blob: 2c37c67ed8c90f0cb64265519ad794abcb275a1d [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;
Nishanth Aravamudan064d9ef2008-02-13 15:03:19 -080027static unsigned long nr_overcommit_huge_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -070028unsigned long max_huge_pages;
Nishanth Aravamudan064d9ef2008-02-13 15:03:19 -080029unsigned long sysctl_overcommit_huge_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -070030static struct list_head hugepage_freelists[MAX_NUMNODES];
31static unsigned int nr_huge_pages_node[MAX_NUMNODES];
32static unsigned int free_huge_pages_node[MAX_NUMNODES];
Adam Litke7893d1d2007-10-16 01:26:18 -070033static unsigned int surplus_huge_pages_node[MAX_NUMNODES];
Mel Gorman396faf02007-07-17 04:03:13 -070034static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
35unsigned long hugepages_treat_as_movable;
Nishanth Aravamudan63b46132007-10-16 01:26:24 -070036static int hugetlb_next_nid;
Mel Gorman396faf02007-07-17 04:03:13 -070037
David Gibson3935baa2006-03-22 00:08:53 -080038/*
39 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
40 */
41static DEFINE_SPINLOCK(hugetlb_lock);
Eric Paris0bd0f9f2005-11-21 21:32:28 -080042
David Gibson79ac6ba2006-03-22 00:08:51 -080043static 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();
Ralf Baechle281e0e32007-10-01 01:20:10 -070050 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
David Gibson79ac6ba2006-03-22 00:08:51 -080051 }
52}
53
54static void copy_huge_page(struct page *dst, struct page *src,
Atsushi Nemoto9de455b2006-12-12 17:14:55 +000055 unsigned long addr, struct vm_area_struct *vma)
David Gibson79ac6ba2006-03-22 00:08:51 -080056{
57 int i;
58
59 might_sleep();
60 for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++) {
61 cond_resched();
Atsushi Nemoto9de455b2006-12-12 17:14:55 +000062 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
David Gibson79ac6ba2006-03-22 00:08:51 -080063 }
64}
65
Linus Torvalds1da177e2005-04-16 15:20:36 -070066static 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
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -080074static struct page *dequeue_huge_page(void)
75{
76 int nid;
77 struct page *page = NULL;
78
79 for (nid = 0; nid < MAX_NUMNODES; ++nid) {
80 if (!list_empty(&hugepage_freelists[nid])) {
81 page = list_entry(hugepage_freelists[nid].next,
82 struct page, lru);
83 list_del(&page->lru);
84 free_huge_pages--;
85 free_huge_pages_node[nid]--;
86 break;
87 }
88 }
89 return page;
90}
91
92static struct page *dequeue_huge_page_vma(struct vm_area_struct *vma,
Christoph Lameter5da7ca82006-01-06 00:10:46 -080093 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -070094{
Nishanth Aravamudan31a5c6e2007-07-15 23:38:02 -070095 int nid;
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 struct page *page = NULL;
Lee Schermerhorn480eccf2007-09-18 22:46:47 -070097 struct mempolicy *mpol;
Mel Gorman19770b32008-04-28 02:12:18 -070098 nodemask_t *nodemask;
Mel Gorman396faf02007-07-17 04:03:13 -070099 struct zonelist *zonelist = huge_zonelist(vma, address,
Mel Gorman19770b32008-04-28 02:12:18 -0700100 htlb_alloc_mask, &mpol, &nodemask);
Mel Gormandd1a2392008-04-28 02:12:17 -0700101 struct zone *zone;
102 struct zoneref *z;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103
Mel Gorman19770b32008-04-28 02:12:18 -0700104 for_each_zone_zonelist_nodemask(zone, z, zonelist,
105 MAX_NR_ZONES - 1, nodemask) {
Mel Gorman54a6eb52008-04-28 02:12:16 -0700106 nid = zone_to_nid(zone);
107 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) &&
Andrew Morton3abf7af2007-07-19 01:49:08 -0700108 !list_empty(&hugepage_freelists[nid])) {
109 page = list_entry(hugepage_freelists[nid].next,
110 struct page, lru);
111 list_del(&page->lru);
112 free_huge_pages--;
113 free_huge_pages_node[nid]--;
Adam Litkee4e574b2007-10-16 01:26:19 -0700114 if (vma && vma->vm_flags & VM_MAYSHARE)
115 resv_huge_pages--;
Ken Chen5ab3ee72007-07-23 18:44:00 -0700116 break;
Andrew Morton3abf7af2007-07-19 01:49:08 -0700117 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 }
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -0700119 mpol_cond_put(mpol);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 return page;
121}
122
Adam Litke6af2acb2007-10-16 01:26:16 -0700123static void update_and_free_page(struct page *page)
124{
125 int i;
126 nr_huge_pages--;
127 nr_huge_pages_node[page_to_nid(page)]--;
128 for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) {
129 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
130 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
131 1 << PG_private | 1<< PG_writeback);
132 }
133 set_compound_page_dtor(page, NULL);
134 set_page_refcounted(page);
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700135 arch_release_hugepage(page);
Adam Litke6af2acb2007-10-16 01:26:16 -0700136 __free_pages(page, HUGETLB_PAGE_ORDER);
137}
138
David Gibson27a85ef2006-03-22 00:08:56 -0800139static void free_huge_page(struct page *page)
140{
Adam Litke7893d1d2007-10-16 01:26:18 -0700141 int nid = page_to_nid(page);
Adam Litkec79fb752007-11-14 16:59:38 -0800142 struct address_space *mapping;
David Gibson27a85ef2006-03-22 00:08:56 -0800143
Adam Litkec79fb752007-11-14 16:59:38 -0800144 mapping = (struct address_space *) page_private(page);
Andy Whitcrofte5df70a2008-02-23 15:23:32 -0800145 set_page_private(page, 0);
Adam Litke7893d1d2007-10-16 01:26:18 -0700146 BUG_ON(page_count(page));
David Gibson27a85ef2006-03-22 00:08:56 -0800147 INIT_LIST_HEAD(&page->lru);
148
149 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700150 if (surplus_huge_pages_node[nid]) {
151 update_and_free_page(page);
152 surplus_huge_pages--;
153 surplus_huge_pages_node[nid]--;
154 } else {
155 enqueue_huge_page(page);
156 }
David Gibson27a85ef2006-03-22 00:08:56 -0800157 spin_unlock(&hugetlb_lock);
Adam Litkec79fb752007-11-14 16:59:38 -0800158 if (mapping)
Adam Litke9a119c02007-11-14 16:59:41 -0800159 hugetlb_put_quota(mapping, 1);
David Gibson27a85ef2006-03-22 00:08:56 -0800160}
161
Adam Litke7893d1d2007-10-16 01:26:18 -0700162/*
163 * Increment or decrement surplus_huge_pages. Keep node-specific counters
164 * balanced by operating on them in a round-robin fashion.
165 * Returns 1 if an adjustment was made.
