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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; |
064d9efe | 27 | static unsigned long nr_overcommit_huge_pages; |
1da177e4 | 28 | unsigned long max_huge_pages; |
064d9efe | 29 | unsigned long sysctl_overcommit_huge_pages; |
1da177e4 LT |
30 | static struct list_head hugepage_freelists[MAX_NUMNODES]; |
31 | static unsigned int nr_huge_pages_node[MAX_NUMNODES]; | |
32 | static unsigned int free_huge_pages_node[MAX_NUMNODES]; | |
7893d1d5 | 33 | static unsigned int surplus_huge_pages_node[MAX_NUMNODES]; |
396faf03 MG |
34 | static gfp_t htlb_alloc_mask = GFP_HIGHUSER; |
35 | unsigned long hugepages_treat_as_movable; | |
63b4613c | 36 | static int hugetlb_next_nid; |
396faf03 | 37 | |
3935baa9 DG |
38 | /* |
39 | * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages | |
40 | */ | |
41 | static DEFINE_SPINLOCK(hugetlb_lock); | |
0bd0f9fb | 42 | |
79ac6ba4 DG |
43 | static void clear_huge_page(struct page *page, unsigned long addr) |
44 | { | |
45 | int i; | |
46 | ||
47 | might_sleep(); | |
48 | for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); i++) { | |
49 | cond_resched(); | |
281e0e3b | 50 | clear_user_highpage(page + i, addr + i * PAGE_SIZE); |
79ac6ba4 DG |
51 | } |
52 | } | |
53 | ||
54 | static void copy_huge_page(struct page *dst, struct page *src, | |
9de455b2 | 55 | unsigned long addr, struct vm_area_struct *vma) |
79ac6ba4 DG |
56 | { |
57 | int i; | |
58 | ||
59 | might_sleep(); | |
60 | for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++) { | |
61 | cond_resched(); | |
9de455b2 | 62 | copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); |
79ac6ba4 DG |
63 | } |
64 | } | |
65 | ||
1da177e4 LT |
66 | static void enqueue_huge_page(struct page *page) |
67 | { | |
68 | int nid = page_to_nid(page); | |
69 | list_add(&page->lru, &hugepage_freelists[nid]); | |
70 | free_huge_pages++; | |
71 | free_huge_pages_node[nid]++; | |
72 | } | |
73 | ||
5da7ca86 CL |
74 | static struct page *dequeue_huge_page(struct vm_area_struct *vma, |
75 | unsigned long address) | |
1da177e4 | 76 | { |
31a5c6e4 | 77 | int nid; |
1da177e4 | 78 | struct page *page = NULL; |
480eccf9 | 79 | struct mempolicy *mpol; |
396faf03 | 80 | struct zonelist *zonelist = huge_zonelist(vma, address, |
480eccf9 | 81 | htlb_alloc_mask, &mpol); |
96df9333 | 82 | struct zone **z; |
1da177e4 | 83 | |
96df9333 | 84 | for (z = zonelist->zones; *z; z++) { |
89fa3024 | 85 | nid = zone_to_nid(*z); |
396faf03 | 86 | if (cpuset_zone_allowed_softwall(*z, htlb_alloc_mask) && |
3abf7afd AM |
87 | !list_empty(&hugepage_freelists[nid])) { |
88 | page = list_entry(hugepage_freelists[nid].next, | |
89 | struct page, lru); | |
90 | list_del(&page->lru); | |
91 | free_huge_pages--; | |
92 | free_huge_pages_node[nid]--; | |
e4e574b7 AL |
93 | if (vma && vma->vm_flags & VM_MAYSHARE) |
94 | resv_huge_pages--; | |
5ab3ee7b | 95 | break; |
3abf7afd | 96 | } |
1da177e4 | 97 | } |
480eccf9 | 98 | mpol_free(mpol); /* unref if mpol !NULL */ |
1da177e4 LT |
99 | return page; |
100 | } | |
101 | ||
6af2acb6 AL |
102 | static void update_and_free_page(struct page *page) |
103 | { | |
104 | int i; | |
105 | nr_huge_pages--; | |
106 | nr_huge_pages_node[page_to_nid(page)]--; | |
107 | for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) { | |
108 | page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | | |
109 | 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | | |
110 | 1 << PG_private | 1<< PG_writeback); | |
111 | } | |
112 | set_compound_page_dtor(page, NULL); | |
113 | set_page_refcounted(page); | |
114 | __free_pages(page, HUGETLB_PAGE_ORDER); | |
115 | } | |
116 | ||
27a85ef1 DG |
117 | static void free_huge_page(struct page *page) |
118 | { | |
7893d1d5 | 119 | int nid = page_to_nid(page); |
c79fb75e | 120 | struct address_space *mapping; |
27a85ef1 | 121 | |
c79fb75e | 122 | mapping = (struct address_space *) page_private(page); |
e5df70ab | 123 | set_page_private(page, 0); |
7893d1d5 | 124 | BUG_ON(page_count(page)); |
27a85ef1 DG |
125 | INIT_LIST_HEAD(&page->lru); |
126 | ||
127 | spin_lock(&hugetlb_lock); | |
7893d1d5 AL |
128 | if (surplus_huge_pages_node[nid]) { |
129 | update_and_free_page(page); | |
130 | surplus_huge_pages--; | |
131 | surplus_huge_pages_node[nid]--; | |
132 | } else { | |
133 | enqueue_huge_page(page); | |
134 | } | |
27a85ef1 | 135 | spin_unlock(&hugetlb_lock); |
c79fb75e | 136 | if (mapping) |
9a119c05 | 137 | hugetlb_put_quota(mapping, 1); |
27a85ef1 DG |
138 | } |
139 | ||
7893d1d5 AL |
140 | /* |
141 | * Increment or decrement surplus_huge_pages. Keep node-specific counters | |
142 | * balanced by operating on them in a round-robin fashion. | |
143 | * Returns 1 if an adjustment was made. | |
144 | */ | |
145 | static int adjust_pool_surplus(int delta) | |
146 | { | |
147 | static int prev_nid; | |
148 | int nid = prev_nid; | |
149 | int ret = 0; | |
150 | ||
151 | VM_BUG_ON(delta != -1 && delta != 1); | |
152 | do { | |
153 | nid = next_node(nid, node_online_map); | |
154 | if (nid == MAX_NUMNODES) | |
155 | nid = first_node(node_online_map); | |
156 | ||
157 | /* To shrink on this node, there must be a surplus page */ | |
158 | if (delta < 0 && !surplus_huge_pages_node[nid]) | |
159 | continue; | |
160 | /* Surplus cannot exceed the total number of pages */ | |
161 | if (delta > 0 && surplus_huge_pages_node[nid] >= | |
162 | nr_huge_pages_node[nid]) | |
163 | continue; | |
164 | ||
165 | surplus_huge_pages += delta; | |
166 | surplus_huge_pages_node[nid] += delta; | |
167 | ret = 1; | |
168 | break; | |
169 | } while (nid != prev_nid); | |
170 | ||
171 | prev_nid = nid; | |
172 | return ret; | |
173 | } | |
174 | ||
63b4613c | 175 | static struct page *alloc_fresh_huge_page_node(int nid) |
