blob: dcacc811e70ede9cda49d4d2cf56a6d5d5404a56 [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 Gorman396faf02007-07-17 04:03:13 -070098 struct zonelist *zonelist = huge_zonelist(vma, address,
Lee Schermerhorn480eccf2007-09-18 22:46:47 -070099 htlb_alloc_mask, &mpol);
Christoph Lameter96df9332006-01-06 00:10:45 -0800100 struct zone **z;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
Christoph Lameter96df9332006-01-06 00:10:45 -0800102 for (z = zonelist->zones; *z; z++) {
Christoph Lameter89fa3022006-09-25 23:31:55 -0700103 nid = zone_to_nid(*z);
Mel Gorman396faf02007-07-17 04:03:13 -0700104 if (cpuset_zone_allowed_softwall(*z, htlb_alloc_mask) &&
Andrew Morton3abf7af2007-07-19 01:49:08 -0700105 !list_empty(&hugepage_freelists[nid])) {
106 page = list_entry(hugepage_freelists[nid].next,
107 struct page, lru);
108 list_del(&page->lru);
109 free_huge_pages--;
110 free_huge_pages_node[nid]--;
Adam Litkee4e574b2007-10-16 01:26:19 -0700111 if (vma && vma->vm_flags & VM_MAYSHARE)
112 resv_huge_pages--;
Ken Chen5ab3ee72007-07-23 18:44:00 -0700113 break;
Andrew Morton3abf7af2007-07-19 01:49:08 -0700114 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 }
Lee Schermerhorn480eccf2007-09-18 22:46:47 -0700116 mpol_free(mpol); /* unref if mpol !NULL */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 return page;
118}
119
Adam Litke6af2acb2007-10-16 01:26:16 -0700120static void update_and_free_page(struct page *page)
121{
122 int i;
123 nr_huge_pages--;
124 nr_huge_pages_node[page_to_nid(page)]--;
125 for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) {
126 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
127 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
128 1 << PG_private | 1<< PG_writeback);
129 }
130 set_compound_page_dtor(page, NULL);
131 set_page_refcounted(page);
132 __free_pages(page, HUGETLB_PAGE_ORDER);
133}
134
David Gibson27a85ef2006-03-22 00:08:56 -0800135static void free_huge_page(struct page *page)
136{
Adam Litke7893d1d2007-10-16 01:26:18 -0700137 int nid = page_to_nid(page);
Adam Litkec79fb752007-11-14 16:59:38 -0800138 struct address_space *mapping;
David Gibson27a85ef2006-03-22 00:08:56 -0800139
Adam Litkec79fb752007-11-14 16:59:38 -0800140 mapping = (struct address_space *) page_private(page);
Andy Whitcrofte5df70a2008-02-23 15:23:32 -0800141 set_page_private(page, 0);
Adam Litke7893d1d2007-10-16 01:26:18 -0700142 BUG_ON(page_count(page));
David Gibson27a85ef2006-03-22 00:08:56 -0800143 INIT_LIST_HEAD(&page->lru);
144
145 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700146 if (surplus_huge_pages_node[nid]) {
147 update_and_free_page(page);
148 surplus_huge_pages--;
149 surplus_huge_pages_node[nid]--;
150 } else {
151 enqueue_huge_page(page);
152 }
David Gibson27a85ef2006-03-22 00:08:56 -0800153 spin_unlock(&hugetlb_lock);
Adam Litkec79fb752007-11-14 16:59:38 -0800154 if (mapping)
Adam Litke9a119c02007-11-14 16:59:41 -0800155 hugetlb_put_quota(mapping, 1);
David Gibson27a85ef2006-03-22 00:08:56 -0800156}
157
Adam Litke7893d1d2007-10-16 01:26:18 -0700158/*
159 * Increment or decrement surplus_huge_pages. Keep node-specific counters
160 * balanced by operating on them in a round-robin fashion.
161 * Returns 1 if an adjustment was made.
162 */
163static int adjust_pool_surplus(int delta)
164{
165 static int prev_nid;
166 int nid = prev_nid;
167 int ret = 0;
168
169 VM_BUG_ON(delta != -1 && delta != 1);
170 do {
171 nid = next_node(nid, node_online_map);
172 if (nid == MAX_NUMNODES)
173 nid = first_node(node_online_map);
174
175 /* To shrink on this node, there must be a surplus page */
176 if (delta < 0 && !surplus_huge_pages_node[nid])
177 continue;
178 /* Surplus cannot exceed the total number of pages */
179 if (delta > 0 && surplus_huge_pages_node[nid] >=
180 nr_huge_pages_node[nid])
181 continue;
182
183 surplus_huge_pages += delta;
184 surplus_huge_pages_node[nid] += delta;
185 ret = 1;
186 break;
187 } while (nid != prev_nid);
188
189 prev_nid = nid;
190 return ret;
191}
192
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700193static struct page *alloc_fresh_huge_page_node(int nid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 struct page *page;
Joe Jinf96efd52007-07-15 23:38:12 -0700196
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700197 page = alloc_pages_node(nid,
198 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|__GFP_NOWARN,
199 HUGETLB_PAGE_ORDER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 if (page) {
Andy Whitcroft33f2ef82006-12-06 20:33:32 -0800201 set_compound_page_dtor(page, free_huge_page);
Eric Paris0bd0f9f2005-11-21 21:32:28 -0800202 spin_lock(&hugetlb_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 nr_huge_pages++;
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700204 nr_huge_pages_node[nid]++;
Eric Paris0bd0f9f2005-11-21 21:32:28 -0800205 spin_unlock(&hugetlb_lock);
Nick Piggina4822892006-03-22 00:08:08 -0800206 put_page(page); /* free it into the hugepage allocator */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 }
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700208
209 return page;
210}
211
212static int alloc_fresh_huge_page(void)
213{
214 struct page *page;
215 int start_nid;
216 int next_nid;
217 int ret = 0;
218
219 start_nid = hugetlb_next_nid;
220
221 do {
222 page = alloc_fresh_huge_page_node(hugetlb_next_nid);
223 if (page)
224 ret = 1;
225 /*
226 * Use a helper variable to find the next node and then
227 * copy it back to hugetlb_next_nid afterwards:
228 * otherwise there's a window in which a racer might
229 * pass invalid nid MAX_NUMNODES to alloc_pages_node.