166 */
167static int adjust_pool_surplus(int delta)
168{
169 static int prev_nid;
170 int nid = prev_nid;
171 int ret = 0;
172
173 VM_BUG_ON(delta != -1 && delta != 1);
174 do {
175 nid = next_node(nid, node_online_map);
176 if (nid == MAX_NUMNODES)
177 nid = first_node(node_online_map);
178
179 /* To shrink on this node, there must be a surplus page */
180 if (delta < 0 && !surplus_huge_pages_node[nid])
181 continue;
182 /* Surplus cannot exceed the total number of pages */
183 if (delta > 0 && surplus_huge_pages_node[nid] >=
184 nr_huge_pages_node[nid])
185 continue;
186
187 surplus_huge_pages += delta;
188 surplus_huge_pages_node[nid] += delta;
189 ret = 1;
190 break;
191 } while (nid != prev_nid);
192
193 prev_nid = nid;
194 return ret;
195}
196
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700197static struct page *alloc_fresh_huge_page_node(int nid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 struct page *page;
Joe Jinf96efd52007-07-15 23:38:12 -0700200
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700201 page = alloc_pages_node(nid,
202 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|__GFP_NOWARN,
203 HUGETLB_PAGE_ORDER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 if (page) {
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700205 if (arch_prepare_hugepage(page)) {
206 __free_pages(page, HUGETLB_PAGE_ORDER);
Harvey Harrison7b8ee842008-04-28 14:13:19 -0700207 return NULL;
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700208 }
Andy Whitcroft33f2ef82006-12-06 20:33:32 -0800209 set_compound_page_dtor(page, free_huge_page);
Eric Paris0bd0f9f2005-11-21 21:32:28 -0800210 spin_lock(&hugetlb_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 nr_huge_pages++;
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700212 nr_huge_pages_node[nid]++;
Eric Paris0bd0f9f2005-11-21 21:32:28 -0800213 spin_unlock(&hugetlb_lock);
Nick Piggina4822892006-03-22 00:08:08 -0800214 put_page(page); /* free it into the hugepage allocator */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 }
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700216
217 return page;
218}
219
220static int alloc_fresh_huge_page(void)
221{
222 struct page *page;
223 int start_nid;
224 int next_nid;
225 int ret = 0;
226
227 start_nid = hugetlb_next_nid;
228
229 do {
230 page = alloc_fresh_huge_page_node(hugetlb_next_nid);
231 if (page)
232 ret = 1;
233 /*
234 * Use a helper variable to find the next node and then
235 * copy it back to hugetlb_next_nid afterwards:
236 * otherwise there's a window in which a racer might
237 * pass invalid nid MAX_NUMNODES to alloc_pages_node.
238 * But we don't need to use a spin_lock here: it really
239 * doesn't matter if occasionally a racer chooses the
240 * same nid as we do. Move nid forward in the mask even
241 * if we just successfully allocated a hugepage so that
242 * the next caller gets hugepages on the next node.
243 */
244 next_nid = next_node(hugetlb_next_nid, node_online_map);
245 if (next_nid == MAX_NUMNODES)
246 next_nid = first_node(node_online_map);
247 hugetlb_next_nid = next_nid;
248 } while (!page && hugetlb_next_nid != start_nid);
249
Adam Litke3b116302008-04-28 02:13:06 -0700250 if (ret)
251 count_vm_event(HTLB_BUDDY_PGALLOC);
252 else
253 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
254
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700255 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256}
257
Adam Litke7893d1d2007-10-16 01:26:18 -0700258static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma,
259 unsigned long address)
260{
261 struct page *page;
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800262 unsigned int nid;
Adam Litke7893d1d2007-10-16 01:26:18 -0700263
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800264 /*
265 * Assume we will successfully allocate the surplus page to
266 * prevent racing processes from causing the surplus to exceed
267 * overcommit
268 *
269 * This however introduces a different race, where a process B
270 * tries to grow the static hugepage pool while alloc_pages() is
271 * called by process A. B will only examine the per-node
272 * counters in determining if surplus huge pages can be
273 * converted to normal huge pages in adjust_pool_surplus(). A
274 * won't be able to increment the per-node counter, until the
275 * lock is dropped by B, but B doesn't drop hugetlb_lock until
276 * no more huge pages can be converted from surplus to normal
277 * state (and doesn't try to convert again). Thus, we have a
278 * case where a surplus huge page exists, the pool is grown, and
279 * the surplus huge page still exists after, even though it
280 * should just have been converted to a normal huge page. This
281 * does not leak memory, though, as the hugepage will be freed
282 * once it is out of use. It also does not allow the counters to
283 * go out of whack in adjust_pool_surplus() as we don't modify
284 * the node values until we've gotten the hugepage and only the
285 * per-node value is checked there.
286 */
287 spin_lock(&hugetlb_lock);
288 if (surplus_huge_pages >= nr_overcommit_huge_pages) {
289 spin_unlock(&hugetlb_lock);
290 return NULL;
291 } else {
292 nr_huge_pages++;
293 surplus_huge_pages++;
294 }
295 spin_unlock(&hugetlb_lock);
296
Adam Litke7893d1d2007-10-16 01:26:18 -0700297 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN,
298 HUGETLB_PAGE_ORDER);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800299
300 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700301 if (page) {
Adam Litke2668db92008-03-10 11:43:50 -0700302 /*
303 * This page is now managed by the hugetlb allocator and has
304 * no users -- drop the buddy allocator's reference.
305 */
306 put_page_testzero(page);
307 VM_BUG_ON(page_count(page));
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800308 nid = page_to_nid(page);
Adam Litke7893d1d2007-10-16 01:26:18 -0700309 set_compound_page_dtor(page, free_huge_page);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800310 /*
311 * We incremented the global counters already
312 */
313 nr_huge_pages_node[nid]++;
314 surplus_huge_pages_node[nid]++;
Adam Litke3b116302008-04-28 02:13:06 -0700315 __count_vm_event(HTLB_BUDDY_PGALLOC);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800316 } else {
317 nr_huge_pages--;
318 surplus_huge_pages--;
Adam Litke3b116302008-04-28 02:13:06 -0700319 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
Adam Litke7893d1d2007-10-16 01:26:18 -0700320 }
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800321 spin_unlock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700322
323 return page;
324}
325
Adam Litkee4e574b2007-10-16 01:26:19 -0700326/*
327 * Increase the hugetlb pool such that it can accomodate a reservation
328 * of size 'delta'.
329 */
330static int gather_surplus_pages(int delta)
331{
332 struct list_head surplus_list;
333 struct page *page, *tmp;
334 int ret, i;
335 int needed, allocated;
336
337 needed = (resv_huge_pages + delta) - free_huge_pages;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800338 if (needed <= 0) {
339 resv_huge_pages += delta;
Adam Litkee4e574b2007-10-16 01:26:19 -0700340 return 0;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800341 }
Adam Litkee4e574b2007-10-16 01:26:19 -0700342
343 allocated = 0;
344 INIT_LIST_HEAD(&surplus_list);
345
346 ret = -ENOMEM;
347retry:
348 spin_unlock(&hugetlb_lock);
349 for (i = 0; i < needed; i++) {
350 page = alloc_buddy_huge_page(NULL, 0);
351 if (!page) {
352 /*
353 * We were not able to allocate enough pages to
354 * satisfy the entire reservation so we free what
355 * we've allocated so far.
