blob: 3737d82f5225b69197fade56bd1c7944905e8af1 [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 Schermerhorn480eccf2007-09-18 22:46:47 -0700119 mpol_free(mpol); /* unref if mpol !NULL */
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
245 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246}
247
Adam Litke7893d1d2007-10-16 01:26:18 -0700248static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma,
249 unsigned long address)
250{
251 struct page *page;
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800252 unsigned int nid;
Adam Litke7893d1d2007-10-16 01:26:18 -0700253
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800254 /*
255 * Assume we will successfully allocate the surplus page to
256 * prevent racing processes from causing the surplus to exceed
257 * overcommit
258 *
259 * This however introduces a different race, where a process B
260 * tries to grow the static hugepage pool while alloc_pages() is
261 * called by process A. B will only examine the per-node
262 * counters in determining if surplus huge pages can be
263 * converted to normal huge pages in adjust_pool_surplus(). A
264 * won't be able to increment the per-node counter, until the
265 * lock is dropped by B, but B doesn't drop hugetlb_lock until
266 * no more huge pages can be converted from surplus to normal
267 * state (and doesn't try to convert again). Thus, we have a
268 * case where a surplus huge page exists, the pool is grown, and
269 * the surplus huge page still exists after, even though it
270 * should just have been converted to a normal huge page. This
271 * does not leak memory, though, as the hugepage will be freed
272 * once it is out of use. It also does not allow the counters to
273 * go out of whack in adjust_pool_surplus() as we don't modify
274 * the node values until we've gotten the hugepage and only the
275 * per-node value is checked there.
276 */
277 spin_lock(&hugetlb_lock);
278 if (surplus_huge_pages >= nr_overcommit_huge_pages) {
279 spin_unlock(&hugetlb_lock);
280 return NULL;
281 } else {
282 nr_huge_pages++;
283 surplus_huge_pages++;
284 }
285 spin_unlock(&hugetlb_lock);
286
Adam Litke7893d1d2007-10-16 01:26:18 -0700287 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN,
288 HUGETLB_PAGE_ORDER);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800289
290 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700291 if (page) {
Adam Litke2668db92008-03-10 11:43:50 -0700292 /*
293 * This page is now managed by the hugetlb allocator and has
294 * no users -- drop the buddy allocator's reference.
295 */
296 put_page_testzero(page);
297 VM_BUG_ON(page_count(page));
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800298 nid = page_to_nid(page);
Adam Litke7893d1d2007-10-16 01:26:18 -0700299 set_compound_page_dtor(page, free_huge_page);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800300 /*
301 * We incremented the global counters already
302 */
303 nr_huge_pages_node[nid]++;
304 surplus_huge_pages_node[nid]++;
305 } else {
306 nr_huge_pages--;
307 surplus_huge_pages--;
Adam Litke7893d1d2007-10-16 01:26:18 -0700308 }
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800309 spin_unlock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700310
311 return page;
312}
313
Adam Litkee4e574b2007-10-16 01:26:19 -0700314/*
315 * Increase the hugetlb pool such that it can accomodate a reservation
316 * of size 'delta'.
317 */
318static int gather_surplus_pages(int delta)
319{
320 struct list_head surplus_list;
321 struct page *page, *tmp;
322 int ret, i;
323 int needed, allocated;
324
325 needed = (resv_huge_pages + delta) - free_huge_pages;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800326 if (needed <= 0) {
327 resv_huge_pages += delta;
Adam Litkee4e574b2007-10-16 01:26:19 -0700328 return 0;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800329 }
Adam Litkee4e574b2007-10-16 01:26:19 -0700330
331 allocated = 0;
332 INIT_LIST_HEAD(&surplus_list);
333
334 ret = -ENOMEM;
335retry:
336 spin_unlock(&hugetlb_lock);
337 for (i = 0; i < needed; i++) {
338 page = alloc_buddy_huge_page(NULL, 0);
339 if (!page) {
340 /*
341 * We were not able to allocate enough pages to
342 * satisfy the entire reservation so we free what
343 * we've allocated so far.
344 */
345 spin_lock(&hugetlb_lock);
346 needed = 0;
347 goto free;
348 }
349
350 list_add(&page->lru, &surplus_list);
351 }
352 allocated += needed;
353
354 /*
355 * After retaking hugetlb_lock, we need to recalculate 'needed'
356 * because either resv_huge_pages or free_huge_pages may have changed.
357 */
358 spin_lock(&hugetlb_lock);
359 needed = (resv_huge_pages + delta) - (free_huge_pages + allocated);
360 if (needed > 0)
361 goto retry;
362
363 /*
364 * The surplus_list now contains _at_least_ the number of extra pages
365 * needed to accomodate the reservation. Add the appropriate number
366 * of pages to the hugetlb pool and free the extras back to the buddy
Adam Litkeac09b3a2008-03-04 14:29:38 -0800367 * allocator. Commit the entire reservation here to prevent another
368 * process from stealing the pages as they are added to the pool but
369 * before they are reserved.
Adam Litkee4e574b2007-10-16 01:26:19 -0700370 */
371 needed += allocated;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800372 resv_huge_pages += delta;
Adam Litkee4e574b2007-10-16 01:26:19 -0700373 ret = 0;
374free:
375 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
376 list_del(&page->lru);
377 if ((--needed) >= 0)
378 enqueue_huge_page(page);
Adam Litkeaf767cb2007-10-16 01:26:25 -0700379 else {
380 /*
Adam Litke2668db92008-03-10 11:43:50 -0700381 * The page has a reference count of zero already, so
382 * call free_huge_page directly instead of using
383 * put_page. This must be done with hugetlb_lock
Adam Litkeaf767cb2007-10-16 01:26:25 -0700384 * unlocked which is safe because free_huge_page takes
385 * hugetlb_lock before deciding how to free the page.