230 * But we don't need to use a spin_lock here: it really
231 * doesn't matter if occasionally a racer chooses the
232 * same nid as we do. Move nid forward in the mask even
233 * if we just successfully allocated a hugepage so that
234 * the next caller gets hugepages on the next node.
235 */
236 next_nid = next_node(hugetlb_next_nid, node_online_map);
237 if (next_nid == MAX_NUMNODES)
238 next_nid = first_node(node_online_map);
239 hugetlb_next_nid = next_nid;
240 } while (!page && hugetlb_next_nid != start_nid);
241
242 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243}
244
Adam Litke7893d1d2007-10-16 01:26:18 -0700245static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma,
246 unsigned long address)
247{
248 struct page *page;
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800249 unsigned int nid;
Adam Litke7893d1d2007-10-16 01:26:18 -0700250
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800251 /*
252 * Assume we will successfully allocate the surplus page to
253 * prevent racing processes from causing the surplus to exceed
254 * overcommit
255 *
256 * This however introduces a different race, where a process B
257 * tries to grow the static hugepage pool while alloc_pages() is
258 * called by process A. B will only examine the per-node
259 * counters in determining if surplus huge pages can be
260 * converted to normal huge pages in adjust_pool_surplus(). A
261 * won't be able to increment the per-node counter, until the
262 * lock is dropped by B, but B doesn't drop hugetlb_lock until
263 * no more huge pages can be converted from surplus to normal
264 * state (and doesn't try to convert again). Thus, we have a
265 * case where a surplus huge page exists, the pool is grown, and
266 * the surplus huge page still exists after, even though it
267 * should just have been converted to a normal huge page. This
268 * does not leak memory, though, as the hugepage will be freed
269 * once it is out of use. It also does not allow the counters to
270 * go out of whack in adjust_pool_surplus() as we don't modify
271 * the node values until we've gotten the hugepage and only the
272 * per-node value is checked there.
273 */
274 spin_lock(&hugetlb_lock);
275 if (surplus_huge_pages >= nr_overcommit_huge_pages) {
276 spin_unlock(&hugetlb_lock);
277 return NULL;
278 } else {
279 nr_huge_pages++;
280 surplus_huge_pages++;
281 }
282 spin_unlock(&hugetlb_lock);
283
Adam Litke7893d1d2007-10-16 01:26:18 -0700284 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN,
285 HUGETLB_PAGE_ORDER);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800286
287 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700288 if (page) {
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800289 nid = page_to_nid(page);
Adam Litke7893d1d2007-10-16 01:26:18 -0700290 set_compound_page_dtor(page, free_huge_page);
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800291 /*
292 * We incremented the global counters already
293 */
294 nr_huge_pages_node[nid]++;
295 surplus_huge_pages_node[nid]++;
296 } else {
297 nr_huge_pages--;
298 surplus_huge_pages--;
Adam Litke7893d1d2007-10-16 01:26:18 -0700299 }
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800300 spin_unlock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700301
302 return page;
303}
304
Adam Litkee4e574b2007-10-16 01:26:19 -0700305/*
306 * Increase the hugetlb pool such that it can accomodate a reservation
307 * of size 'delta'.
308 */
309static int gather_surplus_pages(int delta)
310{
311 struct list_head surplus_list;
312 struct page *page, *tmp;
313 int ret, i;
314 int needed, allocated;
315
316 needed = (resv_huge_pages + delta) - free_huge_pages;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800317 if (needed <= 0) {
318 resv_huge_pages += delta;
Adam Litkee4e574b2007-10-16 01:26:19 -0700319 return 0;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800320 }
Adam Litkee4e574b2007-10-16 01:26:19 -0700321
322 allocated = 0;
323 INIT_LIST_HEAD(&surplus_list);
324
325 ret = -ENOMEM;
326retry:
327 spin_unlock(&hugetlb_lock);
328 for (i = 0; i < needed; i++) {
329 page = alloc_buddy_huge_page(NULL, 0);
330 if (!page) {
331 /*
332 * We were not able to allocate enough pages to
333 * satisfy the entire reservation so we free what
334 * we've allocated so far.
335 */
336 spin_lock(&hugetlb_lock);
337 needed = 0;
338 goto free;
339 }
340
341 list_add(&page->lru, &surplus_list);
342 }
343 allocated += needed;
344
345 /*
346 * After retaking hugetlb_lock, we need to recalculate 'needed'
347 * because either resv_huge_pages or free_huge_pages may have changed.
348 */
349 spin_lock(&hugetlb_lock);
350 needed = (resv_huge_pages + delta) - (free_huge_pages + allocated);
351 if (needed > 0)
352 goto retry;
353
354 /*
355 * The surplus_list now contains _at_least_ the number of extra pages
356 * needed to accomodate the reservation. Add the appropriate number
357 * of pages to the hugetlb pool and free the extras back to the buddy
Adam Litkeac09b3a2008-03-04 14:29:38 -0800358 * allocator. Commit the entire reservation here to prevent another
359 * process from stealing the pages as they are added to the pool but
360 * before they are reserved.
Adam Litkee4e574b2007-10-16 01:26:19 -0700361 */
362 needed += allocated;
Adam Litkeac09b3a2008-03-04 14:29:38 -0800363 resv_huge_pages += delta;
Adam Litkee4e574b2007-10-16 01:26:19 -0700364 ret = 0;
365free:
366 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
367 list_del(&page->lru);
368 if ((--needed) >= 0)
369 enqueue_huge_page(page);
Adam Litkeaf767cb2007-10-16 01:26:25 -0700370 else {
371 /*
372 * Decrement the refcount and free the page using its
373 * destructor. This must be done with hugetlb_lock
374 * unlocked which is safe because free_huge_page takes
375 * hugetlb_lock before deciding how to free the page.
376 */
377 spin_unlock(&hugetlb_lock);
378 put_page(page);
379 spin_lock(&hugetlb_lock);
380 }
Adam Litkee4e574b2007-10-16 01:26:19 -0700381 }
382
383 return ret;
384}
385
386/*
387 * When releasing a hugetlb pool reservation, any surplus pages that were
388 * allocated to satisfy the reservation must be explicitly freed if they were
389 * never used.