356 */
357 spin_lock(&hugetlb_lock);
358 needed = 0;
359 goto free;
360 }
361
362 list_add(&page->lru, &surplus_list);
363 }
364 allocated += needed;
365
366 /*
367 * After retaking hugetlb_lock, we need to recalculate 'needed'
368 * because either resv_huge_pages or free_huge_pages may have changed.
369 */
370 spin_lock(&hugetlb_lock);
371 needed = (resv_huge_pages + delta) - (free_huge_pages + allocated);
372 if (needed > 0)
373 goto retry;
374
375 /*
376 * The surplus_list now contains _at_least_ the number of extra pages
377 * needed to accomodate the reservation. Add the appropriate number
378 * of pages to the hugetlb pool and free the extras back to the buddy
Adam Litkeac09b3a2008-03-04 14:29:38 -0800379 * allocator. Commit the entire reservation here to prevent another
380 * process from stealing the pages as they are added to the pool but
381 * before they are reserved.
Adam Litkee4e574b2007-10-16 01:26:19 -0700382 */
383 needed += allocated;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800384 resv_huge_pages += delta;
Adam Litkee4e574b2007-10-16 01:26:19 -0700385 ret = 0;
386free:
Adam Litke19fc3f02008-04-28 02:12:20 -0700387 /* Free the needed pages to the hugetlb pool */
Adam Litkee4e574b2007-10-16 01:26:19 -0700388 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
Adam Litke19fc3f02008-04-28 02:12:20 -0700389 if ((--needed) < 0)
390 break;
Adam Litkee4e574b2007-10-16 01:26:19 -0700391 list_del(&page->lru);
Adam Litke19fc3f02008-04-28 02:12:20 -0700392 enqueue_huge_page(page);
393 }
394
395 /* Free unnecessary surplus pages to the buddy allocator */
396 if (!list_empty(&surplus_list)) {
397 spin_unlock(&hugetlb_lock);
398 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
399 list_del(&page->lru);
Adam Litkeaf767cb2007-10-16 01:26:25 -0700400 /*
Adam Litke2668db92008-03-10 11:43:50 -0700401 * The page has a reference count of zero already, so
402 * call free_huge_page directly instead of using
403 * put_page. This must be done with hugetlb_lock
Adam Litkeaf767cb2007-10-16 01:26:25 -0700404 * unlocked which is safe because free_huge_page takes
405 * hugetlb_lock before deciding how to free the page.
406 */
Adam Litke2668db92008-03-10 11:43:50 -0700407 free_huge_page(page);
Adam Litkeaf767cb2007-10-16 01:26:25 -0700408 }
Adam Litke19fc3f02008-04-28 02:12:20 -0700409 spin_lock(&hugetlb_lock);
Adam Litkee4e574b2007-10-16 01:26:19 -0700410 }
411
412 return ret;
413}
414
415/*
416 * When releasing a hugetlb pool reservation, any surplus pages that were
417 * allocated to satisfy the reservation must be explicitly freed if they were
418 * never used.
419 */
Adrian Bunk8cde0452007-11-14 16:59:43 -0800420static void return_unused_surplus_pages(unsigned long unused_resv_pages)
Adam Litkee4e574b2007-10-16 01:26:19 -0700421{
422 static int nid = -1;
423 struct page *page;
424 unsigned long nr_pages;
425
Nishanth Aravamudan11320d12008-03-26 14:40:20 -0700426 /*
427 * We want to release as many surplus pages as possible, spread
428 * evenly across all nodes. Iterate across all nodes until we
429 * can no longer free unreserved surplus pages. This occurs when
430 * the nodes with surplus pages have no free pages.
431 */
432 unsigned long remaining_iterations = num_online_nodes();
433
Adam Litkeac09b3a2008-03-04 14:29:38 -0800434 /* Uncommit the reservation */
435 resv_huge_pages -= unused_resv_pages;
436
Adam Litkee4e574b2007-10-16 01:26:19 -0700437 nr_pages = min(unused_resv_pages, surplus_huge_pages);
438
Nishanth Aravamudan11320d12008-03-26 14:40:20 -0700439 while (remaining_iterations-- && nr_pages) {
Adam Litkee4e574b2007-10-16 01:26:19 -0700440 nid = next_node(nid, node_online_map);
441 if (nid == MAX_NUMNODES)
442 nid = first_node(node_online_map);
443
444 if (!surplus_huge_pages_node[nid])
445 continue;
446
447 if (!list_empty(&hugepage_freelists[nid])) {
448 page = list_entry(hugepage_freelists[nid].next,
449 struct page, lru);
450 list_del(&page->lru);
451 update_and_free_page(page);
452 free_huge_pages--;
453 free_huge_pages_node[nid]--;
454 surplus_huge_pages--;
455 surplus_huge_pages_node[nid]--;
456 nr_pages--;
Nishanth Aravamudan11320d12008-03-26 14:40:20 -0700457 remaining_iterations = num_online_nodes();
Adam Litkee4e574b2007-10-16 01:26:19 -0700458 }
459 }
460}
461
Adam Litke348ea202007-11-14 16:59:37 -0800462
463static struct page *alloc_huge_page_shared(struct vm_area_struct *vma,
464 unsigned long addr)
465{
466 struct page *page;
467
468 spin_lock(&hugetlb_lock);
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800469 page = dequeue_huge_page_vma(vma, addr);
Adam Litke348ea202007-11-14 16:59:37 -0800470 spin_unlock(&hugetlb_lock);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800471 return page ? page : ERR_PTR(-VM_FAULT_OOM);
Adam Litke348ea202007-11-14 16:59:37 -0800472}
473
474static struct page *alloc_huge_page_private(struct vm_area_struct *vma,
475 unsigned long addr)
476{
477 struct page *page = NULL;
478
Adam Litke90d8b7e2007-11-14 16:59:42 -0800479 if (hugetlb_get_quota(vma->vm_file->f_mapping, 1))
480 return ERR_PTR(-VM_FAULT_SIGBUS);
481
Adam Litke348ea202007-11-14 16:59:37 -0800482 spin_lock(&hugetlb_lock);
483 if (free_huge_pages > resv_huge_pages)
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800484 page = dequeue_huge_page_vma(vma, addr);
Adam Litke348ea202007-11-14 16:59:37 -0800485 spin_unlock(&hugetlb_lock);
Ken Chen68842c92008-01-14 00:55:19 -0800486 if (!page) {
Adam Litke348ea202007-11-14 16:59:37 -0800487 page = alloc_buddy_huge_page(vma, addr);
Ken Chen68842c92008-01-14 00:55:19 -0800488 if (!page) {
489 hugetlb_put_quota(vma->vm_file->f_mapping, 1);
490 return ERR_PTR(-VM_FAULT_OOM);
491 }
492 }
493 return page;
