blob: d36e1f11a5f267d441ffda665d4b6a6275c3d451 [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);
135 __free_pages(page, HUGETLB_PAGE_ORDER);
136}
137
David Gibson27a85ef2006-03-22 00:08:56 -0800138static void free_huge_page(struct page *page)
139{
Adam Litke7893d1d2007-10-16 01:26:18 -0700140 int nid = page_to_nid(page);
Adam Litkec79fb752007-11-14 16:59:38 -0800141 struct address_space *mapping;
David Gibson27a85ef2006-03-22 00:08:56 -0800142
Adam Litkec79fb752007-11-14 16:59:38 -0800143 mapping = (struct address_space *) page_private(page);
Andy Whitcrofte5df70a2008-02-23 15:23:32 -0800144 set_page_private(page, 0);
Adam Litke7893d1d2007-10-16 01:26:18 -0700145 BUG_ON(page_count(page));
David Gibson27a85ef2006-03-22 00:08:56 -0800146 INIT_LIST_HEAD(&page->lru);
147
148 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700149 if (surplus_huge_pages_node[nid]) {
150 update_and_free_page(page);
151 surplus_huge_pages--;
152 surplus_huge_pages_node[nid]--;
153 } else {
154 enqueue_huge_page(page);
155 }
David Gibson27a85ef2006-03-22 00:08:56 -0800156 spin_unlock(&hugetlb_lock);
Adam Litkec79fb752007-11-14 16:59:38 -0800157 if (mapping)
Adam Litke9a119c02007-11-14 16:59:41 -0800158 hugetlb_put_quota(mapping, 1);
David Gibson27a85ef2006-03-22 00:08:56 -0800159}
160
Adam Litke7893d1d2007-10-16 01:26:18 -0700161/*
162 * Increment or decrement surplus_huge_pages. Keep node-specific counters
163 * balanced by operating on them in a round-robin fashion.
164 * Returns 1 if an adjustment was made.
165 */
166static int adjust_pool_surplus(int delta)
167{
168 static int prev_nid;
169 int nid = prev_nid;
170 int ret = 0;
171
172 VM_BUG_ON(delta != -1 && delta != 1);
173 do {
174 nid = next_node(nid, node_online_map);
175 if (nid == MAX_NUMNODES)
176 nid = first_node(node_online_map);
177
178 /* To shrink on this node, there must be a surplus page */
179 if (delta < 0 && !surplus_huge_pages_node[nid])
180 continue;
181 /* Surplus cannot exceed the total number of pages */
182 if (delta > 0 && surplus_huge_pages_node[nid] >=
183 nr_huge_pages_node[nid])
184 continue;
185
186 surplus_huge_pages += delta;
187 surplus_huge_pages_node[nid] += delta;
188 ret = 1;
189 break;
190 } while (nid != prev_nid);
191
192 prev_nid = nid;
193 return ret;
194}
195
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700196static struct page *alloc_fresh_huge_page_node(int nid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 struct page *page;
Joe Jinf96efd52007-07-15 23:38:12 -0700199
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700200 page = alloc_pages_node(nid,
201 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|__GFP_NOWARN,
202 HUGETLB_PAGE_ORDER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 if (page) {
Andy Whitcroft33f2ef82006-12-06 20:33:32 -0800204 set_compound_page_dtor(page, free_huge_page);
Eric Paris0bd0f9f2005-11-21 21:32:28 -0800205 spin_lock(&hugetlb_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 nr_huge_pages++;
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700207 nr_huge_pages_node[nid]++;
Eric Paris0bd0f9f2005-11-21 21:32:28 -0800208 spin_unlock(&hugetlb_lock);
Nick Piggina4822892006-03-22 00:08:08 -0800209 put_page(page); /* free it into the hugepage allocator */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 }
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700211
212 return page;
213}
214
215static int alloc_fresh_huge_page(void)
216{
217 struct page *page;
218 int start_nid;
219 int next_nid;
220 int ret = 0;
221
222 start_nid = hugetlb_next_nid;
223
224 do {
225 page = alloc_fresh_huge_page_node(hugetlb_next_nid);
226 if (page)
227 ret = 1;
228 /*
229 * Use a helper variable to find the next node and then
230 * copy it back to hugetlb_next_nid afterwards:
231 * otherwise there's a window in which a racer might
232 * pass invalid nid MAX_NUMNODES to alloc_pages_node.
233 * But we don't need to use a spin_lock here: it really
234 * doesn't matter if occasionally a racer chooses the
235 * same nid as we do. Move nid forward in the mask even
236 * if we just successfully allocated a hugepage so that
237 * the next caller gets hugepages on the next node.
238 */
239 next_nid = next_node(hugetlb_next_nid, node_online_map);
240 if (next_nid == MAX_NUMNODES)
241 next_nid = first_node(node_online_map);
242 hugetlb_next_nid = next_nid;
243 } while (!page && hugetlb_next_nid != start_nid);
244
Adam Litke3b116302008-04-28 02:13:06 -0700245 if (ret)
246 count_vm_event(HTLB_BUDDY_PGALLOC);
247 else
248 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
249
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700250 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251}
252
Adam Litke7893d1d2007-10-16 01:26:18 -0700253static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma,
254 unsigned long address)
255{
256 struct page *page;
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800257 unsigned int nid;
Adam Litke7893d1d2007-10-16 01:26:18 -0700258
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800259 /*
260 * Assume we will successfully allocate the surplus page to
261 * prevent racing processes from causing the surplus to exceed
262 * overcommit
263 *
264 * This however introduces a different race, where a process B
265 * tries to grow the static hugepage pool while alloc_pages() is
266 * called by process A. B will only examine the per-node
267 * counters in determining if surplus huge pages can be
268 * converted to normal huge pages in adjust_pool_surplus(). A
269 * won't be able to increment the per-node counter, until the
270 * lock is dropped by B, but B doesn't drop hugetlb_lock until
271 * no more huge pages can be converted from surplus to normal
272 * state (and doesn't try to convert again). Thus, we have a
273 * case where a surplus huge page exists, the pool is grown, and
274 * the surplus huge page still exists after, even though it
275 * should just have been converted to a normal huge page. This
276 * does not leak memory, though, as the hugepage will be freed
277 * once it is out of use. It also does not allow the counters to
278 * go out of whack in adjust_pool_surplus() as we don't modify
279 * the node values until we've gotten the hugepage and only the
280 * per-node value is checked there.
