hugetlb: introduce pud_huge
[linux-2.6.git] / mm / hugetlb.c
1 /*
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>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/nodemask.h>
13 #include <linux/pagemap.h>
14 #include <linux/mempolicy.h>
15 #include <linux/cpuset.h>
16 #include <linux/mutex.h>
17 #include <linux/bootmem.h>
18 #include <linux/sysfs.h>
19
20 #include <asm/page.h>
21 #include <asm/pgtable.h>
22
23 #include <linux/hugetlb.h>
24 #include "internal.h"
25
26 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
27 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
28 unsigned long hugepages_treat_as_movable;
29
30 static int max_hstate;
31 unsigned int default_hstate_idx;
32 struct hstate hstates[HUGE_MAX_HSTATE];
33
34 /* for command line parsing */
35 static struct hstate * __initdata parsed_hstate;
36 static unsigned long __initdata default_hstate_max_huge_pages;
37
38 #define for_each_hstate(h) \
39         for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
40
41 /*
42  * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
43  */
44 static DEFINE_SPINLOCK(hugetlb_lock);
45
46 /*
47  * Region tracking -- allows tracking of reservations and instantiated pages
48  *                    across the pages in a mapping.
49  *
50  * The region data structures are protected by a combination of the mmap_sem
51  * and the hugetlb_instantion_mutex.  To access or modify a region the caller
52  * must either hold the mmap_sem for write, or the mmap_sem for read and
53  * the hugetlb_instantiation mutex:
54  *
55  *      down_write(&mm->mmap_sem);
56  * or
57  *      down_read(&mm->mmap_sem);
58  *      mutex_lock(&hugetlb_instantiation_mutex);
59  */
60 struct file_region {
61         struct list_head link;
62         long from;
63         long to;
64 };
65
66 static long region_add(struct list_head *head, long f, long t)
67 {
68         struct file_region *rg, *nrg, *trg;
69
70         /* Locate the region we are either in or before. */
71         list_for_each_entry(rg, head, link)
72                 if (f <= rg->to)
73                         break;
74
75         /* Round our left edge to the current segment if it encloses us. */
76         if (f > rg->from)
77                 f = rg->from;
78
79         /* Check for and consume any regions we now overlap with. */
80         nrg = rg;
81         list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
82                 if (&rg->link == head)
83                         break;
84                 if (rg->from > t)
85                         break;
86
87                 /* If this area reaches higher then extend our area to
88                  * include it completely.  If this is not the first area
89                  * which we intend to reuse, free it. */
90                 if (rg->to > t)
91                         t = rg->to;
92                 if (rg != nrg) {
93                         list_del(&rg->link);
94                         kfree(rg);
95                 }
96         }
97         nrg->from = f;
98         nrg->to = t;
99         return 0;
100 }
101
102 static long region_chg(struct list_head *head, long f, long t)
103 {
104         struct file_region *rg, *nrg;
105         long chg = 0;
106
107         /* Locate the region we are before or in. */
108         list_for_each_entry(rg, head, link)
109                 if (f <= rg->to)
110                         break;
111
112         /* If we are below the current region then a new region is required.
113          * Subtle, allocate a new region at the position but make it zero
114          * size such that we can guarantee to record the reservation. */
115         if (&rg->link == head || t < rg->from) {
116                 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
117                 if (!nrg)
118                         return -ENOMEM;
119                 nrg->from = f;
120                 nrg->to   = f;
121                 INIT_LIST_HEAD(&nrg->link);
122                 list_add(&nrg->link, rg->link.prev);
123
124                 return t - f;
125         }
126
127         /* Round our left edge to the current segment if it encloses us. */
128         if (f > rg->from)
129                 f = rg->from;
130         chg = t - f;
131
132         /* Check for and consume any regions we now overlap with. */
133         list_for_each_entry(rg, rg->link.prev, link) {
134                 if (&rg->link == head)
135                         break;
136                 if (rg->from > t)
137                         return chg;
138
139                 /* We overlap with this area, if it extends futher than
140                  * us then we must extend ourselves.  Account for its
141                  * existing reservation. */
142                 if (rg->to > t) {
143                         chg += rg->to - t;
144                         t = rg->to;
145                 }
146                 chg -= rg->to - rg->from;
147         }
148         return chg;
149 }
150
151 static long region_truncate(struct list_head *head, long end)
152 {
153         struct file_region *rg, *trg;
154         long chg = 0;
155
156         /* Locate the region we are either in or before. */
157         list_for_each_entry(rg, head, link)
158                 if (end <= rg->to)
159                         break;
160         if (&rg->link == head)
161                 return 0;
162
163         /* If we are in the middle of a region then adjust it. */
164         if (end > rg->from) {
165                 chg = rg->to - end;
166                 rg->to = end;
167                 rg = list_entry(rg->link.next, typeof(*rg), link);
168         }
169
170         /* Drop any remaining regions. */
171         list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
172                 if (&rg->link == head)
173                         break;
174                 chg += rg->to - rg->from;
175                 list_del(&rg->link);
176                 kfree(rg);
177         }
178         return chg;
179 }
180
181 static long region_count(struct list_head *head, long f, long t)
182 {
183         struct file_region *rg;
184         long chg = 0;
185
186         /* Locate each segment we overlap with, and count that overlap. */
187         list_for_each_entry(rg, head, link) {
188                 int seg_from;
189                 int seg_to;
190
191                 if (rg->to <= f)
192                         continue;
193                 if (rg->from >= t)
194                         break;
195
196                 seg_from = max(rg->from, f);
197                 seg_to = min(rg->to, t);
198
199                 chg += seg_to - seg_from;
200         }
201
202         return chg;
203 }
204
205 /*
206  * Convert the address within this vma to the page offset within
207  * the mapping, in pagecache page units; huge pages here.
208  */
209 static pgoff_t vma_hugecache_offset(struct hstate *h,
210                         struct vm_area_struct *vma, unsigned long address)
211 {
212         return ((address - vma->vm_start) >> huge_page_shift(h)) +
213                         (vma->vm_pgoff >> huge_page_order(h));
214 }
215
216 /*
217  * Flags for MAP_PRIVATE reservations.  These are stored in the bottom
218  * bits of the reservation map pointer, which are always clear due to
219  * alignment.
220  */
221 #define HPAGE_RESV_OWNER    (1UL << 0)
222 #define HPAGE_RESV_UNMAPPED (1UL << 1)
223 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
224
225 /*
226  * These helpers are used to track how many pages are reserved for
227  * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
228  * is guaranteed to have their future faults succeed.
229  *
230  * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
231  * the reserve counters are updated with the hugetlb_lock held. It is safe
232  * to reset the VMA at fork() time as it is not in use yet and there is no
233  * chance of the global counters getting corrupted as a result of the values.
234  *
235  * The private mapping reservation is represented in a subtly different
236  * manner to a shared mapping.  A shared mapping has a region map associated
237  * with the underlying file, this region map represents the backing file
238  * pages which have ever had a reservation assigned which this persists even
239  * after the page is instantiated.  A private mapping has a region map
240  * associated with the original mmap which is attached to all VMAs which
241  * reference it, this region map represents those offsets which have consumed
242  * reservation ie. where pages have been instantiated.