Adam Litke348ea202007-11-14 16:59:37 -0800494}
495
David Gibson27a85ef2006-03-22 00:08:56 -0800496static struct page *alloc_huge_page(struct vm_area_struct *vma,
497 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498{
Adam Litke348ea202007-11-14 16:59:37 -0800499 struct page *page;
Adam Litke2fc39ce2007-11-14 16:59:39 -0800500 struct address_space *mapping = vma->vm_file->f_mapping;
501
Adam Litke348ea202007-11-14 16:59:37 -0800502 if (vma->vm_flags & VM_MAYSHARE)
503 page = alloc_huge_page_shared(vma, addr);
504 else
505 page = alloc_huge_page_private(vma, addr);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800506
507 if (!IS_ERR(page)) {
Adam Litke348ea202007-11-14 16:59:37 -0800508 set_page_refcounted(page);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800509 set_page_private(page, (unsigned long) mapping);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800510 }
511 return page;
David Gibsonb45b5bd2006-03-22 00:08:55 -0800512}
513
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514static int __init hugetlb_init(void)
515{
516 unsigned long i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517
Benjamin Herrenschmidt3c726f82005-11-07 11:06:55 +1100518 if (HPAGE_SHIFT == 0)
519 return 0;
520
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 for (i = 0; i < MAX_NUMNODES; ++i)
522 INIT_LIST_HEAD(&hugepage_freelists[i]);
523
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700524 hugetlb_next_nid = first_node(node_online_map);
525
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 for (i = 0; i < max_huge_pages; ++i) {
Nick Piggina4822892006-03-22 00:08:08 -0800527 if (!alloc_fresh_huge_page())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 }
530 max_huge_pages = free_huge_pages = nr_huge_pages = i;
531 printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
532 return 0;
533}
534module_init(hugetlb_init);
535
536static int __init hugetlb_setup(char *s)
537{
538 if (sscanf(s, "%lu", &max_huge_pages) <= 0)
539 max_huge_pages = 0;
540 return 1;
541}
542__setup("hugepages=", hugetlb_setup);
543
Ken Chen8a630112007-05-09 02:33:34 -0700544static unsigned int cpuset_mems_nr(unsigned int *array)
545{
546 int node;
547 unsigned int nr = 0;
548
549 for_each_node_mask(node, cpuset_current_mems_allowed)
550 nr += array[node];
551
552 return nr;
553}
554
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555#ifdef CONFIG_SYSCTL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556#ifdef CONFIG_HIGHMEM
557static void try_to_free_low(unsigned long count)
558{
Christoph Lameter4415cc82006-09-25 23:31:55 -0700559 int i;
560
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 for (i = 0; i < MAX_NUMNODES; ++i) {
562 struct page *page, *next;
563 list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
Adam Litke6b0c8802007-10-16 01:26:23 -0700564 if (count >= nr_huge_pages)
565 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 if (PageHighMem(page))
567 continue;
568 list_del(&page->lru);
569 update_and_free_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 free_huge_pages--;
Christoph Lameter4415cc82006-09-25 23:31:55 -0700571 free_huge_pages_node[page_to_nid(page)]--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 }
573 }
574}
575#else
576static inline void try_to_free_low(unsigned long count)
577{
578}
579#endif
580
Adam Litke7893d1d2007-10-16 01:26:18 -0700581#define persistent_huge_pages (nr_huge_pages - surplus_huge_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582static unsigned long set_max_huge_pages(unsigned long count)
583{
Adam Litke7893d1d2007-10-16 01:26:18 -0700584 unsigned long min_count, ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585
Adam Litke7893d1d2007-10-16 01:26:18 -0700586 /*
587 * Increase the pool size
588 * First take pages out of surplus state. Then make up the
589 * remaining difference by allocating fresh huge pages.
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800590 *
591 * We might race with alloc_buddy_huge_page() here and be unable
592 * to convert a surplus huge page to a normal huge page. That is
593 * not critical, though, it just means the overall size of the
594 * pool might be one hugepage larger than it needs to be, but
595 * within all the constraints specified by the sysctls.
Adam Litke7893d1d2007-10-16 01:26:18 -0700596 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700598 while (surplus_huge_pages && count > persistent_huge_pages) {
599 if (!adjust_pool_surplus(-1))
600 break;
601 }
602
603 while (count > persistent_huge_pages) {
604 int ret;
605 /*
606 * If this allocation races such that we no longer need the
607 * page, free_huge_page will handle it by freeing the page
608 * and reducing the surplus.
609 */
610 spin_unlock(&hugetlb_lock);
611 ret = alloc_fresh_huge_page();
612 spin_lock(&hugetlb_lock);
613 if (!ret)
614 goto out;
615
616 }
Adam Litke7893d1d2007-10-16 01:26:18 -0700617
618 /*
619 * Decrease the pool size
620 * First return free pages to the buddy allocator (being careful
621 * to keep enough around to satisfy reservations). Then place
622 * pages into surplus state as needed so the pool will shrink
623 * to the desired size as pages become free.
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800624 *
625 * By placing pages into the surplus state independent of the
626 * overcommit value, we are allowing the surplus pool size to
627 * exceed overcommit. There are few sane options here. Since
628 * alloc_buddy_huge_page() is checking the global counter,
629 * though, we'll note that we're not allowed to exceed surplus
630 * and won't grow the pool anywhere else. Not until one of the
631 * sysctls are changed, or the surplus pages go out of use.
