blob: 6121b57bbe966735a6c44ae1f77854f2cec7c74b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/sysctl.h>
11#include <linux/highmem.h>
12#include <linux/nodemask.h>
David Gibson63551ae2005-06-21 17:14:44 -070013#include <linux/pagemap.h>
Christoph Lameter5da7ca82006-01-06 00:10:46 -080014#include <linux/mempolicy.h>
Christoph Lameteraea47ff2006-01-08 01:00:57 -080015#include <linux/cpuset.h>
David Gibson3935baa2006-03-22 00:08:53 -080016#include <linux/mutex.h>
Christoph Lameter5da7ca82006-01-06 00:10:46 -080017
David Gibson63551ae2005-06-21 17:14:44 -070018#include <asm/page.h>
19#include <asm/pgtable.h>
20
21#include <linux/hugetlb.h>
Nick Piggin7835e982006-03-22 00:08:40 -080022#include "internal.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
24const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -070025static unsigned long nr_huge_pages, free_huge_pages, resv_huge_pages;
Adam Litke7893d1d2007-10-16 01:26:18 -070026static unsigned long surplus_huge_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -070027unsigned long max_huge_pages;
28static struct list_head hugepage_freelists[MAX_NUMNODES];
29static unsigned int nr_huge_pages_node[MAX_NUMNODES];
30static unsigned int free_huge_pages_node[MAX_NUMNODES];
Adam Litke7893d1d2007-10-16 01:26:18 -070031static unsigned int surplus_huge_pages_node[MAX_NUMNODES];
Mel Gorman396faf02007-07-17 04:03:13 -070032static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
33unsigned long hugepages_treat_as_movable;
Adam Litke54f9f802007-10-16 01:26:20 -070034int hugetlb_dynamic_pool;
Nishanth Aravamudan63b46132007-10-16 01:26:24 -070035static int hugetlb_next_nid;
Mel Gorman396faf02007-07-17 04:03:13 -070036
David Gibson3935baa2006-03-22 00:08:53 -080037/*
38 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
39 */
40static DEFINE_SPINLOCK(hugetlb_lock);
Eric Paris0bd0f9f2005-11-21 21:32:28 -080041
David Gibson79ac6ba2006-03-22 00:08:51 -080042static void clear_huge_page(struct page *page, unsigned long addr)
43{
44 int i;
45
46 might_sleep();
47 for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); i++) {
48 cond_resched();
Ralf Baechle281e0e32007-10-01 01:20:10 -070049 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
David Gibson79ac6ba2006-03-22 00:08:51 -080050 }
51}
52
53static void copy_huge_page(struct page *dst, struct page *src,
Atsushi Nemoto9de455b2006-12-12 17:14:55 +000054 unsigned long addr, struct vm_area_struct *vma)
David Gibson79ac6ba2006-03-22 00:08:51 -080055{
56 int i;
57
58 might_sleep();
59 for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++) {
60 cond_resched();
Atsushi Nemoto9de455b2006-12-12 17:14:55 +000061 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
David Gibson79ac6ba2006-03-22 00:08:51 -080062 }
63}
64
Linus Torvalds1da177e2005-04-16 15:20:36 -070065static void enqueue_huge_page(struct page *page)
66{
67 int nid = page_to_nid(page);
68 list_add(&page->lru, &hugepage_freelists[nid]);
69 free_huge_pages++;
70 free_huge_pages_node[nid]++;
71}
72
Christoph Lameter5da7ca82006-01-06 00:10:46 -080073static struct page *dequeue_huge_page(struct vm_area_struct *vma,
74 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -070075{
Nishanth Aravamudan31a5c6e2007-07-15 23:38:02 -070076 int nid;
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 struct page *page = NULL;
Lee Schermerhorn480eccf2007-09-18 22:46:47 -070078 struct mempolicy *mpol;
Mel Gorman396faf02007-07-17 04:03:13 -070079 struct zonelist *zonelist = huge_zonelist(vma, address,
Lee Schermerhorn480eccf2007-09-18 22:46:47 -070080 htlb_alloc_mask, &mpol);
Christoph Lameter96df9332006-01-06 00:10:45 -080081 struct zone **z;
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
Christoph Lameter96df9332006-01-06 00:10:45 -080083 for (z = zonelist->zones; *z; z++) {
Christoph Lameter89fa3022006-09-25 23:31:55 -070084 nid = zone_to_nid(*z);
Mel Gorman396faf02007-07-17 04:03:13 -070085 if (cpuset_zone_allowed_softwall(*z, htlb_alloc_mask) &&
Andrew Morton3abf7af2007-07-19 01:49:08 -070086 !list_empty(&hugepage_freelists[nid])) {
87 page = list_entry(hugepage_freelists[nid].next,
88 struct page, lru);
89 list_del(&page->lru);
90 free_huge_pages--;
91 free_huge_pages_node[nid]--;
Adam Litkee4e574b2007-10-16 01:26:19 -070092 if (vma && vma->vm_flags & VM_MAYSHARE)
93 resv_huge_pages--;
Ken Chen5ab3ee72007-07-23 18:44:00 -070094 break;
Andrew Morton3abf7af2007-07-19 01:49:08 -070095 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 }
Lee Schermerhorn480eccf2007-09-18 22:46:47 -070097 mpol_free(mpol); /* unref if mpol !NULL */
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 return page;
99}
100
Adam Litke6af2acb2007-10-16 01:26:16 -0700101static void update_and_free_page(struct page *page)
102{
103 int i;
104 nr_huge_pages--;
105 nr_huge_pages_node[page_to_nid(page)]--;
106 for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) {
107 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
108 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
109 1 << PG_private | 1<< PG_writeback);
110 }
111 set_compound_page_dtor(page, NULL);
112 set_page_refcounted(page);
113 __free_pages(page, HUGETLB_PAGE_ORDER);
114}
115
David Gibson27a85ef2006-03-22 00:08:56 -0800116static void free_huge_page(struct page *page)
117{
Adam Litke7893d1d2007-10-16 01:26:18 -0700118 int nid = page_to_nid(page);
Adam Litkec79fb752007-11-14 16:59:38 -0800119 struct address_space *mapping;
David Gibson27a85ef2006-03-22 00:08:56 -0800120
Adam Litkec79fb752007-11-14 16:59:38 -0800121 mapping = (struct address_space *) page_private(page);
Adam Litke7893d1d2007-10-16 01:26:18 -0700122 BUG_ON(page_count(page));
David Gibson27a85ef2006-03-22 00:08:56 -0800123 INIT_LIST_HEAD(&page->lru);
124
125 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700126 if (surplus_huge_pages_node[nid]) {
127 update_and_free_page(page);
128 surplus_huge_pages--;
129 surplus_huge_pages_node[nid]--;
130 } else {
131 enqueue_huge_page(page);
132 }
David Gibson27a85ef2006-03-22 00:08:56 -0800133 spin_unlock(&hugetlb_lock);
Adam Litkec79fb752007-11-14 16:59:38 -0800134 if (mapping)
Adam Litke9a119c02007-11-14 16:59:41 -0800135 hugetlb_put_quota(mapping, 1);
Adam Litkec79fb752007-11-14 16:59:38 -0800136 set_page_private(page, 0);
David Gibson27a85ef2006-03-22 00:08:56 -0800137}
138
Adam Litke7893d1d2007-10-16 01:26:18 -0700139/*
140 * Increment or decrement surplus_huge_pages. Keep node-specific counters
141 * balanced by operating on them in a round-robin fashion.