243  */
244 static unsigned long get_vma_private_data(struct vm_area_struct *vma)
245 {
246         return (unsigned long)vma->vm_private_data;
247 }
248
249 static void set_vma_private_data(struct vm_area_struct *vma,
250                                                         unsigned long value)
251 {
252         vma->vm_private_data = (void *)value;
253 }
254
255 struct resv_map {
256         struct kref refs;
257         struct list_head regions;
258 };
259
260 struct resv_map *resv_map_alloc(void)
261 {
262         struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
263         if (!resv_map)
264                 return NULL;
265
266         kref_init(&resv_map->refs);
267         INIT_LIST_HEAD(&resv_map->regions);
268
269         return resv_map;
270 }
271
272 void resv_map_release(struct kref *ref)
273 {
274         struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
275
276         /* Clear out any active regions before we release the map. */
277         region_truncate(&resv_map->regions, 0);
278         kfree(resv_map);
279 }
280
281 static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
282 {
283         VM_BUG_ON(!is_vm_hugetlb_page(vma));
284         if (!(vma->vm_flags & VM_SHARED))
285                 return (struct resv_map *)(get_vma_private_data(vma) &
286                                                         ~HPAGE_RESV_MASK);
287         return 0;
288 }
289
290 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
291 {
292         VM_BUG_ON(!is_vm_hugetlb_page(vma));
293         VM_BUG_ON(vma->vm_flags & VM_SHARED);
294
295         set_vma_private_data(vma, (get_vma_private_data(vma) &
296                                 HPAGE_RESV_MASK) | (unsigned long)map);
297 }
298
299 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
300 {
301         VM_BUG_ON(!is_vm_hugetlb_page(vma));
302         VM_BUG_ON(vma->vm_flags & VM_SHARED);
303
304         set_vma_private_data(vma, get_vma_private_data(vma) | flags);
305 }
306
307 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
308 {
309         VM_BUG_ON(!is_vm_hugetlb_page(vma));
310
311         return (get_vma_private_data(vma) & flag) != 0;
312 }
313
314 /* Decrement the reserved pages in the hugepage pool by one */
315 static void decrement_hugepage_resv_vma(struct hstate *h,
316                         struct vm_area_struct *vma)
317 {
318         if (vma->vm_flags & VM_NORESERVE)
319                 return;
320
321         if (vma->vm_flags & VM_SHARED) {
322                 /* Shared mappings always use reserves */
323                 h->resv_huge_pages--;
324         } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
325                 /*
326                  * Only the process that called mmap() has reserves for
327                  * private mappings.
328                  */
329                 h->resv_huge_pages--;
330         }
331 }
332
333 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
334 void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
335 {
336         VM_BUG_ON(!is_vm_hugetlb_page(vma));
337         if (!(vma->vm_flags & VM_SHARED))
338                 vma->vm_private_data = (void *)0;
339 }
340
341 /* Returns true if the VMA has associated reserve pages */
342 static int vma_has_private_reserves(struct vm_area_struct *vma)
343 {
344         if (vma->vm_flags & VM_SHARED)
345                 return 0;
346         if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER))
347                 return 0;
348         return 1;
349 }
350
351 static void clear_huge_page(struct page *page,
352                         unsigned long addr, unsigned long sz)
353 {
354         int i;
355
356         might_sleep();
357         for (i = 0; i < sz/PAGE_SIZE; i++) {
358                 cond_resched();
359                 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
360         }
361 }
362
363 static void copy_huge_page(struct page *dst, struct page *src,
364                            unsigned long addr, struct vm_area_struct *vma)
365 {
366         int i;
367         struct hstate *h = hstate_vma(vma);
368
369         might_sleep();
370         for (i = 0; i < pages_per_huge_page(h); i++) {
371                 cond_resched();
372                 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
373         }
374 }
375
376 static void enqueue_huge_page(struct hstate *h, struct page *page)
377 {
378         int nid = page_to_nid(page);
379         list_add(&page->lru, &h->hugepage_freelists[nid]);
380         h->free_huge_pages++;
381         h->free_huge_pages_node[nid]++;
382 }
383
384 static struct page *dequeue_huge_page(struct hstate *h)
385 {
386         int nid;
387         struct page *page = NULL;
388
389         for (nid = 0; nid < MAX_NUMNODES; ++nid) {
390                 if (!list_empty(&h->hugepage_freelists[nid])) {
391                         page = list_entry(h->hugepage_freelists[nid].next,
392                                           struct page, lru);
393                         list_del(&page->lru);
394                         h->free_huge_pages--;
395                         h->free_huge_pages_node[nid]--;
396                         break;
397                 }
398         }
399         return page;
400 }
401
402 static struct page *dequeue_huge_page_vma(struct hstate *h,
403                                 struct vm_area_struct *vma,
404                                 unsigned long address, int avoid_reserve)
405 {
406         int nid;
407         struct page *page = NULL;
408         struct mempolicy *mpol;
409         nodemask_t *nodemask;
410         struct zonelist *zonelist = huge_zonelist(vma, address,
411                                         htlb_alloc_mask, &mpol, &nodemask);
412         struct zone *zone;
413         struct zoneref *z;
414
415         /*
416          * A child process with MAP_PRIVATE mappings created by their parent
417          * have no page reserves. This check ensures that reservations are
418          * not "stolen". The child may still get SIGKILLed
419          */
420         if (!vma_has_private_reserves(vma) &&
421                         h->free_huge_pages - h->resv_huge_pages == 0)
422                 return NULL;
423
424         /* If reserves cannot be used, ensure enough pages are in the pool */
425         if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
426                 return NULL;
427
428         for_each_zone_zonelist_nodemask(zone, z, zonelist,
429                                                 MAX_NR_ZONES - 1, nodemask) {
430                 nid = zone_to_nid(zone);
431                 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) &&
432                     !list_empty(&h->hugepage_freelists[nid])) {
433                         page = list_entry(h->hugepage_freelists[nid].next,
434                                           struct page, lru);
435                         list_del(&page->lru);
436                         h->free_huge_pages--;
437                         h->free_huge_pages_node[nid]--;
438
439                         if (!avoid_reserve)
440                                 decrement_hugepage_resv_vma(h, vma);
441
442                         break;
443                 }
444         }
445         mpol_cond_put(mpol);
446         return page;
447 }
448
449 static void update_and_free_page(struct hstate *h, struct page *page)
450 {
451         int i;
452
453         h->nr_huge_pages--;
454         h->nr_huge_pages_node[page_to_nid(page)]--;
455         for (i = 0; i < pages_per_huge_page(h); i++) {
456                 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
457                                 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
458                                 1 << PG_private | 1<< PG_writeback);
459         }
460         set_compound_page_dtor(page, NULL);
461         set_page_refcounted(page);
462         arch_release_hugepage(page);
463         __free_pages(page, huge_page_order(h));
464 }
465
466 struct hstate *size_to_hstate(unsigned long size)
467 {
468         struct hstate *h;
469
470         for_each_hstate(h) {
471                 if (huge_page_size(h) == size)
472                         return h;
473         }
474         return NULL;
475 }
476
477 static void free_huge_page(struct page *page)
478 {
479         /*
480          * Can't pass hstate in here because it is called from the
481          * compound page destructor.