390 */
Adrian Bunk8cde0452007-11-14 16:59:43 -0800391static void return_unused_surplus_pages(unsigned long unused_resv_pages)
Adam Litkee4e574b2007-10-16 01:26:19 -0700392{
393 static int nid = -1;
394 struct page *page;
395 unsigned long nr_pages;
396
Adam Litkeac09b3a2008-03-04 14:29:38 -0800397 /* Uncommit the reservation */
398 resv_huge_pages -= unused_resv_pages;
399
Adam Litkee4e574b2007-10-16 01:26:19 -0700400 nr_pages = min(unused_resv_pages, surplus_huge_pages);
401
402 while (nr_pages) {
403 nid = next_node(nid, node_online_map);
404 if (nid == MAX_NUMNODES)
405 nid = first_node(node_online_map);
406
407 if (!surplus_huge_pages_node[nid])
408 continue;
409
410 if (!list_empty(&hugepage_freelists[nid])) {
411 page = list_entry(hugepage_freelists[nid].next,
412 struct page, lru);
413 list_del(&page->lru);
414 update_and_free_page(page);
415 free_huge_pages--;
416 free_huge_pages_node[nid]--;
417 surplus_huge_pages--;
418 surplus_huge_pages_node[nid]--;
419 nr_pages--;
420 }
421 }
422}
423
Adam Litke348ea202007-11-14 16:59:37 -0800424
425static struct page *alloc_huge_page_shared(struct vm_area_struct *vma,
426 unsigned long addr)
427{
428 struct page *page;
429
430 spin_lock(&hugetlb_lock);
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800431 page = dequeue_huge_page_vma(vma, addr);
Adam Litke348ea202007-11-14 16:59:37 -0800432 spin_unlock(&hugetlb_lock);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800433 return page ? page : ERR_PTR(-VM_FAULT_OOM);
Adam Litke348ea202007-11-14 16:59:37 -0800434}
435
436static struct page *alloc_huge_page_private(struct vm_area_struct *vma,
437 unsigned long addr)
438{
439 struct page *page = NULL;
440
Adam Litke90d8b7e2007-11-14 16:59:42 -0800441 if (hugetlb_get_quota(vma->vm_file->f_mapping, 1))
442 return ERR_PTR(-VM_FAULT_SIGBUS);
443
Adam Litke348ea202007-11-14 16:59:37 -0800444 spin_lock(&hugetlb_lock);
445 if (free_huge_pages > resv_huge_pages)
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800446 page = dequeue_huge_page_vma(vma, addr);
Adam Litke348ea202007-11-14 16:59:37 -0800447 spin_unlock(&hugetlb_lock);
Ken Chen68842c92008-01-14 00:55:19 -0800448 if (!page) {
Adam Litke348ea202007-11-14 16:59:37 -0800449 page = alloc_buddy_huge_page(vma, addr);
Ken Chen68842c92008-01-14 00:55:19 -0800450 if (!page) {
451 hugetlb_put_quota(vma->vm_file->f_mapping, 1);
452 return ERR_PTR(-VM_FAULT_OOM);
453 }
454 }
455 return page;
Adam Litke348ea202007-11-14 16:59:37 -0800456}
457
David Gibson27a85ef2006-03-22 00:08:56 -0800458static struct page *alloc_huge_page(struct vm_area_struct *vma,
459 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460{
Adam Litke348ea202007-11-14 16:59:37 -0800461 struct page *page;
Adam Litke2fc39ce2007-11-14 16:59:39 -0800462 struct address_space *mapping = vma->vm_file->f_mapping;
463
Adam Litke348ea202007-11-14 16:59:37 -0800464 if (vma->vm_flags & VM_MAYSHARE)
465 page = alloc_huge_page_shared(vma, addr);
466 else
467 page = alloc_huge_page_private(vma, addr);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800468
469 if (!IS_ERR(page)) {
Adam Litke348ea202007-11-14 16:59:37 -0800470 set_page_refcounted(page);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800471 set_page_private(page, (unsigned long) mapping);
Adam Litke90d8b7e2007-11-14 16:59:42 -0800472 }
473 return page;
David Gibsonb45b5bd2006-03-22 00:08:55 -0800474}
475
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476static int __init hugetlb_init(void)
477{
478 unsigned long i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479
Benjamin Herrenschmidt3c726f82005-11-07 11:06:55 +1100480 if (HPAGE_SHIFT == 0)
481 return 0;
482
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 for (i = 0; i < MAX_NUMNODES; ++i)
484 INIT_LIST_HEAD(&hugepage_freelists[i]);
485
Nishanth Aravamudan63b46132007-10-16 01:26:24 -0700486 hugetlb_next_nid = first_node(node_online_map);
487
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 for (i = 0; i < max_huge_pages; ++i) {
Nick Piggina4822892006-03-22 00:08:08 -0800489 if (!alloc_fresh_huge_page())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 }
492 max_huge_pages = free_huge_pages = nr_huge_pages = i;
493 printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
494 return 0;
495}
496module_init(hugetlb_init);
497
498static int __init hugetlb_setup(char *s)
499{
500 if (sscanf(s, "%lu", &max_huge_pages) <= 0)
501 max_huge_pages = 0;
502 return 1;
503}
504__setup("hugepages=", hugetlb_setup);
505
Ken Chen8a630112007-05-09 02:33:34 -0700506static unsigned int cpuset_mems_nr(unsigned int *array)
507{
508 int node;
509 unsigned int nr = 0;
510
511 for_each_node_mask(node, cpuset_current_mems_allowed)
512 nr += array[node];
513
514 return nr;
515}
516
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517#ifdef CONFIG_SYSCTL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518#ifdef CONFIG_HIGHMEM
519static void try_to_free_low(unsigned long count)
520{
Christoph Lameter4415cc82006-09-25 23:31:55 -0700521 int i;
522
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 for (i = 0; i < MAX_NUMNODES; ++i) {
524 struct page *page, *next;
525 list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
Adam Litke6b0c8802007-10-16 01:26:23 -0700526 if (count >= nr_huge_pages)
527 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 if (PageHighMem(page))
529 continue;
530 list_del(&page->lru);
531 update_and_free_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 free_huge_pages--;
Christoph Lameter4415cc82006-09-25 23:31:55 -0700533 free_huge_pages_node[page_to_nid(page)]--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 }
535 }
536}
537#else
538static inline void try_to_free_low(unsigned long count)
539{
540}
541#endif
542
Adam Litke7893d1d2007-10-16 01:26:18 -0700543#define persistent_huge_pages (nr_huge_pages - surplus_huge_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544static unsigned long set_max_huge_pages(unsigned long count)
545{
Adam Litke7893d1d2007-10-16 01:26:18 -0700546 unsigned long min_count, ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547
Adam Litke7893d1d2007-10-16 01:26:18 -0700548 /*
549 * Increase the pool size
550 * First take pages out of surplus state. Then make up the
551 * remaining difference by allocating fresh huge pages.
