blob: ab171274ef217817291667bee226b45bebe259e3 [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,
Nishanth Aravamudan551883a2008-04-29 00:58:26 -0700202 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
203 __GFP_REPEAT|__GFP_NOWARN,
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700204 HUGETLB_PAGE_ORDER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 if (page) {
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700206 if (arch_prepare_hugepage(page)) {
207 __free_pages(page, HUGETLB_PAGE_ORDER);
Harvey Harrison7b8ee842008-04-28 14:13:19 -0700208 return NULL;
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700209 }
Andy Whitcroft33f2ef82006-12-06 20:33:32 -0800210 set_compound_page_dtor(page, free_huge_page);
Eric Paris0bd0f9f2005-11-21 21:32:28 -0800211 spin_lock(&hugetlb_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 nr_huge_pages++;
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700213 nr_huge_pages_node[nid]++;
Eric Paris0bd0f9f2005-11-21 21:32:28 -0800214 spin_unlock(&hugetlb_lock);
Nick Piggina4822892006-03-22 00:08:08 -0800215 put_page(page); /* free it into the hugepage allocator */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 }
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700217
218 return page;
219}
220
221static int alloc_fresh_huge_page(void)
222{
223 struct page *page;
224 int start_nid;
225 int next_nid;
226 int ret = 0;
227
228 start_nid = hugetlb_next_nid;
229
230 do {
231 page = alloc_fresh_huge_page_node(hugetlb_next_nid);
232 if (page)
233 ret = 1;
234 /*
235 * Use a helper variable to find the next node and then
236 * copy it back to hugetlb_next_nid afterwards:
237 * otherwise there's a window in which a racer might
238 * pass invalid nid MAX_NUMNODES to alloc_pages_node.
239 * But we don't need to use a spin_lock here: it really
240 * doesn't matter if occasionally a racer chooses the
241 * same nid as we do. Move nid forward in the mask even
242 * if we just successfully allocated a hugepage so that
243 * the next caller gets hugepages on the next node.
244 */
245 next_nid = next_node(hugetlb_next_nid, node_online_map);
246 if (next_nid == MAX_NUMNODES)
247 next_nid = first_node(node_online_map);
248 hugetlb_next_nid = next_nid;
249 } while (!page && hugetlb_next_nid != start_nid);
250
Adam Litke3b116302008-04-28 02:13:06 -0700251 if (ret)
252 count_vm_event(HTLB_BUDDY_PGALLOC);
253 else
254 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
255
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700256 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257}
258
Adam Litke7893d1d2007-10-16 01:26:18 -0700259static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma,
260 unsigned long address)
261{
262 struct page *page;
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800263 unsigned int nid;
Adam Litke7893d1d2007-10-16 01:26:18 -0700264
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800265 /*
266 * Assume we will successfully allocate the surplus page to
267 * prevent racing processes from causing the surplus to exceed
268 * overcommit
269 *
270 * This however introduces a different race, where a process B
271 * tries to grow the static hugepage pool while alloc_pages() is
272 * called by process A. B will only examine the per-node
273 * counters in determining if surplus huge pages can be
274 * converted to normal huge pages in adjust_pool_surplus(). A
275 * won't be able to increment the per-node counter, until the
276 * lock is dropped by B, but B doesn't drop hugetlb_lock until
277 * no more huge pages can be converted from surplus to normal
278 * state (and doesn't try to convert again). Thus, we have a
279 * case where a surplus huge page exists, the pool is grown, and
280 * the surplus huge page still exists after, even though it
281 * should just have been converted to a normal huge page. This
282 * does not leak memory, though, as the hugepage will be freed
283 * once it is out of use. It also does not allow the counters to
284 * go out of whack in adjust_pool_surplus() as we don't modify
285 * the node values until we've gotten the hugepage and only the
286 * per-node value is checked there.
287 */
288 spin_lock(&hugetlb_lock);
289 if (surplus_huge_pages >= nr_overcommit_huge_pages) {
290 spin_unlock(&hugetlb_lock);
291 return NULL;
292 } else {
293 nr_huge_pages++;
294 surplus_huge_pages++;
295 }
296 spin_unlock(&hugetlb_lock);
297
Nishanth Aravamudan551883a2008-04-29 00:58:26 -0700298 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
299 __GFP_REPEAT|__GFP_NOWARN,
Adam Litke7893d1d2007-10-16 01:26:18 -0700300 HUGETLB_PAGE_ORDER);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800301
302 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700303 if (page) {
Adam Litke2668db92008-03-10 11:43:50 -0700304 /*
305 * This page is now managed by the hugetlb allocator and has
306 * no users -- drop the buddy allocator's reference.
307 */
308 put_page_testzero(page);
309 VM_BUG_ON(page_count(page));
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800310 nid = page_to_nid(page);
Adam Litke7893d1d2007-10-16 01:26:18 -0700311 set_compound_page_dtor(page, free_huge_page);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800312 /*
313 * We incremented the global counters already
314 */
315 nr_huge_pages_node[nid]++;
316 surplus_huge_pages_node[nid]++;
Adam Litke3b116302008-04-28 02:13:06 -0700317 __count_vm_event(HTLB_BUDDY_PGALLOC);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800318 } else {
319 nr_huge_pages--;
320 surplus_huge_pages--;
Adam Litke3b116302008-04-28 02:13:06 -0700321 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
Adam Litke7893d1d2007-10-16 01:26:18 -0700322 }
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800323 spin_unlock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700324
325 return page;
326}
327
Adam Litkee4e574b2007-10-16 01:26:19 -0700328/*
329 * Increase the hugetlb pool such that it can accomodate a reservation
330 * of size 'delta'.