281 */
282 spin_lock(&hugetlb_lock);
283 if (surplus_huge_pages >= nr_overcommit_huge_pages) {
284 spin_unlock(&hugetlb_lock);
285 return NULL;
286 } else {
287 nr_huge_pages++;
288 surplus_huge_pages++;
289 }
290 spin_unlock(&hugetlb_lock);
291
Adam Litke7893d1d2007-10-16 01:26:18 -0700292 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN,
293 HUGETLB_PAGE_ORDER);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800294
295 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700296 if (page) {
Adam Litke2668db92008-03-10 11:43:50 -0700297 /*
298 * This page is now managed by the hugetlb allocator and has
299 * no users -- drop the buddy allocator's reference.
300 */
301 put_page_testzero(page);
302 VM_BUG_ON(page_count(page));
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800303 nid = page_to_nid(page);
Adam Litke7893d1d2007-10-16 01:26:18 -0700304 set_compound_page_dtor(page, free_huge_page);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800305 /*
306 * We incremented the global counters already
307 */
308 nr_huge_pages_node[nid]++;
309 surplus_huge_pages_node[nid]++;
Adam Litke3b116302008-04-28 02:13:06 -0700310 __count_vm_event(HTLB_BUDDY_PGALLOC);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800311 } else {
312 nr_huge_pages--;
313 surplus_huge_pages--;
Adam Litke3b116302008-04-28 02:13:06 -0700314 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
Adam Litke7893d1d2007-10-16 01:26:18 -0700315 }
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800316 spin_unlock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700317
318 return page;
319}
320
Adam Litkee4e574b2007-10-16 01:26:19 -0700321/*
322 * Increase the hugetlb pool such that it can accomodate a reservation
323 * of size 'delta'.
324 */
325static int gather_surplus_pages(int delta)
326{
327 struct list_head surplus_list;
328 struct page *page, *tmp;
329 int ret, i;
330 int needed, allocated;
331
332 needed = (resv_huge_pages + delta) - free_huge_pages;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800333 if (needed <= 0) {
334 resv_huge_pages += delta;
Adam Litkee4e574b2007-10-16 01:26:19 -0700335 return 0;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800336 }
Adam Litkee4e574b2007-10-16 01:26:19 -0700337
338 allocated = 0;
339 INIT_LIST_HEAD(&surplus_list);
340
341 ret = -ENOMEM;
342retry:
343 spin_unlock(&hugetlb_lock);
344 for (i = 0; i < needed; i++) {
345 page = alloc_buddy_huge_page(NULL, 0);
346 if (!page) {
347 /*
348 * We were not able to allocate enough pages to
349 * satisfy the entire reservation so we free what
350 * we've allocated so far.
351 */
352 spin_lock(&hugetlb_lock);
353 needed = 0;
354 goto free;
355 }
356
357 list_add(&page->lru, &surplus_list);
358 }
359 allocated += needed;
360
361 /*
362 * After retaking hugetlb_lock, we need to recalculate 'needed'
363 * because either resv_huge_pages or free_huge_pages may have changed.
364 */
365 spin_lock(&hugetlb_lock);
366 needed = (resv_huge_pages + delta) - (free_huge_pages + allocated);
367 if (needed > 0)
368 goto retry;
369
370 /*
371 * The surplus_list now contains _at_least_ the number of extra pages
372 * needed to accomodate the reservation. Add the appropriate number
373 * of pages to the hugetlb pool and free the extras back to the buddy
Adam Litkeac09b3a2008-03-04 14:29:38 -0800374 * allocator. Commit the entire reservation here to prevent another
375 * process from stealing the pages as they are added to the pool but
376 * before they are reserved.
Adam Litkee4e574b2007-10-16 01:26:19 -0700377 */
378 needed += allocated;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800379 resv_huge_pages += delta;
Adam Litkee4e574b2007-10-16 01:26:19 -0700380 ret = 0;
381free:
Adam Litke19fc3f02008-04-28 02:12:20 -0700382 /* Free the needed pages to the hugetlb pool */
Adam Litkee4e574b2007-10-16 01:26:19 -0700383 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
Adam Litke19fc3f02008-04-28 02:12:20 -0700384 if ((--needed) < 0)
385 break;
Adam Litkee4e574b2007-10-16 01:26:19 -0700386 list_del(&page->lru);
Adam Litke19fc3f02008-04-28 02:12:20 -0700387 enqueue_huge_page(page);
388 }
389
390 /* Free unnecessary surplus pages to the buddy allocator */
391 if (!list_empty(&surplus_list)) {
392 spin_unlock(&hugetlb_lock);
393 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
394 list_del(&page->lru);
Adam Litkeaf767cb2007-10-16 01:26:25 -0700395 /*
Adam Litke2668db92008-03-10 11:43:50 -0700396 * The page has a reference count of zero already, so
397 * call free_huge_page directly instead of using
398 * put_page. This must be done with hugetlb_lock
Adam Litkeaf767cb2007-10-16 01:26:25 -0700399 * unlocked which is safe because free_huge_page takes
400 * hugetlb_lock before deciding how to free the page.
401 */
Adam Litke2668db92008-03-10 11:43:50 -0700402 free_huge_page(page);
Adam Litkeaf767cb2007-10-16 01:26:25 -0700403 }
Adam Litke19fc3f02008-04-28 02:12:20 -0700404 spin_lock(&hugetlb_lock);
Adam Litkee4e574b2007-10-16 01:26:19 -0700405 }
406
407 return ret;
408}
409
410/*
411 * When releasing a hugetlb pool reservation, any surplus pages that were
412 * allocated to satisfy the reservation must be explicitly freed if they were
413 * never used.
414 */
Adrian Bunk8cde0452007-11-14 16:59:43 -0800415static void return_unused_surplus_pages(unsigned long unused_resv_pages)
Adam Litkee4e574b2007-10-16 01:26:19 -0700416{
417 static int nid = -1;
418 struct page *page;
419 unsigned long nr_pages;
420
Nishanth Aravamudan11320d12008-03-26 14:40:20 -0700421 /*
422 * We want to release as many surplus pages as possible, spread
423 * evenly across all nodes. Iterate across all nodes until we
424 * can no longer free unreserved surplus pages. This occurs when
425 * the nodes with surplus pages have no free pages.