1da177e4 | 176 | { |
1da177e4 | 177 | struct page *page; |
f96efd58 | 178 | |
63b4613c NA |
179 | page = alloc_pages_node(nid, |
180 | htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|__GFP_NOWARN, | |
181 | HUGETLB_PAGE_ORDER); | |
1da177e4 | 182 | if (page) { |
33f2ef89 | 183 | set_compound_page_dtor(page, free_huge_page); |
0bd0f9fb | 184 | spin_lock(&hugetlb_lock); |
1da177e4 | 185 | nr_huge_pages++; |
63b4613c | 186 | nr_huge_pages_node[nid]++; |
0bd0f9fb | 187 | spin_unlock(&hugetlb_lock); |
a482289d | 188 | put_page(page); /* free it into the hugepage allocator */ |
1da177e4 | 189 | } |
63b4613c NA |
190 | |
191 | return page; | |
192 | } | |
193 | ||
194 | static int alloc_fresh_huge_page(void) | |
195 | { | |
196 | struct page *page; | |
197 | int start_nid; | |
198 | int next_nid; | |
199 | int ret = 0; | |
200 | ||
201 | start_nid = hugetlb_next_nid; | |
202 | ||
203 | do { | |
204 | page = alloc_fresh_huge_page_node(hugetlb_next_nid); | |
205 | if (page) | |
206 | ret = 1; | |
207 | /* | |
208 | * Use a helper variable to find the next node and then | |
209 | * copy it back to hugetlb_next_nid afterwards: | |
210 | * otherwise there's a window in which a racer might | |
211 | * pass invalid nid MAX_NUMNODES to alloc_pages_node. | |
212 | * But we don't need to use a spin_lock here: it really | |
213 | * doesn't matter if occasionally a racer chooses the | |
214 | * same nid as we do. Move nid forward in the mask even | |
215 | * if we just successfully allocated a hugepage so that | |
216 | * the next caller gets hugepages on the next node. | |
217 | */ | |
218 | next_nid = next_node(hugetlb_next_nid, node_online_map); | |
219 | if (next_nid == MAX_NUMNODES) | |
220 | next_nid = first_node(node_online_map); | |
221 | hugetlb_next_nid = next_nid; | |
222 | } while (!page && hugetlb_next_nid != start_nid); | |
223 | ||
224 | return ret; | |
1da177e4 LT |
225 | } |
226 | ||
7893d1d5 AL |
227 | static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma, |
228 | unsigned long address) | |
229 | { | |
230 | struct page *page; | |
d1c3fb1f | 231 | unsigned int nid; |
7893d1d5 | 232 | |
d1c3fb1f NA |
233 | /* |
234 | * Assume we will successfully allocate the surplus page to | |
235 | * prevent racing processes from causing the surplus to exceed | |
236 | * overcommit | |
237 | * | |
238 | * This however introduces a different race, where a process B | |
239 | * tries to grow the static hugepage pool while alloc_pages() is | |
240 | * called by process A. B will only examine the per-node | |
241 | * counters in determining if surplus huge pages can be | |
242 | * converted to normal huge pages in adjust_pool_surplus(). A | |
243 | * won't be able to increment the per-node counter, until the | |
244 | * lock is dropped by B, but B doesn't drop hugetlb_lock until | |
245 | * no more huge pages can be converted from surplus to normal | |
246 | * state (and doesn't try to convert again). Thus, we have a | |
247 | * case where a surplus huge page exists, the pool is grown, and | |
248 | * the surplus huge page still exists after, even though it | |
249 | * should just have been converted to a normal huge page. This | |
250 | * does not leak memory, though, as the hugepage will be freed | |
251 | * once it is out of use. It also does not allow the counters to | |
252 | * go out of whack in adjust_pool_surplus() as we don't modify | |
253 | * the node values until we've gotten the hugepage and only the | |
254 | * per-node value is checked there. | |
255 | */ | |
256 | spin_lock(&hugetlb_lock); | |
257 | if (surplus_huge_pages >= nr_overcommit_huge_pages) { | |
258 | spin_unlock(&hugetlb_lock); | |
259 | return NULL; | |
260 | } else { | |
261 | nr_huge_pages++; | |
262 | surplus_huge_pages++; | |
263 | } | |
264 | spin_unlock(&hugetlb_lock); | |
265 | ||
7893d1d5 AL |
266 | page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN, |
267 | HUGETLB_PAGE_ORDER); | |
d1c3fb1f NA |
268 | |
269 | spin_lock(&hugetlb_lock); | |
7893d1d5 | 270 | if (page) { |
d1c3fb1f | 271 | nid = page_to_nid(page); |
7893d1d5 | 272 | set_compound_page_dtor(page, free_huge_page); |
d1c3fb1f NA |
273 | /* |
274 | * We incremented the global counters already | |
275 | */ | |
276 | nr_huge_pages_node[nid]++; | |
277 | surplus_huge_pages_node[nid]++; | |
278 | } else { | |
279 | nr_huge_pages--; | |
280 | surplus_huge_pages--; | |
7893d1d5 | 281 | } |
d1c3fb1f | 282 | spin_unlock(&hugetlb_lock); |
7893d1d5 AL |
283 | |
284 | return page; | |
285 | } | |
286 | ||
e4e574b7 AL |
287 | /* |
288 | * Increase the hugetlb pool such that it can accomodate a reservation | |
289 | * of size 'delta'. | |
290 | */ | |
291 | static int gather_surplus_pages(int delta) | |
292 | { | |
293 | struct list_head surplus_list; | |
294 | struct page *page, *tmp; | |
295 | int ret, i; | |
296 | int needed, allocated; | |
297 | ||
298 | needed = (resv_huge_pages + delta) - free_huge_pages; | |
ac09b3a1 AL |
299 | if (needed <= 0) { |
300 | resv_huge_pages += delta; | |
e4e574b7 | 301 | return 0; |
ac09b3a1 | 302 | } |
e4e574b7 AL |
303 | |
304 | allocated = 0; | |
305 | INIT_LIST_HEAD(&surplus_list); | |
306 | ||
307 | ret = -ENOMEM; | |
308 | retry: | |
309 | spin_unlock(&hugetlb_lock); | |
310 | for (i = 0; i < needed; i++) { | |
311 | page = alloc_buddy_huge_page(NULL, 0); | |
312 | if (!page) { | |
313 | /* | |
314 | * We were not able to allocate enough pages to | |
315 | * satisfy the entire reservation so we free what | |
316 | * we've allocated so far. | |
317 | */ | |
318 | spin_lock(&hugetlb_lock); | |
319 | needed = 0; | |
320 | goto free; | |
321 | } | |
322 | ||
323 | list_add(&page->lru, &surplus_list); | |
324 | } | |