331 */
332static int gather_surplus_pages(int delta)
333{
334 struct list_head surplus_list;
335 struct page *page, *tmp;
336 int ret, i;
337 int needed, allocated;
338
339 needed = (resv_huge_pages + delta) - free_huge_pages;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800340 if (needed <= 0) {
341 resv_huge_pages += delta;
Adam Litkee4e574b2007-10-16 01:26:19 -0700342 return 0;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800343 }
Adam Litkee4e574b2007-10-16 01:26:19 -0700344
345 allocated = 0;
346 INIT_LIST_HEAD(&surplus_list);
347
348 ret = -ENOMEM;
349retry:
350 spin_unlock(&hugetlb_lock);
351 for (i = 0; i < needed; i++) {
352 page = alloc_buddy_huge_page(NULL, 0);
353 if (!page) {
354 /*
355 * We were not able to allocate enough pages to
356 * satisfy the entire reservation so we free what
357 * we've allocated so far.
358 */
359 spin_lock(&hugetlb_lock);
360 needed = 0;
361 goto free;
362 }
363
364 list_add(&page->lru, &surplus_list);
365 }
366 allocated += needed;
367
368 /*
369 * After retaking hugetlb_lock, we need to recalculate 'needed'
370 * because either resv_huge_pages or free_huge_pages may have changed.
371 */
372 spin_lock(&hugetlb_lock);
373 needed = (resv_huge_pages + delta) - (free_huge_pages + allocated);
374 if (needed > 0)
375 goto retry;
376
377 /*
378 * The surplus_list now contains _at_least_ the number of extra pages
379 * needed to accomodate the reservation. Add the appropriate number
380 * of pages to the hugetlb pool and free the extras back to the buddy
Adam Litkeac09b3a2008-03-04 14:29:38 -0800381 * allocator. Commit the entire reservation here to prevent another
382 * process from stealing the pages as they are added to the pool but
383 * before they are reserved.
Adam Litkee4e574b2007-10-16 01:26:19 -0700384 */
385 needed += allocated;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800386 resv_huge_pages += delta;
Adam Litkee4e574b2007-10-16 01:26:19 -0700387 ret = 0;
388free:
Adam Litke19fc3f02008-04-28 02:12:20 -0700389 /* Free the needed pages to the hugetlb pool */
Adam Litkee4e574b2007-10-16 01:26:19 -0700390 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
Adam Litke19fc3f02008-04-28 02:12:20 -0700391 if ((--needed) < 0)
392 break;
Adam Litkee4e574b2007-10-16 01:26:19 -0700393 list_del(&page->lru);
Adam Litke19fc3f02008-04-28 02:12:20 -0700394 enqueue_huge_page(page);
395 }
396
397 /* Free unnecessary surplus pages to the buddy allocator */
398 if (!list_empty(&surplus_list)) {
399 spin_unlock(&hugetlb_lock);
400 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
401 list_del(&page->lru);
Adam Litkeaf767cb2007-10-16 01:26:25 -0700402 /*
Adam Litke2668db92008-03-10 11:43:50 -0700403 * The page has a reference count of zero already, so
404 * call free_huge_page directly instead of using
405 * put_page. This must be done with hugetlb_lock
Adam Litkeaf767cb2007-10-16 01:26:25 -0700406 * unlocked which is safe because free_huge_page takes
407 * hugetlb_lock before deciding how to free the page.
408 */
Adam Litke2668db92008-03-10 11:43:50 -0700409 free_huge_page(page);
Adam Litkeaf767cb2007-10-16 01:26:25 -0700410 }
Adam Litke19fc3f02008-04-28 02:12:20 -0700411 spin_lock(&hugetlb_lock);
Adam Litkee4e574b2007-10-16 01:26:19 -0700412 }
413
414 return ret;
415}
416
417/*
418 * When releasing a hugetlb pool reservation, any surplus pages that were
419 * allocated to satisfy the reservation must be explicitly freed if they were
420 * never used.
421 */
Adrian Bunk8cde0452007-11-14 16:59:43 -0800422static void return_unused_surplus_pages(unsigned long unused_resv_pages)
Adam Litkee4e574b2007-10-16 01:26:19 -0700423{
424 static int nid = -1;
425 struct page *page;
426 unsigned long nr_pages;
427
Nishanth Aravamudan11320d12008-03-26 14:40:20 -0700428 /*
429 * We want to release as many surplus pages as possible, spread
430 * evenly across all nodes. Iterate across all nodes until we
431 * can no longer free unreserved surplus pages. This occurs when
432 * the nodes with surplus pages have no free pages.
433 */
434 unsigned long remaining_iterations = num_online_nodes();
435
Adam Litkeac09b3a2008-03-04 14:29:38 -0800436 /* Uncommit the reservation */
437 resv_huge_pages -= unused_resv_pages;
438
Adam Litkee4e574b2007-10-16 01:26:19 -0700439 nr_pages = min(unused_resv_pages, surplus_huge_pages);
440
Nishanth Aravamudan11320d12008-03-26 14:40:20 -0700441 while (remaining_iterations-- && nr_pages) {
Adam Litkee4e574b2007-10-16 01:26:19 -0700442 nid = next_node(nid, node_online_map);
443 if (nid == MAX_NUMNODES)
444 nid = first_node(node_online_map);
445
446 if (!surplus_huge_pages_node[nid])
447 continue;
448
449 if (!list_empty(&hugepage_freelists[nid])) {
450 page = list_entry(hugepage_freelists[nid].next,
451 struct page, lru);
452 list_del(&page->lru);
453 update_and_free_page(page);
454 free_huge_pages--;
455 free_huge_pages_node[nid]--;
456 surplus_huge_pages--;
457 surplus_huge_pages_node[nid]--;
458 nr_pages--;
Nishanth Aravamudan11320d12008-03-26 14:40:20 -0700459 remaining_iterations = num_online_nodes();
Adam Litkee4e574b2007-10-16 01:26:19 -0700460 }
461 }
462}
463
Adam Litke348ea202007-11-14 16:59:37 -0800464
465static struct page *alloc_huge_page_shared(struct vm_area_struct *vma,
466 unsigned long addr)
467{
468 struct page *page;
469
470 spin_lock(&hugetlb_lock);
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800471 page = dequeue_huge_page_vma(vma, addr);
Adam Litke348ea202007-11-14 16:59:37 -0800472 spin_unlock(&hugetlb_lock);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800473 return page ? page : ERR_PTR(-VM_FAULT_OOM);
Adam Litke348ea202007-11-14 16:59:37 -0800474}
475
476static struct page *alloc_huge_page_private(struct vm_area_struct *vma,
477 unsigned long addr)
478{
479 struct page *page = NULL;
480
Adam Litke90d8b7e2007-11-14 16:59:42 -0800481 if (hugetlb_get_quota(vma->vm_file->f_mapping, 1))