142 * Returns 1 if an adjustment was made.
143 */
144static int adjust_pool_surplus(int delta)
145{
146 static int prev_nid;
147 int nid = prev_nid;
148 int ret = 0;
149
150 VM_BUG_ON(delta != -1 && delta != 1);
151 do {
152 nid = next_node(nid, node_online_map);
153 if (nid == MAX_NUMNODES)
154 nid = first_node(node_online_map);
155
156 /* To shrink on this node, there must be a surplus page */
157 if (delta < 0 && !surplus_huge_pages_node[nid])
158 continue;
159 /* Surplus cannot exceed the total number of pages */
160 if (delta > 0 && surplus_huge_pages_node[nid] >=
161 nr_huge_pages_node[nid])
162 continue;
163
164 surplus_huge_pages += delta;
165 surplus_huge_pages_node[nid] += delta;
166 ret = 1;
167 break;
168 } while (nid != prev_nid);
169
170 prev_nid = nid;
171 return ret;
172}
173
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700174static struct page *alloc_fresh_huge_page_node(int nid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 struct page *page;
Joe Jinf96efd52007-07-15 23:38:12 -0700177
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700178 page = alloc_pages_node(nid,
179 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|__GFP_NOWARN,
180 HUGETLB_PAGE_ORDER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 if (page) {
Andy Whitcroft33f2ef82006-12-06 20:33:32 -0800182 set_compound_page_dtor(page, free_huge_page);
Eric Paris0bd0f9f2005-11-21 21:32:28 -0800183 spin_lock(&hugetlb_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 nr_huge_pages++;
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700185 nr_huge_pages_node[nid]++;
Eric Paris0bd0f9f2005-11-21 21:32:28 -0800186 spin_unlock(&hugetlb_lock);
Nick Piggina4822892006-03-22 00:08:08 -0800187 put_page(page); /* free it into the hugepage allocator */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 }
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700189
190 return page;
191}
192
193static int alloc_fresh_huge_page(void)
194{
195 struct page *page;
196 int start_nid;
197 int next_nid;
198 int ret = 0;
199
200 start_nid = hugetlb_next_nid;
201
202 do {
203 page = alloc_fresh_huge_page_node(hugetlb_next_nid);
204 if (page)
205 ret = 1;
206 /*
207 * Use a helper variable to find the next node and then
208 * copy it back to hugetlb_next_nid afterwards:
209 * otherwise there's a window in which a racer might
210 * pass invalid nid MAX_NUMNODES to alloc_pages_node.
211 * But we don't need to use a spin_lock here: it really
212 * doesn't matter if occasionally a racer chooses the
213 * same nid as we do. Move nid forward in the mask even
214 * if we just successfully allocated a hugepage so that
215 * the next caller gets hugepages on the next node.
216 */
217 next_nid = next_node(hugetlb_next_nid, node_online_map);
218 if (next_nid == MAX_NUMNODES)
219 next_nid = first_node(node_online_map);
220 hugetlb_next_nid = next_nid;
221 } while (!page && hugetlb_next_nid != start_nid);
222
223 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224}
225
Adam Litke7893d1d2007-10-16 01:26:18 -0700226static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma,
227 unsigned long address)
228{
229 struct page *page;
230
Adam Litke54f9f802007-10-16 01:26:20 -0700231 /* Check if the dynamic pool is enabled */
232 if (!hugetlb_dynamic_pool)
233 return NULL;
234
Adam Litke7893d1d2007-10-16 01:26:18 -0700235 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN,
236 HUGETLB_PAGE_ORDER);
237 if (page) {
238 set_compound_page_dtor(page, free_huge_page);
239 spin_lock(&hugetlb_lock);
240 nr_huge_pages++;
241 nr_huge_pages_node[page_to_nid(page)]++;
242 surplus_huge_pages++;
243 surplus_huge_pages_node[page_to_nid(page)]++;
244 spin_unlock(&hugetlb_lock);
245 }
246
247 return page;
248}
249
Adam Litkee4e574b2007-10-16 01:26:19 -0700250/*
251 * Increase the hugetlb pool such that it can accomodate a reservation
252 * of size 'delta'.
253 */
254static int gather_surplus_pages(int delta)
255{
256 struct list_head surplus_list;
257 struct page *page, *tmp;
258 int ret, i;
259 int needed, allocated;
260
261 needed = (resv_huge_pages + delta) - free_huge_pages;
262 if (needed <= 0)
263 return 0;
264
265 allocated = 0;
266 INIT_LIST_HEAD(&surplus_list);
267
268 ret = -ENOMEM;
269retry:
270 spin_unlock(&hugetlb_lock);
271 for (i = 0; i < needed; i++) {
272 page = alloc_buddy_huge_page(NULL, 0);
273 if (!page) {
274 /*
275 * We were not able to allocate enough pages to
276 * satisfy the entire reservation so we free what
277 * we've allocated so far.