386 */
387 spin_unlock(&hugetlb_lock);
Adam Litke2668db92008-03-10 11:43:50 -0700388 free_huge_page(page);
Adam Litkeaf767cb2007-10-16 01:26:25 -0700389 spin_lock(&hugetlb_lock);
390 }
Adam Litkee4e574b2007-10-16 01:26:19 -0700391 }
392
393 return ret;
394}
395
396/*
397 * When releasing a hugetlb pool reservation, any surplus pages that were
398 * allocated to satisfy the reservation must be explicitly freed if they were
399 * never used.
400 */
Adrian Bunk8cde0452007-11-14 16:59:43 -0800401static void return_unused_surplus_pages(unsigned long unused_resv_pages)
Adam Litkee4e574b2007-10-16 01:26:19 -0700402{
403 static int nid = -1;
404 struct page *page;
405 unsigned long nr_pages;
406
Nishanth Aravamudan11320d12008-03-26 14:40:20 -0700407 /*
408 * We want to release as many surplus pages as possible, spread
409 * evenly across all nodes. Iterate across all nodes until we
410 * can no longer free unreserved surplus pages. This occurs when
411 * the nodes with surplus pages have no free pages.
412 */
413 unsigned long remaining_iterations = num_online_nodes();
414
Adam Litkeac09b3a2008-03-04 14:29:38 -0800415 /* Uncommit the reservation */
416 resv_huge_pages -= unused_resv_pages;
417
Adam Litkee4e574b2007-10-16 01:26:19 -0700418 nr_pages = min(unused_resv_pages, surplus_huge_pages);
419
Nishanth Aravamudan11320d12008-03-26 14:40:20 -0700420 while (remaining_iterations-- && nr_pages) {
Adam Litkee4e574b2007-10-16 01:26:19 -0700421 nid = next_node(nid, node_online_map);
422 if (nid == MAX_NUMNODES)
423 nid = first_node(node_online_map);
424
425 if (!surplus_huge_pages_node[nid])
426 continue;
427
428 if (!list_empty(&hugepage_freelists[nid])) {
429 page = list_entry(hugepage_freelists[nid].next,
430 struct page, lru);
431 list_del(&page->lru);
432 update_and_free_page(page);
433 free_huge_pages--;
434 free_huge_pages_node[nid]--;
435 surplus_huge_pages--;
436 surplus_huge_pages_node[nid]--;
437 nr_pages--;
Nishanth Aravamudan11320d12008-03-26 14:40:20 -0700438 remaining_iterations = num_online_nodes();
Adam Litkee4e574b2007-10-16 01:26:19 -0700439 }
440 }
441}
442
Adam Litke348ea202007-11-14 16:59:37 -0800443
444static struct page *alloc_huge_page_shared(struct vm_area_struct *vma,
445 unsigned long addr)
446{
447 struct page *page;
448
449 spin_lock(&hugetlb_lock);
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800450 page = dequeue_huge_page_vma(vma, addr);
Adam Litke348ea202007-11-14 16:59:37 -0800451 spin_unlock(&hugetlb_lock);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800452 return page ? page : ERR_PTR(-VM_FAULT_OOM);
Adam Litke348ea202007-11-14 16:59:37 -0800453}
454
455static struct page *alloc_huge_page_private(struct vm_area_struct *vma,
456 unsigned long addr)
457{
458 struct page *page = NULL;
459
Adam Litke90d8b7e2007-11-14 16:59:42 -0800460 if (hugetlb_get_quota(vma->vm_file->f_mapping, 1))
461 return ERR_PTR(-VM_FAULT_SIGBUS);
462
Adam Litke348ea202007-11-14 16:59:37 -0800463 spin_lock(&hugetlb_lock);
464 if (free_huge_pages > resv_huge_pages)
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800465 page = dequeue_huge_page_vma(vma, addr);
Adam Litke348ea202007-11-14 16:59:37 -0800466 spin_unlock(&hugetlb_lock);
Ken Chen68842c92008-01-14 00:55:19 -0800467 if (!page) {
Adam Litke348ea202007-11-14 16:59:37 -0800468 page = alloc_buddy_huge_page(vma, addr);
Ken Chen68842c92008-01-14 00:55:19 -0800469 if (!page) {
470 hugetlb_put_quota(vma->vm_file->f_mapping, 1);
471 return ERR_PTR(-VM_FAULT_OOM);
472 }
473 }
474 return page;
Adam Litke348ea202007-11-14 16:59:37 -0800475}
476
David Gibson27a85ef2006-03-22 00:08:56 -0800477static struct page *alloc_huge_page(struct vm_area_struct *vma,
478 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479{
Adam Litke348ea202007-11-14 16:59:37 -0800480 struct page *page;
Adam Litke2fc39ce2007-11-14 16:59:39 -0800481 struct address_space *mapping = vma->vm_file->f_mapping;
482
Adam Litke348ea202007-11-14 16:59:37 -0800483 if (vma->vm_flags & VM_MAYSHARE)
484 page = alloc_huge_page_shared(vma, addr);
485 else
486 page = alloc_huge_page_private(vma, addr);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800487
488 if (!IS_ERR(page)) {
Adam Litke348ea202007-11-14 16:59:37 -0800489 set_page_refcounted(page);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800490 set_page_private(page, (unsigned long) mapping);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800491 }
492 return page;
David Gibsonb45b5bd2006-03-22 00:08:55 -0800493}
494
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495static int __init hugetlb_init(void)
496{