482 return ERR_PTR(-VM_FAULT_SIGBUS);
483
Adam Litke348ea202007-11-14 16:59:37 -0800484 spin_lock(&hugetlb_lock);
485 if (free_huge_pages > resv_huge_pages)
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800486 page = dequeue_huge_page_vma(vma, addr);
Adam Litke348ea202007-11-14 16:59:37 -0800487 spin_unlock(&hugetlb_lock);
Ken Chen68842c92008-01-14 00:55:19 -0800488 if (!page) {
Adam Litke348ea202007-11-14 16:59:37 -0800489 page = alloc_buddy_huge_page(vma, addr);
Ken Chen68842c92008-01-14 00:55:19 -0800490 if (!page) {
491 hugetlb_put_quota(vma->vm_file->f_mapping, 1);
492 return ERR_PTR(-VM_FAULT_OOM);
493 }
494 }
495 return page;
Adam Litke348ea202007-11-14 16:59:37 -0800496}
497
David Gibson27a85ef2006-03-22 00:08:56 -0800498static struct page *alloc_huge_page(struct vm_area_struct *vma,
499 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500{
Adam Litke348ea202007-11-14 16:59:37 -0800501 struct page *page;
Adam Litke2fc39ce2007-11-14 16:59:39 -0800502 struct address_space *mapping = vma->vm_file->f_mapping;
503
Adam Litke348ea202007-11-14 16:59:37 -0800504 if (vma->vm_flags & VM_MAYSHARE)
505 page = alloc_huge_page_shared(vma, addr);
506 else
507 page = alloc_huge_page_private(vma, addr);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800508
509 if (!IS_ERR(page)) {
Adam Litke348ea202007-11-14 16:59:37 -0800510 set_page_refcounted(page);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800511 set_page_private(page, (unsigned long) mapping);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800512 }
513 return page;
David Gibsonb45b5bd2006-03-22 00:08:55 -0800514}
515
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516static int __init hugetlb_init(void)
517{
518 unsigned long i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519
Benjamin Herrenschmidt3c726f82005-11-07 11:06:55 +1100520 if (HPAGE_SHIFT == 0)
521 return 0;
522
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 for (i = 0; i < MAX_NUMNODES; ++i)
524 INIT_LIST_HEAD(&hugepage_freelists[i]);
525
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700526 hugetlb_next_nid = first_node(node_online_map);
527
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 for (i = 0; i < max_huge_pages; ++i) {
Nick Piggina4822892006-03-22 00:08:08 -0800529 if (!alloc_fresh_huge_page())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 }
532 max_huge_pages = free_huge_pages = nr_huge_pages = i;
533 printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
534 return 0;
535}
536module_init(hugetlb_init);
537
538static int __init hugetlb_setup(char *s)
539{
540 if (sscanf(s, "%lu", &max_huge_pages) <= 0)
541 max_huge_pages = 0;
542 return 1;
543}
544__setup("hugepages=", hugetlb_setup);
545
Ken Chen8a630112007-05-09 02:33:34 -0700546static unsigned int cpuset_mems_nr(unsigned int *array)
547{
548 int node;
549 unsigned int nr = 0;
550
551 for_each_node_mask(node, cpuset_current_mems_allowed)
552 nr += array[node];
553
554 return nr;
555}
556
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557#ifdef CONFIG_SYSCTL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558#ifdef CONFIG_HIGHMEM
559static void try_to_free_low(unsigned long count)
560{
Christoph Lameter4415cc82006-09-25 23:31:55 -0700561 int i;
562
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 for (i = 0; i < MAX_NUMNODES; ++i) {
564 struct page *page, *next;
565 list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
Adam Litke6b0c8802007-10-16 01:26:23 -0700566 if (count >= nr_huge_pages)
567 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 if (PageHighMem(page))
569 continue;
570 list_del(&page->lru);
571 update_and_free_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 free_huge_pages--;
Christoph Lameter4415cc82006-09-25 23:31:55 -0700573 free_huge_pages_node[page_to_nid(page)]--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 }
575 }
576}
577#else
578static inline void try_to_free_low(unsigned long count)
579{
580}
581#endif
582
Adam Litke7893d1d2007-10-16 01:26:18 -0700583#define persistent_huge_pages (nr_huge_pages - surplus_huge_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584static unsigned long set_max_huge_pages(unsigned long count)
585{
Adam Litke7893d1d2007-10-16 01:26:18 -0700586 unsigned long min_count, ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587
Adam Litke7893d1d2007-10-16 01:26:18 -0700588 /*
589 * Increase the pool size
590 * First take pages out of surplus state. Then make up the
591 * remaining difference by allocating fresh huge pages.
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800592 *
593 * We might race with alloc_buddy_huge_page() here and be unable
594 * to convert a surplus huge page to a normal huge page. That is
595 * not critical, though, it just means the overall size of the
596 * pool might be one hugepage larger than it needs to be, but
597 * within all the constraints specified by the sysctls.
Adam Litke7893d1d2007-10-16 01:26:18 -0700598 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700600 while (surplus_huge_pages && count > persistent_huge_pages) {
601 if (!adjust_pool_surplus(-1))
602 break;
603 }
604
605 while (count > persistent_huge_pages) {
606 int ret;
607 /*
608 * If this allocation races such that we no longer need the
609 * page, free_huge_page will handle it by freeing the page
610 * and reducing the surplus.
611 */
612 spin_unlock(&hugetlb_lock);
613 ret = alloc_fresh_huge_page();
614 spin_lock(&hugetlb_lock);
615 if (!ret)
616 goto out;
617
618 }
Adam Litke7893d1d2007-10-16 01:26:18 -0700619
620 /*
621 * Decrease the pool size
622 * First return free pages to the buddy allocator (being careful
623 * to keep enough around to satisfy reservations). Then place
624 * pages into surplus state as needed so the pool will shrink
625 * to the desired size as pages become free.