278 */
279 spin_lock(&hugetlb_lock);
280 needed = 0;
281 goto free;
282 }
283
284 list_add(&page->lru, &surplus_list);
285 }
286 allocated += needed;
287
288 /*
289 * After retaking hugetlb_lock, we need to recalculate 'needed'
290 * because either resv_huge_pages or free_huge_pages may have changed.
291 */
292 spin_lock(&hugetlb_lock);
293 needed = (resv_huge_pages + delta) - (free_huge_pages + allocated);
294 if (needed > 0)
295 goto retry;
296
297 /*
298 * The surplus_list now contains _at_least_ the number of extra pages
299 * needed to accomodate the reservation. Add the appropriate number
300 * of pages to the hugetlb pool and free the extras back to the buddy
301 * allocator.
302 */
303 needed += allocated;
304 ret = 0;
305free:
306 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
307 list_del(&page->lru);
308 if ((--needed) >= 0)
309 enqueue_huge_page(page);
Adam Litkeaf767cb2007-10-16 01:26:25 -0700310 else {
311 /*
312 * Decrement the refcount and free the page using its
313 * destructor. This must be done with hugetlb_lock
314 * unlocked which is safe because free_huge_page takes
315 * hugetlb_lock before deciding how to free the page.
316 */
317 spin_unlock(&hugetlb_lock);
318 put_page(page);
319 spin_lock(&hugetlb_lock);
320 }
Adam Litkee4e574b2007-10-16 01:26:19 -0700321 }
322
323 return ret;
324}
325
326/*
327 * When releasing a hugetlb pool reservation, any surplus pages that were
328 * allocated to satisfy the reservation must be explicitly freed if they were
329 * never used.
330 */
Adrian Bunk8cde0452007-11-14 16:59:43 -0800331static void return_unused_surplus_pages(unsigned long unused_resv_pages)
Adam Litkee4e574b2007-10-16 01:26:19 -0700332{
333 static int nid = -1;
334 struct page *page;
335 unsigned long nr_pages;
336
337 nr_pages = min(unused_resv_pages, surplus_huge_pages);
338
339 while (nr_pages) {
340 nid = next_node(nid, node_online_map);
341 if (nid == MAX_NUMNODES)
342 nid = first_node(node_online_map);
343
344 if (!surplus_huge_pages_node[nid])
345 continue;
346
347 if (!list_empty(&hugepage_freelists[nid])) {
348 page = list_entry(hugepage_freelists[nid].next,
349 struct page, lru);
350 list_del(&page->lru);
351 update_and_free_page(page);
352 free_huge_pages--;
353 free_huge_pages_node[nid]--;
354 surplus_huge_pages--;
355 surplus_huge_pages_node[nid]--;
356 nr_pages--;
357 }
358 }
359}
360
Adam Litke348ea202007-11-14 16:59:37 -0800361
362static struct page *alloc_huge_page_shared(struct vm_area_struct *vma,
363 unsigned long addr)
364{
365 struct page *page;
366
367 spin_lock(&hugetlb_lock);
368 page = dequeue_huge_page(vma, addr);
369 spin_unlock(&hugetlb_lock);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800370 return page ? page : ERR_PTR(-VM_FAULT_OOM);
Adam Litke348ea202007-11-14 16:59:37 -0800371}
372
373static struct page *alloc_huge_page_private(struct vm_area_struct *vma,
374 unsigned long addr)
375{
376 struct page *page = NULL;
377
Adam Litke90d8b7e2007-11-14 16:59:42 -0800378 if (hugetlb_get_quota(vma->vm_file->f_mapping, 1))
379 return ERR_PTR(-VM_FAULT_SIGBUS);
380
Adam Litke348ea202007-11-14 16:59:37 -0800381 spin_lock(&hugetlb_lock);
382 if (free_huge_pages > resv_huge_pages)
383 page = dequeue_huge_page(vma, addr);
384 spin_unlock(&hugetlb_lock);
385 if (!page)
386 page = alloc_buddy_huge_page(vma, addr);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800387 return page ? page : ERR_PTR(-VM_FAULT_OOM);
Adam Litke348ea202007-11-14 16:59:37 -0800388}
389
David Gibson27a85ef2006-03-22 00:08:56 -0800390static struct page *alloc_huge_page(struct vm_area_struct *vma,
391 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392{
Adam Litke348ea202007-11-14 16:59:37 -0800393 struct page *page;
Adam Litke2fc39ce2007-11-14 16:59:39 -0800394 struct address_space *mapping = vma->vm_file->f_mapping;
395
Adam Litke348ea202007-11-14 16:59:37 -0800396 if (vma->vm_flags & VM_MAYSHARE)
397 page = alloc_huge_page_shared(vma, addr);
398 else
399 page = alloc_huge_page_private(vma, addr);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800400
401 if (!IS_ERR(page)) {
Adam Litke348ea202007-11-14 16:59:37 -0800402 set_page_refcounted(page);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800403 set_page_private(page, (unsigned long) mapping);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800404 }
405 return page;
David Gibsonb45b5bd2006-03-22 00:08:55 -0800406}
407
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408static int __init hugetlb_init(void)
409{
410 unsigned long i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411
Benjamin Herrenschmidt3c726f82005-11-07 11:06:55 +1100412 if (HPAGE_SHIFT == 0)
413 return 0;
414
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 for (i = 0; i < MAX_NUMNODES; ++i)
416 INIT_LIST_HEAD(&hugepage_freelists[i]);
417
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700418 hugetlb_next_nid = first_node(node_online_map);
419
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 for (i = 0; i < max_huge_pages; ++i) {
Nick Piggina4822892006-03-22 00:08:08 -0800421 if (!alloc_fresh_huge_page())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 }
424 max_huge_pages = free_huge_pages = nr_huge_pages = i;
425 printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
426 return 0;
427}
428module_init(hugetlb_init);
429
430static int __init hugetlb_setup(char *s)
431{
432 if (sscanf(s, "%lu", &max_huge_pages) <= 0)
433 max_huge_pages = 0;
434 return 1;
435}
436__setup("hugepages=", hugetlb_setup);
437
Ken Chen8a630112007-05-09 02:33:34 -0700438static unsigned int cpuset_mems_nr(unsigned int *array)