482          */
483         struct hstate *h = page_hstate(page);
484         int nid = page_to_nid(page);
485         struct address_space *mapping;
486
487         mapping = (struct address_space *) page_private(page);
488         set_page_private(page, 0);
489         BUG_ON(page_count(page));
490         INIT_LIST_HEAD(&page->lru);
491
492         spin_lock(&hugetlb_lock);
493         if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
494                 update_and_free_page(h, page);
495                 h->surplus_huge_pages--;
496                 h->surplus_huge_pages_node[nid]--;
497         } else {
498                 enqueue_huge_page(h, page);
499         }
500         spin_unlock(&hugetlb_lock);
501         if (mapping)
502                 hugetlb_put_quota(mapping, 1);
503 }
504
505 /*
506  * Increment or decrement surplus_huge_pages.  Keep node-specific counters
507  * balanced by operating on them in a round-robin fashion.
508  * Returns 1 if an adjustment was made.
509  */
510 static int adjust_pool_surplus(struct hstate *h, int delta)
511 {
512         static int prev_nid;
513         int nid = prev_nid;
514         int ret = 0;
515
516         VM_BUG_ON(delta != -1 && delta != 1);
517         do {
518                 nid = next_node(nid, node_online_map);
519                 if (nid == MAX_NUMNODES)
520                         nid = first_node(node_online_map);
521
522                 /* To shrink on this node, there must be a surplus page */
523                 if (delta < 0 && !h->surplus_huge_pages_node[nid])
524                         continue;
525                 /* Surplus cannot exceed the total number of pages */
526                 if (delta > 0 && h->surplus_huge_pages_node[nid] >=
527                                                 h->nr_huge_pages_node[nid])
528                         continue;
529
530                 h->surplus_huge_pages += delta;
531                 h->surplus_huge_pages_node[nid] += delta;
532                 ret = 1;
533                 break;
534         } while (nid != prev_nid);
535
536         prev_nid = nid;
537         return ret;
538 }
539
540 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
541 {
542         set_compound_page_dtor(page, free_huge_page);
543         spin_lock(&hugetlb_lock);
544         h->nr_huge_pages++;
545         h->nr_huge_pages_node[nid]++;
546         spin_unlock(&hugetlb_lock);
547         put_page(page); /* free it into the hugepage allocator */
548 }
549
550 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
551 {
552         struct page *page;
553
554         if (h->order >= MAX_ORDER)
555                 return NULL;
556
557         page = alloc_pages_node(nid,
558                 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
559                                                 __GFP_REPEAT|__GFP_NOWARN,
560                 huge_page_order(h));
561         if (page) {
562                 if (arch_prepare_hugepage(page)) {
563                         __free_pages(page, HUGETLB_PAGE_ORDER);
564                         return NULL;
565                 }
566                 prep_new_huge_page(h, page, nid);
567         }
568
569         return page;
570 }
571
572 /*
573  * Use a helper variable to find the next node and then
574  * copy it back to hugetlb_next_nid afterwards:
575  * otherwise there's a window in which a racer might
576  * pass invalid nid MAX_NUMNODES to alloc_pages_node.
577  * But we don't need to use a spin_lock here: it really
578  * doesn't matter if occasionally a racer chooses the
579  * same nid as we do.  Move nid forward in the mask even
580  * if we just successfully allocated a hugepage so that
581  * the next caller gets hugepages on the next node.
582  */
583 static int hstate_next_node(struct hstate *h)
584 {
585         int next_nid;
586         next_nid = next_node(h->hugetlb_next_nid, node_online_map);
587         if (next_nid == MAX_NUMNODES)
588                 next_nid = first_node(node_online_map);
589         h->hugetlb_next_nid = next_nid;
590         return next_nid;
591 }
592
593 static int alloc_fresh_huge_page(struct hstate *h)
594 {
595         struct page *page;
596         int start_nid;
597         int next_nid;
598         int ret = 0;
599
600         start_nid = h->hugetlb_next_nid;
601
602         do {
603                 page = alloc_fresh_huge_page_node(h, h->hugetlb_next_nid);
604                 if (page)
605                         ret = 1;
606                 next_nid = hstate_next_node(h);
607         } while (!page && h->hugetlb_next_nid != start_nid);
608
609         if (ret)
610                 count_vm_event(HTLB_BUDDY_PGALLOC);
611         else
612                 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
613
614         return ret;
615 }
616
617 static struct page *alloc_buddy_huge_page(struct hstate *h,
618                         struct vm_area_struct *vma, unsigned long address)
619 {
620         struct page *page;
621         unsigned int nid;
622
623         if (h->order >= MAX_ORDER)
624                 return NULL;
625
626         /*
627          * Assume we will successfully allocate the surplus page to
628          * prevent racing processes from causing the surplus to exceed
629          * overcommit
630          *
631          * This however introduces a different race, where a process B
632          * tries to grow the static hugepage pool while alloc_pages() is
633          * called by process A. B will only examine the per-node
634          * counters in determining if surplus huge pages can be
635          * converted to normal huge pages in adjust_pool_surplus(). A
636          * won't be able to increment the per-node counter, until the
637          * lock is dropped by B, but B doesn't drop hugetlb_lock until
638          * no more huge pages can be converted from surplus to normal
639          * state (and doesn't try to convert again). Thus, we have a
640          * case where a surplus huge page exists, the pool is grown, and
641          * the surplus huge page still exists after, even though it
642          * should just have been converted to a normal huge page. This
643          * does not leak memory, though, as the hugepage will be freed
644          * once it is out of use. It also does not allow the counters to
645          * go out of whack in adjust_pool_surplus() as we don't modify
646          * the node values until we've gotten the hugepage and only the
647          * per-node value is checked there.
648          */
649         spin_lock(&hugetlb_lock);
650         if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
651                 spin_unlock(&hugetlb_lock);
652                 return NULL;
653         } else {
654                 h->nr_huge_pages++;
655                 h->surplus_huge_pages++;
656         }
657         spin_unlock(&hugetlb_lock);
658
659         page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
660                                         __GFP_REPEAT|__GFP_NOWARN,
661                                         huge_page_order(h));
662
663         spin_lock(&hugetlb_lock);
664         if (page) {
665                 /*
666                  * This page is now managed by the hugetlb allocator and has
667                  * no users -- drop the buddy allocator's reference.
668                  */
669                 put_page_testzero(page);
670                 VM_BUG_ON(page_count(page));
671                 nid = page_to_nid(page);
672                 set_compound_page_dtor(page, free_huge_page);
673                 /*
674                  * We incremented the global counters already
675                  */
676                 h->nr_huge_pages_node[nid]++;
677                 h->surplus_huge_pages_node[nid]++;
678                 __count_vm_event(HTLB_BUDDY_PGALLOC);
679         } else {
680                 h->nr_huge_pages--;
681                 h->surplus_huge_pages--;
682                 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
683         }
684         spin_unlock(&hugetlb_lock);
685
686         return page;
687 }
688
689 /*
690  * Increase the hugetlb pool such that it can accomodate a reservation
691  * of size 'delta'.