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800626 *
627 * By placing pages into the surplus state independent of the
628 * overcommit value, we are allowing the surplus pool size to
629 * exceed overcommit. There are few sane options here. Since
630 * alloc_buddy_huge_page() is checking the global counter,
631 * though, we'll note that we're not allowed to exceed surplus
632 * and won't grow the pool anywhere else. Not until one of the
633 * sysctls are changed, or the surplus pages go out of use.
Adam Litke7893d1d2007-10-16 01:26:18 -0700634 */
Adam Litke6b0c8802007-10-16 01:26:23 -0700635 min_count = resv_huge_pages + nr_huge_pages - free_huge_pages;
636 min_count = max(count, min_count);
Adam Litke7893d1d2007-10-16 01:26:18 -0700637 try_to_free_low(min_count);
638 while (min_count < persistent_huge_pages) {
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800639 struct page *page = dequeue_huge_page();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 if (!page)
641 break;
642 update_and_free_page(page);
643 }
Adam Litke7893d1d2007-10-16 01:26:18 -0700644 while (count < persistent_huge_pages) {
645 if (!adjust_pool_surplus(1))
646 break;
647 }
648out:
649 ret = persistent_huge_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 spin_unlock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700651 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652}
653
654int hugetlb_sysctl_handler(struct ctl_table *table, int write,
655 struct file *file, void __user *buffer,
656 size_t *length, loff_t *ppos)
657{
658 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
659 max_huge_pages = set_max_huge_pages(max_huge_pages);
660 return 0;
661}
Mel Gorman396faf02007-07-17 04:03:13 -0700662
663int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
664 struct file *file, void __user *buffer,
665 size_t *length, loff_t *ppos)
666{
667 proc_dointvec(table, write, file, buffer, length, ppos);
668 if (hugepages_treat_as_movable)
669 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
670 else
671 htlb_alloc_mask = GFP_HIGHUSER;
672 return 0;
673}
674
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800675int hugetlb_overcommit_handler(struct ctl_table *table, int write,
676 struct file *file, void __user *buffer,
677 size_t *length, loff_t *ppos)
678{
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800679 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
Nishanth Aravamudan064d9ef2008-02-13 15:03:19 -0800680 spin_lock(&hugetlb_lock);
681 nr_overcommit_huge_pages = sysctl_overcommit_huge_pages;
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800682 spin_unlock(&hugetlb_lock);
683 return 0;
684}
685
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686#endif /* CONFIG_SYSCTL */
687
688int hugetlb_report_meminfo(char *buf)
689{
690 return sprintf(buf,
691 "HugePages_Total: %5lu\n"
692 "HugePages_Free: %5lu\n"
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700693 "HugePages_Rsvd: %5lu\n"
Adam Litke7893d1d2007-10-16 01:26:18 -0700694 "HugePages_Surp: %5lu\n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695 "Hugepagesize: %5lu kB\n",
696 nr_huge_pages,
697 free_huge_pages,
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700698 resv_huge_pages,
Adam Litke7893d1d2007-10-16 01:26:18 -0700699 surplus_huge_pages,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 HPAGE_SIZE/1024);
701}
702
703int hugetlb_report_node_meminfo(int nid, char *buf)
704{
705 return sprintf(buf,
706 "Node %d HugePages_Total: %5u\n"
Nishanth Aravamudana1de0912008-03-26 14:37:53 -0700707 "Node %d HugePages_Free: %5u\n"
708 "Node %d HugePages_Surp: %5u\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 nid, nr_huge_pages_node[nid],
Nishanth Aravamudana1de0912008-03-26 14:37:53 -0700710 nid, free_huge_pages_node[nid],
711 nid, surplus_huge_pages_node[nid]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712}
713
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
715unsigned long hugetlb_total_pages(void)
716{
717 return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
718}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719
720/*
721 * We cannot handle pagefaults against hugetlb pages at all. They cause
722 * handle_mm_fault() to try to instantiate regular-sized pages in the
723 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
724 * this far.
725 */
Nick Piggind0217ac2007-07-19 01:47:03 -0700726static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727{
728 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -0700729 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730}
731
732struct vm_operations_struct hugetlb_vm_ops = {
Nick Piggind0217ac2007-07-19 01:47:03 -0700733 .fault = hugetlb_vm_op_fault,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734};
735
David Gibson1e8f8892006-01-06 00:10:44 -0800736static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
737 int writable)
David Gibson63551ae2005-06-21 17:14:44 -0700738{
739 pte_t entry;
740
David Gibson1e8f8892006-01-06 00:10:44 -0800741 if (writable) {
David Gibson63551ae2005-06-21 17:14:44 -0700742 entry =
743 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
744 } else {
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700745 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
David Gibson63551ae2005-06-21 17:14:44 -0700746 }
747 entry = pte_mkyoung(entry);