439{
440 int node;
441 unsigned int nr = 0;
442
443 for_each_node_mask(node, cpuset_current_mems_allowed)
444 nr += array[node];
445
446 return nr;
447}
448
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449#ifdef CONFIG_SYSCTL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450#ifdef CONFIG_HIGHMEM
451static void try_to_free_low(unsigned long count)
452{
Christoph Lameter4415cc82006-09-25 23:31:55 -0700453 int i;
454
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 for (i = 0; i < MAX_NUMNODES; ++i) {
456 struct page *page, *next;
457 list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
Adam Litke6b0c8802007-10-16 01:26:23 -0700458 if (count >= nr_huge_pages)
459 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460 if (PageHighMem(page))
461 continue;
462 list_del(&page->lru);
463 update_and_free_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 free_huge_pages--;
Christoph Lameter4415cc82006-09-25 23:31:55 -0700465 free_huge_pages_node[page_to_nid(page)]--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 }
467 }
468}
469#else
470static inline void try_to_free_low(unsigned long count)
471{
472}
473#endif
474
Adam Litke7893d1d2007-10-16 01:26:18 -0700475#define persistent_huge_pages (nr_huge_pages - surplus_huge_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476static unsigned long set_max_huge_pages(unsigned long count)
477{
Adam Litke7893d1d2007-10-16 01:26:18 -0700478 unsigned long min_count, ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479
Adam Litke7893d1d2007-10-16 01:26:18 -0700480 /*
481 * Increase the pool size
482 * First take pages out of surplus state. Then make up the
483 * remaining difference by allocating fresh huge pages.
484 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700486 while (surplus_huge_pages && count > persistent_huge_pages) {
487 if (!adjust_pool_surplus(-1))
488 break;
489 }
490
491 while (count > persistent_huge_pages) {
492 int ret;
493 /*
494 * If this allocation races such that we no longer need the
495 * page, free_huge_page will handle it by freeing the page
496 * and reducing the surplus.
497 */
498 spin_unlock(&hugetlb_lock);
499 ret = alloc_fresh_huge_page();
500 spin_lock(&hugetlb_lock);
501 if (!ret)
502 goto out;
503
504 }
Adam Litke7893d1d2007-10-16 01:26:18 -0700505
506 /*
507 * Decrease the pool size
508 * First return free pages to the buddy allocator (being careful
509 * to keep enough around to satisfy reservations). Then place
510 * pages into surplus state as needed so the pool will shrink
511 * to the desired size as pages become free.
512 */
Adam Litke6b0c8802007-10-16 01:26:23 -0700513 min_count = resv_huge_pages + nr_huge_pages - free_huge_pages;
514 min_count = max(count, min_count);
Adam Litke7893d1d2007-10-16 01:26:18 -0700515 try_to_free_low(min_count);
516 while (min_count < persistent_huge_pages) {
Christoph Lameter5da7ca82006-01-06 00:10:46 -0800517 struct page *page = dequeue_huge_page(NULL, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 if (!page)
519 break;
520 update_and_free_page(page);
521 }
Adam Litke7893d1d2007-10-16 01:26:18 -0700522 while (count < persistent_huge_pages) {
523 if (!adjust_pool_surplus(1))
524 break;
525 }
526out:
527 ret = persistent_huge_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 spin_unlock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700529 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530}
531
532int hugetlb_sysctl_handler(struct ctl_table *table, int write,
533 struct file *file, void __user *buffer,
534 size_t *length, loff_t *ppos)
535{
536 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
537 max_huge_pages = set_max_huge_pages(max_huge_pages);
538 return 0;
539}
Mel Gorman396faf02007-07-17 04:03:13 -0700540
541int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
542 struct file *file, void __user *buffer,
543 size_t *length, loff_t *ppos)
544{
545 proc_dointvec(table, write, file, buffer, length, ppos);
546 if (hugepages_treat_as_movable)
547 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
548 else
549 htlb_alloc_mask = GFP_HIGHUSER;
550 return 0;
551}
552
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553#endif /* CONFIG_SYSCTL */
554
555int hugetlb_report_meminfo(char *buf)
556{
557 return sprintf(buf,
558 "HugePages_Total: %5lu\n"
559 "HugePages_Free: %5lu\n"
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700560 "HugePages_Rsvd: %5lu\n"
Adam Litke7893d1d2007-10-16 01:26:18 -0700561 "HugePages_Surp: %5lu\n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 "Hugepagesize: %5lu kB\n",
563 nr_huge_pages,
564 free_huge_pages,
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700565 resv_huge_pages,
Adam Litke7893d1d2007-10-16 01:26:18 -0700566 surplus_huge_pages,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 HPAGE_SIZE/1024);
568}
569
570int hugetlb_report_node_meminfo(int nid, char *buf)
571{
572 return sprintf(buf,
573 "Node %d HugePages_Total: %5u\n"
574 "Node %d HugePages_Free: %5u\n",
575 nid, nr_huge_pages_node[nid],
576 nid, free_huge_pages_node[nid]);
577}
578
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
580unsigned long hugetlb_total_pages(void)
581{
582 return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
583}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584
585/*
586 * We cannot handle pagefaults against hugetlb pages at all. They cause
587 * handle_mm_fault() to try to instantiate regular-sized pages in the
588 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
589 * this far.
