto out; | |
786 | } | |
787 | } else | |
788 | lock_page(page); | |
789 | } | |
1e8f889b | 790 | |
ac9b9c66 | 791 | spin_lock(&mm->page_table_lock); |
4c887265 AL |
792 | size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
793 | if (idx >= size) | |
794 | goto backout; | |
795 | ||
83c54070 | 796 | ret = 0; |
86e5216f | 797 | if (!pte_none(*ptep)) |
4c887265 AL |
798 | goto backout; |
799 | ||
1e8f889b DG |
800 | new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) |
801 | && (vma->vm_flags & VM_SHARED))); | |
802 | set_huge_pte_at(mm, address, ptep, new_pte); | |
803 | ||
804 | if (write_access && !(vma->vm_flags & VM_SHARED)) { | |
805 | /* Optimization, do the COW without a second fault */ | |
806 | ret = hugetlb_cow(mm, vma, address, ptep, new_pte); | |
807 | } | |
808 | ||
ac9b9c66 | 809 | spin_unlock(&mm->page_table_lock); |
4c887265 AL |
810 | unlock_page(page); |
811 | out: | |
ac9b9c66 | 812 | return ret; |
4c887265 AL |
813 | |
814 | backout: | |
815 | spin_unlock(&mm->page_table_lock); | |
816 | hugetlb_put_quota(mapping); | |
817 | unlock_page(page); | |
818 | put_page(page); | |
819 | goto out; | |
ac9b9c66 HD |
820 | } |
821 | ||
86e5216f AL |
822 | int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
823 | unsigned long address, int write_access) | |
824 | { | |
825 | pte_t *ptep; | |
826 | pte_t entry; | |
1e8f889b | 827 | int ret; |
3935baa9 | 828 | static DEFINE_MUTEX(hugetlb_instantiation_mutex); |
86e5216f AL |
829 | |
830 | ptep = huge_pte_alloc(mm, address); | |
831 | if (!ptep) | |
832 | return VM_FAULT_OOM; | |
833 | ||
3935baa9 DG |
834 | /* |
835 | * Serialize hugepage allocation and instantiation, so that we don't | |
836 | * get spurious allocation failures if two CPUs race to instantiate | |
837 | * the same page in the page cache. | |
838 | */ | |
839 | mutex_lock(&hugetlb_instantiation_mutex); | |
86e5216f | 840 | entry = *ptep; |
3935baa9 DG |
841 | if (pte_none(entry)) { |
842 | ret = hugetlb_no_page(mm, vma, address, ptep, write_access); | |
843 | mutex_unlock(&hugetlb_instantiation_mutex); | |
844 | return ret; | |
845 | } | |
86e5216f | 846 | |
83c54070 | 847 | ret = 0; |
1e8f889b DG |
848 | |
849 | spin_lock(&mm->page_table_lock); | |
850 | /* Check for a racing update before calling hugetlb_cow */ | |
851 | if (likely(pte_same(entry, *ptep))) | |
852 | if (write_access && !pte_write(entry)) | |
853 | ret = hugetlb_cow(mm, vma, address, ptep, entry); | |
854 | spin_unlock(&mm->page_table_lock); | |
3935baa9 | 855 | mutex_unlock(&hugetlb_instantiation_mutex); |
1e8f889b DG |
856 | |
857 | return ret; | |
86e5216f AL |
858 | } |
859 | ||
63551ae0 DG |
860 | int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, |
861 | struct page **pages, struct vm_area_struct **vmas, | |
862 | unsigned long *position, int *length, int i) | |
863 | { | |
d5d4b0aa KC |
864 | unsigned long pfn_offset; |
865 | unsigned long vaddr = *position; | |
63551ae0 DG |
866 | int remainder = *length; |
867 | ||
1c59827d | 868 | spin_lock(&mm->page_table_lock); |
63551ae0 | 869 | while (vaddr < vma->vm_end && remainder) { |
4c887265 AL |
870 | pte_t *pte; |
871 | struct page *page; | |
63551ae0 | 872 | |
4c887265 AL |
873 | /* |
874 | * Some archs (sparc64, sh*) have multiple pte_ts to | |
875 | * each hugepage. We have to make * sure we get the | |
876 | * first, for the page indexing below to work. | |
877 | */ | |
878 | pte = huge_pte_offset(mm, vaddr & HPAGE_MASK); | |
63551ae0 | 879 | |
4c887265 AL |
880 | if (!pte || pte_none(*pte)) { |
881 | int ret; | |
63551ae0 | 882 | |
4c887265 AL |
883 | spin_unlock(&mm->page_table_lock); |
884 | ret = hugetlb_fault(mm, vma, vaddr, 0); | |
885 | spin_lock(&mm->page_table_lock); | |
a89182c7 | 886 | if (!(ret & VM_FAULT_ERROR)) |
4c887265 | 887 | continue; |
63551ae0 | 888 | |
4c887265 AL |
889 | remainder = 0; |
890 | if (!i) | |
891 | i = -EFAULT; | |
892 | break; | |
893 | } | |
894 | ||
d5d4b0aa KC |
895 | pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT; |
896 | page = pte_page(*pte); | |
897 | same_page: | |
d6692183 KC |
898 | if (pages) { |
899 | get_page(page); | |