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800552 *
553 * We might race with alloc_buddy_huge_page() here and be unable
554 * to convert a surplus huge page to a normal huge page. That is
555 * not critical, though, it just means the overall size of the
556 * pool might be one hugepage larger than it needs to be, but
557 * within all the constraints specified by the sysctls.
Adam Litke7893d1d2007-10-16 01:26:18 -0700558 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 spin_lock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700560 while (surplus_huge_pages && count > persistent_huge_pages) {
561 if (!adjust_pool_surplus(-1))
562 break;
563 }
564
565 while (count > persistent_huge_pages) {
566 int ret;
567 /*
568 * If this allocation races such that we no longer need the
569 * page, free_huge_page will handle it by freeing the page
570 * and reducing the surplus.
571 */
572 spin_unlock(&hugetlb_lock);
573 ret = alloc_fresh_huge_page();
574 spin_lock(&hugetlb_lock);
575 if (!ret)
576 goto out;
577
578 }
Adam Litke7893d1d2007-10-16 01:26:18 -0700579
580 /*
581 * Decrease the pool size
582 * First return free pages to the buddy allocator (being careful
583 * to keep enough around to satisfy reservations). Then place
584 * pages into surplus state as needed so the pool will shrink
585 * to the desired size as pages become free.
Nishanth Aravamudand1c3fb12007-12-17 16:20:12 -0800586 *
587 * By placing pages into the surplus state independent of the
588 * overcommit value, we are allowing the surplus pool size to
589 * exceed overcommit. There are few sane options here. Since
590 * alloc_buddy_huge_page() is checking the global counter,
591 * though, we'll note that we're not allowed to exceed surplus
592 * and won't grow the pool anywhere else. Not until one of the
593 * sysctls are changed, or the surplus pages go out of use.
Adam Litke7893d1d2007-10-16 01:26:18 -0700594 */
Adam Litke6b0c8802007-10-16 01:26:23 -0700595 min_count = resv_huge_pages + nr_huge_pages - free_huge_pages;
596 min_count = max(count, min_count);
Adam Litke7893d1d2007-10-16 01:26:18 -0700597 try_to_free_low(min_count);
598 while (min_count < persistent_huge_pages) {
Nishanth Aravamudan348e1e02008-03-04 14:29:42 -0800599 struct page *page = dequeue_huge_page();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 if (!page)
601 break;
602 update_and_free_page(page);
603 }
Adam Litke7893d1d2007-10-16 01:26:18 -0700604 while (count < persistent_huge_pages) {
605 if (!adjust_pool_surplus(1))
606 break;
607 }
608out:
609 ret = persistent_huge_pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 spin_unlock(&hugetlb_lock);
Adam Litke7893d1d2007-10-16 01:26:18 -0700611 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612}
613
614int hugetlb_sysctl_handler(struct ctl_table *table, int write,
615 struct file *file, void __user *buffer,
616 size_t *length, loff_t *ppos)
617{
618 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
619 max_huge_pages = set_max_huge_pages(max_huge_pages);
620 return 0;
621}
Mel Gorman396faf02007-07-17 04:03:13 -0700622
623int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
624 struct file *file, void __user *buffer,
625 size_t *length, loff_t *ppos)
626{
627 proc_dointvec(table, write, file, buffer, length, ppos);
628 if (hugepages_treat_as_movable)
629 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
630 else
631 htlb_alloc_mask = GFP_HIGHUSER;
632 return 0;
633}
634
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800635int hugetlb_overcommit_handler(struct ctl_table *table, int write,
636 struct file *file, void __user *buffer,
637 size_t *length, loff_t *ppos)
638{
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800639 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
Nishanth Aravamudan064d9ef2008-02-13 15:03:19 -0800640 spin_lock(&hugetlb_lock);
641 nr_overcommit_huge_pages = sysctl_overcommit_huge_pages;
Nishanth Aravamudana3d0c6a2008-02-08 04:18:18 -0800642 spin_unlock(&hugetlb_lock);
643 return 0;
644}
645
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646#endif /* CONFIG_SYSCTL */
647
648int hugetlb_report_meminfo(char *buf)
649{
650 return sprintf(buf,
651 "HugePages_Total: %5lu\n"
652 "HugePages_Free: %5lu\n"
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700653 "HugePages_Rsvd: %5lu\n"
Adam Litke7893d1d2007-10-16 01:26:18 -0700654 "HugePages_Surp: %5lu\n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 "Hugepagesize: %5lu kB\n",
656 nr_huge_pages,
657 free_huge_pages,
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -0700658 resv_huge_pages,
Adam Litke7893d1d2007-10-16 01:26:18 -0700659 surplus_huge_pages,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 HPAGE_SIZE/1024);
661}
662
663int hugetlb_report_node_meminfo(int nid, char *buf)
664{
665 return sprintf(buf,
666 "Node %d HugePages_Total: %5u\n"
667 "Node %d HugePages_Free: %5u\n",
668 nid, nr_huge_pages_node[nid],
669 nid, free_huge_pages_node[nid]);
670}
671
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
673unsigned long hugetlb_total_pages(void)
674{
675 return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
676}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677
678/*
679 * We cannot handle pagefaults against hugetlb pages at all. They cause
680 * handle_mm_fault() to try to instantiate regular-sized pages in the
681 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
682 * this far.