Adam Litke7893d1d2007-10-16 01:26:18 -0700632 */
Adam Litke6b0c8802007-10-16 01:26:23 -0700633 min_count = resv_huge_pages + nr_huge_pages - free_huge_pages;
634 min_count = max(count, min_count);
Adam Litke7893d1d2007-10-16 01:26:18 -0700635 try_to_free_low(min_count);
636 while (min_count < persistent_huge_pages) {
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800637 struct page *page = dequeue_huge_page();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 if (!page)
639 break;
640 update_and_free_page(page);
641 }
Adam Litke7893d1d2007-10-16 01:26:18 -0700642 while (count < persistent_huge_pages) {
643 if (!adjust_pool_surplus(1))
644 break;
645 }
646out:
647 ret = persistent_huge_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 spin_unlock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700649 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650}
651
652int hugetlb_sysctl_handler(struct ctl_table *table, int write,
653 struct file *file, void __user *buffer,
654 size_t *length, loff_t *ppos)
655{
656 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
657 max_huge_pages = set_max_huge_pages(max_huge_pages);
658 return 0;
659}
Mel Gorman396faf02007-07-17 04:03:13 -0700660
661int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
662 struct file *file, void __user *buffer,
663 size_t *length, loff_t *ppos)
664{
665 proc_dointvec(table, write, file, buffer, length, ppos);
666 if (hugepages_treat_as_movable)
667 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
668 else
669 htlb_alloc_mask = GFP_HIGHUSER;
670 return 0;
671}
672
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800673int hugetlb_overcommit_handler(struct ctl_table *table, int write,
674 struct file *file, void __user *buffer,
675 size_t *length, loff_t *ppos)
676{
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800677 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
Nishanth Aravamudan064d9ef2008-02-13 15:03:19 -0800678 spin_lock(&hugetlb_lock);
679 nr_overcommit_huge_pages = sysctl_overcommit_huge_pages;
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800680 spin_unlock(&hugetlb_lock);
681 return 0;
682}
683
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684#endif /* CONFIG_SYSCTL */
685
686int hugetlb_report_meminfo(char *buf)
687{
688 return sprintf(buf,
689 "HugePages_Total: %5lu\n"
690 "HugePages_Free: %5lu\n"
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700691 "HugePages_Rsvd: %5lu\n"
Adam Litke7893d1d2007-10-16 01:26:18 -0700692 "HugePages_Surp: %5lu\n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 "Hugepagesize: %5lu kB\n",
694 nr_huge_pages,
695 free_huge_pages,
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700696 resv_huge_pages,
Adam Litke7893d1d2007-10-16 01:26:18 -0700697 surplus_huge_pages,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 HPAGE_SIZE/1024);
699}
700
701int hugetlb_report_node_meminfo(int nid, char *buf)
702{
703 return sprintf(buf,
704 "Node %d HugePages_Total: %5u\n"
Nishanth Aravamudana1de0912008-03-26 14:37:53 -0700705 "Node %d HugePages_Free: %5u\n"
706 "Node %d HugePages_Surp: %5u\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 nid, nr_huge_pages_node[nid],
Nishanth Aravamudana1de0912008-03-26 14:37:53 -0700708 nid, free_huge_pages_node[nid],
709 nid, surplus_huge_pages_node[nid]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710}
711
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
713unsigned long hugetlb_total_pages(void)
714{
715 return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
716}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717
718/*
719 * We cannot handle pagefaults against hugetlb pages at all. They cause
720 * handle_mm_fault() to try to instantiate regular-sized pages in the
721 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
722 * this far.
723 */
Nick Piggind0217ac2007-07-19 01:47:03 -0700724static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725{
726 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -0700727 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728}
729
730struct vm_operations_struct hugetlb_vm_ops = {
Nick Piggind0217ac2007-07-19 01:47:03 -0700731 .fault = hugetlb_vm_op_fault,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732};
733
David Gibson1e8f8892006-01-06 00:10:44 -0800734static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
735 int writable)
David Gibson63551ae2005-06-21 17:14:44 -0700736{
737 pte_t entry;
738
David Gibson1e8f8892006-01-06 00:10:44 -0800739 if (writable) {
David Gibson63551ae2005-06-21 17:14:44 -0700740 entry =
741 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
742 } else {
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700743 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
David Gibson63551ae2005-06-21 17:14:44 -0700744 }
745 entry = pte_mkyoung(entry);
746 entry = pte_mkhuge(entry);
747
748 return entry;
749}
750
David Gibson1e8f8892006-01-06 00:10:44 -0800751static void set_huge_ptep_writable(struct vm_area_struct *vma,
752 unsigned long address, pte_t *ptep)
753{
754 pte_t entry;
755
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700756 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
757 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -0700758 update_mmu_cache(vma, address, entry);
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -0700759 }
David Gibson1e8f8892006-01-06 00:10:44 -0800760}
761
762
David Gibson63551ae2005-06-21 17:14:44 -0700763int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
764 struct vm_area_struct *vma)
765{
766 pte_t *src_pte, *dst_pte, entry;
767 struct page *ptepage;
Hugh Dickins1c598272005-10-19 21:23:43 -0700768 unsigned long addr;
David Gibson1e8f8892006-01-06 00:10:44 -0800769 int cow;
770
771 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
David Gibson63551ae2005-06-21 17:14:44 -0700772
Hugh Dickins1c598272005-10-19 21:23:43 -0700773 for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
Hugh Dickinsc74df322005-10-29 18:16:23 -0700774 src_pte = huge_pte_offset(src, addr);
775 if (!src_pte)
776 continue;
David Gibson63551ae2005-06-21 17:14:44 -0700777 dst_pte = huge_pte_alloc(dst, addr);
778 if (!dst_pte)
779 goto nomem;
Larry Woodmanc5c99422008-01-24 05:49:25 -0800780
781 /* If the pagetables are shared don't copy or take references */
782 if (dst_pte == src_pte)
783 continue;
784
Hugh Dickinsc74df322005-10-29 18:16:23 -0700785 spin_lock(&dst->page_table_lock);
Hugh Dickins1c598272005-10-19 21:23:43 -0700786 spin_lock(&src->page_table_lock);
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700787 if (!huge_pte_none(huge_ptep_get(src_pte))) {
David Gibson1e8f8892006-01-06 00:10:44 -0800788 if (cow)
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700789 huge_ptep_set_wrprotect(src, addr, src_pte);
790 entry = huge_ptep_get(src_pte);
Hugh Dickins1c598272005-10-19 21:23:43 -0700791 ptepage = pte_page(entry);
792 get_page(ptepage);
Hugh Dickins1c598272005-10-19 21:23:43 -0700793 set_huge_pte_at(dst, addr, dst_pte, entry);
794 }
795 spin_unlock(&src->page_table_lock);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700796 spin_unlock(&dst->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700797 }
798 return 0;
799
800nomem:
801 return -ENOMEM;
802}
803
Chen, Kenneth W502717f2006-10-11 01:20:46 -0700804void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
805 unsigned long end)
David Gibson63551ae2005-06-21 17:14:44 -0700806{
807 struct mm_struct *mm = vma->vm_mm;
808 unsigned long address;
David Gibsonc7546f82005-08-05 11:59:35 -0700809 pte_t *ptep;
David Gibson63551ae2005-06-21 17:14:44 -0700810 pte_t pte;
811 struct page *page;
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700812 struct page *tmp;
Chen, Kenneth Wc0a499c2006-12-06 20:31:39 -0800813 /*
814 * A page gathering list, protected by per file i_mmap_lock. The
815 * lock is used to avoid list corruption from multiple unmapping
816 * of the same page since we are using page->lru.