692  */
693 static int gather_surplus_pages(struct hstate *h, int delta)
694 {
695         struct list_head surplus_list;
696         struct page *page, *tmp;
697         int ret, i;
698         int needed, allocated;
699
700         needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
701         if (needed <= 0) {
702                 h->resv_huge_pages += delta;
703                 return 0;
704         }
705
706         allocated = 0;
707         INIT_LIST_HEAD(&surplus_list);
708
709         ret = -ENOMEM;
710 retry:
711         spin_unlock(&hugetlb_lock);
712         for (i = 0; i < needed; i++) {
713                 page = alloc_buddy_huge_page(h, NULL, 0);
714                 if (!page) {
715                         /*
716                          * We were not able to allocate enough pages to
717                          * satisfy the entire reservation so we free what
718                          * we've allocated so far.
719                          */
720                         spin_lock(&hugetlb_lock);
721                         needed = 0;
722                         goto free;
723                 }
724
725                 list_add(&page->lru, &surplus_list);
726         }
727         allocated += needed;
728
729         /*
730          * After retaking hugetlb_lock, we need to recalculate 'needed'
731          * because either resv_huge_pages or free_huge_pages may have changed.
732          */
733         spin_lock(&hugetlb_lock);
734         needed = (h->resv_huge_pages + delta) -
735                         (h->free_huge_pages + allocated);
736         if (needed > 0)
737                 goto retry;
738
739         /*
740          * The surplus_list now contains _at_least_ the number of extra pages
741          * needed to accomodate the reservation.  Add the appropriate number
742          * of pages to the hugetlb pool and free the extras back to the buddy
743          * allocator.  Commit the entire reservation here to prevent another
744          * process from stealing the pages as they are added to the pool but
745          * before they are reserved.
746          */
747         needed += allocated;
748         h->resv_huge_pages += delta;
749         ret = 0;
750 free:
751         /* Free the needed pages to the hugetlb pool */
752         list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
753                 if ((--needed) < 0)
754                         break;
755                 list_del(&page->lru);
756                 enqueue_huge_page(h, page);
757         }
758
759         /* Free unnecessary surplus pages to the buddy allocator */
760         if (!list_empty(&surplus_list)) {
761                 spin_unlock(&hugetlb_lock);
762                 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
763                         list_del(&page->lru);
764                         /*
765                          * The page has a reference count of zero already, so
766                          * call free_huge_page directly instead of using
767                          * put_page.  This must be done with hugetlb_lock
768                          * unlocked which is safe because free_huge_page takes
769                          * hugetlb_lock before deciding how to free the page.
770                          */
771                         free_huge_page(page);
772                 }
773                 spin_lock(&hugetlb_lock);
774         }
775
776         return ret;
777 }
778
779 /*
780  * When releasing a hugetlb pool reservation, any surplus pages that were
781  * allocated to satisfy the reservation must be explicitly freed if they were
782  * never used.
783  */
784 static void return_unused_surplus_pages(struct hstate *h,
785                                         unsigned long unused_resv_pages)
786 {
787         static int nid = -1;
788         struct page *page;
789         unsigned long nr_pages;
790
791         /*
792          * We want to release as many surplus pages as possible, spread
793          * evenly across all nodes. Iterate across all nodes until we
794          * can no longer free unreserved surplus pages. This occurs when
795          * the nodes with surplus pages have no free pages.
796          */
797         unsigned long remaining_iterations = num_online_nodes();
798
799         /* Uncommit the reservation */
800         h->resv_huge_pages -= unused_resv_pages;
801
802         /* Cannot return gigantic pages currently */
803         if (h->order >= MAX_ORDER)
804                 return;
805
806         nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
807
808         while (remaining_iterations-- && nr_pages) {
809                 nid = next_node(nid, node_online_map);
810                 if (nid == MAX_NUMNODES)
811                         nid = first_node(node_online_map);
812
813                 if (!h->surplus_huge_pages_node[nid])
814                         continue;
815
816                 if (!list_empty(&h->hugepage_freelists[nid])) {
817                         page = list_entry(h->hugepage_freelists[nid].next,
818                                           struct page, lru);
819                         list_del(&page->lru);
820                         update_and_free_page(h, page);
821                         h->free_huge_pages--;
822                         h->free_huge_pages_node[nid]--;
823                         h->surplus_huge_pages--;
824                         h->surplus_huge_pages_node[nid]--;
825                         nr_pages--;
826                         remaining_iterations = num_online_nodes();
827                 }
828         }
829 }
830
831 /*
832  * Determine if the huge page at addr within the vma has an associated
833  * reservation.  Where it does not we will need to logically increase
834  * reservation and actually increase quota before an allocation can occur.
835  * Where any new reservation would be required the reservation change is
836  * prepared, but not committed.  Once the page has been quota'd allocated
837  * an instantiated the change should be committed via vma_commit_reservation.
838  * No action is required on failure.
839  */
840 static int vma_needs_reservation(struct hstate *h,
841                         struct vm_area_struct *vma, unsigned long addr)
842 {
843         struct address_space *mapping = vma->vm_file->f_mapping;
844         struct inode *inode = mapping->host;
845
846         if (vma->vm_flags & VM_SHARED) {
847                 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
848                 return region_chg(&inode->i_mapping->private_list,
849                                                         idx, idx + 1);
850
851         } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
852                 return 1;
853
854         } else  {
855                 int err;
856                 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
857                 struct resv_map *reservations = vma_resv_map(vma);
858
859                 err = region_chg(&reservations->regions, idx, idx + 1);
860                 if (err < 0)
861                         return err;
862                 return 0;
863         }
864 }
865 static void vma_commit_reservation(struct hstate *h,
866                         struct vm_area_struct *vma, unsigned long addr)
867 {
868         struct address_space *mapping = vma->vm_file->f_mapping;
869         struct inode *inode = mapping->host;
870
871         if (vma->vm_flags & VM_SHARED) {
872                 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
873                 region_add(&inode->i_mapping->private_list, idx, idx + 1);
874
875         } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
876                 pgoff_t idx = vma_hugecache_offset(h, vma, addr);
877                 struct resv_map *reservations = vma_resv_map(vma);
878
879                 /* Mark this page used in the map. */
880                 region_add(&reservations->regions, idx, idx + 1);
881         }
882 }
883
884 static struct page *alloc_huge_page(struct vm_area_struct *vma,
885                                     unsigned long addr, int avoid_reserve)
886 {
887         struct hstate *h = hstate_vma(vma);
888         struct page *page;
889         struct address_space *mapping = vma->vm_file->f_mapping;
890         struct inode *inode = mapping->host;
891         unsigned int chg;
892
893         /*
894          * Processes that did not create the mapping will have no reserves and
895          * will not have accounted against quota. Check that the quota can be
896          * made before satisfying the allocation
897          * MAP_NORESERVE mappings may also need pages and quota allocated
898          * if no reserve mapping overlaps.