748 entry = pte_mkhuge(entry);
749
750 return entry;
751}
752
David Gibson1e8f8892006-01-06 00:10:44 -0800753static void set_huge_ptep_writable(struct vm_area_struct *vma,
754 unsigned long address, pte_t *ptep)
755{
756 pte_t entry;
757
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700758 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
759 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -0700760 update_mmu_cache(vma, address, entry);
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -0700761 }
David Gibson1e8f8892006-01-06 00:10:44 -0800762}
763
764
David Gibson63551ae2005-06-21 17:14:44 -0700765int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
766 struct vm_area_struct *vma)
767{
768 pte_t *src_pte, *dst_pte, entry;
769 struct page *ptepage;
Hugh Dickins1c598272005-10-19 21:23:43 -0700770 unsigned long addr;
David Gibson1e8f8892006-01-06 00:10:44 -0800771 int cow;
772
773 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
David Gibson63551ae2005-06-21 17:14:44 -0700774
Hugh Dickins1c598272005-10-19 21:23:43 -0700775 for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
Hugh Dickinsc74df322005-10-29 18:16:23 -0700776 src_pte = huge_pte_offset(src, addr);
777 if (!src_pte)
778 continue;
David Gibson63551ae2005-06-21 17:14:44 -0700779 dst_pte = huge_pte_alloc(dst, addr);
780 if (!dst_pte)
781 goto nomem;
Larry Woodmanc5c99422008-01-24 05:49:25 -0800782
783 /* If the pagetables are shared don't copy or take references */
784 if (dst_pte == src_pte)
785 continue;
786
Hugh Dickinsc74df322005-10-29 18:16:23 -0700787 spin_lock(&dst->page_table_lock);
Nick Piggin46478752008-06-05 22:45:57 -0700788 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700789 if (!huge_pte_none(huge_ptep_get(src_pte))) {
David Gibson1e8f8892006-01-06 00:10:44 -0800790 if (cow)
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700791 huge_ptep_set_wrprotect(src, addr, src_pte);
792 entry = huge_ptep_get(src_pte);
Hugh Dickins1c598272005-10-19 21:23:43 -0700793 ptepage = pte_page(entry);
794 get_page(ptepage);
Hugh Dickins1c598272005-10-19 21:23:43 -0700795 set_huge_pte_at(dst, addr, dst_pte, entry);
796 }
797 spin_unlock(&src->page_table_lock);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700798 spin_unlock(&dst->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700799 }
800 return 0;
801
802nomem:
803 return -ENOMEM;
804}
805
Chen, Kenneth W502717f2006-10-11 01:20:46 -0700806void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
807 unsigned long end)
David Gibson63551ae2005-06-21 17:14:44 -0700808{
809 struct mm_struct *mm = vma->vm_mm;
810 unsigned long address;
David Gibsonc7546f82005-08-05 11:59:35 -0700811 pte_t *ptep;
David Gibson63551ae2005-06-21 17:14:44 -0700812 pte_t pte;
813 struct page *page;
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700814 struct page *tmp;
Chen, Kenneth Wc0a499c2006-12-06 20:31:39 -0800815 /*
816 * A page gathering list, protected by per file i_mmap_lock. The
817 * lock is used to avoid list corruption from multiple unmapping
818 * of the same page since we are using page->lru.
819 */
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700820 LIST_HEAD(page_list);
David Gibson63551ae2005-06-21 17:14:44 -0700821
822 WARN_ON(!is_vm_hugetlb_page(vma));
823 BUG_ON(start & ~HPAGE_MASK);
824 BUG_ON(end & ~HPAGE_MASK);
825
Hugh Dickins508034a2005-10-29 18:16:30 -0700826 spin_lock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700827 for (address = start; address < end; address += HPAGE_SIZE) {
David Gibsonc7546f82005-08-05 11:59:35 -0700828 ptep = huge_pte_offset(mm, address);
Adam Litke4c887262005-10-29 18:16:46 -0700829 if (!ptep)
David Gibsonc7546f82005-08-05 11:59:35 -0700830 continue;
831
Chen, Kenneth W39dde652006-12-06 20:32:03 -0800832 if (huge_pmd_unshare(mm, &address, ptep))
833 continue;
834
David Gibsonc7546f82005-08-05 11:59:35 -0700835 pte = huge_ptep_get_and_clear(mm, address, ptep);
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700836 if (huge_pte_none(pte))
David Gibson63551ae2005-06-21 17:14:44 -0700837 continue;
David Gibsonc7546f82005-08-05 11:59:35 -0700838
David Gibson63551ae2005-06-21 17:14:44 -0700839 page = pte_page(pte);
Ken Chen6649a382007-02-08 14:20:27 -0800840 if (pte_dirty(pte))
841 set_page_dirty(page);
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700842 list_add(&page->lru, &page_list);
David Gibson63551ae2005-06-21 17:14:44 -0700843 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 spin_unlock(&mm->page_table_lock);
Hugh Dickins508034a2005-10-29 18:16:30 -0700845 flush_tlb_range(vma, start, end);
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700846 list_for_each_entry_safe(page, tmp, &page_list, lru) {
847 list_del(&page->lru);
848 put_page(page);
849 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850}
David Gibson63551ae2005-06-21 17:14:44 -0700851
Chen, Kenneth W502717f2006-10-11 01:20:46 -0700852void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
853 unsigned long end)
854{
855 /*
856 * It is undesirable to test vma->vm_file as it should be non-null
857 * for valid hugetlb area. However, vm_file will be NULL in the error
858 * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails,
859 * do_mmap_pgoff() nullifies vma->vm_file before calling this function
860 * to clean up. Since no pte has actually been setup, it is safe to
861 * do nothing in this case.