683 */
Nick Piggind0217ac2007-07-19 01:47:03 -0700684static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685{
686 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -0700687 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688}
689
690struct vm_operations_struct hugetlb_vm_ops = {
Nick Piggind0217ac2007-07-19 01:47:03 -0700691 .fault = hugetlb_vm_op_fault,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692};
693
David Gibson1e8f8892006-01-06 00:10:44 -0800694static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
695 int writable)
David Gibson63551ae2005-06-21 17:14:44 -0700696{
697 pte_t entry;
698
David Gibson1e8f8892006-01-06 00:10:44 -0800699 if (writable) {
David Gibson63551ae2005-06-21 17:14:44 -0700700 entry =
701 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
702 } else {
703 entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
704 }
705 entry = pte_mkyoung(entry);
706 entry = pte_mkhuge(entry);
707
708 return entry;
709}
710
David Gibson1e8f8892006-01-06 00:10:44 -0800711static void set_huge_ptep_writable(struct vm_area_struct *vma,
712 unsigned long address, pte_t *ptep)
713{
714 pte_t entry;
715
716 entry = pte_mkwrite(pte_mkdirty(*ptep));
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -0700717 if (ptep_set_access_flags(vma, address, ptep, entry, 1)) {
718 update_mmu_cache(vma, address, entry);
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -0700719 }
David Gibson1e8f8892006-01-06 00:10:44 -0800720}
721
722
David Gibson63551ae2005-06-21 17:14:44 -0700723int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
724 struct vm_area_struct *vma)
725{
726 pte_t *src_pte, *dst_pte, entry;
727 struct page *ptepage;
Hugh Dickins1c598272005-10-19 21:23:43 -0700728 unsigned long addr;
David Gibson1e8f8892006-01-06 00:10:44 -0800729 int cow;
730
731 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
David Gibson63551ae2005-06-21 17:14:44 -0700732
Hugh Dickins1c598272005-10-19 21:23:43 -0700733 for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
Hugh Dickinsc74df322005-10-29 18:16:23 -0700734 src_pte = huge_pte_offset(src, addr);
735 if (!src_pte)
736 continue;
David Gibson63551ae2005-06-21 17:14:44 -0700737 dst_pte = huge_pte_alloc(dst, addr);
738 if (!dst_pte)
739 goto nomem;
Larry Woodmanc5c99422008-01-24 05:49:25 -0800740
741 /* If the pagetables are shared don't copy or take references */
742 if (dst_pte == src_pte)
743 continue;
744
Hugh Dickinsc74df322005-10-29 18:16:23 -0700745 spin_lock(&dst->page_table_lock);
Hugh Dickins1c598272005-10-19 21:23:43 -0700746 spin_lock(&src->page_table_lock);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700747 if (!pte_none(*src_pte)) {
David Gibson1e8f8892006-01-06 00:10:44 -0800748 if (cow)
749 ptep_set_wrprotect(src, addr, src_pte);
Hugh Dickins1c598272005-10-19 21:23:43 -0700750 entry = *src_pte;
751 ptepage = pte_page(entry);
752 get_page(ptepage);
Hugh Dickins1c598272005-10-19 21:23:43 -0700753 set_huge_pte_at(dst, addr, dst_pte, entry);
754 }
755 spin_unlock(&src->page_table_lock);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700756 spin_unlock(&dst->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700757 }
758 return 0;
759
760nomem:
761 return -ENOMEM;
762}
763
Chen, Kenneth W502717f2006-10-11 01:20:46 -0700764void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
765 unsigned long end)
David Gibson63551ae2005-06-21 17:14:44 -0700766{
767 struct mm_struct *mm = vma->vm_mm;
768 unsigned long address;
David Gibsonc7546f82005-08-05 11:59:35 -0700769 pte_t *ptep;
David Gibson63551ae2005-06-21 17:14:44 -0700770 pte_t pte;
771 struct page *page;
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700772 struct page *tmp;
Chen, Kenneth Wc0a499c2006-12-06 20:31:39 -0800773 /*
774 * A page gathering list, protected by per file i_mmap_lock. The
775 * lock is used to avoid list corruption from multiple unmapping
776 * of the same page since we are using page->lru.
777 */
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700778 LIST_HEAD(page_list);
David Gibson63551ae2005-06-21 17:14:44 -0700779
780 WARN_ON(!is_vm_hugetlb_page(vma));
781 BUG_ON(start & ~HPAGE_MASK);
782 BUG_ON(end & ~HPAGE_MASK);
783
Hugh Dickins508034a2005-10-29 18:16:30 -0700784 spin_lock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700785 for (address = start; address < end; address += HPAGE_SIZE) {
David Gibsonc7546f82005-08-05 11:59:35 -0700786 ptep = huge_pte_offset(mm, address);
Adam Litke4c887262005-10-29 18:16:46 -0700787 if (!ptep)
David Gibsonc7546f82005-08-05 11:59:35 -0700788 continue;
789
Chen, Kenneth W39dde652006-12-06 20:32:03 -0800790 if (huge_pmd_unshare(mm, &address, ptep))
791 continue;
792
David Gibsonc7546f82005-08-05 11:59:35 -0700793 pte = huge_ptep_get_and_clear(mm, address, ptep);
David Gibson63551ae2005-06-21 17:14:44 -0700794 if (pte_none(pte))
795 continue;
David Gibsonc7546f82005-08-05 11:59:35 -0700796
David Gibson63551ae2005-06-21 17:14:44 -0700797 page = pte_page(pte);
Ken Chen6649a382007-02-08 14:20:27 -0800798 if (pte_dirty(pte))
799 set_page_dirty(page);
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700800 list_add(&page->lru, &page_list);
David Gibson63551ae2005-06-21 17:14:44 -0700801 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 spin_unlock(&mm->page_table_lock);
Hugh Dickins508034a2005-10-29 18:16:30 -0700803 flush_tlb_range(vma, start, end);
Chen, Kenneth Wfe1668a2006-10-04 02:15:24 -0700804 list_for_each_entry_safe(page, tmp, &page_list, lru) {
805 list_del(&page->lru);
806 put_page(page);
807 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808}
David Gibson63551ae2005-06-21 17:14:44 -0700809
Chen, Kenneth W502717f2006-10-11 01:20:46 -0700810void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
811 unsigned long end)
812{
813 /*
814 * It is undesirable to test vma->vm_file as it should be non-null
815 * for valid hugetlb area. However, vm_file will be NULL in the error
816 * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails,
817 * do_mmap_pgoff() nullifies vma->vm_file before calling this function
818 * to clean up. Since no pte has actually been setup, it is safe to
819 * do nothing in this case.