325 | allocated += needed; | |
326 | ||
327 | /* | |
328 | * After retaking hugetlb_lock, we need to recalculate 'needed' | |
329 | * because either resv_huge_pages or free_huge_pages may have changed. | |
330 | */ | |
331 | spin_lock(&hugetlb_lock); | |
332 | needed = (resv_huge_pages + delta) - (free_huge_pages + allocated); | |
333 | if (needed > 0) | |
334 | goto retry; | |
335 | ||
336 | /* | |
337 | * The surplus_list now contains _at_least_ the number of extra pages | |
338 | * needed to accomodate the reservation. Add the appropriate number | |
339 | * of pages to the hugetlb pool and free the extras back to the buddy | |
ac09b3a1 AL |
340 | * allocator. Commit the entire reservation here to prevent another |
341 | * process from stealing the pages as they are added to the pool but | |
342 | * before they are reserved. | |
e4e574b7 AL |
343 | */ |
344 | needed += allocated; | |
ac09b3a1 | 345 | resv_huge_pages += delta; |
e4e574b7 AL |
346 | ret = 0; |
347 | free: | |
348 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) { | |
349 | list_del(&page->lru); | |
350 | if ((--needed) >= 0) | |
351 | enqueue_huge_page(page); | |
af767cbd AL |
352 | else { |
353 | /* | |
354 | * Decrement the refcount and free the page using its | |
355 | * destructor. This must be done with hugetlb_lock | |
356 | * unlocked which is safe because free_huge_page takes | |
357 | * hugetlb_lock before deciding how to free the page. | |
358 | */ | |
359 | spin_unlock(&hugetlb_lock); | |
360 | put_page(page); | |
361 | spin_lock(&hugetlb_lock); | |
362 | } | |
e4e574b7 AL |
363 | } |
364 | ||
365 | return ret; | |
366 | } | |
367 | ||
368 | /* | |
369 | * When releasing a hugetlb pool reservation, any surplus pages that were | |
370 | * allocated to satisfy the reservation must be explicitly freed if they were | |
371 | * never used. | |
372 | */ | |
8cde045c | 373 | static void return_unused_surplus_pages(unsigned long unused_resv_pages) |
e4e574b7 AL |
374 | { |
375 | static int nid = -1; | |
376 | struct page *page; | |
377 | unsigned long nr_pages; | |
378 | ||
ac09b3a1 AL |
379 | /* Uncommit the reservation */ |
380 | resv_huge_pages -= unused_resv_pages; | |
381 | ||
e4e574b7 AL |
382 | nr_pages = min(unused_resv_pages, surplus_huge_pages); |
383 | ||
384 | while (nr_pages) { | |
385 | nid = next_node(nid, node_online_map); | |
386 | if (nid == MAX_NUMNODES) | |
387 | nid = first_node(node_online_map); | |
388 | ||
389 | if (!surplus_huge_pages_node[nid]) | |
390 | continue; | |
391 | ||
392 | if (!list_empty(&hugepage_freelists[nid])) { | |
393 | page = list_entry(hugepage_freelists[nid].next, | |
394 | struct page, lru); | |
395 | list_del(&page->lru); | |
396 | update_and_free_page(page); | |
397 | free_huge_pages--; | |
398 | free_huge_pages_node[nid]--; | |
399 | surplus_huge_pages--; | |
400 | surplus_huge_pages_node[nid]--; | |
401 | nr_pages--; | |
402 | } | |
403 | } | |
404 | } | |
405 | ||
348ea204 AL |
406 | |
407 | static struct page *alloc_huge_page_shared(struct vm_area_struct *vma, | |
408 | unsigned long addr) | |
1da177e4 | 409 | { |
348ea204 | 410 | struct page *page; |
1da177e4 LT |
411 | |
412 | spin_lock(&hugetlb_lock); | |
b45b5bd6 | 413 | page = dequeue_huge_page(vma, addr); |
1da177e4 | 414 | spin_unlock(&hugetlb_lock); |
90d8b7e6 | 415 | return page ? page : ERR_PTR(-VM_FAULT_OOM); |
348ea204 | 416 | } |
b45b5bd6 | 417 | |
348ea204 AL |
418 | static struct page *alloc_huge_page_private(struct vm_area_struct *vma, |
419 | unsigned long addr) | |
420 | { | |
421 | struct page *page = NULL; | |
7893d1d5 | 422 | |
90d8b7e6 AL |
423 | if (hugetlb_get_quota(vma->vm_file->f_mapping, 1)) |
424 | return ERR_PTR(-VM_FAULT_SIGBUS); | |
425 | ||
348ea204 AL |
426 | spin_lock(&hugetlb_lock); |
427 | if (free_huge_pages > resv_huge_pages) | |
428 | page = dequeue_huge_page(vma, addr); | |
429 | spin_unlock(&hugetlb_lock); | |
68842c9b | 430 | if (!page) { |
7893d1d5 | 431 | page = alloc_buddy_huge_page(vma, addr); |
68842c9b KC |
432 | if (!page) { |
433 | hugetlb_put_quota(vma->vm_file->f_mapping, 1); | |
434 | return ERR_PTR(-VM_FAULT_OOM); | |
435 | } | |
436 | } | |
437 | return page; | |
348ea204 AL |
438 | } |
439 | ||
440 | static struct page *alloc_huge_page(struct vm_area_struct *vma, | |
441 | unsigned long addr) | |
442 | { | |
443 | struct page *page; | |
2fc39cec AL |
444 | struct address_space *mapping = vma->vm_file->f_mapping; |
445 | ||
348ea204 AL |
446 | if (vma->vm_flags & VM_MAYSHARE) |
447 | page = alloc_huge_page_shared(vma, addr); | |
448 | else | |
449 | page = alloc_huge_page_private(vma, addr); | |
90d8b7e6 AL |
450 | |
451 | if (!IS_ERR(page)) { | |
348ea204 | 452 | set_page_refcounted(page); |
2fc39cec | 453 | set_page_private(page, (unsigned long) mapping); |
90d8b7e6 AL |
454 | } |
455 | return page; | |
b45b5bd6 DG |
456 | } |
457 | ||
1da177e4 LT |
458 | static int __init hugetlb_init(void) |
459 | { | |
460 | unsigned long i; | |
1da177e4 | 461 | |
3c726f8d BH |
462 | if (HPAGE_SHIFT == 0) |
463 | return 0; | |
464 | ||
1da177e4 LT |
465 | for (i = 0; i < MAX_NUMNODES; ++i) |
466 | INIT_LIST_HEAD(&hugepage_freelists[i]); | |
467 | ||
63b4613c NA |
468 | hugetlb_next_nid = first_node(node_online_map); |
469 | ||
1da177e4 | 470 | for (i = 0; i < max_huge_pages; ++i) { |
a482289d | 471 | if (!alloc_fresh_huge_page()) |
1da177e4 | 472 | break; |
1da177e4 LT |
473 | } |
474 | max_huge_pages = free_huge_pages = nr_huge_pages = i; | |
475 | printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages); | |
476 | return 0; | |
477 | } | |
478 | module_init(hugetlb_init); | |
479 | ||
480 | static int __init hugetlb_setup(char *s) | |
481 | { | |
482 | if (sscanf(s, "%lu", &max_huge_pages) <= 0) | |