862 */
863 if (vma->vm_file) {
864 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
865 __unmap_hugepage_range(vma, start, end);
866 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
867 }
868}
869
David Gibson1e8f8892006-01-06 00:10:44 -0800870static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
871 unsigned long address, pte_t *ptep, pte_t pte)
872{
873 struct page *old_page, *new_page;
David Gibson79ac6ba2006-03-22 00:08:51 -0800874 int avoidcopy;
David Gibson1e8f8892006-01-06 00:10:44 -0800875
876 old_page = pte_page(pte);
877
878 /* If no-one else is actually using this page, avoid the copy
879 * and just make the page writable */
880 avoidcopy = (page_count(old_page) == 1);
881 if (avoidcopy) {
882 set_huge_ptep_writable(vma, address, ptep);
Nick Piggin83c54072007-07-19 01:47:05 -0700883 return 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800884 }
885
886 page_cache_get(old_page);
Christoph Lameter5da7ca82006-01-06 00:10:46 -0800887 new_page = alloc_huge_page(vma, address);
David Gibson1e8f8892006-01-06 00:10:44 -0800888
Adam Litke2fc39ce2007-11-14 16:59:39 -0800889 if (IS_ERR(new_page)) {
David Gibson1e8f8892006-01-06 00:10:44 -0800890 page_cache_release(old_page);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800891 return -PTR_ERR(new_page);
David Gibson1e8f8892006-01-06 00:10:44 -0800892 }
893
894 spin_unlock(&mm->page_table_lock);
Atsushi Nemoto9de455b2006-12-12 17:14:55 +0000895 copy_huge_page(new_page, old_page, address, vma);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800896 __SetPageUptodate(new_page);
David Gibson1e8f8892006-01-06 00:10:44 -0800897 spin_lock(&mm->page_table_lock);
898
899 ptep = huge_pte_offset(mm, address & HPAGE_MASK);
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700900 if (likely(pte_same(huge_ptep_get(ptep), pte))) {
David Gibson1e8f8892006-01-06 00:10:44 -0800901 /* Break COW */
Gerald Schaefer8fe627e2008-04-28 02:13:28 -0700902 huge_ptep_clear_flush(vma, address, ptep);
David Gibson1e8f8892006-01-06 00:10:44 -0800903 set_huge_pte_at(mm, address, ptep,
904 make_huge_pte(vma, new_page, 1));
905 /* Make the old page be freed below */
906 new_page = old_page;
907 }
908 page_cache_release(new_page);
909 page_cache_release(old_page);
Nick Piggin83c54072007-07-19 01:47:05 -0700910 return 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800911}
912
Robert P. J. Daya1ed3dd2007-07-17 04:03:33 -0700913static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
David Gibson1e8f8892006-01-06 00:10:44 -0800914 unsigned long address, pte_t *ptep, int write_access)
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100915{
916 int ret = VM_FAULT_SIGBUS;
Adam Litke4c887262005-10-29 18:16:46 -0700917 unsigned long idx;
918 unsigned long size;
Adam Litke4c887262005-10-29 18:16:46 -0700919 struct page *page;
920 struct address_space *mapping;
David Gibson1e8f8892006-01-06 00:10:44 -0800921 pte_t new_pte;
Adam Litke4c887262005-10-29 18:16:46 -0700922
Adam Litke4c887262005-10-29 18:16:46 -0700923 mapping = vma->vm_file->f_mapping;
924 idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
925 + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
926
927 /*
928 * Use page lock to guard against racing truncation
929 * before we get page_table_lock.
930 */
Christoph Lameter6bda6662006-01-06 00:10:49 -0800931retry:
932 page = find_lock_page(mapping, idx);
933 if (!page) {
Hugh Dickinsebed4bf2006-10-28 10:38:43 -0700934 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
935 if (idx >= size)
936 goto out;
Christoph Lameter6bda6662006-01-06 00:10:49 -0800937 page = alloc_huge_page(vma, address);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800938 if (IS_ERR(page)) {
939 ret = -PTR_ERR(page);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800940 goto out;
941 }
David Gibson79ac6ba2006-03-22 00:08:51 -0800942 clear_huge_page(page, address);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800943 __SetPageUptodate(page);
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100944
Christoph Lameter6bda6662006-01-06 00:10:49 -0800945 if (vma->vm_flags & VM_SHARED) {
946 int err;
Ken Chen45c682a2007-11-14 16:59:44 -0800947 struct inode *inode = mapping->host;
Christoph Lameter6bda6662006-01-06 00:10:49 -0800948
949 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
950 if (err) {
951 put_page(page);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800952 if (err == -EEXIST)
953 goto retry;
954 goto out;
955 }
Ken Chen45c682a2007-11-14 16:59:44 -0800956
957 spin_lock(&inode->i_lock);
958 inode->i_blocks += BLOCKS_PER_HUGEPAGE;
959 spin_unlock(&inode->i_lock);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800960 } else
961 lock_page(page);
962 }
David Gibson1e8f8892006-01-06 00:10:44 -0800963
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100964 spin_lock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700965 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
966 if (idx >= size)
967 goto backout;
968
Nick Piggin83c54072007-07-19 01:47:05 -0700969 ret = 0;
Gerald Schaefer7f2e9522008-04-28 02:13:29 -0700970 if (!huge_pte_none(huge_ptep_get(ptep)))
Adam Litke4c887262005-10-29 18:16:46 -0700971 goto backout;
972
David Gibson1e8f8892006-01-06 00:10:44 -0800973 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
974 && (vma->vm_flags & VM_SHARED)));
975 set_huge_pte_at(mm, address, ptep, new_pte);
976
977 if (write_access && !(vma->vm_flags & VM_SHARED)) {
978 /* Optimization, do the COW without a second fault */
979 ret = hugetlb_cow(mm, vma, address, ptep, new_pte);
980 }
981
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100982 spin_unlock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700983 unlock_page(page);
984out:
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100985 return ret;
Adam Litke4c887262005-10-29 18:16:46 -0700986
987backout:
988 spin_unlock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700989 unlock_page(page);
990 put_page(page);
991 goto out;
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100992}
993
Adam Litke86e52162006-01-06 00:10:43 -0800994int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
995 unsigned long address, int write_access)
996{
997 pte_t *ptep;
998 pte_t entry;
David Gibson1e8f8892006-01-06 00:10:44 -0800999 int ret;
David Gibson3935baa2006-03-22 00:08:53 -08001000 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
Adam Litke86e52162006-01-06 00:10:43 -08001001
1002 ptep = huge_pte_alloc(mm, address);
1003 if (!ptep)
1004 return VM_FAULT_OOM;
1005
David Gibson3935baa2006-03-22 00:08:53 -08001006 /*
1007 * Serialize hugepage allocation and instantiation, so that we don't
1008 * get spurious allocation failures if two CPUs race to instantiate
1009 * the same page in the page cache.