497 unsigned long i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498
Benjamin Herrenschmidt3c726f82005-11-07 11:06:55 +1100499 if (HPAGE_SHIFT == 0)
500 return 0;
501
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 for (i = 0; i < MAX_NUMNODES; ++i)
503 INIT_LIST_HEAD(&hugepage_freelists[i]);
504
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700505 hugetlb_next_nid = first_node(node_online_map);
506
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 for (i = 0; i < max_huge_pages; ++i) {
Nick Piggina4822892006-03-22 00:08:08 -0800508 if (!alloc_fresh_huge_page())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 }
511 max_huge_pages = free_huge_pages = nr_huge_pages = i;
512 printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
513 return 0;
514}
515module_init(hugetlb_init);
516
517static int __init hugetlb_setup(char *s)
518{
519 if (sscanf(s, "%lu", &max_huge_pages) <= 0)
520 max_huge_pages = 0;
521 return 1;
522}
523__setup("hugepages=", hugetlb_setup);
524
Ken Chen8a630112007-05-09 02:33:34 -0700525static unsigned int cpuset_mems_nr(unsigned int *array)
526{
527 int node;
528 unsigned int nr = 0;
529
530 for_each_node_mask(node, cpuset_current_mems_allowed)
531 nr += array[node];
532
533 return nr;
534}
535
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536#ifdef CONFIG_SYSCTL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537#ifdef CONFIG_HIGHMEM
538static void try_to_free_low(unsigned long count)
539{
Christoph Lameter4415cc82006-09-25 23:31:55 -0700540 int i;
541
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 for (i = 0; i < MAX_NUMNODES; ++i) {
543 struct page *page, *next;
544 list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
Adam Litke6b0c8802007-10-16 01:26:23 -0700545 if (count >= nr_huge_pages)
546 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 if (PageHighMem(page))
548 continue;
549 list_del(&page->lru);
550 update_and_free_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 free_huge_pages--;
Christoph Lameter4415cc82006-09-25 23:31:55 -0700552 free_huge_pages_node[page_to_nid(page)]--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 }
554 }
555}
556#else
557static inline void try_to_free_low(unsigned long count)
558{
559}
560#endif
561
Adam Litke7893d1d2007-10-16 01:26:18 -0700562#define persistent_huge_pages (nr_huge_pages - surplus_huge_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563static unsigned long set_max_huge_pages(unsigned long count)
564{
Adam Litke7893d1d2007-10-16 01:26:18 -0700565 unsigned long min_count, ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566
Adam Litke7893d1d2007-10-16 01:26:18 -0700567 /*
568 * Increase the pool size
569 * First take pages out of surplus state. Then make up the
570 * remaining difference by allocating fresh huge pages.
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800571 *
572 * We might race with alloc_buddy_huge_page() here and be unable
573 * to convert a surplus huge page to a normal huge page. That is
574 * not critical, though, it just means the overall size of the
575 * pool might be one hugepage larger than it needs to be, but
576 * within all the constraints specified by the sysctls.
Adam Litke7893d1d2007-10-16 01:26:18 -0700577 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700579 while (surplus_huge_pages && count > persistent_huge_pages) {
580 if (!adjust_pool_surplus(-1))
581 break;
582 }
583
584 while (count > persistent_huge_pages) {
585 int ret;
586 /*
587 * If this allocation races such that we no longer need the
588 * page, free_huge_page will handle it by freeing the page
589 * and reducing the surplus.
590 */
591 spin_unlock(&hugetlb_lock);
592 ret = alloc_fresh_huge_page();
593 spin_lock(&hugetlb_lock);
594 if (!ret)
595 goto out;
596
597 }
Adam Litke7893d1d2007-10-16 01:26:18 -0700598
599 /*
600 * Decrease the pool size
601 * First return free pages to the buddy allocator (being careful
602 * to keep enough around to satisfy reservations). Then place
603 * pages into surplus state as needed so the pool will shrink
604 * to the desired size as pages become free.
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800605 *
606 * By placing pages into the surplus state independent of the
607 * overcommit value, we are allowing the surplus pool size to
608 * exceed overcommit. There are few sane options here. Since
609 * alloc_buddy_huge_page() is checking the global counter,
610 * though, we'll note that we're not allowed to exceed surplus
611 * and won't grow the pool anywhere else. Not until one of the
612 * sysctls are changed, or the surplus pages go out of use.