d5d4b0aa | 900 | pages[i] = page + pfn_offset; |
d6692183 | 901 | } |
63551ae0 DG |
902 | |
903 | if (vmas) | |
904 | vmas[i] = vma; | |
905 | ||
906 | vaddr += PAGE_SIZE; | |
d5d4b0aa | 907 | ++pfn_offset; |
63551ae0 DG |
908 | --remainder; |
909 | ++i; | |
d5d4b0aa KC |
910 | if (vaddr < vma->vm_end && remainder && |
911 | pfn_offset < HPAGE_SIZE/PAGE_SIZE) { | |
912 | /* | |
913 | * We use pfn_offset to avoid touching the pageframes | |
914 | * of this compound page. | |
915 | */ | |
916 | goto same_page; | |
917 | } | |
63551ae0 | 918 | } |
1c59827d | 919 | spin_unlock(&mm->page_table_lock); |
63551ae0 DG |
920 | *length = remainder; |
921 | *position = vaddr; | |
922 | ||
923 | return i; | |
924 | } | |
8f860591 ZY |
925 | |
926 | void hugetlb_change_protection(struct vm_area_struct *vma, | |
927 | unsigned long address, unsigned long end, pgprot_t newprot) | |
928 | { | |
929 | struct mm_struct *mm = vma->vm_mm; | |
930 | unsigned long start = address; | |
931 | pte_t *ptep; | |
932 | pte_t pte; | |
933 | ||
934 | BUG_ON(address >= end); | |
935 | flush_cache_range(vma, address, end); | |
936 | ||
39dde65c | 937 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); |
8f860591 ZY |
938 | spin_lock(&mm->page_table_lock); |
939 | for (; address < end; address += HPAGE_SIZE) { | |
940 | ptep = huge_pte_offset(mm, address); | |
941 | if (!ptep) | |
942 | continue; | |
39dde65c KC |
943 | if (huge_pmd_unshare(mm, &address, ptep)) |
944 | continue; | |
8f860591 ZY |
945 | if (!pte_none(*ptep)) { |
946 | pte = huge_ptep_get_and_clear(mm, address, ptep); | |
947 | pte = pte_mkhuge(pte_modify(pte, newprot)); | |
948 | set_huge_pte_at(mm, address, ptep, pte); | |
8f860591 ZY |
949 | } |
950 | } | |
951 | spin_unlock(&mm->page_table_lock); | |
39dde65c | 952 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); |
8f860591 ZY |
953 | |
954 | flush_tlb_range(vma, start, end); | |
955 | } | |
956 | ||
a43a8c39 KC |
957 | struct file_region { |
958 | struct list_head link; | |
959 | long from; | |
960 | long to; | |
961 | }; | |
962 | ||
963 | static long region_add(struct list_head *head, long f, long t) | |
964 | { | |
965 | struct file_region *rg, *nrg, *trg; | |
966 | ||
967 | /* Locate the region we are either in or before. */ | |
968 | list_for_each_entry(rg, head, link) | |
969 | if (f <= rg->to) | |
970 | break; | |
971 | ||
972 | /* Round our left edge to the current segment if it encloses us. */ | |
973 | if (f > rg->from) | |
974 | f = rg->from; | |
975 | ||
976 | /* Check for and consume any regions we now overlap with. */ | |
977 | nrg = rg; | |
978 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { | |
979 | if (&rg->link == head) | |
980 | break; | |
981 | if (rg->from > t) | |
982 | break; | |
983 | ||
984 | /* If this area reaches higher then extend our area to | |
985 | * include it completely. If this is not the first area | |
986 | * which we intend to reuse, free it. */ | |
987 | if (rg->to > t) | |
988 | t = rg->to; | |
989 | if (rg != nrg) { | |
990 | list_del(&rg->link); | |
991 | kfree(rg); | |
992 | } | |
993 | } | |
994 | nrg->from = f; | |
995 | nrg->to = t; | |
996 | return 0; | |
997 | } | |
998 | ||
999 | static long region_chg(struct list_head *head, long f, long t) | |
1000 | { | |
1001 | struct file_region *rg, *nrg; | |
1002 | long chg = 0; | |
1003 | ||
1004 | /* Locate the region we are before or in. */ | |
1005 | list_for_each_entry(rg, head, link) | |
1006 | if (f <= rg->to) | |
1007 | break; | |
1008 | ||
1009 | /* If we are below the current region then a new region is required. | |
1010 | * Subtle, allocate a new region at the position but make it zero | |
1011 | * size such that we can guarentee to record the reservation. */ | |
1012 | if (&rg->link == head || t < rg->from) { | |
1013 | nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); | |
1014 | if (nrg == 0) | |
1015 | return -ENOMEM; | |
1016 | nrg->from = f; | |
1017 | nrg->to = f; | |
1018 | INIT_LIST_HEAD(&nrg->link); | |
1019 | list_add(&nrg->link, rg->link.prev); | |
1020 | ||
1021 | return t - f; | |
1022 | } | |
1023 | ||