483 | max_huge_pages = 0; | |
484 | return 1; | |
485 | } | |
486 | __setup("hugepages=", hugetlb_setup); | |
487 | ||
8a630112 KC |
488 | static unsigned int cpuset_mems_nr(unsigned int *array) |
489 | { | |
490 | int node; | |
491 | unsigned int nr = 0; | |
492 | ||
493 | for_each_node_mask(node, cpuset_current_mems_allowed) | |
494 | nr += array[node]; | |
495 | ||
496 | return nr; | |
497 | } | |
498 | ||
1da177e4 | 499 | #ifdef CONFIG_SYSCTL |
1da177e4 LT |
500 | #ifdef CONFIG_HIGHMEM |
501 | static void try_to_free_low(unsigned long count) | |
502 | { | |
4415cc8d CL |
503 | int i; |
504 | ||
1da177e4 LT |
505 | for (i = 0; i < MAX_NUMNODES; ++i) { |
506 | struct page *page, *next; | |
507 | list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) { | |
6b0c880d AL |
508 | if (count >= nr_huge_pages) |
509 | return; | |
1da177e4 LT |
510 | if (PageHighMem(page)) |
511 | continue; | |
512 | list_del(&page->lru); | |
513 | update_and_free_page(page); | |
1da177e4 | 514 | free_huge_pages--; |
4415cc8d | 515 | free_huge_pages_node[page_to_nid(page)]--; |
1da177e4 LT |
516 | } |
517 | } | |
518 | } | |
519 | #else | |
520 | static inline void try_to_free_low(unsigned long count) | |
521 | { | |
522 | } | |
523 | #endif | |
524 | ||
7893d1d5 | 525 | #define persistent_huge_pages (nr_huge_pages - surplus_huge_pages) |
1da177e4 LT |
526 | static unsigned long set_max_huge_pages(unsigned long count) |
527 | { | |
7893d1d5 | 528 | unsigned long min_count, ret; |
1da177e4 | 529 | |
7893d1d5 AL |
530 | /* |
531 | * Increase the pool size | |
532 | * First take pages out of surplus state. Then make up the | |
533 | * remaining difference by allocating fresh huge pages. | |
d1c3fb1f NA |
534 | * |
535 | * We might race with alloc_buddy_huge_page() here and be unable | |
536 | * to convert a surplus huge page to a normal huge page. That is | |
537 | * not critical, though, it just means the overall size of the | |
538 | * pool might be one hugepage larger than it needs to be, but | |
539 | * within all the constraints specified by the sysctls. | |
7893d1d5 | 540 | */ |
1da177e4 | 541 | spin_lock(&hugetlb_lock); |
7893d1d5 AL |
542 | while (surplus_huge_pages && count > persistent_huge_pages) { |
543 | if (!adjust_pool_surplus(-1)) | |
544 | break; | |
545 | } | |
546 | ||
547 | while (count > persistent_huge_pages) { | |
548 | int ret; | |
549 | /* | |
550 | * If this allocation races such that we no longer need the | |
551 | * page, free_huge_page will handle it by freeing the page | |
552 | * and reducing the surplus. | |
553 | */ | |
554 | spin_unlock(&hugetlb_lock); | |
555 | ret = alloc_fresh_huge_page(); | |
556 | spin_lock(&hugetlb_lock); | |
557 | if (!ret) | |
558 | goto out; | |
559 | ||
560 | } | |
7893d1d5 AL |
561 | |
562 | /* | |
563 | * Decrease the pool size | |
564 | * First return free pages to the buddy allocator (being careful | |
565 | * to keep enough around to satisfy reservations). Then place | |
566 | * pages into surplus state as needed so the pool will shrink | |
567 | * to the desired size as pages become free. | |
d1c3fb1f NA |
568 | * |
569 | * By placing pages into the surplus state independent of the | |
570 | * overcommit value, we are allowing the surplus pool size to | |
571 | * exceed overcommit. There are few sane options here. Since | |
572 | * alloc_buddy_huge_page() is checking the global counter, | |
573 | * though, we'll note that we're not allowed to exceed surplus | |
574 | * and won't grow the pool anywhere else. Not until one of the | |
575 | * sysctls are changed, or the surplus pages go out of use. | |
7893d1d5 | 576 | */ |
6b0c880d AL |
577 | min_count = resv_huge_pages + nr_huge_pages - free_huge_pages; |
578 | min_count = max(count, min_count); | |
7893d1d5 AL |
579 | try_to_free_low(min_count); |
580 | while (min_count < persistent_huge_pages) { | |
5da7ca86 | 581 | struct page *page = dequeue_huge_page(NULL, 0); |
1da177e4 LT |
582 | if (!page) |
583 | break; | |
584 | update_and_free_page(page); | |
585 | } | |
7893d1d5 AL |
586 | while (count < persistent_huge_pages) { |
587 | if (!adjust_pool_surplus(1)) | |
588 | break; | |
589 | } | |
590 | out: | |
591 | ret = persistent_huge_pages; | |
1da177e4 | 592 | spin_unlock(&hugetlb_lock); |
7893d1d5 | 593 | return ret; |
1da177e4 LT |
594 | } |
595 | ||
596 | int hugetlb_sysctl_handler(struct ctl_table *table, int write, | |
597 | struct file *file, void __user *buffer, | |
598 | size_t *length, loff_t *ppos) | |
599 | { | |
600 | proc_doulongvec_minmax(table, write, file, buffer, length, ppos); | |
601 | max_huge_pages = set_max_huge_pages(max_huge_pages); | |
602 | return 0; | |
603 | } | |
396faf03 MG |
604 | |
605 | int hugetlb_treat_movable_handler(struct ctl_table *table, int write, | |
606 | struct file *file, void __user *buffer, | |
607 | size_t *length, loff_t *ppos) | |
608 | { | |
609 | proc_dointvec(table, write, file, buffer, length, ppos); | |
610 | if (hugepages_treat_as_movable) | |
611 | htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; | |
612 | else | |
613 | htlb_alloc_mask = GFP_HIGHUSER; | |
614 | return 0; | |
615 | } | |
616 | ||
a3d0c6aa NA |
617 | int hugetlb_overcommit_handler(struct ctl_table *table, int write, |
618 | struct file *file, void __user *buffer, | |
619 | size_t *length, loff_t *ppos) | |
620 | { | |
a3d0c6aa | 621 | proc_doulongvec_minmax(table, write, file, buffer, length, ppos); |
064d9efe NA |
622 | spin_lock(&hugetlb_lock); |
623 | nr_overcommit_huge_pages = sysctl_overcommit_huge_pages; | |
a3d0c6aa NA |
624 | spin_unlock(&hugetlb_lock); |
625 | return 0; | |
626 | } | |
627 | ||
1da177e4 LT |
628 | #endif /* CONFIG_SYSCTL */ |
629 | ||
630 | int hugetlb_report_meminfo(char *buf) | |