Adam Litke7893d1d2007-10-16 01:26:18 -0700613 */
Adam Litke6b0c8802007-10-16 01:26:23 -0700614 min_count = resv_huge_pages + nr_huge_pages - free_huge_pages;
615 min_count = max(count, min_count);
Adam Litke7893d1d2007-10-16 01:26:18 -0700616 try_to_free_low(min_count);
617 while (min_count < persistent_huge_pages) {
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800618 struct page *page = dequeue_huge_page();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 if (!page)
620 break;
621 update_and_free_page(page);
622 }
Adam Litke7893d1d2007-10-16 01:26:18 -0700623 while (count < persistent_huge_pages) {
624 if (!adjust_pool_surplus(1))
625 break;
626 }
627out:
628 ret = persistent_huge_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 spin_unlock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700630 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631}
632
633int hugetlb_sysctl_handler(struct ctl_table *table, int write,
634 struct file *file, void __user *buffer,
635 size_t *length, loff_t *ppos)
636{
637 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
638 max_huge_pages = set_max_huge_pages(max_huge_pages);
639 return 0;
640}
Mel Gorman396faf02007-07-17 04:03:13 -0700641
642int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
643 struct file *file, void __user *buffer,
644 size_t *length, loff_t *ppos)
645{
646 proc_dointvec(table, write, file, buffer, length, ppos);
647 if (hugepages_treat_as_movable)
648 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
649 else
650 htlb_alloc_mask = GFP_HIGHUSER;
651 return 0;
652}
653
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800654int hugetlb_overcommit_handler(struct ctl_table *table, int write,
655 struct file *file, void __user *buffer,
656 size_t *length, loff_t *ppos)
657{
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800658 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
Nishanth Aravamudan064d9ef2008-02-13 15:03:19 -0800659 spin_lock(&hugetlb_lock);
660 nr_overcommit_huge_pages = sysctl_overcommit_huge_pages;
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800661 spin_unlock(&hugetlb_lock);
662 return 0;
663}
664
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665#endif /* CONFIG_SYSCTL */
666
667int hugetlb_report_meminfo(char *buf)
668{
669 return sprintf(buf,
670 "HugePages_Total: %5lu\n"
671 "HugePages_Free: %5lu\n"
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700672 "HugePages_Rsvd: %5lu\n"
Adam Litke7893d1d2007-10-16 01:26:18 -0700673 "HugePages_Surp: %5lu\n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 "Hugepagesize: %5lu kB\n",
675 nr_huge_pages,
676 free_huge_pages,
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700677 resv_huge_pages,
Adam Litke7893d1d2007-10-16 01:26:18 -0700678 surplus_huge_pages,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 HPAGE_SIZE/1024);
680}
681
682int hugetlb_report_node_meminfo(int nid, char *buf)
683{
684 return sprintf(buf,
685 "Node %d HugePages_Total: %5u\n"
Nishanth Aravamudana1de0912008-03-26 14:37:53 -0700686 "Node %d HugePages_Free: %5u\n"
687 "Node %d HugePages_Surp: %5u\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 nid, nr_huge_pages_node[nid],
Nishanth Aravamudana1de0912008-03-26 14:37:53 -0700689 nid, free_huge_pages_node[nid],
690 nid, surplus_huge_pages_node[nid]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691}
692
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
694unsigned long hugetlb_total_pages(void)
695{
696 return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
697}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698
699/*
700 * We cannot handle pagefaults against hugetlb pages at all. They cause
701 * handle_mm_fault() to try to instantiate regular-sized pages in the
702 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
703 * this far.
704 */
Nick Piggind0217ac2007-07-19 01:47:03 -0700705static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706{
707 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -0700708 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709}
710
711struct vm_operations_struct hugetlb_vm_ops = {
Nick Piggind0217ac2007-07-19 01:47:03 -0700712 .fault = hugetlb_vm_op_fault,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713};
714
David Gibson1e8f8892006-01-06 00:10:44 -0800715static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
716 int writable)
David Gibson63551ae2005-06-21 17:14:44 -0700717{
718 pte_t entry;
719
David Gibson1e8f8892006-01-06 00:10:44 -0800720 if (writable) {
David Gibson63551ae2005-06-21 17:14:44 -0700721 entry =
722 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
723 } else {
724 entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
725 }
726 entry = pte_mkyoung(entry);
727 entry = pte_mkhuge(entry);
728
729 return entry;
730}
731
David Gibson1e8f8892006-01-06 00:10:44 -0800732static void set_huge_ptep_writable(struct vm_area_struct *vma,
733 unsigned long address, pte_t *ptep)
734{
735 pte_t entry;
736
737 entry = pte_mkwrite(pte_mkdirty(*ptep));
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -0700738 if (ptep_set_access_flags(vma, address, ptep, entry, 1)) {
739 update_mmu_cache(vma, address, entry);
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -0700740 }
David Gibson1e8f8892006-01-06 00:10:44 -0800741}
742
743
David Gibson63551ae2005-06-21 17:14:44 -0700744int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
745 struct vm_area_struct *vma)
746{
747 pte_t *src_pte, *dst_pte, entry;
748 struct page *ptepage;
Hugh Dickins1c598272005-10-19 21:23:43 -0700749 unsigned long addr;
David Gibson1e8f8892006-01-06 00:10:44 -0800750 int cow;
751
752 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
David Gibson63551ae2005-06-21 17:14:44 -0700753
Hugh Dickins1c598272005-10-19 21:23:43 -0700754 for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
Hugh Dickinsc74df322005-10-29 18:16:23 -0700755 src_pte = huge_pte_offset(src, addr);
756 if (!src_pte)
757 continue;
David Gibson63551ae2005-06-21 17:14:44 -0700758 dst_pte = huge_pte_alloc(dst, addr);
759 if (!dst_pte)
760 goto nomem;
Larry Woodmanc5c99422008-01-24 05:49:25 -0800761
762 /* If the pagetables are shared don't copy or take references */
763 if (dst_pte == src_pte)
764 continue;
765
Hugh Dickinsc74df322005-10-29 18:16:23 -0700766 spin_lock(&dst->page_table_lock);
Hugh Dickins1c598272005-10-19 21:23:43 -0700767 spin_lock(&src->page_table_lock);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700768 if (!pte_none(*src_pte)) {
David Gibson1e8f8892006-01-06 00:10:44 -0800769 if (cow)
770 ptep_set_wrprotect(src, addr, src_pte);
Hugh Dickins1c598272005-10-19 21:23:43 -0700771 entry = *src_pte;
772 ptepage = pte_page(entry);
773 get_page(ptepage);
Hugh Dickins1c598272005-10-19 21:23:43 -0700774 set_huge_pte_at(dst, addr, dst_pte, entry);
775 }
776 spin_unlock(&src->page_table_lock);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700777 spin_unlock(&dst->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700778 }
779 return 0;
780
781nomem:
782 return -ENOMEM;
783}
784
Chen, Kenneth W502717f2006-10-11 01:20:46 -0700785void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
786 unsigned long end)
David Gibson63551ae2005-06-21 17:14:44 -0700787{
788 struct mm_struct *mm = vma->vm_mm;
789 unsigned long address;
David Gibsonc7546f82005-08-05 11:59:35 -0700790 pte_t *ptep;
David Gibson63551ae2005-06-21 17:14:44 -0700791 pte_t pte;
792 struct page *page;
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700793 struct page *tmp;
Chen, Kenneth Wc0a499c2006-12-06 20:31:39 -0800794 /*
795 * A page gathering list, protected by per file i_mmap_lock. The
796 * lock is used to avoid list corruption from multiple unmapping
797 * of the same page since we are using page->lru.