820 */
821 if (vma->vm_file) {
822 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
823 __unmap_hugepage_range(vma, start, end);
824 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
825 }
826}
827
David Gibson1e8f8892006-01-06 00:10:44 -0800828static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
829 unsigned long address, pte_t *ptep, pte_t pte)
830{
831 struct page *old_page, *new_page;
David Gibson79ac6ba2006-03-22 00:08:51 -0800832 int avoidcopy;
David Gibson1e8f8892006-01-06 00:10:44 -0800833
834 old_page = pte_page(pte);
835
836 /* If no-one else is actually using this page, avoid the copy
837 * and just make the page writable */
838 avoidcopy = (page_count(old_page) == 1);
839 if (avoidcopy) {
840 set_huge_ptep_writable(vma, address, ptep);
Nick Piggin83c54072007-07-19 01:47:05 -0700841 return 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800842 }
843
844 page_cache_get(old_page);
Christoph Lameter5da7ca82006-01-06 00:10:46 -0800845 new_page = alloc_huge_page(vma, address);
David Gibson1e8f8892006-01-06 00:10:44 -0800846
Adam Litke2fc39ce2007-11-14 16:59:39 -0800847 if (IS_ERR(new_page)) {
David Gibson1e8f8892006-01-06 00:10:44 -0800848 page_cache_release(old_page);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800849 return -PTR_ERR(new_page);
David Gibson1e8f8892006-01-06 00:10:44 -0800850 }
851
852 spin_unlock(&mm->page_table_lock);
Atsushi Nemoto9de455b2006-12-12 17:14:55 +0000853 copy_huge_page(new_page, old_page, address, vma);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800854 __SetPageUptodate(new_page);
David Gibson1e8f8892006-01-06 00:10:44 -0800855 spin_lock(&mm->page_table_lock);
856
857 ptep = huge_pte_offset(mm, address & HPAGE_MASK);
858 if (likely(pte_same(*ptep, pte))) {
859 /* Break COW */
860 set_huge_pte_at(mm, address, ptep,
861 make_huge_pte(vma, new_page, 1));
862 /* Make the old page be freed below */
863 new_page = old_page;
864 }
865 page_cache_release(new_page);
866 page_cache_release(old_page);
Nick Piggin83c54072007-07-19 01:47:05 -0700867 return 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800868}
869
Robert P. J. Daya1ed3dd2007-07-17 04:03:33 -0700870static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
David Gibson1e8f8892006-01-06 00:10:44 -0800871 unsigned long address, pte_t *ptep, int write_access)
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100872{
873 int ret = VM_FAULT_SIGBUS;
Adam Litke4c887262005-10-29 18:16:46 -0700874 unsigned long idx;
875 unsigned long size;
Adam Litke4c887262005-10-29 18:16:46 -0700876 struct page *page;
877 struct address_space *mapping;
David Gibson1e8f8892006-01-06 00:10:44 -0800878 pte_t new_pte;
Adam Litke4c887262005-10-29 18:16:46 -0700879
Adam Litke4c887262005-10-29 18:16:46 -0700880 mapping = vma->vm_file->f_mapping;
881 idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
882 + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
883
884 /*
885 * Use page lock to guard against racing truncation
886 * before we get page_table_lock.
887 */
Christoph Lameter6bda6662006-01-06 00:10:49 -0800888retry:
889 page = find_lock_page(mapping, idx);
890 if (!page) {
Hugh Dickinsebed4bf2006-10-28 10:38:43 -0700891 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
892 if (idx >= size)
893 goto out;
Christoph Lameter6bda6662006-01-06 00:10:49 -0800894 page = alloc_huge_page(vma, address);
Adam Litke2fc39ce2007-11-14 16:59:39 -0800895 if (IS_ERR(page)) {
896 ret = -PTR_ERR(page);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800897 goto out;
898 }
David Gibson79ac6ba2006-03-22 00:08:51 -0800899 clear_huge_page(page, address);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800900 __SetPageUptodate(page);
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100901
Christoph Lameter6bda6662006-01-06 00:10:49 -0800902 if (vma->vm_flags & VM_SHARED) {
903 int err;
Ken Chen45c682a2007-11-14 16:59:44 -0800904 struct inode *inode = mapping->host;
Christoph Lameter6bda6662006-01-06 00:10:49 -0800905
906 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
907 if (err) {
908 put_page(page);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800909 if (err == -EEXIST)
910 goto retry;
911 goto out;
912 }
Ken Chen45c682a2007-11-14 16:59:44 -0800913
914 spin_lock(&inode->i_lock);
915 inode->i_blocks += BLOCKS_PER_HUGEPAGE;
916 spin_unlock(&inode->i_lock);
Christoph Lameter6bda6662006-01-06 00:10:49 -0800917 } else
918 lock_page(page);
919 }
David Gibson1e8f8892006-01-06 00:10:44 -0800920
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100921 spin_lock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700922 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
923 if (idx >= size)
924 goto backout;
925
Nick Piggin83c54072007-07-19 01:47:05 -0700926 ret = 0;
Adam Litke86e52162006-01-06 00:10:43 -0800927 if (!pte_none(*ptep))
Adam Litke4c887262005-10-29 18:16:46 -0700928 goto backout;
929
David Gibson1e8f8892006-01-06 00:10:44 -0800930 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
931 && (vma->vm_flags & VM_SHARED)));
932 set_huge_pte_at(mm, address, ptep, new_pte);
933
934 if (write_access && !(vma->vm_flags & VM_SHARED)) {
935 /* Optimization, do the COW without a second fault */
936 ret = hugetlb_cow(mm, vma, address, ptep, new_pte);
937 }
938
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100939 spin_unlock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700940 unlock_page(page);
941out:
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100942 return ret;
Adam Litke4c887262005-10-29 18:16:46 -0700943
944backout:
945 spin_unlock(&mm->page_table_lock);
Adam Litke4c887262005-10-29 18:16:46 -0700946 unlock_page(page);
947 put_page(page);
948 goto out;
Hugh Dickinsac9b9c62005-10-20 16:24:28 +0100949}
950
Adam Litke86e52162006-01-06 00:10:43 -0800951int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
952 unsigned long address, int write_access)
953{
954 pte_t *ptep;
955 pte_t entry;
David Gibson1e8f8892006-01-06 00:10:44 -0800956 int ret;
David Gibson3935baa2006-03-22 00:08:53 -0800957 static DEFINE_MUTEX(hugetlb_instantiation_mutex);
Adam Litke86e52162006-01-06 00:10:43 -0800958
959 ptep = huge_pte_alloc(mm, address);
960 if (!ptep)
961 return VM_FAULT_OOM;
962
David Gibson3935baa2006-03-22 00:08:53 -0800963 /*
964 * Serialize hugepage allocation and instantiation, so that we don't
965 * get spurious allocation failures if two CPUs race to instantiate
966 * the same page in the page cache.
