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