798 */
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700799 LIST_HEAD(page_list);
David Gibson63551ae2005-06-21 17:14:44 -0700800
801 WARN_ON(!is_vm_hugetlb_page(vma));
802 BUG_ON(start & ~HPAGE_MASK);
803 BUG_ON(end & ~HPAGE_MASK);
804
Hugh Dickins508034a2005-10-29 18:16:30 -0700805 spin_lock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700806 for (address = start; address < end; address += HPAGE_SIZE) {
David Gibsonc7546f82005-08-05 11:59:35 -0700807 ptep = huge_pte_offset(mm, address);
Adam Litke4c887262005-10-29 18:16:46 -0700808 if (!ptep)
David Gibsonc7546f82005-08-05 11:59:35 -0700809 continue;
810
Chen, Kenneth W39dde652006-12-06 20:32:03 -0800811 if (huge_pmd_unshare(mm, &address, ptep))
812 continue;
813
David Gibsonc7546f82005-08-05 11:59:35 -0700814 pte = huge_ptep_get_and_clear(mm, address, ptep);
David Gibson63551ae2005-06-21 17:14:44 -0700815 if (pte_none(pte))
816 continue;
David Gibsonc7546f82005-08-05 11:59:35 -0700817
David Gibson63551ae2005-06-21 17:14:44 -0700818 page = pte_page(pte);
Ken Chen6649a382007-02-08 14:20:27 -0800819 if (pte_dirty(pte))
820 set_page_dirty(page);
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700821 list_add(&page->lru, &page_list);
David Gibson63551ae2005-06-21 17:14:44 -0700822 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 spin_unlock(&mm->page_table_lock);
Hugh Dickins508034a2005-10-29 18:16:30 -0700824 flush_tlb_range(vma, start, end);
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700825 list_for_each_entry_safe(page, tmp, &page_list, lru) {
826 list_del(&page->lru);
827 put_page(page);
828 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829}
David Gibson63551ae2005-06-21 17:14:44 -0700830
Chen, Kenneth W502717f2006-10-11 01:20:46 -0700831void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
832 unsigned long end)
833{
834 /*
835 * It is undesirable to test vma->vm_file as it should be non-null
836 * for valid hugetlb area. However, vm_file will be NULL in the error
837 * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails,
838 * do_mmap_pgoff() nullifies vma->vm_file before calling this function
839 * to clean up. Since no pte has actually been setup, it is safe to
840 * do nothing in this case.
841 */
842 if (vma->vm_file) {
843 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
844 __unmap_hugepage_range(vma, start, end);
845 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
846 }
847}
848
David Gibson1e8f8892006-01-06 00:10:44 -0800849static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
850 unsigned long address, pte_t *ptep, pte_t pte)
851{
852 struct page *old_page, *new_page;
David Gibson79ac6ba2006-03-22 00:08:51 -0800853 int avoidcopy;
David Gibson1e8f8892006-01-06 00:10:44 -0800854
855 old_page = pte_page(pte);
856
857 /* If no-one else is actually using this page, avoid the copy
858 * and just make the page writable */
859 avoidcopy = (page_count(old_page) == 1);
860 if (avoidcopy) {
861 set_huge_ptep_writable(vma, address, ptep);
Nick Piggin83c54072007-07-19 01:47:05 -0700862 return 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800863 }
864
865 page_cache_get(old_page);
Christoph Lameter5da7ca82006-01-06 00:10:46 -0800866 new_page = alloc_huge_page(vma, address);
David Gibson1e8f8892006-01-06 00:10:44 -0800867
Adam Litke2fc39ce2007-11-14 16:59:39 -0800868 if (IS_ERR(new_page)) {
David Gibson1e8f8892006-01-06 00:10:44 -0800869 page_cache_release(old_page);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800870 return -PTR_ERR(new_page);
David Gibson1e8f8892006-01-06 00:10:44 -0800871 }
872
873 spin_unlock(&mm->page_table_lock);
Atsushi Nemoto9de455b2006-12-12 17:14:55 +0000874 copy_huge_page(new_page, old_page, address, vma);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800875 __SetPageUptodate(new_page);
David Gibson1e8f8892006-01-06 00:10:44 -0800876 spin_lock(&mm->page_table_lock);
877
878 ptep = huge_pte_offset(mm, address & HPAGE_MASK);
879 if (likely(pte_same(*ptep, pte))) {
880 /* Break COW */
881 set_huge_pte_at(mm, address, ptep,
882 make_huge_pte(vma, new_page, 1));
883 /* Make the old page be freed below */
884 new_page = old_page;
885 }
886 page_cache_release(new_page);
887 page_cache_release(old_page);
Nick Piggin83c54072007-07-19 01:47:05 -0700888 return 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800889}
890
Robert P. J. Daya1ed3dd2007-07-17 04:03:33 -0700891static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
David Gibson1e8f8892006-01-06 00:10:44 -0800892 unsigned long address, pte_t *ptep, int write_access)
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100893{
894 int ret = VM_FAULT_SIGBUS;
Adam Litke4c887262005-10-29 18:16:46 -0700895 unsigned long idx;
896 unsigned long size;
Adam Litke4c887262005-10-29 18:16:46 -0700897 struct page *page;
898 struct address_space *mapping;
David Gibson1e8f8892006-01-06 00:10:44 -0800899 pte_t new_pte;
Adam Litke4c887262005-10-29 18:16:46 -0700900
Adam Litke4c887262005-10-29 18:16:46 -0700901 mapping = vma->vm_file->f_mapping;
902 idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
903 + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
904
905 /*
906 * Use page lock to guard against racing truncation
907 * before we get page_table_lock.