426 */
427 unsigned long remaining_iterations = num_online_nodes();
428
Adam Litkeac09b3a2008-03-04 14:29:38 -0800429 /* Uncommit the reservation */
430 resv_huge_pages -= unused_resv_pages;
431
Adam Litkee4e574b2007-10-16 01:26:19 -0700432 nr_pages = min(unused_resv_pages, surplus_huge_pages);
433
Nishanth Aravamudan11320d12008-03-26 14:40:20 -0700434 while (remaining_iterations-- && nr_pages) {
Adam Litkee4e574b2007-10-16 01:26:19 -0700435 nid = next_node(nid, node_online_map);
436 if (nid == MAX_NUMNODES)
437 nid = first_node(node_online_map);
438
439 if (!surplus_huge_pages_node[nid])
440 continue;
441
442 if (!list_empty(&hugepage_freelists[nid])) {
443 page = list_entry(hugepage_freelists[nid].next,
444 struct page, lru);
445 list_del(&page->lru);
446 update_and_free_page(page);
447 free_huge_pages--;
448 free_huge_pages_node[nid]--;
449 surplus_huge_pages--;
450 surplus_huge_pages_node[nid]--;
451 nr_pages--;
Nishanth Aravamudan11320d12008-03-26 14:40:20 -0700452 remaining_iterations = num_online_nodes();
Adam Litkee4e574b2007-10-16 01:26:19 -0700453 }
454 }
455}
456
Adam Litke348ea202007-11-14 16:59:37 -0800457
458static struct page *alloc_huge_page_shared(struct vm_area_struct *vma,
459 unsigned long addr)
460{
461 struct page *page;
462
463 spin_lock(&hugetlb_lock);
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800464 page = dequeue_huge_page_vma(vma, addr);
Adam Litke348ea202007-11-14 16:59:37 -0800465 spin_unlock(&hugetlb_lock);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800466 return page ? page : ERR_PTR(-VM_FAULT_OOM);
Adam Litke348ea202007-11-14 16:59:37 -0800467}
468
469static struct page *alloc_huge_page_private(struct vm_area_struct *vma,
470 unsigned long addr)
471{
472 struct page *page = NULL;
473
Adam Litke90d8b7e2007-11-14 16:59:42 -0800474 if (hugetlb_get_quota(vma->vm_file->f_mapping, 1))
475 return ERR_PTR(-VM_FAULT_SIGBUS);
476
Adam Litke348ea202007-11-14 16:59:37 -0800477 spin_lock(&hugetlb_lock);
478 if (free_huge_pages > resv_huge_pages)
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800479 page = dequeue_huge_page_vma(vma, addr);
Adam Litke348ea202007-11-14 16:59:37 -0800480 spin_unlock(&hugetlb_lock);
Ken Chen68842c92008-01-14 00:55:19 -0800481 if (!page) {
Adam Litke348ea202007-11-14 16:59:37 -0800482 page = alloc_buddy_huge_page(vma, addr);
Ken Chen68842c92008-01-14 00:55:19 -0800483 if (!page) {
484 hugetlb_put_quota(vma->vm_file->f_mapping, 1);
485 return ERR_PTR(-VM_FAULT_OOM);
486 }
487 }
488 return page;
Adam Litke348ea202007-11-14 16:59:37 -0800489}
490
David Gibson27a85ef2006-03-22 00:08:56 -0800491static struct page *alloc_huge_page(struct vm_area_struct *vma,
492 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493{
Adam Litke348ea202007-11-14 16:59:37 -0800494 struct page *page;
Adam Litke2fc39ce2007-11-14 16:59:39 -0800495 struct address_space *mapping = vma->vm_file->f_mapping;
496
Adam Litke348ea202007-11-14 16:59:37 -0800497 if (vma->vm_flags & VM_MAYSHARE)
498 page = alloc_huge_page_shared(vma, addr);
499 else
500 page = alloc_huge_page_private(vma, addr);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800501
502 if (!IS_ERR(page)) {
Adam Litke348ea202007-11-14 16:59:37 -0800503 set_page_refcounted(page);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800504 set_page_private(page, (unsigned long) mapping);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800505 }
506 return page;
David Gibsonb45b5bd2006-03-22 00:08:55 -0800507}
508
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509static int __init hugetlb_init(void)
510{
511 unsigned long i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512
Benjamin Herrenschmidt3c726f82005-11-07 11:06:55 +1100513 if (HPAGE_SHIFT == 0)
514 return 0;
515
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 for (i = 0; i < MAX_NUMNODES; ++i)
517 INIT_LIST_HEAD(&hugepage_freelists[i]);
518
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700519 hugetlb_next_nid = first_node(node_online_map);
520
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 for (i = 0; i < max_huge_pages; ++i) {
Nick Piggina4822892006-03-22 00:08:08 -0800522 if (!alloc_fresh_huge_page())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 }
525 max_huge_pages = free_huge_pages = nr_huge_pages = i;
526 printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
527 return 0;
528}
529module_init(hugetlb_init);
530
531static int __init hugetlb_setup(char *s)
532{
533 if (sscanf(s, "%lu", &max_huge_pages) <= 0)
534 max_huge_pages = 0;
535 return 1;
536}
537__setup("hugepages=", hugetlb_setup);
538
Ken Chen8a630112007-05-09 02:33:34 -0700539static unsigned int cpuset_mems_nr(unsigned int *array)
540{
541 int node;
542 unsigned int nr = 0;
543
544 for_each_node_mask(node, cpuset_current_mems_allowed)
545 nr += array[node];
546
547 return nr;
548}
549
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550#ifdef CONFIG_SYSCTL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551#ifdef CONFIG_HIGHMEM
552static void try_to_free_low(unsigned long count)
553{
Christoph Lameter4415cc82006-09-25 23:31:55 -0700554 int i;
555
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 for (i = 0; i < MAX_NUMNODES; ++i) {
557 struct page *page, *next;
558 list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
Adam Litke6b0c8802007-10-16 01:26:23 -0700559 if (count >= nr_huge_pages)
560 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 if (PageHighMem(page))
562 continue;
563 list_del(&page->lru);
564 update_and_free_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 free_huge_pages--;
Christoph Lameter4415cc82006-09-25 23:31:55 -0700566 free_huge_pages_node[page_to_nid(page)]--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 }
568 }
569}
570#else
571static inline void try_to_free_low(unsigned long count)
572{
573}
574#endif
575
Adam Litke7893d1d2007-10-16 01:26:18 -0700576#define persistent_huge_pages (nr_huge_pages - surplus_huge_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577static unsigned long set_max_huge_pages(unsigned long count)
578{
Adam Litke7893d1d2007-10-16 01:26:18 -0700579 unsigned long min_count, ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580
Adam Litke7893d1d2007-10-16 01:26:18 -0700581 /*
582 * Increase the pool size
583 * First take pages out of surplus state. Then make up the
584 * remaining difference by allocating fresh huge pages.