631 | { | |
632 | return sprintf(buf, | |
633 | "HugePages_Total: %5lu\n" | |
634 | "HugePages_Free: %5lu\n" | |
a43a8c39 | 635 | "HugePages_Rsvd: %5lu\n" |
7893d1d5 | 636 | "HugePages_Surp: %5lu\n" |
1da177e4 LT |
637 | "Hugepagesize: %5lu kB\n", |
638 | nr_huge_pages, | |
639 | free_huge_pages, | |
a43a8c39 | 640 | resv_huge_pages, |
7893d1d5 | 641 | surplus_huge_pages, |
1da177e4 LT |
642 | HPAGE_SIZE/1024); |
643 | } | |
644 | ||
645 | int hugetlb_report_node_meminfo(int nid, char *buf) | |
646 | { | |
647 | return sprintf(buf, | |
648 | "Node %d HugePages_Total: %5u\n" | |
649 | "Node %d HugePages_Free: %5u\n", | |
650 | nid, nr_huge_pages_node[nid], | |
651 | nid, free_huge_pages_node[nid]); | |
652 | } | |
653 | ||
1da177e4 LT |
654 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
655 | unsigned long hugetlb_total_pages(void) | |
656 | { | |
657 | return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE); | |
658 | } | |
1da177e4 LT |
659 | |
660 | /* | |
661 | * We cannot handle pagefaults against hugetlb pages at all. They cause | |
662 | * handle_mm_fault() to try to instantiate regular-sized pages in the | |
663 | * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get | |
664 | * this far. | |
665 | */ | |
d0217ac0 | 666 | static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 LT |
667 | { |
668 | BUG(); | |
d0217ac0 | 669 | return 0; |
1da177e4 LT |
670 | } |
671 | ||
672 | struct vm_operations_struct hugetlb_vm_ops = { | |
d0217ac0 | 673 | .fault = hugetlb_vm_op_fault, |
1da177e4 LT |
674 | }; |
675 | ||
1e8f889b DG |
676 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
677 | int writable) | |
63551ae0 DG |
678 | { |
679 | pte_t entry; | |
680 | ||
1e8f889b | 681 | if (writable) { |
63551ae0 DG |
682 | entry = |
683 | pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); | |
684 | } else { | |
685 | entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot)); | |
686 | } | |
687 | entry = pte_mkyoung(entry); | |
688 | entry = pte_mkhuge(entry); | |
689 | ||
690 | return entry; | |
691 | } | |
692 | ||
1e8f889b DG |
693 | static void set_huge_ptep_writable(struct vm_area_struct *vma, |
694 | unsigned long address, pte_t *ptep) | |
695 | { | |
696 | pte_t entry; | |
697 | ||
698 | entry = pte_mkwrite(pte_mkdirty(*ptep)); | |
8dab5241 BH |
699 | if (ptep_set_access_flags(vma, address, ptep, entry, 1)) { |
700 | update_mmu_cache(vma, address, entry); | |
8dab5241 | 701 | } |
1e8f889b DG |
702 | } |
703 | ||
704 | ||
63551ae0 DG |
705 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
706 | struct vm_area_struct *vma) | |
707 | { | |
708 | pte_t *src_pte, *dst_pte, entry; | |
709 | struct page *ptepage; | |
1c59827d | 710 | unsigned long addr; |
1e8f889b DG |
711 | int cow; |
712 | ||
713 | cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; | |
63551ae0 | 714 | |
1c59827d | 715 | for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) { |
c74df32c HD |
716 | src_pte = huge_pte_offset(src, addr); |
717 | if (!src_pte) | |
718 | continue; | |
63551ae0 DG |
719 | dst_pte = huge_pte_alloc(dst, addr); |
720 | if (!dst_pte) | |
721 | goto nomem; | |
c5c99429 LW |
722 | |
723 | /* If the pagetables are shared don't copy or take references */ | |
724 | if (dst_pte == src_pte) | |
725 | continue; | |
726 | ||
c74df32c | 727 | spin_lock(&dst->page_table_lock); |
1c59827d | 728 | spin_lock(&src->page_table_lock); |
c74df32c | 729 | if (!pte_none(*src_pte)) { |
1e8f889b DG |
730 | if (cow) |
731 | ptep_set_wrprotect(src, addr, src_pte); | |
1c59827d HD |
732 | entry = *src_pte; |
733 | ptepage = pte_page(entry); | |
734 | get_page(ptepage); | |
1c59827d HD |
735 | set_huge_pte_at(dst, addr, dst_pte, entry); |
736 | } | |
737 | spin_unlock(&src->page_table_lock); | |
c74df32c | 738 | spin_unlock(&dst->page_table_lock); |
63551ae0 DG |
739 | } |
740 | return 0; | |
741 | ||
742 | nomem: | |
743 | return -ENOMEM; | |
744 | } | |
745 | ||
502717f4 KC |
746 | void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
747 | unsigned long end) | |
63551ae0 DG |
748 | { |
749 | struct mm_struct *mm = vma->vm_mm; | |
750 | unsigned long address; | |
c7546f8f | 751 | pte_t *ptep; |
63551ae0 DG |
752 | pte_t pte; |
753 | struct page *page; | |
fe1668ae | 754 | struct page *tmp; |
c0a499c2 KC |
755 | /* |
756 | * A page gathering list, protected by per file i_mmap_lock. The | |
757 | * lock is used to avoid list corruption from multiple unmapping | |
758 | * of the same page since we are using page->lru. | |
759 | */ | |
fe1668ae | 760 | LIST_HEAD(page_list); |
63551ae0 DG |
761 | |
762 | WARN_ON(!is_vm_hugetlb_page(vma)); | |
763 | BUG_ON(start & ~HPAGE_MASK); | |
764 | BUG_ON(end & ~HPAGE_MASK); | |
765 | ||
508034a3 | 766 | spin_lock(&mm->page_table_lock); |
63551ae0 | 767 | for (address = start; address < end; address += HPAGE_SIZE) { |
c7546f8f | 768 | ptep = huge_pte_offset(mm, address); |
4c887265 | 769 | if (!ptep) |
c7546f8f DG |
770 | continue; |
771 | ||
39dde65c KC |
772 | if (huge_pmd_unshare(mm, &address, ptep)) |
773 | continue; | |
774 | ||
c7546f8f | 775 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
63551ae0 DG |
776 | if (pte_none(pte)) |
777 | continue; | |
c7546f8f | 778 | |
63551ae0 | 779 | page = pte_page(pte); |
6649a386 KC |
780 | if (pte_dirty(pte)) |
781 | set_page_dirty(page); | |
fe1668ae | 782 | list_add(&page->lru, &page_list); |
63551ae0 | 783 | } |
1da177e4 | 784 | spin_unlock(&mm->page_table_lock); |
508034a3 | 785 | flush_tlb_range(vma, start, end); |
fe1668ae KC |
786 | list_for_each_entry_safe(page, tmp, &page_list, lru) { |
787 | list_del(&page->lru); | |
788 | put_page(page); | |
789 | } | |
1da177e4 | 790 | } |
63551ae0 | 791 | |
502717f4 KC |