908 */
Christoph Lameter6bda6662006-01-06 00:10:49 -0800909retry:
910 page = find_lock_page(mapping, idx);
911 if (!page) {
Hugh Dickinsebed4bf2006-10-28 10:38:43 -0700912 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
913 if (idx >= size)
914 goto out;
Christoph Lameter6bda6662006-01-06 00:10:49 -0800915 page = alloc_huge_page(vma, address);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800916 if (IS_ERR(page)) {
917 ret = -PTR_ERR(page);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800918 goto out;
919 }
David Gibson79ac6ba2006-03-22 00:08:51 -0800920 clear_huge_page(page, address);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800921 __SetPageUptodate(page);
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100922
Christoph Lameter6bda6662006-01-06 00:10:49 -0800923 if (vma->vm_flags & VM_SHARED) {
924 int err;
Ken Chen45c682a2007-11-14 16:59:44 -0800925 struct inode *inode = mapping->host;
Christoph Lameter6bda6662006-01-06 00:10:49 -0800926
927 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
928 if (err) {
929 put_page(page);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800930 if (err == -EEXIST)
931 goto retry;
932 goto out;
933 }
Ken Chen45c682a2007-11-14 16:59:44 -0800934
935 spin_lock(&inode->i_lock);
936 inode->i_blocks += BLOCKS_PER_HUGEPAGE;
937 spin_unlock(&inode->i_lock);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800938 } else
939 lock_page(page);
940 }
David Gibson1e8f8892006-01-06 00:10:44 -0800941
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100942 spin_lock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700943 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
944 if (idx >= size)
945 goto backout;
946
Nick Piggin83c54072007-07-19 01:47:05 -0700947 ret = 0;
Adam Litke86e52162006-01-06 00:10:43 -0800948 if (!pte_none(*ptep))
Adam Litke4c887262005-10-29 18:16:46 -0700949 goto backout;
950
David Gibson1e8f8892006-01-06 00:10:44 -0800951 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
952 && (vma->vm_flags & VM_SHARED)));
953 set_huge_pte_at(mm, address, ptep, new_pte);
954
955 if (write_access && !(vma->vm_flags & VM_SHARED)) {
956 /* Optimization, do the COW without a second fault */
957 ret = hugetlb_cow(mm, vma, address, ptep, new_pte);
958 }
959
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100960 spin_unlock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700961 unlock_page(page);
962out:
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100963 return ret;
Adam Litke4c887262005-10-29 18:16:46 -0700964
965backout:
966 spin_unlock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700967 unlock_page(page);
968 put_page(page);
969 goto out;
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100970}
971
Adam Litke86e52162006-01-06 00:10:43 -0800972int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
973 unsigned long address, int write_access)
974{
975 pte_t *ptep;
976 pte_t entry;
David Gibson1e8f8892006-01-06 00:10:44 -0800977 int ret;
David Gibson3935baa2006-03-22 00:08:53 -0800978 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
Adam Litke86e52162006-01-06 00:10:43 -0800979
980 ptep = huge_pte_alloc(mm, address);
981 if (!ptep)
982 return VM_FAULT_OOM;
983
David Gibson3935baa2006-03-22 00:08:53 -0800984 /*
985 * Serialize hugepage allocation and instantiation, so that we don't
986 * get spurious allocation failures if two CPUs race to instantiate
987 * the same page in the page cache.
988 */
989 mutex_lock(&hugetlb_instantiation_mutex);
Adam Litke86e52162006-01-06 00:10:43 -0800990 entry = *ptep;
David Gibson3935baa2006-03-22 00:08:53 -0800991 if (pte_none(entry)) {
992 ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
993 mutex_unlock(&hugetlb_instantiation_mutex);
994 return ret;
995 }
Adam Litke86e52162006-01-06 00:10:43 -0800996
Nick Piggin83c54072007-07-19 01:47:05 -0700997 ret = 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800998
999 spin_lock(&mm->page_table_lock);
1000 /* Check for a racing update before calling hugetlb_cow */
1001 if (likely(pte_same(entry, *ptep)))
1002 if (write_access && !pte_write(entry))
1003 ret = hugetlb_cow(mm, vma, address, ptep, entry);
1004 spin_unlock(&mm->page_table_lock);
David Gibson3935baa2006-03-22 00:08:53 -08001005 mutex_unlock(&hugetlb_instantiation_mutex);
David Gibson1e8f8892006-01-06 00:10:44 -08001006
1007 return ret;
Adam Litke86e52162006-01-06 00:10:43 -08001008}
1009
David Gibson63551ae2005-06-21 17:14:44 -07001010int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
1011 struct page **pages, struct vm_area_struct **vmas,
Adam Litke5b23dbe2007-11-14 16:59:33 -08001012 unsigned long *position, int *length, int i,
1013 int write)
David Gibson63551ae2005-06-21 17:14:44 -07001014{
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001015 unsigned long pfn_offset;
1016 unsigned long vaddr = *position;
David Gibson63551ae2005-06-21 17:14:44 -07001017 int remainder = *length;
1018
Hugh Dickins1c598272005-10-19 21:23:43 -07001019 spin_lock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -07001020 while (vaddr < vma->vm_end && remainder) {
Adam Litke4c887262005-10-29 18:16:46 -07001021 pte_t *pte;
1022 struct page *page;
1023
1024 /*
1025 * Some archs (sparc64, sh*) have multiple pte_ts to
1026 * each hugepage. We have to make * sure we get the
1027 * first, for the page indexing below to work.