967 */
968 mutex_lock(&hugetlb_instantiation_mutex);
Adam Litke86e52162006-01-06 00:10:43 -0800969 entry = *ptep;
David Gibson3935baa2006-03-22 00:08:53 -0800970 if (pte_none(entry)) {
971 ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
972 mutex_unlock(&hugetlb_instantiation_mutex);
973 return ret;
974 }
Adam Litke86e52162006-01-06 00:10:43 -0800975
Nick Piggin83c54072007-07-19 01:47:05 -0700976 ret = 0;
David Gibson1e8f8892006-01-06 00:10:44 -0800977
978 spin_lock(&mm->page_table_lock);
979 /* Check for a racing update before calling hugetlb_cow */
980 if (likely(pte_same(entry, *ptep)))
981 if (write_access && !pte_write(entry))
982 ret = hugetlb_cow(mm, vma, address, ptep, entry);
983 spin_unlock(&mm->page_table_lock);
David Gibson3935baa2006-03-22 00:08:53 -0800984 mutex_unlock(&hugetlb_instantiation_mutex);
David Gibson1e8f8892006-01-06 00:10:44 -0800985
986 return ret;
Adam Litke86e52162006-01-06 00:10:43 -0800987}
988
David Gibson63551ae2005-06-21 17:14:44 -0700989int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
990 struct page **pages, struct vm_area_struct **vmas,
Adam Litke5b23dbe2007-11-14 16:59:33 -0800991 unsigned long *position, int *length, int i,
992 int write)
David Gibson63551ae2005-06-21 17:14:44 -0700993{
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -0800994 unsigned long pfn_offset;
995 unsigned long vaddr = *position;
David Gibson63551ae2005-06-21 17:14:44 -0700996 int remainder = *length;
997
Hugh Dickins1c598272005-10-19 21:23:43 -0700998 spin_lock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -0700999 while (vaddr < vma->vm_end && remainder) {
Adam Litke4c887262005-10-29 18:16:46 -07001000 pte_t *pte;
1001 struct page *page;
1002
1003 /*
1004 * Some archs (sparc64, sh*) have multiple pte_ts to
1005 * each hugepage. We have to make * sure we get the
1006 * first, for the page indexing below to work.
1007 */
1008 pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
1009
Adam Litke72fad712007-12-10 15:49:28 -08001010 if (!pte || pte_none(*pte) || (write && !pte_write(*pte))) {
Adam Litke4c887262005-10-29 18:16:46 -07001011 int ret;
1012
1013 spin_unlock(&mm->page_table_lock);
Adam Litke5b23dbe2007-11-14 16:59:33 -08001014 ret = hugetlb_fault(mm, vma, vaddr, write);
Adam Litke4c887262005-10-29 18:16:46 -07001015 spin_lock(&mm->page_table_lock);
Adam Litkea89182c2007-08-22 14:01:51 -07001016 if (!(ret & VM_FAULT_ERROR))
Adam Litke4c887262005-10-29 18:16:46 -07001017 continue;
1018
1019 remainder = 0;
1020 if (!i)
1021 i = -EFAULT;
1022 break;
1023 }
David Gibson63551ae2005-06-21 17:14:44 -07001024
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001025 pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT;
1026 page = pte_page(*pte);
1027same_page:
Chen, Kenneth Wd6692182006-03-31 02:29:57 -08001028 if (pages) {
1029 get_page(page);
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001030 pages[i] = page + pfn_offset;
Chen, Kenneth Wd6692182006-03-31 02:29:57 -08001031 }
David Gibson63551ae2005-06-21 17:14:44 -07001032
1033 if (vmas)
1034 vmas[i] = vma;
1035
1036 vaddr += PAGE_SIZE;
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001037 ++pfn_offset;
David Gibson63551ae2005-06-21 17:14:44 -07001038 --remainder;
1039 ++i;
Chen, Kenneth Wd5d4b0a2006-03-22 00:09:03 -08001040 if (vaddr < vma->vm_end && remainder &&
1041 pfn_offset < HPAGE_SIZE/PAGE_SIZE) {
1042 /*
1043 * We use pfn_offset to avoid touching the pageframes
1044 * of this compound page.
1045 */
1046 goto same_page;
1047 }
David Gibson63551ae2005-06-21 17:14:44 -07001048 }
Hugh Dickins1c598272005-10-19 21:23:43 -07001049 spin_unlock(&mm->page_table_lock);
David Gibson63551ae2005-06-21 17:14:44 -07001050 *length = remainder;
1051 *position = vaddr;
1052
1053 return i;
1054}
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001055
1056void hugetlb_change_protection(struct vm_area_struct *vma,
1057 unsigned long address, unsigned long end, pgprot_t newprot)
1058{
1059 struct mm_struct *mm = vma->vm_mm;
1060 unsigned long start = address;
1061 pte_t *ptep;
1062 pte_t pte;
1063
1064 BUG_ON(address >= end);
1065 flush_cache_range(vma, address, end);
1066
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001067 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001068 spin_lock(&mm->page_table_lock);
1069 for (; address < end; address += HPAGE_SIZE) {
1070 ptep = huge_pte_offset(mm, address);
1071 if (!ptep)
1072 continue;
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001073 if (huge_pmd_unshare(mm, &address, ptep))
1074 continue;
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001075 if (!pte_none(*ptep)) {
1076 pte = huge_ptep_get_and_clear(mm, address, ptep);
1077 pte = pte_mkhuge(pte_modify(pte, newprot));
1078 set_huge_pte_at(mm, address, ptep, pte);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001079 }
1080 }
1081 spin_unlock(&mm->page_table_lock);
Chen, Kenneth W39dde652006-12-06 20:32:03 -08001082 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
Zhang, Yanmin8f860592006-03-22 00:08:50 -08001083
1084 flush_tlb_range(vma, start, end);
1085}
1086
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001087struct file_region {
1088 struct list_head link;
1089 long from;
1090 long to;
1091};
1092
1093static long region_add(struct list_head *head, long f, long t)
1094{
1095 struct file_region *rg, *nrg, *trg;
1096
1097 /* Locate the region we are either in or before. */
1098 list_for_each_entry(rg, head, link)
1099 if (f <= rg->to)
1100 break;
1101
1102 /* Round our left edge to the current segment if it encloses us. */
1103 if (f > rg->from)
1104 f = rg->from;
1105
1106 /* Check for and consume any regions we now overlap with. */
1107 nrg = rg;
1108 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
1109 if (&rg->link == head)
1110 break;
1111 if (rg->from > t)
1112 break;
1113
1114 /* If this area reaches higher then extend our area to
1115 * include it completely. If this is not the first area
1116 * which we intend to reuse, free it. */
1117 if (rg->to > t)
1118 t = rg->to;
1119 if (rg != nrg) {
1120 list_del(&rg->link);
1121 kfree(rg);
1122 }
1123 }
1124 nrg->from = f;
1125 nrg->to = t;
1126 return 0;
1127}
1128
1129static long region_chg(struct list_head *head, long f, long t)
1130{
1131 struct file_region *rg, *nrg;
1132 long chg = 0;
1133
1134 /* Locate the region we are before or in. */
1135 list_for_each_entry(rg, head, link)
1136 if (f <= rg->to)
1137 break;
1138
1139 /* If we are below the current region then a new region is required.