792 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
793 | unsigned long end) | |
794 | { | |
795 | /* | |
796 | * It is undesirable to test vma->vm_file as it should be non-null | |
797 | * for valid hugetlb area. However, vm_file will be NULL in the error | |
798 | * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails, | |
799 | * do_mmap_pgoff() nullifies vma->vm_file before calling this function | |
800 | * to clean up. Since no pte has actually been setup, it is safe to | |
801 | * do nothing in this case. | |
802 | */ | |
803 | if (vma->vm_file) { | |
804 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); | |
805 | __unmap_hugepage_range(vma, start, end); | |
806 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); | |
807 | } | |
808 | } | |
809 | ||
1e8f889b DG |
810 | static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
811 | unsigned long address, pte_t *ptep, pte_t pte) | |
812 | { | |
813 | struct page *old_page, *new_page; | |
79ac6ba4 | 814 | int avoidcopy; |
1e8f889b DG |
815 | |
816 | old_page = pte_page(pte); | |
817 | ||
818 | /* If no-one else is actually using this page, avoid the copy | |
819 | * and just make the page writable */ | |
820 | avoidcopy = (page_count(old_page) == 1); | |
821 | if (avoidcopy) { | |
822 | set_huge_ptep_writable(vma, address, ptep); | |
83c54070 | 823 | return 0; |
1e8f889b DG |
824 | } |
825 | ||
826 | page_cache_get(old_page); | |
5da7ca86 | 827 | new_page = alloc_huge_page(vma, address); |
1e8f889b | 828 | |
2fc39cec | 829 | if (IS_ERR(new_page)) { |
1e8f889b | 830 | page_cache_release(old_page); |
2fc39cec | 831 | return -PTR_ERR(new_page); |
1e8f889b DG |
832 | } |
833 | ||
834 | spin_unlock(&mm->page_table_lock); | |
9de455b2 | 835 | copy_huge_page(new_page, old_page, address, vma); |
0ed361de | 836 | __SetPageUptodate(new_page); |
1e8f889b DG |
837 | spin_lock(&mm->page_table_lock); |
838 | ||
839 | ptep = huge_pte_offset(mm, address & HPAGE_MASK); | |
840 | if (likely(pte_same(*ptep, pte))) { | |
841 | /* Break COW */ | |
842 | set_huge_pte_at(mm, address, ptep, | |
843 | make_huge_pte(vma, new_page, 1)); | |
844 | /* Make the old page be freed below */ | |
845 | new_page = old_page; | |
846 | } | |
847 | page_cache_release(new_page); | |
848 | page_cache_release(old_page); | |
83c54070 | 849 | return 0; |
1e8f889b DG |
850 | } |
851 | ||
a1ed3dda | 852 | static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1e8f889b | 853 | unsigned long address, pte_t *ptep, int write_access) |
ac9b9c66 HD |
854 | { |
855 | int ret = VM_FAULT_SIGBUS; | |
4c887265 AL |
856 | unsigned long idx; |
857 | unsigned long size; | |
4c887265 AL |
858 | struct page *page; |
859 | struct address_space *mapping; | |
1e8f889b | 860 | pte_t new_pte; |
4c887265 | 861 | |
4c887265 AL |
862 | mapping = vma->vm_file->f_mapping; |
863 | idx = ((address - vma->vm_start) >> HPAGE_SHIFT) | |
864 | + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT)); | |
865 | ||
866 | /* | |
867 | * Use page lock to guard against racing truncation | |
868 | * before we get page_table_lock. | |
869 | */ | |
6bda666a CL |
870 | retry: |
871 | page = find_lock_page(mapping, idx); | |
872 | if (!page) { | |
ebed4bfc HD |
873 | size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
874 | if (idx >= size) | |
875 | goto out; | |
6bda666a | 876 | page = alloc_huge_page(vma, address); |
2fc39cec AL |
877 | if (IS_ERR(page)) { |
878 | ret = -PTR_ERR(page); | |
6bda666a CL |
879 | goto out; |
880 | } | |
79ac6ba4 | 881 | clear_huge_page(page, address); |
0ed361de | 882 | __SetPageUptodate(page); |
ac9b9c66 | 883 | |
6bda666a CL |
884 | if (vma->vm_flags & VM_SHARED) { |
885 | int err; | |
45c682a6 | 886 | struct inode *inode = mapping->host; |
6bda666a CL |
887 | |
888 | err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); | |
889 | if (err) { | |
890 | put_page(page); | |
6bda666a CL |
891 | if (err == -EEXIST) |
892 | goto retry; | |
893 | goto out; | |
894 | } | |
45c682a6 KC |
895 | |
896 | spin_lock(&inode->i_lock); | |
897 | inode->i_blocks += BLOCKS_PER_HUGEPAGE; | |
898 | spin_unlock(&inode->i_lock); | |
6bda666a CL |
899 | } else |
900 | lock_page(page); | |
901 | } | |
1e8f889b | 902 | |
ac9b9c66 | 903 | spin_lock(&mm->page_table_lock); |
4c887265 AL |
904 | size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
905 | if (idx >= size) | |
906 | goto backout; | |
907 | ||
83c54070 | 908 | ret = 0; |
86e5216f | 909 | if (!pte_none(*ptep)) |
4c887265 AL |
910 | goto backout; |
911 | ||
1e8f889b DG |
912 | new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) |
913 | && (vma->vm_flags & VM_SHARED))); | |
914 | set_huge_pte_at(mm, address, ptep, new_pte); | |
915 | ||
916 | if (write_access && !(vma->vm_flags & VM_SHARED)) { | |
917 | /* Optimization, do the COW without a second fault */ | |
918 | ret = hugetlb_cow(mm, vma, address, ptep, new_pte); | |
919 | } | |
920 | ||
ac9b9c66 | 921 | spin_unlock(&mm->page_table_lock); |
4c887265 AL |
922 | unlock_page(page); |
923 | out: | |
ac9b9c66 | 924 | return ret; |
4c887265 AL |
925 | |
926 | backout: | |
927 | spin_unlock(&mm->page_table_lock); | |
4c887265 AL |
928 | unlock_page(page); |
929 | put_page(page); | |
930 | goto out; | |
ac9b9c66 HD |
931 | } |
932 | ||
86e5216f AL |
933 | int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
934 | unsigned long address, int write_access) | |
935 | { | |
936 | pte_t *ptep; | |
937 | pte_t entry; | |
1e8f889b | 938 | int ret; |
3935baa9 | 939 | static DEFINE_MUTEX(hugetlb_instantiation_mutex); |
86e5216f AL |
940 | |
941 | ptep = huge_pte_alloc(mm, address); | |
942 | if (!ptep) | |
943 | return VM_FAULT_OOM; | |
944 | ||
3935baa9 DG |
945 | /* |
946 | * Serialize hugepage allocation and instantiation, so that we don't | |