817 */
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700818 LIST_HEAD(page_list);
David Gibson63551ae2005-06-21 17:14:44 -0700819
820 WARN_ON(!is_vm_hugetlb_page(vma));
821 BUG_ON(start & ~HPAGE_MASK);
822 BUG_ON(end & ~HPAGE_MASK);
823
Hugh Dickins508034a2005-10-29 18:16:30 -0700824 spin_lock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700825 for (address = start; address < end; address += HPAGE_SIZE) {
David Gibsonc7546f82005-08-05 11:59:35 -0700826 ptep = huge_pte_offset(mm, address);
Adam Litke4c887262005-10-29 18:16:46 -0700827 if (!ptep)
David Gibsonc7546f82005-08-05 11:59:35 -0700828 continue;
829
Chen, Kenneth W39dde652006-12-06 20:32:03 -0800830 if (huge_pmd_unshare(mm, &address, ptep))
831 continue;
832
David Gibsonc7546f82005-08-05 11:59:35 -0700833 pte = huge_ptep_get_and_clear(mm, address, ptep);
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700834 if (huge_pte_none(pte))
David Gibson63551ae2005-06-21 17:14:44 -0700835 continue;
David Gibsonc7546f82005-08-05 11:59:35 -0700836
David Gibson63551ae2005-06-21 17:14:44 -0700837 page = pte_page(pte);
Ken Chen6649a382007-02-08 14:20:27 -0800838 if (pte_dirty(pte))
839 set_page_dirty(page);
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700840 list_add(&page->lru, &page_list);
David Gibson63551ae2005-06-21 17:14:44 -0700841 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 spin_unlock(&mm->page_table_lock);
Hugh Dickins508034a2005-10-29 18:16:30 -0700843 flush_tlb_range(vma, start, end);
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700844 list_for_each_entry_safe(page, tmp, &page_list, lru) {
845 list_del(&page->lru);
846 put_page(page);
847 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848}
David Gibson63551ae2005-06-21 17:14:44 -0700849
Chen, Kenneth W502717f2006-10-11 01:20:46 -0700850void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
851 unsigned long end)
852{
853 /*
854 * It is undesirable to test vma->vm_file as it should be non-null
855 * for valid hugetlb area. However, vm_file will be NULL in the error
856 * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails,
857 * do_mmap_pgoff() nullifies vma->vm_file before calling this function
858 * to clean up. Since no pte has actually been setup, it is safe to
859 * do nothing in this case.
860 */
861 if (vma->vm_file) {
862 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
863 __unmap_hugepage_range(vma, start, end);
864 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
865 }
866}
867
David Gibson1e8f8892006-01-06 00:10:44 -0800868static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
869 unsigned long address, pte_t *ptep, pte_t pte)
870{
871 struct page *old_page, *new_page;
David Gibson79ac6ba2006-03-22 00:08:51 -0800872 int avoidcopy;
David Gibson1e8f8892006-01-06 00:10:44 -0800873
874 old_page = pte_page(pte);
875
876 /* If no-one else is actually using this page, avoid the copy
877 * and just make the page writable */
878 avoidcopy = (page_count(old_page) == 1);
879 if (avoidcopy) {
880 set_huge_ptep_writable(vma, address, ptep);
Nick Piggin83c54072007-07-19 01:47:05 -0700881 return 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800882 }
883
884 page_cache_get(old_page);
Christoph Lameter5da7ca82006-01-06 00:10:46 -0800885 new_page = alloc_huge_page(vma, address);
David Gibson1e8f8892006-01-06 00:10:44 -0800886
Adam Litke2fc39ce2007-11-14 16:59:39 -0800887 if (IS_ERR(new_page)) {
David Gibson1e8f8892006-01-06 00:10:44 -0800888 page_cache_release(old_page);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800889 return -PTR_ERR(new_page);
David Gibson1e8f8892006-01-06 00:10:44 -0800890 }
891
892 spin_unlock(&mm->page_table_lock);
Atsushi Nemoto9de455b2006-12-12 17:14:55 +0000893 copy_huge_page(new_page, old_page, address, vma);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800894 __SetPageUptodate(new_page);
David Gibson1e8f8892006-01-06 00:10:44 -0800895 spin_lock(&mm->page_table_lock);
896
897 ptep = huge_pte_offset(mm, address & HPAGE_MASK);
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700898 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
David Gibson1e8f8892006-01-06 00:10:44 -0800899 /* Break COW */
Gerald Schaefer8fe627e2008-04-28 02:13:28 -0700900 huge_ptep_clear_flush(vma, address, ptep);
David Gibson1e8f8892006-01-06 00:10:44 -0800901 set_huge_pte_at(mm, address, ptep,
902 make_huge_pte(vma, new_page, 1));
903 /* Make the old page be freed below */
904 new_page = old_page;
905 }
906 page_cache_release(new_page);
907 page_cache_release(old_page);
Nick Piggin83c54072007-07-19 01:47:05 -0700908 return 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800909}
910
Robert P. J. Daya1ed3dd2007-07-17 04:03:33 -0700911static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
David Gibson1e8f8892006-01-06 00:10:44 -0800912 unsigned long address, pte_t *ptep, int write_access)
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100913{
914 int ret = VM_FAULT_SIGBUS;
Adam Litke4c887262005-10-29 18:16:46 -0700915 unsigned long idx;
916 unsigned long size;
Adam Litke4c887262005-10-29 18:16:46 -0700917 struct page *page;
918 struct address_space *mapping;
David Gibson1e8f8892006-01-06 00:10:44 -0800919 pte_t new_pte;
Adam Litke4c887262005-10-29 18:16:46 -0700920
Adam Litke4c887262005-10-29 18:16:46 -0700921 mapping = vma->vm_file->f_mapping;
922 idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
923 + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
924
925 /*
926 * Use page lock to guard against racing truncation
927 * before we get page_table_lock.
928 */
Christoph Lameter6bda6662006-01-06 00:10:49 -0800929retry:
930 page = find_lock_page(mapping, idx);
931 if (!page) {
Hugh Dickinsebed4bf2006-10-28 10:38:43 -0700932 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
933 if (idx >= size)
934 goto out;
Christoph Lameter6bda6662006-01-06 00:10:49 -0800935 page = alloc_huge_page(vma, address);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800936 if (IS_ERR(page)) {
937 ret = -PTR_ERR(page);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800938 goto out;
939 }
David Gibson79ac6ba2006-03-22 00:08:51 -0800940 clear_huge_page(page, address);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800941 __SetPageUptodate(page);
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100942
Christoph Lameter6bda6662006-01-06 00:10:49 -0800943 if (vma->vm_flags & VM_SHARED) {
944 int err;
Ken Chen45c682a2007-11-14 16:59:44 -0800945 struct inode *inode = mapping->host;
Christoph Lameter6bda6662006-01-06 00:10:49 -0800946
947 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
948 if (err) {
949 put_page(page);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800950 if (err == -EEXIST)
951 goto retry;
952 goto out;
953 }
Ken Chen45c682a2007-11-14 16:59:44 -0800954
955 spin_lock(&inode->i_lock);
956 inode->i_blocks += BLOCKS_PER_HUGEPAGE;
957 spin_unlock(&inode->i_lock);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800958 } else
959 lock_page(page);
960 }
David Gibson1e8f8892006-01-06 00:10:44 -0800961
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100962 spin_lock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700963 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
964 if (idx >= size)
965 goto backout;
966
Nick Piggin83c54072007-07-19 01:47:05 -0700967 ret = 0;
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700968 if (!huge_pte_none(huge_ptep_get(ptep)))
Adam Litke4c887262005-10-29 18:16:46 -0700969 goto backout;
970
David Gibson1e8f8892006-01-06 00:10:44 -0800971 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
972 && (vma->vm_flags & VM_SHARED)));
973 set_huge_pte_at(mm, address, ptep, new_pte);
974
975 if (write_access && !(vma->vm_flags & VM_SHARED)) {
976 /* Optimization, do the COW without a second fault */
977 ret = hugetlb_cow(mm, vma, address, ptep, new_pte);
978 }
979
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100980 spin_unlock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700981 unlock_page(page);
982out:
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100983 return ret;
Adam Litke4c887262005-10-29 18:16:46 -0700984
985backout:
986 spin_unlock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700987 unlock_page(page);
988 put_page(page);
989 goto out;
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100990}
991
Adam Litke86e52162006-01-06 00:10:43 -0800992int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
993 unsigned long address, int write_access)
994{
995 pte_t *ptep;
996 pte_t entry;
David Gibson1e8f8892006-01-06 00:10:44 -0800997 int ret;
David Gibson3935baa2006-03-22 00:08:53 -0800998 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
Adam Litke86e52162006-01-06 00:10:43 -0800999
1000 ptep = huge_pte_alloc(mm, address);
1001 if (!ptep)
1002 return VM_FAULT_OOM;
1003
David Gibson3935baa2006-03-22 00:08:53 -08001004 /*
1005 * Serialize hugepage allocation and instantiation, so that we don't
1006 * get spurious allocation failures if two CPUs race to instantiate
1007 * the same page in the page cache.