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800585 *
586 * We might race with alloc_buddy_huge_page() here and be unable
587 * to convert a surplus huge page to a normal huge page. That is
588 * not critical, though, it just means the overall size of the
589 * pool might be one hugepage larger than it needs to be, but
590 * within all the constraints specified by the sysctls.
Adam Litke7893d1d2007-10-16 01:26:18 -0700591 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700593 while (surplus_huge_pages && count > persistent_huge_pages) {
594 if (!adjust_pool_surplus(-1))
595 break;
596 }
597
598 while (count > persistent_huge_pages) {
599 int ret;
600 /*
601 * If this allocation races such that we no longer need the
602 * page, free_huge_page will handle it by freeing the page
603 * and reducing the surplus.
604 */
605 spin_unlock(&hugetlb_lock);
606 ret = alloc_fresh_huge_page();
607 spin_lock(&hugetlb_lock);
608 if (!ret)
609 goto out;
610
611 }
Adam Litke7893d1d2007-10-16 01:26:18 -0700612
613 /*
614 * Decrease the pool size
615 * First return free pages to the buddy allocator (being careful
616 * to keep enough around to satisfy reservations). Then place
617 * pages into surplus state as needed so the pool will shrink
618 * to the desired size as pages become free.
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800619 *
620 * By placing pages into the surplus state independent of the
621 * overcommit value, we are allowing the surplus pool size to
622 * exceed overcommit. There are few sane options here. Since
623 * alloc_buddy_huge_page() is checking the global counter,
624 * though, we'll note that we're not allowed to exceed surplus
625 * and won't grow the pool anywhere else. Not until one of the
626 * sysctls are changed, or the surplus pages go out of use.
Adam Litke7893d1d2007-10-16 01:26:18 -0700627 */
Adam Litke6b0c8802007-10-16 01:26:23 -0700628 min_count = resv_huge_pages + nr_huge_pages - free_huge_pages;
629 min_count = max(count, min_count);
Adam Litke7893d1d2007-10-16 01:26:18 -0700630 try_to_free_low(min_count);
631 while (min_count < persistent_huge_pages) {
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800632 struct page *page = dequeue_huge_page();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 if (!page)
634 break;
635 update_and_free_page(page);
636 }
Adam Litke7893d1d2007-10-16 01:26:18 -0700637 while (count < persistent_huge_pages) {
638 if (!adjust_pool_surplus(1))
639 break;
640 }
641out:
642 ret = persistent_huge_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 spin_unlock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700644 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645}
646
647int hugetlb_sysctl_handler(struct ctl_table *table, int write,
648 struct file *file, void __user *buffer,
649 size_t *length, loff_t *ppos)
650{
651 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
652 max_huge_pages = set_max_huge_pages(max_huge_pages);
653 return 0;
654}
Mel Gorman396faf02007-07-17 04:03:13 -0700655
656int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
657 struct file *file, void __user *buffer,
658 size_t *length, loff_t *ppos)
659{
660 proc_dointvec(table, write, file, buffer, length, ppos);
661 if (hugepages_treat_as_movable)
662 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
663 else
664 htlb_alloc_mask = GFP_HIGHUSER;
665 return 0;
666}
667
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800668int hugetlb_overcommit_handler(struct ctl_table *table, int write,
669 struct file *file, void __user *buffer,
670 size_t *length, loff_t *ppos)
671{
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800672 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
Nishanth Aravamudan064d9ef2008-02-13 15:03:19 -0800673 spin_lock(&hugetlb_lock);
674 nr_overcommit_huge_pages = sysctl_overcommit_huge_pages;
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800675 spin_unlock(&hugetlb_lock);
676 return 0;
677}
678
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679#endif /* CONFIG_SYSCTL */
680
681int hugetlb_report_meminfo(char *buf)
682{
683 return sprintf(buf,
684 "HugePages_Total: %5lu\n"
685 "HugePages_Free: %5lu\n"
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700686 "HugePages_Rsvd: %5lu\n"
Adam Litke7893d1d2007-10-16 01:26:18 -0700687 "HugePages_Surp: %5lu\n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 "Hugepagesize: %5lu kB\n",
689 nr_huge_pages,
690 free_huge_pages,
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700691 resv_huge_pages,
Adam Litke7893d1d2007-10-16 01:26:18 -0700692 surplus_huge_pages,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 HPAGE_SIZE/1024);
694}
695
696int hugetlb_report_node_meminfo(int nid, char *buf)
697{
698 return sprintf(buf,
699 "Node %d HugePages_Total: %5u\n"
Nishanth Aravamudana1de0912008-03-26 14:37:53 -0700700 "Node %d HugePages_Free: %5u\n"
701 "Node %d HugePages_Surp: %5u\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 nid, nr_huge_pages_node[nid],
Nishanth Aravamudana1de0912008-03-26 14:37:53 -0700703 nid, free_huge_pages_node[nid],
704 nid, surplus_huge_pages_node[nid]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705}
706
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
708unsigned long hugetlb_total_pages(void)
709{
710 return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
711}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712
713/*
714 * We cannot handle pagefaults against hugetlb pages at all. They cause
715 * handle_mm_fault() to try to instantiate regular-sized pages in the
716 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
717 * this far.