947 | * get spurious allocation failures if two CPUs race to instantiate | |
948 | * the same page in the page cache. | |
949 | */ | |
950 | mutex_lock(&hugetlb_instantiation_mutex); | |
86e5216f | 951 | entry = *ptep; |
3935baa9 DG |
952 | if (pte_none(entry)) { |
953 | ret = hugetlb_no_page(mm, vma, address, ptep, write_access); | |
954 | mutex_unlock(&hugetlb_instantiation_mutex); | |
955 | return ret; | |
956 | } | |
86e5216f | 957 | |
83c54070 | 958 | ret = 0; |
1e8f889b DG |
959 | |
960 | spin_lock(&mm->page_table_lock); | |
961 | /* Check for a racing update before calling hugetlb_cow */ | |
962 | if (likely(pte_same(entry, *ptep))) | |
963 | if (write_access && !pte_write(entry)) | |
964 | ret = hugetlb_cow(mm, vma, address, ptep, entry); | |
965 | spin_unlock(&mm->page_table_lock); | |
3935baa9 | 966 | mutex_unlock(&hugetlb_instantiation_mutex); |
1e8f889b DG |
967 | |
968 | return ret; | |
86e5216f AL |
969 | } |
970 | ||
63551ae0 DG |
971 | int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, |
972 | struct page **pages, struct vm_area_struct **vmas, | |
5b23dbe8 AL |
973 | unsigned long *position, int *length, int i, |
974 | int write) | |
63551ae0 | 975 | { |
d5d4b0aa KC |
976 | unsigned long pfn_offset; |
977 | unsigned long vaddr = *position; | |
63551ae0 DG |
978 | int remainder = *length; |
979 | ||
1c59827d | 980 | spin_lock(&mm->page_table_lock); |
63551ae0 | 981 | while (vaddr < vma->vm_end && remainder) { |
4c887265 AL |
982 | pte_t *pte; |
983 | struct page *page; | |
63551ae0 | 984 | |
4c887265 AL |
985 | /* |
986 | * Some archs (sparc64, sh*) have multiple pte_ts to | |
987 | * each hugepage. We have to make * sure we get the | |
988 | * first, for the page indexing below to work. | |
989 | */ | |
990 | pte = huge_pte_offset(mm, vaddr & HPAGE_MASK); | |
63551ae0 | 991 | |
72fad713 | 992 | if (!pte || pte_none(*pte) || (write && !pte_write(*pte))) { |
4c887265 | 993 | int ret; |
63551ae0 | 994 | |
4c887265 | 995 | spin_unlock(&mm->page_table_lock); |
5b23dbe8 | 996 | ret = hugetlb_fault(mm, vma, vaddr, write); |
4c887265 | 997 | spin_lock(&mm->page_table_lock); |
a89182c7 | 998 | if (!(ret & VM_FAULT_ERROR)) |
4c887265 | 999 | continue; |
63551ae0 | 1000 | |
4c887265 AL |
1001 | remainder = 0; |
1002 | if (!i) | |
1003 | i = -EFAULT; | |
1004 | break; | |
1005 | } | |
1006 | ||
d5d4b0aa KC |
1007 | pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT; |
1008 | page = pte_page(*pte); | |
1009 | same_page: | |
d6692183 KC |
1010 | if (pages) { |
1011 | get_page(page); | |
d5d4b0aa | 1012 | pages[i] = page + pfn_offset; |
d6692183 | 1013 | } |
63551ae0 DG |
1014 | |
1015 | if (vmas) | |
1016 | vmas[i] = vma; | |
1017 | ||
1018 | vaddr += PAGE_SIZE; | |
d5d4b0aa | 1019 | ++pfn_offset; |
63551ae0 DG |
1020 | --remainder; |
1021 | ++i; | |
d5d4b0aa KC |
1022 | if (vaddr < vma->vm_end && remainder && |
1023 | pfn_offset < HPAGE_SIZE/PAGE_SIZE) { | |
1024 | /* | |
1025 | * We use pfn_offset to avoid touching the pageframes | |
1026 | * of this compound page. | |
1027 | */ | |
1028 | goto same_page; | |
1029 | } | |
63551ae0 | 1030 | } |
1c59827d | 1031 | spin_unlock(&mm->page_table_lock); |
63551ae0 DG |
1032 | *length = remainder; |
1033 | *position = vaddr; | |
1034 | ||
1035 | return i; | |
1036 | } | |
8f860591 ZY |
1037 | |
1038 | void hugetlb_change_protection(struct vm_area_struct *vma, | |
1039 | unsigned long address, unsigned long end, pgprot_t newprot) | |
1040 | { | |
1041 | struct mm_struct *mm = vma->vm_mm; | |
1042 | unsigned long start = address; | |
1043 | pte_t *ptep; | |
1044 | pte_t pte; | |
1045 | ||
1046 | BUG_ON(address >= end); | |
1047 | flush_cache_range(vma, address, end); | |
1048 | ||
39dde65c | 1049 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); |
8f860591 ZY |
1050 | spin_lock(&mm->page_table_lock); |
1051 | for (; address < end; address += HPAGE_SIZE) { | |
1052 | ptep = huge_pte_offset(mm, address); | |
1053 | if (!ptep) | |
1054 | continue; | |
39dde65c KC |
1055 | if (huge_pmd_unshare(mm, &address, ptep)) |
1056 | continue; | |
8f860591 ZY |
1057 | if (!pte_none(*ptep)) { |
1058 | pte = huge_ptep_get_and_clear(mm, address, ptep); | |
1059 | pte = pte_mkhuge(pte_modify(pte, newprot)); | |
1060 | set_huge_pte_at(mm, address, ptep, pte); | |
8f860591 ZY |
1061 | } |
1062 | } | |
1063 | spin_unlock(&mm->page_table_lock); | |
39dde65c | 1064 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); |
8f860591 ZY |
1065 | |
1066 | flush_tlb_range(vma, start, end); | |
1067 | } | |
1068 | ||
a43a8c39 KC |
1069 | struct file_region { |
1070 | struct list_head link; | |
1071 | long from; | |
1072 | long to; | |
1073 | }; | |
1074 | ||
1075 | static long region_add(struct list_head *head, long f, long t) | |
1076 | { | |
1077 | struct file_region *rg, *nrg, *trg; | |
1078 | ||
1079 | /* Locate the region we are either in or before. */ | |
1080 | list_for_each_entry(rg, head, link) | |
1081 | if (f <= rg->to) | |
1082 | break; | |
1083 | ||
1084 | /* Round our left edge to the current segment if it encloses us. */ | |
1085 | if (f > rg->from) | |
1086 | f = rg->from; | |
1087 | ||
1088 | /* Check for and consume any regions we now overlap with. */ | |
1089 | nrg = rg; | |
1090 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { | |
1091 | if (&rg->link == head) | |
1092 | break; | |
1093 | if (rg->from > t) | |
1094 | break; | |
1095 | ||
1096 | /* If this area reaches higher then extend our area to | |
1097 | * include it completely. If this is not the first area | |
1098 | * which we intend to reuse, free it. */ | |
1099 | if (rg->to > t) | |
1100 | t = rg->to; | |
1101 | if (rg != nrg) { | |
1102 | list_del(&rg->link); | |
1103 | kfree(rg); | |
1104 | } | |