1010 */
1011 mutex_lock(&hugetlb_instantiation_mutex);
Gerald Schaefer7f2e9522008-04-28 02:13:29 -07001012 entry = huge_ptep_get(ptep);
1013 if (huge_pte_none(entry)) {
David Gibson3935baa2006-03-22 00:08:53 -08001014 ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
1015 mutex_unlock(&hugetlb_instantiation_mutex);
1016 return ret;
1017 }
Adam Litke86e52162006-01-06 00:10:43 -08001018
Nick Piggin83c54072007-07-19 01:47:05 -07001019 ret = 0;
David Gibson1e8f8892006-01-06 00:10:44 -08001020
1021 spin_lock(&mm->page_table_lock);
1022 /* Check for a racing update before calling hugetlb_cow */
Gerald Schaefer7f2e9522008-04-28 02:13:29 -07001023 if (likely(pte_same(entry, huge_ptep_get(ptep))))
David Gibson1e8f8892006-01-06 00:10:44 -08001024 if (write_access && !pte_write(entry))
1025 ret = hugetlb_cow(mm, vma, address, ptep, entry);
1026 spin_unlock(&mm->page_table_lock);
David Gibson3935baa2006-03-22 00:08:53 -08001027 mutex_unlock(&hugetlb_instantiation_mutex);
David Gibson1e8f8892006-01-06 00:10:44 -08001028
1029 return ret;
Adam Litke86e52162006-01-06 00:10:43 -08001030}
1031
David Gibson63551ae2005-06-21 17:14:44 -07001032int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
1033 struct page **pages, struct vm_area_struct **vmas,
Adam Litke5b23dbe2007-11-14 16:59:33 -08001034 unsigned long *position, int *length, int i,
1035 int write)
David Gibson63551ae2005-06-21 17:14:44 -07001036{
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001037 unsigned long pfn_offset;
1038 unsigned long vaddr = *position;
David Gibson63551ae2005-06-21 17:14:44 -07001039 int remainder = *length;
1040
Hugh Dickins1c598272005-10-19 21:23:43 -07001041 spin_lock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -07001042 while (vaddr < vma->vm_end && remainder) {
Adam Litke4c887262005-10-29 18:16:46 -07001043 pte_t *pte;
1044 struct page *page;
1045
1046 /*
1047 * Some archs (sparc64, sh*) have multiple pte_ts to
1048 * each hugepage. We have to make * sure we get the
1049 * first, for the page indexing below to work.
1050 */
1051 pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
1052
Gerald Schaefer7f2e9522008-04-28 02:13:29 -07001053 if (!pte || huge_pte_none(huge_ptep_get(pte)) ||
1054 (write && !pte_write(huge_ptep_get(pte)))) {
Adam Litke4c887262005-10-29 18:16:46 -07001055 int ret;
1056
1057 spin_unlock(&mm->page_table_lock);
Adam Litke5b23dbe2007-11-14 16:59:33 -08001058 ret = hugetlb_fault(mm, vma, vaddr, write);
Adam Litke4c887262005-10-29 18:16:46 -07001059 spin_lock(&mm->page_table_lock);
Adam Litkea89182c2007-08-22 14:01:51 -07001060 if (!(ret & VM_FAULT_ERROR))
Adam Litke4c887262005-10-29 18:16:46 -07001061 continue;
1062
1063 remainder = 0;
1064 if (!i)
1065 i = -EFAULT;
1066 break;
1067 }
David Gibson63551ae2005-06-21 17:14:44 -07001068
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001069 pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT;
Gerald Schaefer7f2e9522008-04-28 02:13:29 -07001070 page = pte_page(huge_ptep_get(pte));
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001071same_page:
Chen, Kenneth Wd6692182006-03-31 02:29:57 -08001072 if (pages) {
1073 get_page(page);
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001074 pages[i] = page + pfn_offset;
Chen, Kenneth Wd6692182006-03-31 02:29:57 -08001075 }
David Gibson63551ae2005-06-21 17:14:44 -07001076
1077 if (vmas)
1078 vmas[i] = vma;
1079
1080 vaddr += PAGE_SIZE;
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001081 ++pfn_offset;
David Gibson63551ae2005-06-21 17:14:44 -07001082 --remainder;
1083 ++i;
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001084 if (vaddr < vma->vm_end && remainder &&
1085 pfn_offset < HPAGE_SIZE/PAGE_SIZE) {
1086 /*
1087 * We use pfn_offset to avoid touching the pageframes
1088 * of this compound page.
1089 */
1090 goto same_page;
1091 }
David Gibson63551ae2005-06-21 17:14:44 -07001092 }
Hugh Dickins1c598272005-10-19 21:23:43 -07001093 spin_unlock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -07001094 *length = remainder;
1095 *position = vaddr;
1096
1097 return i;
1098}
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001099
1100void hugetlb_change_protection(struct vm_area_struct *vma,
1101 unsigned long address, unsigned long end, pgprot_t newprot)
1102{
1103 struct mm_struct *mm = vma->vm_mm;
1104 unsigned long start = address;
1105 pte_t *ptep;
1106 pte_t pte;
1107
1108 BUG_ON(address >= end);
1109 flush_cache_range(vma, address, end);
1110
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001111 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001112 spin_lock(&mm->page_table_lock);
1113 for (; address < end; address += HPAGE_SIZE) {
1114 ptep = huge_pte_offset(mm, address);
1115 if (!ptep)
1116 continue;
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001117 if (huge_pmd_unshare(mm, &address, ptep))
1118 continue;
Gerald Schaefer7f2e9522008-04-28 02:13:29 -07001119 if (!huge_pte_none(huge_ptep_get(ptep))) {
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001120 pte = huge_ptep_get_and_clear(mm, address, ptep);
1121 pte = pte_mkhuge(pte_modify(pte, newprot));
1122 set_huge_pte_at(mm, address, ptep, pte);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001123 }
1124 }
1125 spin_unlock(&mm->page_table_lock);
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001126 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001127
1128 flush_tlb_range(vma, start, end);
1129}
1130
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001131struct file_region {
1132 struct list_head link;
1133 long from;
1134 long to;
1135};
1136
1137static long region_add(struct list_head *head, long f, long t)
1138{
1139 struct file_region *rg, *nrg, *trg;
1140
1141 /* Locate the region we are either in or before. */
1142 list_for_each_entry(rg, head, link)
1143 if (f <= rg->to)
1144 break;
1145
1146 /* Round our left edge to the current segment if it encloses us. */
1147 if (f > rg->from)
1148 f = rg->from;
1149
1150 /* Check for and consume any regions we now overlap with. */
1151 nrg = rg;
1152 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
1153 if (&rg->link == head)
1154 break;
1155 if (rg->from > t)
1156 break;
1157
1158 /* If this area reaches higher then extend our area to
1159 * include it completely. If this is not the first area
1160 * which we intend to reuse, free it. */
1161 if (rg->to > t)
1162 t = rg->to;
1163 if (rg != nrg) {
1164 list_del(&rg->link);
1165 kfree(rg);
1166 }
1167 }
1168 nrg->from = f;
1169 nrg->to = t;
1170 return 0;
1171}
1172
1173static long region_chg(struct list_head *head, long f, long t)
1174{
1175 struct file_region *rg, *nrg;
1176 long chg = 0;
1177
1178 /* Locate the region we are before or in. */
1179 list_for_each_entry(rg, head, link)
1180 if (f <= rg->to)
1181 break;
1182
1183 /* If we are below the current region then a new region is required.