899          */
900         chg = vma_needs_reservation(h, vma, addr);
901         if (chg < 0)
902                 return ERR_PTR(chg);
903         if (chg)
904                 if (hugetlb_get_quota(inode->i_mapping, chg))
905                         return ERR_PTR(-ENOSPC);
906
907         spin_lock(&hugetlb_lock);
908         page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
909         spin_unlock(&hugetlb_lock);
910
911         if (!page) {
912                 page = alloc_buddy_huge_page(h, vma, addr);
913                 if (!page) {
914                         hugetlb_put_quota(inode->i_mapping, chg);
915                         return ERR_PTR(-VM_FAULT_OOM);
916                 }
917         }
918
919         set_page_refcounted(page);
920         set_page_private(page, (unsigned long) mapping);
921
922         vma_commit_reservation(h, vma, addr);
923
924         return page;
925 }
926
927 static __initdata LIST_HEAD(huge_boot_pages);
928
929 struct huge_bootmem_page {
930         struct list_head list;
931         struct hstate *hstate;
932 };
933
934 static int __init alloc_bootmem_huge_page(struct hstate *h)
935 {
936         struct huge_bootmem_page *m;
937         int nr_nodes = nodes_weight(node_online_map);
938
939         while (nr_nodes) {
940                 void *addr;
941
942                 addr = __alloc_bootmem_node_nopanic(
943                                 NODE_DATA(h->hugetlb_next_nid),
944                                 huge_page_size(h), huge_page_size(h), 0);
945
946                 if (addr) {
947                         /*
948                          * Use the beginning of the huge page to store the
949                          * huge_bootmem_page struct (until gather_bootmem
950                          * puts them into the mem_map).
951                          */
952                         m = addr;
953                         if (m)
954                                 goto found;
955                 }
956                 hstate_next_node(h);
957                 nr_nodes--;
958         }
959         return 0;
960
961 found:
962         BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
963         /* Put them into a private list first because mem_map is not up yet */
964         list_add(&m->list, &huge_boot_pages);
965         m->hstate = h;
966         return 1;
967 }
968
969 /* Put bootmem huge pages into the standard lists after mem_map is up */
970 static void __init gather_bootmem_prealloc(void)
971 {
972         struct huge_bootmem_page *m;
973
974         list_for_each_entry(m, &huge_boot_pages, list) {
975                 struct page *page = virt_to_page(m);
976                 struct hstate *h = m->hstate;
977                 __ClearPageReserved(page);
978                 WARN_ON(page_count(page) != 1);
979                 prep_compound_page(page, h->order);
980                 prep_new_huge_page(h, page, page_to_nid(page));
981         }
982 }
983
984 static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
985 {
986         unsigned long i;
987
988         for (i = 0; i < h->max_huge_pages; ++i) {
989                 if (h->order >= MAX_ORDER) {
990                         if (!alloc_bootmem_huge_page(h))
991                                 break;
992                 } else if (!alloc_fresh_huge_page(h))
993                         break;
994         }
995         h->max_huge_pages = i;
996 }
997
998 static void __init hugetlb_init_hstates(void)
999 {
1000         struct hstate *h;
1001
1002         for_each_hstate(h) {
1003                 /* oversize hugepages were init'ed in early boot */
1004                 if (h->order < MAX_ORDER)
1005                         hugetlb_hstate_alloc_pages(h);
1006         }
1007 }
1008
1009 static char * __init memfmt(char *buf, unsigned long n)
1010 {
1011         if (n >= (1UL << 30))
1012                 sprintf(buf, "%lu GB", n >> 30);
1013         else if (n >= (1UL << 20))
1014                 sprintf(buf, "%lu MB", n >> 20);
1015         else
1016                 sprintf(buf, "%lu KB", n >> 10);
1017         return buf;
1018 }
1019
1020 static void __init report_hugepages(void)
1021 {
1022         struct hstate *h;
1023
1024         for_each_hstate(h) {
1025                 char buf[32];
1026                 printk(KERN_INFO "HugeTLB registered %s page size, "
1027                                  "pre-allocated %ld pages\n",
1028                         memfmt(buf, huge_page_size(h)),
1029                         h->free_huge_pages);
1030         }
1031 }
1032
1033 #ifdef CONFIG_SYSCTL
1034 #ifdef CONFIG_HIGHMEM
1035 static void try_to_free_low(struct hstate *h, unsigned long count)
1036 {
1037         int i;
1038
1039         if (h->order >= MAX_ORDER)
1040                 return;
1041
1042         for (i = 0; i < MAX_NUMNODES; ++i) {
1043                 struct page *page, *next;
1044                 struct list_head *freel = &h->hugepage_freelists[i];
1045                 list_for_each_entry_safe(page, next, freel, lru) {
1046                         if (count >= h->nr_huge_pages)
1047                                 return;
1048                         if (PageHighMem(page))
1049                                 continue;
1050                         list_del(&page->lru);
1051                         update_and_free_page(h, page);
1052                         h->free_huge_pages--;
1053                         h->free_huge_pages_node[page_to_nid(page)]--;
1054                 }
1055         }
1056 }
1057 #else
1058 static inline void try_to_free_low(struct hstate *h, unsigned long count)
1059 {
1060 }
1061 #endif
1062
1063 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1064 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count)
1065 {
1066         unsigned long min_count, ret;
1067
1068         if (h->order >= MAX_ORDER)
1069                 return h->max_huge_pages;
1070
1071         /*
1072          * Increase the pool size
1073          * First take pages out of surplus state.  Then make up the
1074          * remaining difference by allocating fresh huge pages.
1075          *
1076          * We might race with alloc_buddy_huge_page() here and be unable
1077          * to convert a surplus huge page to a normal huge page. That is
1078          * not critical, though, it just means the overall size of the
1079          * pool might be one hugepage larger than it needs to be, but
1080          * within all the constraints specified by the sysctls.
1081          */
1082         spin_lock(&hugetlb_lock);
1083         while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1084                 if (!adjust_pool_surplus(h, -1))
1085                         break;
1086         }
1087
1088         while (count > persistent_huge_pages(h)) {
1089                 /*
1090                  * If this allocation races such that we no longer need the
1091                  * page, free_huge_page will handle it by freeing the page
1092                  * and reducing the surplus.
1093                  */
1094                 spin_unlock(&hugetlb_lock);
1095                 ret = alloc_fresh_huge_page(h);
1096                 spin_lock(&hugetlb_lock);
1097                 if (!ret)
1098                         goto out;
1099
1100         }
1101
1102         /*
1103          * Decrease the pool size
1104          * First return free pages to the buddy allocator (being careful
1105          * to keep enough around to satisfy reservations).  Then place
1106          * pages into surplus state as needed so the pool will shrink
1107          * to the desired size as pages become free.
1108          *
1109          * By placing pages into the surplus state independent of the
1110          * overcommit value, we are allowing the surplus pool size to
1111          * exceed overcommit. There are few sane options here. Since
1112          * alloc_buddy_huge_page() is checking the global counter,
1113          * though, we'll note that we're not allowed to exceed surplus
1114          * and won't grow the pool anywhere else. Not until one of the
1115          * sysctls are changed, or the surplus pages go out of use.