1140 * Subtle, allocate a new region at the position but make it zero
Simon Arlott183ff222007-10-20 01:27:18 +02001141 * size such that we can guarantee to record the reservation. */
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001142 if (&rg->link == head || t < rg->from) {
1143 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
Stephen Hemmingerc80544d2007-10-18 03:07:05 -07001144 if (!nrg)
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001145 return -ENOMEM;
1146 nrg->from = f;
1147 nrg->to = f;
1148 INIT_LIST_HEAD(&nrg->link);
1149 list_add(&nrg->link, rg->link.prev);
1150
1151 return t - f;
1152 }
1153
1154 /* Round our left edge to the current segment if it encloses us. */
1155 if (f > rg->from)
1156 f = rg->from;
1157 chg = t - f;
1158
1159 /* Check for and consume any regions we now overlap with. */
1160 list_for_each_entry(rg, rg->link.prev, link) {
1161 if (&rg->link == head)
1162 break;
1163 if (rg->from > t)
1164 return chg;
1165
1166 /* We overlap with this area, if it extends futher than
1167 * us then we must extend ourselves. Account for its
1168 * existing reservation. */
1169 if (rg->to > t) {
1170 chg += rg->to - t;
1171 t = rg->to;
1172 }
1173 chg -= rg->to - rg->from;
1174 }
1175 return chg;
1176}
1177
1178static long region_truncate(struct list_head *head, long end)
1179{
1180 struct file_region *rg, *trg;
1181 long chg = 0;
1182
1183 /* Locate the region we are either in or before. */
1184 list_for_each_entry(rg, head, link)
1185 if (end <= rg->to)
1186 break;
1187 if (&rg->link == head)
1188 return 0;
1189
1190 /* If we are in the middle of a region then adjust it. */
1191 if (end > rg->from) {
1192 chg = rg->to - end;
1193 rg->to = end;
1194 rg = list_entry(rg->link.next, typeof(*rg), link);
1195 }
1196
1197 /* Drop any remaining regions. */
1198 list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
1199 if (&rg->link == head)
1200 break;
1201 chg += rg->to - rg->from;
1202 list_del(&rg->link);
1203 kfree(rg);
1204 }
1205 return chg;
1206}
1207
1208static int hugetlb_acct_memory(long delta)
1209{
1210 int ret = -ENOMEM;
1211
1212 spin_lock(&hugetlb_lock);
Ken Chen8a630112007-05-09 02:33:34 -07001213 /*
1214 * When cpuset is configured, it breaks the strict hugetlb page
1215 * reservation as the accounting is done on a global variable. Such
1216 * reservation is completely rubbish in the presence of cpuset because
1217 * the reservation is not checked against page availability for the
1218 * current cpuset. Application can still potentially OOM'ed by kernel
1219 * with lack of free htlb page in cpuset that the task is in.
1220 * Attempt to enforce strict accounting with cpuset is almost
1221 * impossible (or too ugly) because cpuset is too fluid that
1222 * task or memory node can be dynamically moved between cpusets.
1223 *
1224 * The change of semantics for shared hugetlb mapping with cpuset is
1225 * undesirable. However, in order to preserve some of the semantics,
1226 * we fall back to check against current free page availability as
1227 * a best attempt and hopefully to minimize the impact of changing
1228 * semantics that cpuset has.
1229 */
Adam Litkee4e574b2007-10-16 01:26:19 -07001230 if (delta > 0) {
1231 if (gather_surplus_pages(delta) < 0)
1232 goto out;
1233
Adam Litkeac09b3a2008-03-04 14:29:38 -08001234 if (delta > cpuset_mems_nr(free_huge_pages_node)) {
1235 return_unused_surplus_pages(delta);
Adam Litkee4e574b2007-10-16 01:26:19 -07001236 goto out;
Adam Litkeac09b3a2008-03-04 14:29:38 -08001237 }
Adam Litkee4e574b2007-10-16 01:26:19 -07001238 }
1239
1240 ret = 0;
Adam Litkee4e574b2007-10-16 01:26:19 -07001241 if (delta < 0)
1242 return_unused_surplus_pages((unsigned long) -delta);
1243
1244out:
1245 spin_unlock(&hugetlb_lock);
1246 return ret;
1247}
1248
1249int hugetlb_reserve_pages(struct inode *inode, long from, long to)
1250{
1251 long ret, chg;
1252
1253 chg = region_chg(&inode->i_mapping->private_list, from, to);
1254 if (chg < 0)
1255 return chg;
Ken Chen8a630112007-05-09 02:33:34 -07001256
Adam Litke90d8b7e2007-11-14 16:59:42 -08001257 if (hugetlb_get_quota(inode->i_mapping, chg))
1258 return -ENOSPC;
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001259 ret = hugetlb_acct_memory(chg);
Ken Chen68842c92008-01-14 00:55:19 -08001260 if (ret < 0) {
1261 hugetlb_put_quota(inode->i_mapping, chg);
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001262 return ret;
Ken Chen68842c92008-01-14 00:55:19 -08001263 }
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001264 region_add(&inode->i_mapping->private_list, from, to);
1265 return 0;
1266}
1267
1268void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
1269{
1270 long chg = region_truncate(&inode->i_mapping->private_list, offset);
Ken Chen45c682a2007-11-14 16:59:44 -08001271
1272 spin_lock(&inode->i_lock);
1273 inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed;
1274 spin_unlock(&inode->i_lock);
1275
Adam Litke90d8b7e2007-11-14 16:59:42 -08001276 hugetlb_put_quota(inode->i_mapping, (chg - freed));
1277 hugetlb_acct_memory(-(chg - freed));
Chen, Kenneth Wa43a8c32006-06-23 02:03:15 -07001278}