1008 */
1009 mutex_lock(&hugetlb_instantiation_mutex);
Gerald Schaefer7f2e9522008-04-28 02:13:29 -07001010 entry = huge_ptep_get(ptep);
1011 if (huge_pte_none(entry)) {
David Gibson3935baa2006-03-22 00:08:53 -08001012 ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
1013 mutex_unlock(&hugetlb_instantiation_mutex);
1014 return ret;
1015 }
Adam Litke86e52162006-01-06 00:10:43 -08001016
Nick Piggin83c54072007-07-19 01:47:05 -07001017 ret = 0;
David Gibson1e8f8892006-01-06 00:10:44 -08001018
1019 spin_lock(&mm->page_table_lock);
1020 /* Check for a racing update before calling hugetlb_cow */
Gerald Schaefer7f2e9522008-04-28 02:13:29 -07001021 if (likely(pte_same(entry, huge_ptep_get(ptep))))
David Gibson1e8f8892006-01-06 00:10:44 -08001022 if (write_access && !pte_write(entry))
1023 ret = hugetlb_cow(mm, vma, address, ptep, entry);
1024 spin_unlock(&mm->page_table_lock);
David Gibson3935baa2006-03-22 00:08:53 -08001025 mutex_unlock(&hugetlb_instantiation_mutex);
David Gibson1e8f8892006-01-06 00:10:44 -08001026
1027 return ret;
Adam Litke86e52162006-01-06 00:10:43 -08001028}
1029
David Gibson63551ae2005-06-21 17:14:44 -07001030int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
1031 struct page **pages, struct vm_area_struct **vmas,
Adam Litke5b23dbe2007-11-14 16:59:33 -08001032 unsigned long *position, int *length, int i,
1033 int write)
David Gibson63551ae2005-06-21 17:14:44 -07001034{
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001035 unsigned long pfn_offset;
1036 unsigned long vaddr = *position;
David Gibson63551ae2005-06-21 17:14:44 -07001037 int remainder = *length;
1038
Hugh Dickins1c598272005-10-19 21:23:43 -07001039 spin_lock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -07001040 while (vaddr < vma->vm_end && remainder) {
Adam Litke4c887262005-10-29 18:16:46 -07001041 pte_t *pte;
1042 struct page *page;
1043
1044 /*
1045 * Some archs (sparc64, sh*) have multiple pte_ts to
1046 * each hugepage. We have to make * sure we get the
1047 * first, for the page indexing below to work.
1048 */
1049 pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
1050
Gerald Schaefer7f2e9522008-04-28 02:13:29 -07001051 if (!pte || huge_pte_none(huge_ptep_get(pte)) ||
1052 (write && !pte_write(huge_ptep_get(pte)))) {
Adam Litke4c887262005-10-29 18:16:46 -07001053 int ret;
1054
1055 spin_unlock(&mm->page_table_lock);
Adam Litke5b23dbe2007-11-14 16:59:33 -08001056 ret = hugetlb_fault(mm, vma, vaddr, write);
Adam Litke4c887262005-10-29 18:16:46 -07001057 spin_lock(&mm->page_table_lock);
Adam Litkea89182c2007-08-22 14:01:51 -07001058 if (!(ret & VM_FAULT_ERROR))
Adam Litke4c887262005-10-29 18:16:46 -07001059 continue;
1060
1061 remainder = 0;
1062 if (!i)
1063 i = -EFAULT;
1064 break;
1065 }
David Gibson63551ae2005-06-21 17:14:44 -07001066
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001067 pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT;
Gerald Schaefer7f2e9522008-04-28 02:13:29 -07001068 page = pte_page(huge_ptep_get(pte));
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001069same_page:
Chen, Kenneth Wd6692182006-03-31 02:29:57 -08001070 if (pages) {
1071 get_page(page);
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001072 pages[i] = page + pfn_offset;
Chen, Kenneth Wd6692182006-03-31 02:29:57 -08001073 }
David Gibson63551ae2005-06-21 17:14:44 -07001074
1075 if (vmas)
1076 vmas[i] = vma;
1077
1078 vaddr += PAGE_SIZE;
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001079 ++pfn_offset;
David Gibson63551ae2005-06-21 17:14:44 -07001080 --remainder;
1081 ++i;
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001082 if (vaddr < vma->vm_end && remainder &&
1083 pfn_offset < HPAGE_SIZE/PAGE_SIZE) {
1084 /*
1085 * We use pfn_offset to avoid touching the pageframes
1086 * of this compound page.
1087 */
1088 goto same_page;
1089 }
David Gibson63551ae2005-06-21 17:14:44 -07001090 }
Hugh Dickins1c598272005-10-19 21:23:43 -07001091 spin_unlock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -07001092 *length = remainder;
1093 *position = vaddr;
1094
1095 return i;
1096}
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001097
1098void hugetlb_change_protection(struct vm_area_struct *vma,
1099 unsigned long address, unsigned long end, pgprot_t newprot)
1100{
1101 struct mm_struct *mm = vma->vm_mm;
1102 unsigned long start = address;
1103 pte_t *ptep;
1104 pte_t pte;
1105
1106 BUG_ON(address >= end);
1107 flush_cache_range(vma, address, end);
1108
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001109 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001110 spin_lock(&mm->page_table_lock);
1111 for (; address < end; address += HPAGE_SIZE) {
1112 ptep = huge_pte_offset(mm, address);
1113 if (!ptep)
1114 continue;
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001115 if (huge_pmd_unshare(mm, &address, ptep))
1116 continue;
Gerald Schaefer7f2e9522008-04-28 02:13:29 -07001117 if (!huge_pte_none(huge_ptep_get(ptep))) {
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001118 pte = huge_ptep_get_and_clear(mm, address, ptep);
1119 pte = pte_mkhuge(pte_modify(pte, newprot));
1120 set_huge_pte_at(mm, address, ptep, pte);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001121 }
1122 }
1123 spin_unlock(&mm->page_table_lock);
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001124 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001125
1126 flush_tlb_range(vma, start, end);
1127}
1128
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001129struct file_region {
1130 struct list_head link;
1131 long from;
1132 long to;
1133};
1134
1135static long region_add(struct list_head *head, long f, long t)
1136{
1137 struct file_region *rg, *nrg, *trg;
1138
1139 /* Locate the region we are either in or before. */
1140 list_for_each_entry(rg, head, link)
1141 if (f <= rg->to)
1142 break;
1143
1144 /* Round our left edge to the current segment if it encloses us. */
1145 if (f > rg->from)
1146 f = rg->from;
1147
1148 /* Check for and consume any regions we now overlap with. */
1149 nrg = rg;
1150 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
1151 if (&rg->link == head)
1152 break;
1153 if (rg->from > t)
1154 break;
1155
1156 /* If this area reaches higher then extend our area to
1157 * include it completely. If this is not the first area
1158 * which we intend to reuse, free it. */
1159 if (rg->to > t)
1160 t = rg->to;
1161 if (rg != nrg) {
1162 list_del(&rg->link);
1163 kfree(rg);
1164 }
1165 }
1166 nrg->from = f;
1167 nrg->to = t;
1168 return 0;
1169}
1170
1171static long region_chg(struct list_head *head, long f, long t)
1172{
1173 struct file_region *rg, *nrg;
1174 long chg = 0;
1175
1176 /* Locate the region we are before or in. */
1177 list_for_each_entry(rg, head, link)
1178 if (f <= rg->to)
1179 break;
1180
1181 /* If we are below the current region then a new region is required.