718 */
Nick Piggind0217ac2007-07-19 01:47:03 -0700719static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720{
721 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -0700722 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723}
724
725struct vm_operations_struct hugetlb_vm_ops = {
Nick Piggind0217ac2007-07-19 01:47:03 -0700726 .fault = hugetlb_vm_op_fault,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727};
728
David Gibson1e8f8892006-01-06 00:10:44 -0800729static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
730 int writable)
David Gibson63551ae2005-06-21 17:14:44 -0700731{
732 pte_t entry;
733
David Gibson1e8f8892006-01-06 00:10:44 -0800734 if (writable) {
David Gibson63551ae2005-06-21 17:14:44 -0700735 entry =
736 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
737 } else {
738 entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
739 }
740 entry = pte_mkyoung(entry);
741 entry = pte_mkhuge(entry);
742
743 return entry;
744}
745
David Gibson1e8f8892006-01-06 00:10:44 -0800746static void set_huge_ptep_writable(struct vm_area_struct *vma,
747 unsigned long address, pte_t *ptep)
748{
749 pte_t entry;
750
751 entry = pte_mkwrite(pte_mkdirty(*ptep));
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -0700752 if (ptep_set_access_flags(vma, address, ptep, entry, 1)) {
753 update_mmu_cache(vma, address, entry);
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -0700754 }
David Gibson1e8f8892006-01-06 00:10:44 -0800755}
756
757
David Gibson63551ae2005-06-21 17:14:44 -0700758int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
759 struct vm_area_struct *vma)
760{
761 pte_t *src_pte, *dst_pte, entry;
762 struct page *ptepage;
Hugh Dickins1c598272005-10-19 21:23:43 -0700763 unsigned long addr;
David Gibson1e8f8892006-01-06 00:10:44 -0800764 int cow;
765
766 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
David Gibson63551ae2005-06-21 17:14:44 -0700767
Hugh Dickins1c598272005-10-19 21:23:43 -0700768 for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
Hugh Dickinsc74df322005-10-29 18:16:23 -0700769 src_pte = huge_pte_offset(src, addr);
770 if (!src_pte)
771 continue;
David Gibson63551ae2005-06-21 17:14:44 -0700772 dst_pte = huge_pte_alloc(dst, addr);
773 if (!dst_pte)
774 goto nomem;
Larry Woodmanc5c99422008-01-24 05:49:25 -0800775
776 /* If the pagetables are shared don't copy or take references */
777 if (dst_pte == src_pte)
778 continue;
779
Hugh Dickinsc74df322005-10-29 18:16:23 -0700780 spin_lock(&dst->page_table_lock);
Hugh Dickins1c598272005-10-19 21:23:43 -0700781 spin_lock(&src->page_table_lock);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700782 if (!pte_none(*src_pte)) {
David Gibson1e8f8892006-01-06 00:10:44 -0800783 if (cow)
784 ptep_set_wrprotect(src, addr, src_pte);
Hugh Dickins1c598272005-10-19 21:23:43 -0700785 entry = *src_pte;
786 ptepage = pte_page(entry);
787 get_page(ptepage);
Hugh Dickins1c598272005-10-19 21:23:43 -0700788 set_huge_pte_at(dst, addr, dst_pte, entry);
789 }
790 spin_unlock(&src->page_table_lock);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700791 spin_unlock(&dst->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700792 }
793 return 0;
794
795nomem:
796 return -ENOMEM;
797}
798
Chen, Kenneth W502717f2006-10-11 01:20:46 -0700799void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
800 unsigned long end)
David Gibson63551ae2005-06-21 17:14:44 -0700801{
802 struct mm_struct *mm = vma->vm_mm;
803 unsigned long address;
David Gibsonc7546f82005-08-05 11:59:35 -0700804 pte_t *ptep;
David Gibson63551ae2005-06-21 17:14:44 -0700805 pte_t pte;
806 struct page *page;
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700807 struct page *tmp;
Chen, Kenneth Wc0a499c2006-12-06 20:31:39 -0800808 /*
809 * A page gathering list, protected by per file i_mmap_lock. The
810 * lock is used to avoid list corruption from multiple unmapping
811 * of the same page since we are using page->lru.
812 */
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700813 LIST_HEAD(page_list);
David Gibson63551ae2005-06-21 17:14:44 -0700814
815 WARN_ON(!is_vm_hugetlb_page(vma));
816 BUG_ON(start & ~HPAGE_MASK);
817 BUG_ON(end & ~HPAGE_MASK);
818
Hugh Dickins508034a2005-10-29 18:16:30 -0700819 spin_lock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700820 for (address = start; address < end; address += HPAGE_SIZE) {
David Gibsonc7546f82005-08-05 11:59:35 -0700821 ptep = huge_pte_offset(mm, address);
Adam Litke4c887262005-10-29 18:16:46 -0700822 if (!ptep)
David Gibsonc7546f82005-08-05 11:59:35 -0700823 continue;
824
Chen, Kenneth W39dde652006-12-06 20:32:03 -0800825 if (huge_pmd_unshare(mm, &address, ptep))
826 continue;
827
David Gibsonc7546f82005-08-05 11:59:35 -0700828 pte = huge_ptep_get_and_clear(mm, address, ptep);
David Gibson63551ae2005-06-21 17:14:44 -0700829 if (pte_none(pte))
830 continue;
David Gibsonc7546f82005-08-05 11:59:35 -0700831
David Gibson63551ae2005-06-21 17:14:44 -0700832 page = pte_page(pte);
Ken Chen6649a382007-02-08 14:20:27 -0800833 if (pte_dirty(pte))
834 set_page_dirty(page);
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700835 list_add(&page->lru, &page_list);
David Gibson63551ae2005-06-21 17:14:44 -0700836 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 spin_unlock(&mm->page_table_lock);
Hugh Dickins508034a2005-10-29 18:16:30 -0700838 flush_tlb_range(vma, start, end);
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700839 list_for_each_entry_safe(page, tmp, &page_list, lru) {
840 list_del(&page->lru);
841 put_page(page);
842 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843}
David Gibson63551ae2005-06-21 17:14:44 -0700844
Chen, Kenneth W502717f2006-10-11 01:20:46 -0700845void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
846 unsigned long end)
847{
848 /*
849 * It is undesirable to test vma->vm_file as it should be non-null
850 * for valid hugetlb area. However, vm_file will be NULL in the error
851 * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails,
852 * do_mmap_pgoff() nullifies vma->vm_file before calling this function
853 * to clean up. Since no pte has actually been setup, it is safe to
854 * do nothing in this case.