1184 * Subtle, allocate a new region at the position but make it zero
Simon Arlott183ff222007-10-20 01:27:18 +02001185 * size such that we can guarantee to record the reservation. */
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001186 if (&rg->link == head || t < rg->from) {
1187 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
Stephen Hemmingerc80544d2007-10-18 03:07:05 -07001188 if (!nrg)
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001189 return -ENOMEM;
1190 nrg->from = f;
1191 nrg->to = f;
1192 INIT_LIST_HEAD(&nrg->link);
1193 list_add(&nrg->link, rg->link.prev);
1194
1195 return t - f;
1196 }
1197
1198 /* Round our left edge to the current segment if it encloses us. */
1199 if (f > rg->from)
1200 f = rg->from;
1201 chg = t - f;
1202
1203 /* Check for and consume any regions we now overlap with. */
1204 list_for_each_entry(rg, rg->link.prev, link) {
1205 if (&rg->link == head)
1206 break;
1207 if (rg->from > t)
1208 return chg;
1209
1210 /* We overlap with this area, if it extends futher than
1211 * us then we must extend ourselves. Account for its
1212 * existing reservation. */
1213 if (rg->to > t) {
1214 chg += rg->to - t;
1215 t = rg->to;
1216 }
1217 chg -= rg->to - rg->from;
1218 }
1219 return chg;
1220}
1221
1222static long region_truncate(struct list_head *head, long end)
1223{
1224 struct file_region *rg, *trg;
1225 long chg = 0;
1226
1227 /* Locate the region we are either in or before. */
1228 list_for_each_entry(rg, head, link)
1229 if (end <= rg->to)
1230 break;
1231 if (&rg->link == head)
1232 return 0;
1233
1234 /* If we are in the middle of a region then adjust it. */
1235 if (end > rg->from) {
1236 chg = rg->to - end;
1237 rg->to = end;
1238 rg = list_entry(rg->link.next, typeof(*rg), link);
1239 }
1240
1241 /* Drop any remaining regions. */
1242 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
1243 if (&rg->link == head)
1244 break;
1245 chg += rg->to - rg->from;
1246 list_del(&rg->link);
1247 kfree(rg);
1248 }
1249 return chg;
1250}
1251
1252static int hugetlb_acct_memory(long delta)
1253{
1254 int ret = -ENOMEM;
1255
1256 spin_lock(&hugetlb_lock);
Ken Chen8a630112007-05-09 02:33:34 -07001257 /*
1258 * When cpuset is configured, it breaks the strict hugetlb page
1259 * reservation as the accounting is done on a global variable. Such
1260 * reservation is completely rubbish in the presence of cpuset because
1261 * the reservation is not checked against page availability for the
1262 * current cpuset. Application can still potentially OOM'ed by kernel
1263 * with lack of free htlb page in cpuset that the task is in.
1264 * Attempt to enforce strict accounting with cpuset is almost
1265 * impossible (or too ugly) because cpuset is too fluid that
1266 * task or memory node can be dynamically moved between cpusets.
1267 *
1268 * The change of semantics for shared hugetlb mapping with cpuset is
1269 * undesirable. However, in order to preserve some of the semantics,
1270 * we fall back to check against current free page availability as
1271 * a best attempt and hopefully to minimize the impact of changing
1272 * semantics that cpuset has.
1273 */
Adam Litkee4e574b2007-10-16 01:26:19 -07001274 if (delta > 0) {
1275 if (gather_surplus_pages(delta) < 0)
1276 goto out;
1277
Adam Litkeac09b3a2008-03-04 14:29:38 -08001278 if (delta > cpuset_mems_nr(free_huge_pages_node)) {
1279 return_unused_surplus_pages(delta);
Adam Litkee4e574b2007-10-16 01:26:19 -07001280 goto out;
Adam Litkeac09b3a2008-03-04 14:29:38 -08001281 }
Adam Litkee4e574b2007-10-16 01:26:19 -07001282 }
1283
1284 ret = 0;
Adam Litkee4e574b2007-10-16 01:26:19 -07001285 if (delta < 0)
1286 return_unused_surplus_pages((unsigned long) -delta);
1287
1288out:
1289 spin_unlock(&hugetlb_lock);
1290 return ret;
1291}
1292
1293int hugetlb_reserve_pages(struct inode *inode, long from, long to)
1294{
1295 long ret, chg;
1296
1297 chg = region_chg(&inode->i_mapping->private_list, from, to);
1298 if (chg < 0)
1299 return chg;
Ken Chen8a630112007-05-09 02:33:34 -07001300
Adam Litke90d8b7e2007-11-14 16:59:42 -08001301 if (hugetlb_get_quota(inode->i_mapping, chg))
1302 return -ENOSPC;
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001303 ret = hugetlb_acct_memory(chg);
Ken Chen68842c92008-01-14 00:55:19 -08001304 if (ret < 0) {
1305 hugetlb_put_quota(inode->i_mapping, chg);
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001306 return ret;
Ken Chen68842c92008-01-14 00:55:19 -08001307 }
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001308 region_add(&inode->i_mapping->private_list, from, to);
1309 return 0;
1310}
1311
1312void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
1313{
1314 long chg = region_truncate(&inode->i_mapping->private_list, offset);
Ken Chen45c682a2007-11-14 16:59:44 -08001315
1316 spin_lock(&inode->i_lock);
1317 inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed;
1318 spin_unlock(&inode->i_lock);
1319
Adam Litke90d8b7e2007-11-14 16:59:42 -08001320 hugetlb_put_quota(inode->i_mapping, (chg - freed));
1321 hugetlb_acct_memory(-(chg - freed));
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001322}