1182 * Subtle, allocate a new region at the position but make it zero
Simon Arlott183ff222007-10-20 01:27:18 +02001183 * size such that we can guarantee to record the reservation. */
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001184 if (&rg->link == head || t < rg->from) {
1185 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
Stephen Hemmingerc80544d2007-10-18 03:07:05 -07001186 if (!nrg)
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001187 return -ENOMEM;
1188 nrg->from = f;
1189 nrg->to = f;
1190 INIT_LIST_HEAD(&nrg->link);
1191 list_add(&nrg->link, rg->link.prev);
1192
1193 return t - f;
1194 }
1195
1196 /* Round our left edge to the current segment if it encloses us. */
1197 if (f > rg->from)
1198 f = rg->from;
1199 chg = t - f;
1200
1201 /* Check for and consume any regions we now overlap with. */
1202 list_for_each_entry(rg, rg->link.prev, link) {
1203 if (&rg->link == head)
1204 break;
1205 if (rg->from > t)
1206 return chg;
1207
1208 /* We overlap with this area, if it extends futher than
1209 * us then we must extend ourselves. Account for its
1210 * existing reservation. */
1211 if (rg->to > t) {
1212 chg += rg->to - t;
1213 t = rg->to;
1214 }
1215 chg -= rg->to - rg->from;
1216 }
1217 return chg;
1218}
1219
1220static long region_truncate(struct list_head *head, long end)
1221{
1222 struct file_region *rg, *trg;
1223 long chg = 0;
1224
1225 /* Locate the region we are either in or before. */
1226 list_for_each_entry(rg, head, link)
1227 if (end <= rg->to)
1228 break;
1229 if (&rg->link == head)
1230 return 0;
1231
1232 /* If we are in the middle of a region then adjust it. */
1233 if (end > rg->from) {
1234 chg = rg->to - end;
1235 rg->to = end;
1236 rg = list_entry(rg->link.next, typeof(*rg), link);
1237 }
1238
1239 /* Drop any remaining regions. */
1240 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
1241 if (&rg->link == head)
1242 break;
1243 chg += rg->to - rg->from;
1244 list_del(&rg->link);
1245 kfree(rg);
1246 }
1247 return chg;
1248}
1249
1250static int hugetlb_acct_memory(long delta)
1251{
1252 int ret = -ENOMEM;
1253
1254 spin_lock(&hugetlb_lock);
Ken Chen8a630112007-05-09 02:33:34 -07001255 /*
1256 * When cpuset is configured, it breaks the strict hugetlb page
1257 * reservation as the accounting is done on a global variable. Such
1258 * reservation is completely rubbish in the presence of cpuset because
1259 * the reservation is not checked against page availability for the
1260 * current cpuset. Application can still potentially OOM'ed by kernel
1261 * with lack of free htlb page in cpuset that the task is in.
1262 * Attempt to enforce strict accounting with cpuset is almost
1263 * impossible (or too ugly) because cpuset is too fluid that
1264 * task or memory node can be dynamically moved between cpusets.
1265 *
1266 * The change of semantics for shared hugetlb mapping with cpuset is
1267 * undesirable. However, in order to preserve some of the semantics,
1268 * we fall back to check against current free page availability as
1269 * a best attempt and hopefully to minimize the impact of changing
1270 * semantics that cpuset has.
1271 */
Adam Litkee4e574b2007-10-16 01:26:19 -07001272 if (delta > 0) {
1273 if (gather_surplus_pages(delta) < 0)
1274 goto out;
1275
Adam Litkeac09b3a2008-03-04 14:29:38 -08001276 if (delta > cpuset_mems_nr(free_huge_pages_node)) {
1277 return_unused_surplus_pages(delta);
Adam Litkee4e574b2007-10-16 01:26:19 -07001278 goto out;
Adam Litkeac09b3a2008-03-04 14:29:38 -08001279 }
Adam Litkee4e574b2007-10-16 01:26:19 -07001280 }
1281
1282 ret = 0;
Adam Litkee4e574b2007-10-16 01:26:19 -07001283 if (delta < 0)
1284 return_unused_surplus_pages((unsigned long) -delta);
1285
1286out:
1287 spin_unlock(&hugetlb_lock);
1288 return ret;
1289}
1290
1291int hugetlb_reserve_pages(struct inode *inode, long from, long to)
1292{
1293 long ret, chg;
1294
1295 chg = region_chg(&inode->i_mapping->private_list, from, to);
1296 if (chg < 0)
1297 return chg;
Ken Chen8a630112007-05-09 02:33:34 -07001298
Adam Litke90d8b7e2007-11-14 16:59:42 -08001299 if (hugetlb_get_quota(inode->i_mapping, chg))
1300 return -ENOSPC;
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001301 ret = hugetlb_acct_memory(chg);
Ken Chen68842c92008-01-14 00:55:19 -08001302 if (ret < 0) {
1303 hugetlb_put_quota(inode->i_mapping, chg);
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001304 return ret;
Ken Chen68842c92008-01-14 00:55:19 -08001305 }
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001306 region_add(&inode->i_mapping->private_list, from, to);
1307 return 0;
1308}
1309
1310void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
1311{
1312 long chg = region_truncate(&inode->i_mapping->private_list, offset);
Ken Chen45c682a2007-11-14 16:59:44 -08001313
1314 spin_lock(&inode->i_lock);
1315 inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed;
1316 spin_unlock(&inode->i_lock);
1317
Adam Litke90d8b7e2007-11-14 16:59:42 -08001318 hugetlb_put_quota(inode->i_mapping, (chg - freed));
1319 hugetlb_acct_memory(-(chg - freed));
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001320}