855 */
856 if (vma->vm_file) {
857 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
858 __unmap_hugepage_range(vma, start, end);
859 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
860 }
861}
862
David Gibson1e8f8892006-01-06 00:10:44 -0800863static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
864 unsigned long address, pte_t *ptep, pte_t pte)
865{
866 struct page *old_page, *new_page;
David Gibson79ac6ba2006-03-22 00:08:51 -0800867 int avoidcopy;
David Gibson1e8f8892006-01-06 00:10:44 -0800868
869 old_page = pte_page(pte);
870
871 /* If no-one else is actually using this page, avoid the copy
872 * and just make the page writable */
873 avoidcopy = (page_count(old_page) == 1);
874 if (avoidcopy) {
875 set_huge_ptep_writable(vma, address, ptep);
Nick Piggin83c54072007-07-19 01:47:05 -0700876 return 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800877 }
878
879 page_cache_get(old_page);
Christoph Lameter5da7ca82006-01-06 00:10:46 -0800880 new_page = alloc_huge_page(vma, address);
David Gibson1e8f8892006-01-06 00:10:44 -0800881
Adam Litke2fc39ce2007-11-14 16:59:39 -0800882 if (IS_ERR(new_page)) {
David Gibson1e8f8892006-01-06 00:10:44 -0800883 page_cache_release(old_page);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800884 return -PTR_ERR(new_page);
David Gibson1e8f8892006-01-06 00:10:44 -0800885 }
886
887 spin_unlock(&mm->page_table_lock);
Atsushi Nemoto9de455b2006-12-12 17:14:55 +0000888 copy_huge_page(new_page, old_page, address, vma);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800889 __SetPageUptodate(new_page);
David Gibson1e8f8892006-01-06 00:10:44 -0800890 spin_lock(&mm->page_table_lock);
891
892 ptep = huge_pte_offset(mm, address & HPAGE_MASK);
893 if (likely(pte_same(*ptep, pte))) {
894 /* Break COW */
895 set_huge_pte_at(mm, address, ptep,
896 make_huge_pte(vma, new_page, 1));
897 /* Make the old page be freed below */
898 new_page = old_page;
899 }
900 page_cache_release(new_page);
901 page_cache_release(old_page);
Nick Piggin83c54072007-07-19 01:47:05 -0700902 return 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800903}
904
Robert P. J. Daya1ed3dd2007-07-17 04:03:33 -0700905static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
David Gibson1e8f8892006-01-06 00:10:44 -0800906 unsigned long address, pte_t *ptep, int write_access)
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100907{
908 int ret = VM_FAULT_SIGBUS;
Adam Litke4c887262005-10-29 18:16:46 -0700909 unsigned long idx;
910 unsigned long size;
Adam Litke4c887262005-10-29 18:16:46 -0700911 struct page *page;
912 struct address_space *mapping;
David Gibson1e8f8892006-01-06 00:10:44 -0800913 pte_t new_pte;
Adam Litke4c887262005-10-29 18:16:46 -0700914
Adam Litke4c887262005-10-29 18:16:46 -0700915 mapping = vma->vm_file->f_mapping;
916 idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
917 + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
918
919 /*
920 * Use page lock to guard against racing truncation
921 * before we get page_table_lock.
922 */
Christoph Lameter6bda6662006-01-06 00:10:49 -0800923retry:
924 page = find_lock_page(mapping, idx);
925 if (!page) {
Hugh Dickinsebed4bf2006-10-28 10:38:43 -0700926 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
927 if (idx >= size)
928 goto out;
Christoph Lameter6bda6662006-01-06 00:10:49 -0800929 page = alloc_huge_page(vma, address);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800930 if (IS_ERR(page)) {
931 ret = -PTR_ERR(page);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800932 goto out;
933 }
David Gibson79ac6ba2006-03-22 00:08:51 -0800934 clear_huge_page(page, address);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800935 __SetPageUptodate(page);
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100936
Christoph Lameter6bda6662006-01-06 00:10:49 -0800937 if (vma->vm_flags & VM_SHARED) {
938 int err;
Ken Chen45c682a2007-11-14 16:59:44 -0800939 struct inode *inode = mapping->host;
Christoph Lameter6bda6662006-01-06 00:10:49 -0800940
941 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
942 if (err) {
943 put_page(page);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800944 if (err == -EEXIST)
945 goto retry;
946 goto out;
947 }
Ken Chen45c682a2007-11-14 16:59:44 -0800948
949 spin_lock(&inode->i_lock);
950 inode->i_blocks += BLOCKS_PER_HUGEPAGE;
951 spin_unlock(&inode->i_lock);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800952 } else
953 lock_page(page);
954 }
David Gibson1e8f8892006-01-06 00:10:44 -0800955
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100956 spin_lock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700957 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
958 if (idx >= size)
959 goto backout;
960
Nick Piggin83c54072007-07-19 01:47:05 -0700961 ret = 0;
Adam Litke86e52162006-01-06 00:10:43 -0800962 if (!pte_none(*ptep))
Adam Litke4c887262005-10-29 18:16:46 -0700963 goto backout;
964
David Gibson1e8f8892006-01-06 00:10:44 -0800965 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
966 && (vma->vm_flags & VM_SHARED)));
967 set_huge_pte_at(mm, address, ptep, new_pte);
968
969 if (write_access && !(vma->vm_flags & VM_SHARED)) {
970 /* Optimization, do the COW without a second fault */
971 ret = hugetlb_cow(mm, vma, address, ptep, new_pte);
972 }
973
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100974 spin_unlock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700975 unlock_page(page);
976out:
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100977 return ret;
Adam Litke4c887262005-10-29 18:16:46 -0700978
979backout:
980 spin_unlock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700981 unlock_page(page);
982 put_page(page);
983 goto out;
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100984}
985
Adam Litke86e52162006-01-06 00:10:43 -0800986int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
987 unsigned long address, int write_access)
988{
989 pte_t *ptep;
990 pte_t entry;
David Gibson1e8f8892006-01-06 00:10:44 -0800991 int ret;
David Gibson3935baa2006-03-22 00:08:53 -0800992 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
Adam Litke86e52162006-01-06 00:10:43 -0800993
994 ptep = huge_pte_alloc(mm, address);
995 if (!ptep)
996 return VM_FAULT_OOM;
997
David Gibson3935baa2006-03-22 00:08:53 -0800998 /*
999 * Serialize hugepage allocation and instantiation, so that we don't
1000 * get spurious allocation failures if two CPUs race to instantiate
1001 * the same page in the page cache.