1116          */
1117         min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1118         min_count = max(count, min_count);
1119         try_to_free_low(h, min_count);
1120         while (min_count < persistent_huge_pages(h)) {
1121                 struct page *page = dequeue_huge_page(h);
1122                 if (!page)
1123                         break;
1124                 update_and_free_page(h, page);
1125         }
1126         while (count < persistent_huge_pages(h)) {
1127                 if (!adjust_pool_surplus(h, 1))
1128                         break;
1129         }
1130 out:
1131         ret = persistent_huge_pages(h);
1132         spin_unlock(&hugetlb_lock);
1133         return ret;
1134 }
1135
1136 #define HSTATE_ATTR_RO(_name) \
1137         static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1138
1139 #define HSTATE_ATTR(_name) \
1140         static struct kobj_attribute _name##_attr = \
1141                 __ATTR(_name, 0644, _name##_show, _name##_store)
1142
1143 static struct kobject *hugepages_kobj;
1144 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1145
1146 static struct hstate *kobj_to_hstate(struct kobject *kobj)
1147 {
1148         int i;
1149         for (i = 0; i < HUGE_MAX_HSTATE; i++)
1150                 if (hstate_kobjs[i] == kobj)
1151                         return &hstates[i];
1152         BUG();
1153         return NULL;
1154 }
1155
1156 static ssize_t nr_hugepages_show(struct kobject *kobj,
1157                                         struct kobj_attribute *attr, char *buf)
1158 {
1159         struct hstate *h = kobj_to_hstate(kobj);
1160         return sprintf(buf, "%lu\n", h->nr_huge_pages);
1161 }
1162 static ssize_t nr_hugepages_store(struct kobject *kobj,
1163                 struct kobj_attribute *attr, const char *buf, size_t count)
1164 {
1165         int err;
1166         unsigned long input;
1167         struct hstate *h = kobj_to_hstate(kobj);
1168
1169         err = strict_strtoul(buf, 10, &input);
1170         if (err)
1171                 return 0;
1172
1173         h->max_huge_pages = set_max_huge_pages(h, input);
1174
1175         return count;
1176 }
1177 HSTATE_ATTR(nr_hugepages);
1178
1179 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1180                                         struct kobj_attribute *attr, char *buf)
1181 {
1182         struct hstate *h = kobj_to_hstate(kobj);
1183         return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1184 }
1185 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1186                 struct kobj_attribute *attr, const char *buf, size_t count)
1187 {
1188         int err;
1189         unsigned long input;
1190         struct hstate *h = kobj_to_hstate(kobj);
1191
1192         err = strict_strtoul(buf, 10, &input);
1193         if (err)
1194                 return 0;
1195
1196         spin_lock(&hugetlb_lock);
1197         h->nr_overcommit_huge_pages = input;
1198         spin_unlock(&hugetlb_lock);
1199
1200         return count;
1201 }
1202 HSTATE_ATTR(nr_overcommit_hugepages);
1203
1204 static ssize_t free_hugepages_show(struct kobject *kobj,
1205                                         struct kobj_attribute *attr, char *buf)
1206 {
1207         struct hstate *h = kobj_to_hstate(kobj);
1208         return sprintf(buf, "%lu\n", h->free_huge_pages);
1209 }
1210 HSTATE_ATTR_RO(free_hugepages);
1211
1212 static ssize_t resv_hugepages_show(struct kobject *kobj,
1213                                         struct kobj_attribute *attr, char *buf)
1214 {
1215         struct hstate *h = kobj_to_hstate(kobj);
1216         return sprintf(buf, "%lu\n", h->resv_huge_pages);
1217 }
1218 HSTATE_ATTR_RO(resv_hugepages);
1219
1220 static ssize_t surplus_hugepages_show(struct kobject *kobj,
1221                                         struct kobj_attribute *attr, char *buf)
1222 {
1223         struct hstate *h = kobj_to_hstate(kobj);
1224         return sprintf(buf, "%lu\n", h->surplus_huge_pages);
1225 }
1226 HSTATE_ATTR_RO(surplus_hugepages);
1227
1228 static struct attribute *hstate_attrs[] = {
1229         &nr_hugepages_attr.attr,
1230         &nr_overcommit_hugepages_attr.attr,
1231         &free_hugepages_attr.attr,
1232         &resv_hugepages_attr.attr,
1233         &surplus_hugepages_attr.attr,
1234         NULL,
1235 };
1236
1237 static struct attribute_group hstate_attr_group = {
1238         .attrs = hstate_attrs,
1239 };
1240
1241 static int __init hugetlb_sysfs_add_hstate(struct hstate *h)
1242 {
1243         int retval;
1244
1245         hstate_kobjs[h - hstates] = kobject_create_and_add(h->name,
1246                                                         hugepages_kobj);
1247         if (!hstate_kobjs[h - hstates])
1248                 return -ENOMEM;
1249
1250         retval = sysfs_create_group(hstate_kobjs[h - hstates],
1251                                                         &hstate_attr_group);
1252         if (retval)
1253                 kobject_put(hstate_kobjs[h - hstates]);
1254
1255         return retval;
1256 }
1257
1258 static void __init hugetlb_sysfs_init(void)
1259 {
1260         struct hstate *h;
1261         int err;
1262
1263         hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1264         if (!hugepages_kobj)
1265                 return;
1266
1267         for_each_hstate(h) {
1268                 err = hugetlb_sysfs_add_hstate(h);
1269                 if (err)
1270                         printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
1271                                                                 h->name);
1272         }
1273 }
1274
1275 static void __exit hugetlb_exit(void)
1276 {
1277         struct hstate *h;
1278
1279         for_each_hstate(h) {
1280                 kobject_put(hstate_kobjs[h - hstates]);
1281         }
1282
1283         kobject_put(hugepages_kobj);
1284 }
1285 module_exit(hugetlb_exit);
1286
1287 static int __init hugetlb_init(void)
1288 {
1289         BUILD_BUG_ON(HPAGE_SHIFT == 0);
1290
1291         if (!size_to_hstate(HPAGE_SIZE)) {
1292                 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1293                 parsed_hstate->max_huge_pages = default_hstate_max_huge_pages;
1294         }
1295         default_hstate_idx = size_to_hstate(HPAGE_SIZE) - hstates;
1296
1297         hugetlb_init_hstates();
1298
1299         gather_bootmem_prealloc();
1300
1301         report_hugepages();
1302
1303         hugetlb_sysfs_init();
1304
1305         return 0;
1306 }
1307 module_init(hugetlb_init);
1308
1309 /* Should be called on processing a hugepagesz=... option */
1310 void __init hugetlb_add_hstate(unsigned order)
1311 {
1312         struct hstate *h;
1313         unsigned long i;
1314
1315         if (size_to_hstate(PAGE_SIZE << order)) {
1316                 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
1317                 return;
1318         }
1319         BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
1320         BUG_ON(order == 0);
1321         h = &hstates[max_hstate++];
1322         h->order = order;
1323         h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1324         h->nr_huge_pages = 0;
1325         h->free_huge_pages = 0;
1326         for (i = 0; i < MAX_NUMNODES; ++i)
1327                 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
1328         h->hugetlb_next_nid = first_node(node_online_map);
1329         snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
1330                                         huge_page_size(h)/1024);
1331
1332         parsed_hstate = h;
1333 }
1334
1335 static int __init hugetlb_setup(char *s)
1336 {
1337         unsigned long *mhp;
1338         static unsigned long *last_mhp;
1339
1340         /*
1341          * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
1342          * so this hugepages= parameter goes to the "default hstate".