590 */
Nick Piggind0217ac2007-07-19 01:47:03 -0700591static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592{
593 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -0700594 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595}
596
597struct vm_operations_struct hugetlb_vm_ops = {
Nick Piggind0217ac2007-07-19 01:47:03 -0700598 .fault = hugetlb_vm_op_fault,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599};
600
David Gibson1e8f8892006-01-06 00:10:44 -0800601static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
602 int writable)
David Gibson63551ae2005-06-21 17:14:44 -0700603{
604 pte_t entry;
605
David Gibson1e8f8892006-01-06 00:10:44 -0800606 if (writable) {
David Gibson63551ae2005-06-21 17:14:44 -0700607 entry =
608 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
609 } else {
610 entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
611 }
612 entry = pte_mkyoung(entry);
613 entry = pte_mkhuge(entry);
614
615 return entry;
616}
617
David Gibson1e8f8892006-01-06 00:10:44 -0800618static void set_huge_ptep_writable(struct vm_area_struct *vma,
619 unsigned long address, pte_t *ptep)
620{
621 pte_t entry;
622
623 entry = pte_mkwrite(pte_mkdirty(*ptep));
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -0700624 if (ptep_set_access_flags(vma, address, ptep, entry, 1)) {
625 update_mmu_cache(vma, address, entry);
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -0700626 }
David Gibson1e8f8892006-01-06 00:10:44 -0800627}
628
629
David Gibson63551ae2005-06-21 17:14:44 -0700630int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
631 struct vm_area_struct *vma)
632{
633 pte_t *src_pte, *dst_pte, entry;
634 struct page *ptepage;
Hugh Dickins1c598272005-10-19 21:23:43 -0700635 unsigned long addr;
David Gibson1e8f8892006-01-06 00:10:44 -0800636 int cow;
637
638 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
David Gibson63551ae2005-06-21 17:14:44 -0700639
Hugh Dickins1c598272005-10-19 21:23:43 -0700640 for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
Hugh Dickinsc74df322005-10-29 18:16:23 -0700641 src_pte = huge_pte_offset(src, addr);
642 if (!src_pte)
643 continue;
David Gibson63551ae2005-06-21 17:14:44 -0700644 dst_pte = huge_pte_alloc(dst, addr);
645 if (!dst_pte)
646 goto nomem;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700647 spin_lock(&dst->page_table_lock);
Hugh Dickins1c598272005-10-19 21:23:43 -0700648 spin_lock(&src->page_table_lock);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700649 if (!pte_none(*src_pte)) {
David Gibson1e8f8892006-01-06 00:10:44 -0800650 if (cow)
651 ptep_set_wrprotect(src, addr, src_pte);
Hugh Dickins1c598272005-10-19 21:23:43 -0700652 entry = *src_pte;
653 ptepage = pte_page(entry);
654 get_page(ptepage);
Hugh Dickins1c598272005-10-19 21:23:43 -0700655 set_huge_pte_at(dst, addr, dst_pte, entry);
656 }
657 spin_unlock(&src->page_table_lock);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700658 spin_unlock(&dst->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700659 }
660 return 0;
661
662nomem:
663 return -ENOMEM;
664}
665
Chen, Kenneth W502717f2006-10-11 01:20:46 -0700666void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
667 unsigned long end)
David Gibson63551ae2005-06-21 17:14:44 -0700668{
669 struct mm_struct *mm = vma->vm_mm;
670 unsigned long address;
David Gibsonc7546f82005-08-05 11:59:35 -0700671 pte_t *ptep;
David Gibson63551ae2005-06-21 17:14:44 -0700672 pte_t pte;
673 struct page *page;
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700674 struct page *tmp;
Chen, Kenneth Wc0a499c2006-12-06 20:31:39 -0800675 /*
676 * A page gathering list, protected by per file i_mmap_lock. The
677 * lock is used to avoid list corruption from multiple unmapping
678 * of the same page since we are using page->lru.
679 */
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700680 LIST_HEAD(page_list);
David Gibson63551ae2005-06-21 17:14:44 -0700681
682 WARN_ON(!is_vm_hugetlb_page(vma));
683 BUG_ON(start & ~HPAGE_MASK);
684 BUG_ON(end & ~HPAGE_MASK);
685
Hugh Dickins508034a2005-10-29 18:16:30 -0700686 spin_lock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700687 for (address = start; address < end; address += HPAGE_SIZE) {
David Gibsonc7546f82005-08-05 11:59:35 -0700688 ptep = huge_pte_offset(mm, address);
Adam Litke4c887262005-10-29 18:16:46 -0700689 if (!ptep)
David Gibsonc7546f82005-08-05 11:59:35 -0700690 continue;
691
Chen, Kenneth W39dde652006-12-06 20:32:03 -0800692 if (huge_pmd_unshare(mm, &address, ptep))
693 continue;
694
David Gibsonc7546f82005-08-05 11:59:35 -0700695 pte = huge_ptep_get_and_clear(mm, address, ptep);
David Gibson63551ae2005-06-21 17:14:44 -0700696 if (pte_none(pte))
697 continue;
David Gibsonc7546f82005-08-05 11:59:35 -0700698
David Gibson63551ae2005-06-21 17:14:44 -0700699 page = pte_page(pte);
Ken Chen6649a382007-02-08 14:20:27 -0800700 if (pte_dirty(pte))
701 set_page_dirty(page);
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700702 list_add(&page->lru, &page_list);
David Gibson63551ae2005-06-21 17:14:44 -0700703 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 spin_unlock(&mm->page_table_lock);
Hugh Dickins508034a2005-10-29 18:16:30 -0700705 flush_tlb_range(vma, start, end);
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700706 list_for_each_entry_safe(page, tmp, &page_list, lru) {
707 list_del(&page->lru);
708 put_page(page);
709 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710}
David Gibson63551ae2005-06-21 17:14:44 -0700711
Chen, Kenneth W502717f2006-10-11 01:20:46 -0700712void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
713 unsigned long end)
714{
715 /*
716 * It is undesirable to test vma->vm_file as it should be non-null
717 * for valid hugetlb area. However, vm_file will be NULL in the error
718 * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails,
719 * do_mmap_pgoff() nullifies vma->vm_file before calling this function
720 * to clean up. Since no pte has actually been setup, it is safe to
721 * do nothing in this case.