1002 */
1003 mutex_lock(&hugetlb_instantiation_mutex);
Adam Litke86e52162006-01-06 00:10:43 -08001004 entry = *ptep;
David Gibson3935baa2006-03-22 00:08:53 -08001005 if (pte_none(entry)) {
1006 ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
1007 mutex_unlock(&hugetlb_instantiation_mutex);
1008 return ret;
1009 }
Adam Litke86e52162006-01-06 00:10:43 -08001010
Nick Piggin83c54072007-07-19 01:47:05 -07001011 ret = 0;
David Gibson1e8f8892006-01-06 00:10:44 -08001012
1013 spin_lock(&mm->page_table_lock);
1014 /* Check for a racing update before calling hugetlb_cow */
1015 if (likely(pte_same(entry, *ptep)))
1016 if (write_access && !pte_write(entry))
1017 ret = hugetlb_cow(mm, vma, address, ptep, entry);
1018 spin_unlock(&mm->page_table_lock);
David Gibson3935baa2006-03-22 00:08:53 -08001019 mutex_unlock(&hugetlb_instantiation_mutex);
David Gibson1e8f8892006-01-06 00:10:44 -08001020
1021 return ret;
Adam Litke86e52162006-01-06 00:10:43 -08001022}
1023
David Gibson63551ae2005-06-21 17:14:44 -07001024int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
1025 struct page **pages, struct vm_area_struct **vmas,
Adam Litke5b23dbe2007-11-14 16:59:33 -08001026 unsigned long *position, int *length, int i,
1027 int write)
David Gibson63551ae2005-06-21 17:14:44 -07001028{
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001029 unsigned long pfn_offset;
1030 unsigned long vaddr = *position;
David Gibson63551ae2005-06-21 17:14:44 -07001031 int remainder = *length;
1032
Hugh Dickins1c598272005-10-19 21:23:43 -07001033 spin_lock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -07001034 while (vaddr < vma->vm_end && remainder) {
Adam Litke4c887262005-10-29 18:16:46 -07001035 pte_t *pte;
1036 struct page *page;
1037
1038 /*
1039 * Some archs (sparc64, sh*) have multiple pte_ts to
1040 * each hugepage. We have to make * sure we get the
1041 * first, for the page indexing below to work.
1042 */
1043 pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
1044
Adam Litke72fad712007-12-10 15:49:28 -08001045 if (!pte || pte_none(*pte) || (write && !pte_write(*pte))) {
Adam Litke4c887262005-10-29 18:16:46 -07001046 int ret;
1047
1048 spin_unlock(&mm->page_table_lock);
Adam Litke5b23dbe2007-11-14 16:59:33 -08001049 ret = hugetlb_fault(mm, vma, vaddr, write);
Adam Litke4c887262005-10-29 18:16:46 -07001050 spin_lock(&mm->page_table_lock);
Adam Litkea89182c2007-08-22 14:01:51 -07001051 if (!(ret & VM_FAULT_ERROR))
Adam Litke4c887262005-10-29 18:16:46 -07001052 continue;
1053
1054 remainder = 0;
1055 if (!i)
1056 i = -EFAULT;
1057 break;
1058 }
David Gibson63551ae2005-06-21 17:14:44 -07001059
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001060 pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT;
1061 page = pte_page(*pte);
1062same_page:
Chen, Kenneth Wd6692182006-03-31 02:29:57 -08001063 if (pages) {
1064 get_page(page);
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001065 pages[i] = page + pfn_offset;
Chen, Kenneth Wd6692182006-03-31 02:29:57 -08001066 }
David Gibson63551ae2005-06-21 17:14:44 -07001067
1068 if (vmas)
1069 vmas[i] = vma;
1070
1071 vaddr += PAGE_SIZE;
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001072 ++pfn_offset;
David Gibson63551ae2005-06-21 17:14:44 -07001073 --remainder;
1074 ++i;
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001075 if (vaddr < vma->vm_end && remainder &&
1076 pfn_offset < HPAGE_SIZE/PAGE_SIZE) {
1077 /*
1078 * We use pfn_offset to avoid touching the pageframes
1079 * of this compound page.
1080 */
1081 goto same_page;
1082 }
David Gibson63551ae2005-06-21 17:14:44 -07001083 }
Hugh Dickins1c598272005-10-19 21:23:43 -07001084 spin_unlock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -07001085 *length = remainder;
1086 *position = vaddr;
1087
1088 return i;
1089}
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001090
1091void hugetlb_change_protection(struct vm_area_struct *vma,
1092 unsigned long address, unsigned long end, pgprot_t newprot)
1093{
1094 struct mm_struct *mm = vma->vm_mm;
1095 unsigned long start = address;
1096 pte_t *ptep;
1097 pte_t pte;
1098
1099 BUG_ON(address >= end);
1100 flush_cache_range(vma, address, end);
1101
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001102 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001103 spin_lock(&mm->page_table_lock);
1104 for (; address < end; address += HPAGE_SIZE) {
1105 ptep = huge_pte_offset(mm, address);
1106 if (!ptep)
1107 continue;
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001108 if (huge_pmd_unshare(mm, &address, ptep))
1109 continue;
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001110 if (!pte_none(*ptep)) {
1111 pte = huge_ptep_get_and_clear(mm, address, ptep);
1112 pte = pte_mkhuge(pte_modify(pte, newprot));
1113 set_huge_pte_at(mm, address, ptep, pte);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001114 }
1115 }
1116 spin_unlock(&mm->page_table_lock);
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001117 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001118
1119 flush_tlb_range(vma, start, end);
1120}
1121
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001122struct file_region {
1123 struct list_head link;
1124 long from;
1125 long to;
1126};
1127
1128static long region_add(struct list_head *head, long f, long t)
1129{
1130 struct file_region *rg, *nrg, *trg;
1131
1132 /* Locate the region we are either in or before. */
1133 list_for_each_entry(rg, head, link)
1134 if (f <= rg->to)
1135 break;
1136
1137 /* Round our left edge to the current segment if it encloses us. */
1138 if (f > rg->from)
1139 f = rg->from;
1140
1141 /* Check for and consume any regions we now overlap with. */
1142 nrg = rg;
1143 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
1144 if (&rg->link == head)
1145 break;
1146 if (rg->from > t)
1147 break;
1148
1149 /* If this area reaches higher then extend our area to
1150 * include it completely. If this is not the first area
1151 * which we intend to reuse, free it. */
1152 if (rg->to > t)
1153 t = rg->to;
1154 if (rg != nrg) {
1155 list_del(&rg->link);
1156 kfree(rg);
1157 }
1158 }
1159 nrg->from = f;
1160 nrg->to = t;
1161 return 0;
1162}
1163
1164static long region_chg(struct list_head *head, long f, long t)
1165{
1166 struct file_region *rg, *nrg;
1167 long chg = 0;
1168
1169 /* Locate the region we are before or in. */
1170 list_for_each_entry(rg, head, link)
1171 if (f <= rg->to)
1172 break;
1173
1174 /* If we are below the current region then a new region is required.