1028 */
1029 pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
1030
Adam Litke72fad712007-12-10 15:49:28 -08001031 if (!pte || pte_none(*pte) || (write && !pte_write(*pte))) {
Adam Litke4c887262005-10-29 18:16:46 -07001032 int ret;
1033
1034 spin_unlock(&mm->page_table_lock);
Adam Litke5b23dbe2007-11-14 16:59:33 -08001035 ret = hugetlb_fault(mm, vma, vaddr, write);
Adam Litke4c887262005-10-29 18:16:46 -07001036 spin_lock(&mm->page_table_lock);
Adam Litkea89182c2007-08-22 14:01:51 -07001037 if (!(ret & VM_FAULT_ERROR))
Adam Litke4c887262005-10-29 18:16:46 -07001038 continue;
1039
1040 remainder = 0;
1041 if (!i)
1042 i = -EFAULT;
1043 break;
1044 }
David Gibson63551ae2005-06-21 17:14:44 -07001045
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001046 pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT;
1047 page = pte_page(*pte);
1048same_page:
Chen, Kenneth Wd6692182006-03-31 02:29:57 -08001049 if (pages) {
1050 get_page(page);
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001051 pages[i] = page + pfn_offset;
Chen, Kenneth Wd6692182006-03-31 02:29:57 -08001052 }
David Gibson63551ae2005-06-21 17:14:44 -07001053
1054 if (vmas)
1055 vmas[i] = vma;
1056
1057 vaddr += PAGE_SIZE;
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001058 ++pfn_offset;
David Gibson63551ae2005-06-21 17:14:44 -07001059 --remainder;
1060 ++i;
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001061 if (vaddr < vma->vm_end && remainder &&
1062 pfn_offset < HPAGE_SIZE/PAGE_SIZE) {
1063 /*
1064 * We use pfn_offset to avoid touching the pageframes
1065 * of this compound page.
1066 */
1067 goto same_page;
1068 }
David Gibson63551ae2005-06-21 17:14:44 -07001069 }
Hugh Dickins1c598272005-10-19 21:23:43 -07001070 spin_unlock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -07001071 *length = remainder;
1072 *position = vaddr;
1073
1074 return i;
1075}
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001076
1077void hugetlb_change_protection(struct vm_area_struct *vma,
1078 unsigned long address, unsigned long end, pgprot_t newprot)
1079{
1080 struct mm_struct *mm = vma->vm_mm;
1081 unsigned long start = address;
1082 pte_t *ptep;
1083 pte_t pte;
1084
1085 BUG_ON(address >= end);
1086 flush_cache_range(vma, address, end);
1087
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001088 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001089 spin_lock(&mm->page_table_lock);
1090 for (; address < end; address += HPAGE_SIZE) {
1091 ptep = huge_pte_offset(mm, address);
1092 if (!ptep)
1093 continue;
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001094 if (huge_pmd_unshare(mm, &address, ptep))
1095 continue;
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001096 if (!pte_none(*ptep)) {
1097 pte = huge_ptep_get_and_clear(mm, address, ptep);
1098 pte = pte_mkhuge(pte_modify(pte, newprot));
1099 set_huge_pte_at(mm, address, ptep, pte);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001100 }
1101 }
1102 spin_unlock(&mm->page_table_lock);
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001103 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001104
1105 flush_tlb_range(vma, start, end);
1106}
1107
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001108struct file_region {
1109 struct list_head link;
1110 long from;
1111 long to;
1112};
1113
1114static long region_add(struct list_head *head, long f, long t)
1115{
1116 struct file_region *rg, *nrg, *trg;
1117
1118 /* Locate the region we are either in or before. */
1119 list_for_each_entry(rg, head, link)
1120 if (f <= rg->to)
1121 break;
1122
1123 /* Round our left edge to the current segment if it encloses us. */
1124 if (f > rg->from)
1125 f = rg->from;
1126
1127 /* Check for and consume any regions we now overlap with. */
1128 nrg = rg;
1129 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
1130 if (&rg->link == head)
1131 break;
1132 if (rg->from > t)
1133 break;
1134
1135 /* If this area reaches higher then extend our area to
1136 * include it completely. If this is not the first area
1137 * which we intend to reuse, free it. */
1138 if (rg->to > t)
1139 t = rg->to;
1140 if (rg != nrg) {
1141 list_del(&rg->link);
1142 kfree(rg);
1143 }
1144 }
1145 nrg->from = f;
1146 nrg->to = t;
1147 return 0;
1148}
1149
1150static long region_chg(struct list_head *head, long f, long t)
1151{
1152 struct file_region *rg, *nrg;
1153 long chg = 0;
1154
1155 /* Locate the region we are before or in. */
1156 list_for_each_entry(rg, head, link)
1157 if (f <= rg->to)
1158 break;
1159
1160 /* If we are below the current region then a new region is required.