722 */
723 if (vma->vm_file) {
724 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
725 __unmap_hugepage_range(vma, start, end);
726 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
727 }
728}
729
David Gibson1e8f8892006-01-06 00:10:44 -0800730static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
731 unsigned long address, pte_t *ptep, pte_t pte)
732{
733 struct page *old_page, *new_page;
David Gibson79ac6ba2006-03-22 00:08:51 -0800734 int avoidcopy;
David Gibson1e8f8892006-01-06 00:10:44 -0800735
736 old_page = pte_page(pte);
737
738 /* If no-one else is actually using this page, avoid the copy
739 * and just make the page writable */
740 avoidcopy = (page_count(old_page) == 1);
741 if (avoidcopy) {
742 set_huge_ptep_writable(vma, address, ptep);
Nick Piggin83c54072007-07-19 01:47:05 -0700743 return 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800744 }
745
746 page_cache_get(old_page);
Christoph Lameter5da7ca82006-01-06 00:10:46 -0800747 new_page = alloc_huge_page(vma, address);
David Gibson1e8f8892006-01-06 00:10:44 -0800748
Adam Litke2fc39ce2007-11-14 16:59:39 -0800749 if (IS_ERR(new_page)) {
David Gibson1e8f8892006-01-06 00:10:44 -0800750 page_cache_release(old_page);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800751 return -PTR_ERR(new_page);
David Gibson1e8f8892006-01-06 00:10:44 -0800752 }
753
754 spin_unlock(&mm->page_table_lock);
Atsushi Nemoto9de455b2006-12-12 17:14:55 +0000755 copy_huge_page(new_page, old_page, address, vma);
David Gibson1e8f8892006-01-06 00:10:44 -0800756 spin_lock(&mm->page_table_lock);
757
758 ptep = huge_pte_offset(mm, address & HPAGE_MASK);
759 if (likely(pte_same(*ptep, pte))) {
760 /* Break COW */
761 set_huge_pte_at(mm, address, ptep,
762 make_huge_pte(vma, new_page, 1));
763 /* Make the old page be freed below */
764 new_page = old_page;
765 }
766 page_cache_release(new_page);
767 page_cache_release(old_page);
Nick Piggin83c54072007-07-19 01:47:05 -0700768 return 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800769}
770
Robert P. J. Daya1ed3dd2007-07-17 04:03:33 -0700771static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
David Gibson1e8f8892006-01-06 00:10:44 -0800772 unsigned long address, pte_t *ptep, int write_access)
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100773{
774 int ret = VM_FAULT_SIGBUS;
Adam Litke4c887262005-10-29 18:16:46 -0700775 unsigned long idx;
776 unsigned long size;
Adam Litke4c887262005-10-29 18:16:46 -0700777 struct page *page;
778 struct address_space *mapping;
David Gibson1e8f8892006-01-06 00:10:44 -0800779 pte_t new_pte;
Adam Litke4c887262005-10-29 18:16:46 -0700780
Adam Litke4c887262005-10-29 18:16:46 -0700781 mapping = vma->vm_file->f_mapping;
782 idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
783 + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
784
785 /*
786 * Use page lock to guard against racing truncation
787 * before we get page_table_lock.
788 */
Christoph Lameter6bda6662006-01-06 00:10:49 -0800789retry:
790 page = find_lock_page(mapping, idx);
791 if (!page) {
Hugh Dickinsebed4bf2006-10-28 10:38:43 -0700792 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
793 if (idx >= size)
794 goto out;
Christoph Lameter6bda6662006-01-06 00:10:49 -0800795 page = alloc_huge_page(vma, address);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800796 if (IS_ERR(page)) {
797 ret = -PTR_ERR(page);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800798 goto out;
799 }
David Gibson79ac6ba2006-03-22 00:08:51 -0800800 clear_huge_page(page, address);
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100801
Christoph Lameter6bda6662006-01-06 00:10:49 -0800802 if (vma->vm_flags & VM_SHARED) {
803 int err;
Ken Chen45c682a2007-11-14 16:59:44 -0800804 struct inode *inode = mapping->host;
Christoph Lameter6bda6662006-01-06 00:10:49 -0800805
806 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
807 if (err) {
808 put_page(page);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800809 if (err == -EEXIST)
810 goto retry;
811 goto out;
812 }
Ken Chen45c682a2007-11-14 16:59:44 -0800813
814 spin_lock(&inode->i_lock);
815 inode->i_blocks += BLOCKS_PER_HUGEPAGE;
816 spin_unlock(&inode->i_lock);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800817 } else
818 lock_page(page);
819 }
David Gibson1e8f8892006-01-06 00:10:44 -0800820
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100821 spin_lock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700822 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
823 if (idx >= size)
824 goto backout;
825
Nick Piggin83c54072007-07-19 01:47:05 -0700826 ret = 0;
Adam Litke86e52162006-01-06 00:10:43 -0800827 if (!pte_none(*ptep))
Adam Litke4c887262005-10-29 18:16:46 -0700828 goto backout;
829
David Gibson1e8f8892006-01-06 00:10:44 -0800830 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
831 && (vma->vm_flags & VM_SHARED)));
832 set_huge_pte_at(mm, address, ptep, new_pte);
833
834 if (write_access && !(vma->vm_flags & VM_SHARED)) {
835 /* Optimization, do the COW without a second fault */
836 ret = hugetlb_cow(mm, vma, address, ptep, new_pte);
837 }
838
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100839 spin_unlock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700840 unlock_page(page);
841out:
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100842 return ret;
Adam Litke4c887262005-10-29 18:16:46 -0700843
844backout:
845 spin_unlock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700846 unlock_page(page);
847 put_page(page);
848 goto out;
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100849}
850
Adam Litke86e52162006-01-06 00:10:43 -0800851int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
852 unsigned long address, int write_access)
853{
854 pte_t *ptep;
855 pte_t entry;
David Gibson1e8f8892006-01-06 00:10:44 -0800856 int ret;
David Gibson3935baa2006-03-22 00:08:53 -0800857 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
Adam Litke86e52162006-01-06 00:10:43 -0800858
859 ptep = huge_pte_alloc(mm, address);
860 if (!ptep)
861 return VM_FAULT_OOM;
862
David Gibson3935baa2006-03-22 00:08:53 -0800863 /*
864 * Serialize hugepage allocation and instantiation, so that we don't
865 * get spurious allocation failures if two CPUs race to instantiate
866 * the same page in the page cache.