1175 * Subtle, allocate a new region at the position but make it zero
Simon Arlott183ff222007-10-20 01:27:18 +02001176 * size such that we can guarantee to record the reservation. */
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001177 if (&rg->link == head || t < rg->from) {
1178 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
Stephen Hemmingerc80544d2007-10-18 03:07:05 -07001179 if (!nrg)
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001180 return -ENOMEM;
1181 nrg->from = f;
1182 nrg->to = f;
1183 INIT_LIST_HEAD(&nrg->link);
1184 list_add(&nrg->link, rg->link.prev);
1185
1186 return t - f;
1187 }
1188
1189 /* Round our left edge to the current segment if it encloses us. */
1190 if (f > rg->from)
1191 f = rg->from;
1192 chg = t - f;
1193
1194 /* Check for and consume any regions we now overlap with. */
1195 list_for_each_entry(rg, rg->link.prev, link) {
1196 if (&rg->link == head)
1197 break;
1198 if (rg->from > t)
1199 return chg;
1200
1201 /* We overlap with this area, if it extends futher than
1202 * us then we must extend ourselves. Account for its
1203 * existing reservation. */
1204 if (rg->to > t) {
1205 chg += rg->to - t;
1206 t = rg->to;
1207 }
1208 chg -= rg->to - rg->from;
1209 }
1210 return chg;
1211}
1212
1213static long region_truncate(struct list_head *head, long end)
1214{
1215 struct file_region *rg, *trg;
1216 long chg = 0;
1217
1218 /* Locate the region we are either in or before. */
1219 list_for_each_entry(rg, head, link)
1220 if (end <= rg->to)
1221 break;
1222 if (&rg->link == head)
1223 return 0;
1224
1225 /* If we are in the middle of a region then adjust it. */
1226 if (end > rg->from) {
1227 chg = rg->to - end;
1228 rg->to = end;
1229 rg = list_entry(rg->link.next, typeof(*rg), link);
1230 }
1231
1232 /* Drop any remaining regions. */
1233 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
1234 if (&rg->link == head)
1235 break;
1236 chg += rg->to - rg->from;
1237 list_del(&rg->link);
1238 kfree(rg);
1239 }
1240 return chg;
1241}
1242
1243static int hugetlb_acct_memory(long delta)
1244{
1245 int ret = -ENOMEM;
1246
1247 spin_lock(&hugetlb_lock);
Ken Chen8a630112007-05-09 02:33:34 -07001248 /*
1249 * When cpuset is configured, it breaks the strict hugetlb page
1250 * reservation as the accounting is done on a global variable. Such
1251 * reservation is completely rubbish in the presence of cpuset because
1252 * the reservation is not checked against page availability for the
1253 * current cpuset. Application can still potentially OOM'ed by kernel
1254 * with lack of free htlb page in cpuset that the task is in.
1255 * Attempt to enforce strict accounting with cpuset is almost
1256 * impossible (or too ugly) because cpuset is too fluid that
1257 * task or memory node can be dynamically moved between cpusets.
1258 *
1259 * The change of semantics for shared hugetlb mapping with cpuset is
1260 * undesirable. However, in order to preserve some of the semantics,
1261 * we fall back to check against current free page availability as
1262 * a best attempt and hopefully to minimize the impact of changing
1263 * semantics that cpuset has.
1264 */
Adam Litkee4e574b2007-10-16 01:26:19 -07001265 if (delta > 0) {
1266 if (gather_surplus_pages(delta) < 0)
1267 goto out;
1268
Adam Litkeac09b3a2008-03-04 14:29:38 -08001269 if (delta > cpuset_mems_nr(free_huge_pages_node)) {
1270 return_unused_surplus_pages(delta);
Adam Litkee4e574b2007-10-16 01:26:19 -07001271 goto out;
Adam Litkeac09b3a2008-03-04 14:29:38 -08001272 }
Adam Litkee4e574b2007-10-16 01:26:19 -07001273 }
1274
1275 ret = 0;
Adam Litkee4e574b2007-10-16 01:26:19 -07001276 if (delta < 0)
1277 return_unused_surplus_pages((unsigned long) -delta);
1278
1279out:
1280 spin_unlock(&hugetlb_lock);
1281 return ret;
1282}
1283
1284int hugetlb_reserve_pages(struct inode *inode, long from, long to)
1285{
1286 long ret, chg;
1287
1288 chg = region_chg(&inode->i_mapping->private_list, from, to);
1289 if (chg < 0)
1290 return chg;
Ken Chen8a630112007-05-09 02:33:34 -07001291
Adam Litke90d8b7e2007-11-14 16:59:42 -08001292 if (hugetlb_get_quota(inode->i_mapping, chg))
1293 return -ENOSPC;
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001294 ret = hugetlb_acct_memory(chg);
Ken Chen68842c92008-01-14 00:55:19 -08001295 if (ret < 0) {
1296 hugetlb_put_quota(inode->i_mapping, chg);
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001297 return ret;
Ken Chen68842c92008-01-14 00:55:19 -08001298 }
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001299 region_add(&inode->i_mapping->private_list, from, to);
1300 return 0;
1301}
1302
1303void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
1304{
1305 long chg = region_truncate(&inode->i_mapping->private_list, offset);
Ken Chen45c682a2007-11-14 16:59:44 -08001306
1307 spin_lock(&inode->i_lock);
1308 inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed;
1309 spin_unlock(&inode->i_lock);
1310
Adam Litke90d8b7e2007-11-14 16:59:42 -08001311 hugetlb_put_quota(inode->i_mapping, (chg - freed));
1312 hugetlb_acct_memory(-(chg - freed));
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001313}