1343          */
1344         if (!max_hstate)
1345                 mhp = &default_hstate_max_huge_pages;
1346         else
1347                 mhp = &parsed_hstate->max_huge_pages;
1348
1349         if (mhp == last_mhp) {
1350                 printk(KERN_WARNING "hugepages= specified twice without "
1351                         "interleaving hugepagesz=, ignoring\n");
1352                 return 1;
1353         }
1354
1355         if (sscanf(s, "%lu", mhp) <= 0)
1356                 *mhp = 0;
1357
1358         /*
1359          * Global state is always initialized later in hugetlb_init.
1360          * But we need to allocate >= MAX_ORDER hstates here early to still
1361          * use the bootmem allocator.
1362          */
1363         if (max_hstate && parsed_hstate->order >= MAX_ORDER)
1364                 hugetlb_hstate_alloc_pages(parsed_hstate);
1365
1366         last_mhp = mhp;
1367
1368         return 1;
1369 }
1370 __setup("hugepages=", hugetlb_setup);
1371
1372 static unsigned int cpuset_mems_nr(unsigned int *array)
1373 {
1374         int node;
1375         unsigned int nr = 0;
1376
1377         for_each_node_mask(node, cpuset_current_mems_allowed)
1378                 nr += array[node];
1379
1380         return nr;
1381 }
1382
1383 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
1384                            struct file *file, void __user *buffer,
1385                            size_t *length, loff_t *ppos)
1386 {
1387         struct hstate *h = &default_hstate;
1388         unsigned long tmp;
1389
1390         if (!write)
1391                 tmp = h->max_huge_pages;
1392
1393         table->data = &tmp;
1394         table->maxlen = sizeof(unsigned long);
1395         proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
1396
1397         if (write)
1398                 h->max_huge_pages = set_max_huge_pages(h, tmp);
1399
1400         return 0;
1401 }
1402
1403 int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
1404                         struct file *file, void __user *buffer,
1405                         size_t *length, loff_t *ppos)
1406 {
1407         proc_dointvec(table, write, file, buffer, length, ppos);
1408         if (hugepages_treat_as_movable)
1409                 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
1410         else
1411                 htlb_alloc_mask = GFP_HIGHUSER;
1412         return 0;
1413 }
1414
1415 int hugetlb_overcommit_handler(struct ctl_table *table, int write,
1416                         struct file *file, void __user *buffer,
1417                         size_t *length, loff_t *ppos)
1418 {
1419         struct hstate *h = &default_hstate;
1420         unsigned long tmp;
1421
1422         if (!write)
1423                 tmp = h->nr_overcommit_huge_pages;
1424
1425         table->data = &tmp;
1426         table->maxlen = sizeof(unsigned long);
1427         proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
1428
1429         if (write) {
1430                 spin_lock(&hugetlb_lock);
1431                 h->nr_overcommit_huge_pages = tmp;
1432                 spin_unlock(&hugetlb_lock);
1433         }
1434
1435         return 0;
1436 }
1437
1438 #endif /* CONFIG_SYSCTL */
1439
1440 int hugetlb_report_meminfo(char *buf)
1441 {
1442         struct hstate *h = &default_hstate;
1443         return sprintf(buf,
1444                         "HugePages_Total: %5lu\n"
1445                         "HugePages_Free:  %5lu\n"
1446                         "HugePages_Rsvd:  %5lu\n"
1447                         "HugePages_Surp:  %5lu\n"
1448                         "Hugepagesize:    %5lu kB\n",
1449                         h->nr_huge_pages,
1450                         h->free_huge_pages,
1451                         h->resv_huge_pages,
1452                         h->surplus_huge_pages,
1453                         1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
1454 }
1455
1456 int hugetlb_report_node_meminfo(int nid, char *buf)
1457 {
1458         struct hstate *h = &default_hstate;
1459         return sprintf(buf,
1460                 "Node %d HugePages_Total: %5u\n"
1461                 "Node %d HugePages_Free:  %5u\n"
1462                 "Node %d HugePages_Surp:  %5u\n",
1463                 nid, h->nr_huge_pages_node[nid],
1464                 nid, h->free_huge_pages_node[nid],
1465                 nid, h->surplus_huge_pages_node[nid]);
1466 }
1467
1468 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
1469 unsigned long hugetlb_total_pages(void)
1470 {
1471         struct hstate *h = &default_hstate;
1472         return h->nr_huge_pages * pages_per_huge_page(h);
1473 }
1474
1475 static int hugetlb_acct_memory(struct hstate *h, long delta)
1476 {
1477         int ret = -ENOMEM;
1478
1479         spin_lock(&hugetlb_lock);
1480         /*
1481          * When cpuset is configured, it breaks the strict hugetlb page
1482          * reservation as the accounting is done on a global variable. Such
1483          * reservation is completely rubbish in the presence of cpuset because
1484          * the reservation is not checked against page availability for the
1485          * current cpuset. Application can still potentially OOM'ed by kernel
1486          * with lack of free htlb page in cpuset that the task is in.
1487          * Attempt to enforce strict accounting with cpuset is almost
1488          * impossible (or too ugly) because cpuset is too fluid that
1489          * task or memory node can be dynamically moved between cpusets.
1490          *
1491          * The change of semantics for shared hugetlb mapping with cpuset is
1492          * undesirable. However, in order to preserve some of the semantics,
1493          * we fall back to check against current free page availability as
1494          * a best attempt and hopefully to minimize the impact of changing
1495          * semantics that cpuset has.
1496          */
1497         if (delta > 0) {
1498                 if (gather_surplus_pages(h, delta) < 0)
1499                         goto out;
1500
1501                 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
1502                         return_unused_surplus_pages(h, delta);
1503                         goto out;
1504                 }
1505         }
1506
1507         ret = 0;
1508         if (delta < 0)
1509                 return_unused_surplus_pages(h, (unsigned long) -delta);
1510
1511 out:
1512         spin_unlock(&hugetlb_lock);
1513         return ret;
1514 }
1515
1516 static void hugetlb_vm_op_open(struct vm_area_struct *vma)
1517 {
1518         struct resv_map *reservations = vma_resv_map(vma);
1519
1520         /*
1521          * This new VMA should share its siblings reservation map if present.
1522          * The VMA will only ever have a valid reservation map pointer where
1523          * it is being copied for another still existing VMA.  As that VMA
1524          * has a reference to the reservation map it cannot dissappear until
1525          * after this open call completes.  It is therefore safe to take a
1526          * new reference here without additional locking.
1527          */
1528         if (reservations)
1529                 kref_get(&reservations->refs);
1530 }
1531
1532 static void hugetlb_vm_op_close(struct vm_area_struct *vma)
1533 {
1534         struct hstate *h = hstate_vma(vma);
1535         struct resv_map *reservations = vma_resv_map(vma);
1536         unsigned long reserve;
1537         unsigned long start;
1538         unsigned long end;
1539
1540         if (reservations) {
1541                 start = vma_hugecache_offset(h, vma, vma->vm_start);
1542                 end = vma_hugecache_offset(h, vma, vma->vm_end);
1543
1544                 reserve = (end - start) -
1545                         region_count(&reservations->regions, start, end);
1546
1547                 kref_put(&reservations->refs, resv_map_release);
1548
1549                 if (reserve)
1550                         hugetlb_acct_memory(h, -reserve);
1551         }
1552 }
1553
1554 /*
1555  * We cannot handle pagefaults against hugetlb pages at all.  They cause
1556  * handle_mm_fault() to try to instantiate regular-sized pages in the
1557  * hugegpage VMA.  do_page_fault() is supposed to trap this, so BUG is we get
1558  * this far.