1024 | /* Round our left edge to the current segment if it encloses us. */ | |
1025 | if (f > rg->from) | |
1026 | f = rg->from; | |
1027 | chg = t - f; | |
1028 | ||
1029 | /* Check for and consume any regions we now overlap with. */ | |
1030 | list_for_each_entry(rg, rg->link.prev, link) { | |
1031 | if (&rg->link == head) | |
1032 | break; | |
1033 | if (rg->from > t) | |
1034 | return chg; | |
1035 | ||
1036 | /* We overlap with this area, if it extends futher than | |
1037 | * us then we must extend ourselves. Account for its | |
1038 | * existing reservation. */ | |
1039 | if (rg->to > t) { | |
1040 | chg += rg->to - t; | |
1041 | t = rg->to; | |
1042 | } | |
1043 | chg -= rg->to - rg->from; | |
1044 | } | |
1045 | return chg; | |
1046 | } | |
1047 | ||
1048 | static long region_truncate(struct list_head *head, long end) | |
1049 | { | |
1050 | struct file_region *rg, *trg; | |
1051 | long chg = 0; | |
1052 | ||
1053 | /* Locate the region we are either in or before. */ | |
1054 | list_for_each_entry(rg, head, link) | |
1055 | if (end <= rg->to) | |
1056 | break; | |
1057 | if (&rg->link == head) | |
1058 | return 0; | |
1059 | ||
1060 | /* If we are in the middle of a region then adjust it. */ | |
1061 | if (end > rg->from) { | |
1062 | chg = rg->to - end; | |
1063 | rg->to = end; | |
1064 | rg = list_entry(rg->link.next, typeof(*rg), link); | |
1065 | } | |
1066 | ||
1067 | /* Drop any remaining regions. */ | |
1068 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { | |
1069 | if (&rg->link == head) | |
1070 | break; | |
1071 | chg += rg->to - rg->from; | |
1072 | list_del(&rg->link); | |
1073 | kfree(rg); | |
1074 | } | |
1075 | return chg; | |
1076 | } | |
1077 | ||
1078 | static int hugetlb_acct_memory(long delta) | |
1079 | { | |
1080 | int ret = -ENOMEM; | |
1081 | ||
1082 | spin_lock(&hugetlb_lock); | |
8a630112 KC |
1083 | /* |
1084 | * When cpuset is configured, it breaks the strict hugetlb page | |
1085 | * reservation as the accounting is done on a global variable. Such | |
1086 | * reservation is completely rubbish in the presence of cpuset because | |
1087 | * the reservation is not checked against page availability for the | |
1088 | * current cpuset. Application can still potentially OOM'ed by kernel | |
1089 | * with lack of free htlb page in cpuset that the task is in. | |
1090 | * Attempt to enforce strict accounting with cpuset is almost | |
1091 | * impossible (or too ugly) because cpuset is too fluid that | |
1092 | * task or memory node can be dynamically moved between cpusets. | |
1093 | * | |
1094 | * The change of semantics for shared hugetlb mapping with cpuset is | |
1095 | * undesirable. However, in order to preserve some of the semantics, | |
1096 | * we fall back to check against current free page availability as | |
1097 | * a best attempt and hopefully to minimize the impact of changing | |
1098 | * semantics that cpuset has. | |
1099 | */ | |
e4e574b7 AL |
1100 | if (delta > 0) { |
1101 | if (gather_surplus_pages(delta) < 0) | |
1102 | goto out; | |
1103 | ||
1104 | if (delta > cpuset_mems_nr(free_huge_pages_node)) | |
1105 | goto out; | |
1106 | } | |
1107 | ||
1108 | ret = 0; | |
1109 | resv_huge_pages += delta; | |
1110 | if (delta < 0) | |
1111 | return_unused_surplus_pages((unsigned long) -delta); | |
1112 | ||
1113 | out: | |
1114 | spin_unlock(&hugetlb_lock); | |
1115 | return ret; | |
1116 | } | |
1117 | ||
1118 | int hugetlb_reserve_pages(struct inode *inode, long from, long to) | |
1119 | { | |
1120 | long ret, chg; | |
1121 | ||
1122 | chg = region_chg(&inode->i_mapping->private_list, from, to); | |
1123 | if (chg < 0) | |
1124 | return chg; | |
8a630112 | 1125 | |
a43a8c39 KC |
1126 | ret = hugetlb_acct_memory(chg); |
1127 | if (ret < 0) | |
1128 | return ret; | |
1129 | region_add(&inode->i_mapping->private_list, from, to); | |
1130 | return 0; | |
1131 | } | |
1132 | ||
1133 | void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) | |
1134 | { | |
1135 | long chg = region_truncate(&inode->i_mapping->private_list, offset); | |
1136 | hugetlb_acct_memory(freed - chg); | |
1137 | } |