867 */
868 mutex_lock(&hugetlb_instantiation_mutex);
Adam Litke86e52162006-01-06 00:10:43 -0800869 entry = *ptep;
David Gibson3935baa2006-03-22 00:08:53 -0800870 if (pte_none(entry)) {
871 ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
872 mutex_unlock(&hugetlb_instantiation_mutex);
873 return ret;
874 }
Adam Litke86e52162006-01-06 00:10:43 -0800875
Nick Piggin83c54072007-07-19 01:47:05 -0700876 ret = 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800877
878 spin_lock(&mm->page_table_lock);
879 /* Check for a racing update before calling hugetlb_cow */
880 if (likely(pte_same(entry, *ptep)))
881 if (write_access && !pte_write(entry))
882 ret = hugetlb_cow(mm, vma, address, ptep, entry);
883 spin_unlock(&mm->page_table_lock);
David Gibson3935baa2006-03-22 00:08:53 -0800884 mutex_unlock(&hugetlb_instantiation_mutex);
David Gibson1e8f8892006-01-06 00:10:44 -0800885
886 return ret;
Adam Litke86e52162006-01-06 00:10:43 -0800887}
888
David Gibson63551ae2005-06-21 17:14:44 -0700889int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
890 struct page **pages, struct vm_area_struct **vmas,
Adam Litke5b23dbe2007-11-14 16:59:33 -0800891 unsigned long *position, int *length, int i,
892 int write)
David Gibson63551ae2005-06-21 17:14:44 -0700893{
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -0800894 unsigned long pfn_offset;
895 unsigned long vaddr = *position;
David Gibson63551ae2005-06-21 17:14:44 -0700896 int remainder = *length;
897
Hugh Dickins1c598272005-10-19 21:23:43 -0700898 spin_lock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700899 while (vaddr < vma->vm_end && remainder) {
Adam Litke4c887262005-10-29 18:16:46 -0700900 pte_t *pte;
901 struct page *page;
902
903 /*
904 * Some archs (sparc64, sh*) have multiple pte_ts to
905 * each hugepage. We have to make * sure we get the
906 * first, for the page indexing below to work.
907 */
908 pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
909
910 if (!pte || pte_none(*pte)) {
911 int ret;
912
913 spin_unlock(&mm->page_table_lock);
Adam Litke5b23dbe2007-11-14 16:59:33 -0800914 ret = hugetlb_fault(mm, vma, vaddr, write);
Adam Litke4c887262005-10-29 18:16:46 -0700915 spin_lock(&mm->page_table_lock);
Adam Litkea89182c2007-08-22 14:01:51 -0700916 if (!(ret & VM_FAULT_ERROR))
Adam Litke4c887262005-10-29 18:16:46 -0700917 continue;
918
919 remainder = 0;
920 if (!i)
921 i = -EFAULT;
922 break;
923 }
David Gibson63551ae2005-06-21 17:14:44 -0700924
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -0800925 pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT;
926 page = pte_page(*pte);
927same_page:
Chen, Kenneth Wd6692182006-03-31 02:29:57 -0800928 if (pages) {
929 get_page(page);
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -0800930 pages[i] = page + pfn_offset;
Chen, Kenneth Wd6692182006-03-31 02:29:57 -0800931 }
David Gibson63551ae2005-06-21 17:14:44 -0700932
933 if (vmas)
934 vmas[i] = vma;
935
936 vaddr += PAGE_SIZE;
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -0800937 ++pfn_offset;
David Gibson63551ae2005-06-21 17:14:44 -0700938 --remainder;
939 ++i;
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -0800940 if (vaddr < vma->vm_end && remainder &&
941 pfn_offset < HPAGE_SIZE/PAGE_SIZE) {
942 /*
943 * We use pfn_offset to avoid touching the pageframes
944 * of this compound page.
945 */
946 goto same_page;
947 }
David Gibson63551ae2005-06-21 17:14:44 -0700948 }
Hugh Dickins1c598272005-10-19 21:23:43 -0700949 spin_unlock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700950 *length = remainder;
951 *position = vaddr;
952
953 return i;
954}
Zhang, Yanmin8f860592006-03-22 00:08:50 -0800955
956void hugetlb_change_protection(struct vm_area_struct *vma,
957 unsigned long address, unsigned long end, pgprot_t newprot)
958{
959 struct mm_struct *mm = vma->vm_mm;
960 unsigned long start = address;
961 pte_t *ptep;
962 pte_t pte;
963
964 BUG_ON(address >= end);
965 flush_cache_range(vma, address, end);
966
Chen, Kenneth W39dde652006-12-06 20:32:03 -0800967 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
Zhang, Yanmin8f860592006-03-22 00:08:50 -0800968 spin_lock(&mm->page_table_lock);
969 for (; address < end; address += HPAGE_SIZE) {
970 ptep = huge_pte_offset(mm, address);
971 if (!ptep)
972 continue;
Chen, Kenneth W39dde652006-12-06 20:32:03 -0800973 if (huge_pmd_unshare(mm, &address, ptep))
974 continue;
Zhang, Yanmin8f860592006-03-22 00:08:50 -0800975 if (!pte_none(*ptep)) {
976 pte = huge_ptep_get_and_clear(mm, address, ptep);
977 pte = pte_mkhuge(pte_modify(pte, newprot));
978 set_huge_pte_at(mm, address, ptep, pte);
Zhang, Yanmin8f860592006-03-22 00:08:50 -0800979 }
980 }
981 spin_unlock(&mm->page_table_lock);
Chen, Kenneth W39dde652006-12-06 20:32:03 -0800982 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
Zhang, Yanmin8f860592006-03-22 00:08:50 -0800983
984 flush_tlb_range(vma, start, end);
985}
986
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700987struct file_region {
988 struct list_head link;
989 long from;
990 long to;
991};
992
993static long region_add(struct list_head *head, long f, long t)
994{
995 struct file_region *rg, *nrg, *trg;
996
997 /* Locate the region we are either in or before. */
998 list_for_each_entry(rg, head, link)
999 if (f <= rg->to)
1000 break;
1001
1002 /* Round our left edge to the current segment if it encloses us. */
1003 if (f > rg->from)
1004 f = rg->from;
1005
1006 /* Check for and consume any regions we now overlap with. */
1007 nrg = rg;
1008 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
1009 if (&rg->link == head)
1010 break;
1011 if (rg->from > t)
1012 break;
1013
1014 /* If this area reaches higher then extend our area to
1015 * include it completely. If this is not the first area
1016 * which we intend to reuse, free it. */
1017 if (rg->to > t)
1018 t = rg->to;
1019 if (rg != nrg) {
1020 list_del(&rg->link);
1021 kfree(rg);
1022 }
1023 }
1024 nrg->from = f;
1025 nrg->to = t;
1026 return 0;
1027}
1028
1029static long region_chg(struct list_head *head, long f, long t)
1030{
1031 struct file_region *rg, *nrg;
1032 long chg = 0;
1033
1034 /* Locate the region we are before or in. */
1035 list_for_each_entry(rg, head, link)
1036 if (f <= rg->to)
1037 break;
1038
1039 /* If we are below the current region then a new region is required.