1105 | } | |
1106 | nrg->from = f; | |
1107 | nrg->to = t; | |
1108 | return 0; | |
1109 | } | |
1110 | ||
1111 | static long region_chg(struct list_head *head, long f, long t) | |
1112 | { | |
1113 | struct file_region *rg, *nrg; | |
1114 | long chg = 0; | |
1115 | ||
1116 | /* Locate the region we are before or in. */ | |
1117 | list_for_each_entry(rg, head, link) | |
1118 | if (f <= rg->to) | |
1119 | break; | |
1120 | ||
1121 | /* If we are below the current region then a new region is required. | |
1122 | * Subtle, allocate a new region at the position but make it zero | |
183ff22b | 1123 | * size such that we can guarantee to record the reservation. */ |
a43a8c39 KC |
1124 | if (&rg->link == head || t < rg->from) { |
1125 | nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); | |
c80544dc | 1126 | if (!nrg) |
a43a8c39 KC |
1127 | return -ENOMEM; |
1128 | nrg->from = f; | |
1129 | nrg->to = f; | |
1130 | INIT_LIST_HEAD(&nrg->link); | |
1131 | list_add(&nrg->link, rg->link.prev); | |
1132 | ||
1133 | return t - f; | |
1134 | } | |
1135 | ||
1136 | /* Round our left edge to the current segment if it encloses us. */ | |
1137 | if (f > rg->from) | |
1138 | f = rg->from; | |
1139 | chg = t - f; | |
1140 | ||
1141 | /* Check for and consume any regions we now overlap with. */ | |
1142 | list_for_each_entry(rg, rg->link.prev, link) { | |
1143 | if (&rg->link == head) | |
1144 | break; | |
1145 | if (rg->from > t) | |
1146 | return chg; | |
1147 | ||
1148 | /* We overlap with this area, if it extends futher than | |
1149 | * us then we must extend ourselves. Account for its | |
1150 | * existing reservation. */ | |
1151 | if (rg->to > t) { | |
1152 | chg += rg->to - t; | |
1153 | t = rg->to; | |
1154 | } | |
1155 | chg -= rg->to - rg->from; | |
1156 | } | |
1157 | return chg; | |
1158 | } | |
1159 | ||
1160 | static long region_truncate(struct list_head *head, long end) | |
1161 | { | |
1162 | struct file_region *rg, *trg; | |
1163 | long chg = 0; | |
1164 | ||
1165 | /* Locate the region we are either in or before. */ | |
1166 | list_for_each_entry(rg, head, link) | |
1167 | if (end <= rg->to) | |
1168 | break; | |
1169 | if (&rg->link == head) | |
1170 | return 0; | |
1171 | ||
1172 | /* If we are in the middle of a region then adjust it. */ | |
1173 | if (end > rg->from) { | |
1174 | chg = rg->to - end; | |
1175 | rg->to = end; | |
1176 | rg = list_entry(rg->link.next, typeof(*rg), link); | |
1177 | } | |
1178 | ||
1179 | /* Drop any remaining regions. */ | |
1180 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { | |
1181 | if (&rg->link == head) | |
1182 | break; | |
1183 | chg += rg->to - rg->from; | |
1184 | list_del(&rg->link); | |
1185 | kfree(rg); | |
1186 | } | |
1187 | return chg; | |
1188 | } | |
1189 | ||
1190 | static int hugetlb_acct_memory(long delta) | |
1191 | { | |
1192 | int ret = -ENOMEM; | |
1193 | ||
1194 | spin_lock(&hugetlb_lock); | |
8a630112 KC |
1195 | /* |
1196 | * When cpuset is configured, it breaks the strict hugetlb page | |
1197 | * reservation as the accounting is done on a global variable. Such | |
1198 | * reservation is completely rubbish in the presence of cpuset because | |
1199 | * the reservation is not checked against page availability for the | |
1200 | * current cpuset. Application can still potentially OOM'ed by kernel | |
1201 | * with lack of free htlb page in cpuset that the task is in. | |
1202 | * Attempt to enforce strict accounting with cpuset is almost | |
1203 | * impossible (or too ugly) because cpuset is too fluid that | |
1204 | * task or memory node can be dynamically moved between cpusets. | |
1205 | * | |
1206 | * The change of semantics for shared hugetlb mapping with cpuset is | |
1207 | * undesirable. However, in order to preserve some of the semantics, | |
1208 | * we fall back to check against current free page availability as | |
1209 | * a best attempt and hopefully to minimize the impact of changing | |
1210 | * semantics that cpuset has. | |
1211 | */ | |
e4e574b7 AL |
1212 | if (delta > 0) { |
1213 | if (gather_surplus_pages(delta) < 0) | |
1214 | goto out; | |
1215 | ||
ac09b3a1 AL |
1216 | if (delta > cpuset_mems_nr(free_huge_pages_node)) { |
1217 | return_unused_surplus_pages(delta); | |
e4e574b7 | 1218 | goto out; |
ac09b3a1 | 1219 | } |
e4e574b7 AL |
1220 | } |
1221 | ||
1222 | ret = 0; | |
e4e574b7 AL |
1223 | if (delta < 0) |
1224 | return_unused_surplus_pages((unsigned long) -delta); | |
1225 | ||
1226 | out: | |
1227 | spin_unlock(&hugetlb_lock); | |
1228 | return ret; | |
1229 | } | |
1230 | ||
1231 | int hugetlb_reserve_pages(struct inode *inode, long from, long to) | |
1232 | { | |
1233 | long ret, chg; | |
1234 | ||
1235 | chg = region_chg(&inode->i_mapping->private_list, from, to); | |
1236 | if (chg < 0) | |
1237 | return chg; | |
8a630112 | 1238 | |
90d8b7e6 AL |
1239 | if (hugetlb_get_quota(inode->i_mapping, chg)) |
1240 | return -ENOSPC; | |
a43a8c39 | 1241 | ret = hugetlb_acct_memory(chg); |
68842c9b KC |
1242 | if (ret < 0) { |
1243 | hugetlb_put_quota(inode->i_mapping, chg); | |
a43a8c39 | 1244 | return ret; |
68842c9b | 1245 | } |
a43a8c39 KC |
1246 | region_add(&inode->i_mapping->private_list, from, to); |
1247 | return 0; | |
1248 | } | |
1249 | ||
1250 | void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) | |
1251 | { | |
1252 | long chg = region_truncate(&inode->i_mapping->private_list, offset); | |
45c682a6 KC |
1253 | |
1254 | spin_lock(&inode->i_lock); | |
1255 | inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed; | |
1256 | spin_unlock(&inode->i_lock); | |
1257 | ||
90d8b7e6 AL |
1258 | hugetlb_put_quota(inode->i_mapping, (chg - freed)); |
1259 | hugetlb_acct_memory(-(chg - freed)); | |
a43a8c39 | 1260 | } |