1161 * Subtle, allocate a new region at the position but make it zero
Simon Arlott183ff222007-10-20 01:27:18 +02001162 * size such that we can guarantee to record the reservation. */
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001163 if (&rg->link == head || t < rg->from) {
1164 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
Stephen Hemmingerc80544d2007-10-18 03:07:05 -07001165 if (!nrg)
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001166 return -ENOMEM;
1167 nrg->from = f;
1168 nrg->to = f;
1169 INIT_LIST_HEAD(&nrg->link);
1170 list_add(&nrg->link, rg->link.prev);
1171
1172 return t - f;
1173 }
1174
1175 /* Round our left edge to the current segment if it encloses us. */
1176 if (f > rg->from)
1177 f = rg->from;
1178 chg = t - f;
1179
1180 /* Check for and consume any regions we now overlap with. */
1181 list_for_each_entry(rg, rg->link.prev, link) {
1182 if (&rg->link == head)
1183 break;
1184 if (rg->from > t)
1185 return chg;
1186
1187 /* We overlap with this area, if it extends futher than
1188 * us then we must extend ourselves. Account for its
1189 * existing reservation. */
1190 if (rg->to > t) {
1191 chg += rg->to - t;
1192 t = rg->to;
1193 }
1194 chg -= rg->to - rg->from;
1195 }
1196 return chg;
1197}
1198
1199static long region_truncate(struct list_head *head, long end)
1200{
1201 struct file_region *rg, *trg;
1202 long chg = 0;
1203
1204 /* Locate the region we are either in or before. */
1205 list_for_each_entry(rg, head, link)
1206 if (end <= rg->to)
1207 break;
1208 if (&rg->link == head)
1209 return 0;
1210
1211 /* If we are in the middle of a region then adjust it. */
1212 if (end > rg->from) {
1213 chg = rg->to - end;
1214 rg->to = end;
1215 rg = list_entry(rg->link.next, typeof(*rg), link);
1216 }
1217
1218 /* Drop any remaining regions. */
1219 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
1220 if (&rg->link == head)
1221 break;
1222 chg += rg->to - rg->from;
1223 list_del(&rg->link);
1224 kfree(rg);
1225 }
1226 return chg;
1227}
1228
1229static int hugetlb_acct_memory(long delta)
1230{
1231 int ret = -ENOMEM;
1232
1233 spin_lock(&hugetlb_lock);
Ken Chen8a630112007-05-09 02:33:34 -07001234 /*
1235 * When cpuset is configured, it breaks the strict hugetlb page
1236 * reservation as the accounting is done on a global variable. Such
1237 * reservation is completely rubbish in the presence of cpuset because
1238 * the reservation is not checked against page availability for the
1239 * current cpuset. Application can still potentially OOM'ed by kernel
1240 * with lack of free htlb page in cpuset that the task is in.
1241 * Attempt to enforce strict accounting with cpuset is almost
1242 * impossible (or too ugly) because cpuset is too fluid that
1243 * task or memory node can be dynamically moved between cpusets.
1244 *
1245 * The change of semantics for shared hugetlb mapping with cpuset is
1246 * undesirable. However, in order to preserve some of the semantics,
1247 * we fall back to check against current free page availability as
1248 * a best attempt and hopefully to minimize the impact of changing
1249 * semantics that cpuset has.
1250 */
Adam Litkee4e574b2007-10-16 01:26:19 -07001251 if (delta > 0) {
1252 if (gather_surplus_pages(delta) < 0)
1253 goto out;
1254
Adam Litkeac09b3a2008-03-04 14:29:38 -08001255 if (delta > cpuset_mems_nr(free_huge_pages_node)) {
1256 return_unused_surplus_pages(delta);
Adam Litkee4e574b2007-10-16 01:26:19 -07001257 goto out;
Adam Litkeac09b3a2008-03-04 14:29:38 -08001258 }
Adam Litkee4e574b2007-10-16 01:26:19 -07001259 }
1260
1261 ret = 0;
Adam Litkee4e574b2007-10-16 01:26:19 -07001262 if (delta < 0)
1263 return_unused_surplus_pages((unsigned long) -delta);
1264
1265out:
1266 spin_unlock(&hugetlb_lock);
1267 return ret;
1268}
1269
1270int hugetlb_reserve_pages(struct inode *inode, long from, long to)
1271{
1272 long ret, chg;
1273
1274 chg = region_chg(&inode->i_mapping->private_list, from, to);
1275 if (chg < 0)
1276 return chg;
Ken Chen8a630112007-05-09 02:33:34 -07001277
Adam Litke90d8b7e2007-11-14 16:59:42 -08001278 if (hugetlb_get_quota(inode->i_mapping, chg))
1279 return -ENOSPC;
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001280 ret = hugetlb_acct_memory(chg);
Ken Chen68842c92008-01-14 00:55:19 -08001281 if (ret < 0) {
1282 hugetlb_put_quota(inode->i_mapping, chg);
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001283 return ret;
Ken Chen68842c92008-01-14 00:55:19 -08001284 }
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001285 region_add(&inode->i_mapping->private_list, from, to);
1286 return 0;
1287}
1288
1289void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
1290{
1291 long chg = region_truncate(&inode->i_mapping->private_list, offset);
Ken Chen45c682a2007-11-14 16:59:44 -08001292
1293 spin_lock(&inode->i_lock);
1294 inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed;
1295 spin_unlock(&inode->i_lock);
1296
Adam Litke90d8b7e2007-11-14 16:59:42 -08001297 hugetlb_put_quota(inode->i_mapping, (chg - freed));
1298 hugetlb_acct_memory(-(chg - freed));
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001299}