1040 * Subtle, allocate a new region at the position but make it zero
Simon Arlott183ff222007-10-20 01:27:18 +02001041 * size such that we can guarantee to record the reservation. */
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001042 if (&rg->link == head || t < rg->from) {
1043 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
Stephen Hemmingerc80544d2007-10-18 03:07:05 -07001044 if (!nrg)
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001045 return -ENOMEM;
1046 nrg->from = f;
1047 nrg->to = f;
1048 INIT_LIST_HEAD(&nrg->link);
1049 list_add(&nrg->link, rg->link.prev);
1050
1051 return t - f;
1052 }
1053
1054 /* Round our left edge to the current segment if it encloses us. */
1055 if (f > rg->from)
1056 f = rg->from;
1057 chg = t - f;
1058
1059 /* Check for and consume any regions we now overlap with. */
1060 list_for_each_entry(rg, rg->link.prev, link) {
1061 if (&rg->link == head)
1062 break;
1063 if (rg->from > t)
1064 return chg;
1065
1066 /* We overlap with this area, if it extends futher than
1067 * us then we must extend ourselves. Account for its
1068 * existing reservation. */
1069 if (rg->to > t) {
1070 chg += rg->to - t;
1071 t = rg->to;
1072 }
1073 chg -= rg->to - rg->from;
1074 }
1075 return chg;
1076}
1077
1078static long region_truncate(struct list_head *head, long end)
1079{
1080 struct file_region *rg, *trg;
1081 long chg = 0;
1082
1083 /* Locate the region we are either in or before. */
1084 list_for_each_entry(rg, head, link)
1085 if (end <= rg->to)
1086 break;
1087 if (&rg->link == head)
1088 return 0;
1089
1090 /* If we are in the middle of a region then adjust it. */
1091 if (end > rg->from) {
1092 chg = rg->to - end;
1093 rg->to = end;
1094 rg = list_entry(rg->link.next, typeof(*rg), link);
1095 }
1096
1097 /* Drop any remaining regions. */
1098 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
1099 if (&rg->link == head)
1100 break;
1101 chg += rg->to - rg->from;
1102 list_del(&rg->link);
1103 kfree(rg);
1104 }
1105 return chg;
1106}
1107
1108static int hugetlb_acct_memory(long delta)
1109{
1110 int ret = -ENOMEM;
1111
1112 spin_lock(&hugetlb_lock);
Ken Chen8a630112007-05-09 02:33:34 -07001113 /*
1114 * When cpuset is configured, it breaks the strict hugetlb page
1115 * reservation as the accounting is done on a global variable. Such
1116 * reservation is completely rubbish in the presence of cpuset because
1117 * the reservation is not checked against page availability for the
1118 * current cpuset. Application can still potentially OOM'ed by kernel
1119 * with lack of free htlb page in cpuset that the task is in.
1120 * Attempt to enforce strict accounting with cpuset is almost
1121 * impossible (or too ugly) because cpuset is too fluid that
1122 * task or memory node can be dynamically moved between cpusets.
1123 *
1124 * The change of semantics for shared hugetlb mapping with cpuset is
1125 * undesirable. However, in order to preserve some of the semantics,
1126 * we fall back to check against current free page availability as
1127 * a best attempt and hopefully to minimize the impact of changing
1128 * semantics that cpuset has.
1129 */
Adam Litkee4e574b2007-10-16 01:26:19 -07001130 if (delta > 0) {
1131 if (gather_surplus_pages(delta) < 0)
1132 goto out;
1133
1134 if (delta > cpuset_mems_nr(free_huge_pages_node))
1135 goto out;
1136 }
1137
1138 ret = 0;
1139 resv_huge_pages += delta;
1140 if (delta < 0)
1141 return_unused_surplus_pages((unsigned long) -delta);
1142
1143out:
1144 spin_unlock(&hugetlb_lock);
1145 return ret;
1146}
1147
1148int hugetlb_reserve_pages(struct inode *inode, long from, long to)
1149{
1150 long ret, chg;
1151
1152 chg = region_chg(&inode->i_mapping->private_list, from, to);
1153 if (chg < 0)
1154 return chg;
Ken Chen8a630112007-05-09 02:33:34 -07001155
Adam Litke90d8b7e2007-11-14 16:59:42 -08001156 if (hugetlb_get_quota(inode->i_mapping, chg))
1157 return -ENOSPC;
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001158 ret = hugetlb_acct_memory(chg);
1159 if (ret < 0)
1160 return ret;
1161 region_add(&inode->i_mapping->private_list, from, to);
1162 return 0;
1163}
1164
1165void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
1166{
1167 long chg = region_truncate(&inode->i_mapping->private_list, offset);
Ken Chen45c682a2007-11-14 16:59:44 -08001168
1169 spin_lock(&inode->i_lock);
1170 inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed;
1171 spin_unlock(&inode->i_lock);
1172
Adam Litke90d8b7e2007-11-14 16:59:42 -08001173 hugetlb_put_quota(inode->i_mapping, (chg - freed));
1174 hugetlb_acct_memory(-(chg - freed));
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001175}