1559  */
1560 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1561 {
1562         BUG();
1563         return 0;
1564 }
1565
1566 struct vm_operations_struct hugetlb_vm_ops = {
1567         .fault = hugetlb_vm_op_fault,
1568         .open = hugetlb_vm_op_open,
1569         .close = hugetlb_vm_op_close,
1570 };
1571
1572 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
1573                                 int writable)
1574 {
1575         pte_t entry;
1576
1577         if (writable) {
1578                 entry =
1579                     pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
1580         } else {
1581                 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
1582         }
1583         entry = pte_mkyoung(entry);
1584         entry = pte_mkhuge(entry);
1585
1586         return entry;
1587 }
1588
1589 static void set_huge_ptep_writable(struct vm_area_struct *vma,
1590                                    unsigned long address, pte_t *ptep)
1591 {
1592         pte_t entry;
1593
1594         entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
1595         if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
1596                 update_mmu_cache(vma, address, entry);
1597         }
1598 }
1599
1600
1601 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
1602                             struct vm_area_struct *vma)
1603 {
1604         pte_t *src_pte, *dst_pte, entry;
1605         struct page *ptepage;
1606         unsigned long addr;
1607         int cow;
1608         struct hstate *h = hstate_vma(vma);
1609         unsigned long sz = huge_page_size(h);
1610
1611         cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
1612
1613         for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
1614                 src_pte = huge_pte_offset(src, addr);
1615                 if (!src_pte)
1616                         continue;
1617                 dst_pte = huge_pte_alloc(dst, addr, sz);
1618                 if (!dst_pte)
1619                         goto nomem;
1620
1621                 /* If the pagetables are shared don't copy or take references */
1622                 if (dst_pte == src_pte)
1623                         continue;
1624
1625                 spin_lock(&dst->page_table_lock);
1626                 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
1627                 if (!huge_pte_none(huge_ptep_get(src_pte))) {
1628                         if (cow)
1629                                 huge_ptep_set_wrprotect(src, addr, src_pte);
1630                         entry = huge_ptep_get(src_pte);
1631                         ptepage = pte_page(entry);
1632                         get_page(ptepage);
1633                         set_huge_pte_at(dst, addr, dst_pte, entry);
1634                 }
1635                 spin_unlock(&src->page_table_lock);
1636                 spin_unlock(&dst->page_table_lock);
1637         }
1638         return 0;
1639
1640 nomem:
1641         return -ENOMEM;
1642 }
1643
1644 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
1645                             unsigned long end, struct page *ref_page)
1646 {
1647         struct mm_struct *mm = vma->vm_mm;
1648         unsigned long address;
1649         pte_t *ptep;
1650         pte_t pte;
1651         struct page *page;
1652         struct page *tmp;
1653         struct hstate *h = hstate_vma(vma);
1654         unsigned long sz = huge_page_size(h);
1655
1656         /*
1657          * A page gathering list, protected by per file i_mmap_lock. The
1658          * lock is used to avoid list corruption from multiple unmapping
1659          * of the same page since we are using page->lru.
1660          */
1661         LIST_HEAD(page_list);
1662
1663         WARN_ON(!is_vm_hugetlb_page(vma));
1664         BUG_ON(start & ~huge_page_mask(h));
1665         BUG_ON(end & ~huge_page_mask(h));
1666
1667         spin_lock(&mm->page_table_lock);
1668         for (address = start; address < end; address += sz) {
1669                 ptep = huge_pte_offset(mm, address);
1670                 if (!ptep)
1671                         continue;
1672
1673                 if (huge_pmd_unshare(mm, &address, ptep))
1674                         continue;
1675
1676                 /*
1677                  * If a reference page is supplied, it is because a specific
1678                  * page is being unmapped, not a range. Ensure the page we
1679                  * are about to unmap is the actual page of interest.
1680                  */
1681                 if (ref_page) {
1682                         pte = huge_ptep_get(ptep);
1683                         if (huge_pte_none(pte))
1684                                 continue;
1685                         page = pte_page(pte);
1686                         if (page != ref_page)
1687                                 continue;
1688
1689                         /*
1690                          * Mark the VMA as having unmapped its page so that
1691                          * future faults in this VMA will fail rather than
1692                          * looking like data was lost
1693                          */
1694                         set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
1695                 }
1696
1697                 pte = huge_ptep_get_and_clear(mm, address, ptep);
1698                 if (huge_pte_none(pte))
1699                         continue;
1700
1701                 page = pte_page(pte);
1702                 if (pte_dirty(pte))
1703                         set_page_dirty(page);
1704                 list_add(&page->lru, &page_list);
1705         }
1706         spin_unlock(&mm->page_table_lock);
1707         flush_tlb_range(vma, start, end);
1708         list_for_each_entry_safe(page, tmp, &page_list, lru) {
1709                 list_del(&page->lru);
1710                 put_page(page);
1711         }
1712 }
1713
1714 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
1715                           unsigned long end, struct page *ref_page)
1716 {
1717         spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
1718         __unmap_hugepage_range(vma, start, end, ref_page);
1719         spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
1720 }
1721
1722 /*
1723  * This is called when the original mapper is failing to COW a MAP_PRIVATE
1724  * mappping it owns the reserve page for. The intention is to unmap the page
1725  * from other VMAs and let the children be SIGKILLed if they are faulting the
1726  * same region.
1727  */
1728 int unmap_ref_private(struct mm_struct *mm,
1729                                         struct vm_area_struct *vma,
1730                                         struct page *page,
1731                                         unsigned long address)
1732 {
1733         struct vm_area_struct *iter_vma;
1734         struct address_space *mapping;
1735         struct prio_tree_iter iter;
1736         pgoff_t pgoff;
1737
1738         /*
1739          * vm_pgoff is in PAGE_SIZE units, hence the different calculation
1740          * from page cache lookup which is in HPAGE_SIZE units.
1741          */
1742         address = address & huge_page_mask(hstate_vma(vma));
1743         pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
1744                 + (vma->vm_pgoff >> PAGE_SHIFT);
1745         mapping = (struct address_space *)page_private(page);
1746
1747         vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
1748                 /* Do not unmap the current VMA */
1749                 if (iter_vma == vma)
1750                         continue;
1751
1752                 /*
1753                  * Unmap the page from other VMAs without their own reserves.
1754                  * They get marked to be SIGKILLed if they fault in these
1755                  * areas. This is because a future no-page fault on this VMA
1756                  * could insert a zeroed page instead of the data existing
1757                  * from the time of fork. This would look like data corruption
1758                  */
1759                 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
1760                         unmap_hugepage_range(iter_vma,
1761                                 address, address + HPAGE_SIZE,
1762                                 page);
1763         }
1764
1765         return 1;
1766 }
1767
1768 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
1769                         unsigned long address, pte_t *ptep, pte_t pte,
1770                         struct page *pagecache_page)
1771 {
1772         struct hstate *h = hstate_vma(vma);
1773         struct page *old_page, *new_page;
1774         int avoidcopy;
1775         int outside_reserve = 0;
1776
1777         old_page = pte_page(pte);
1778
1779 retry_avoidcopy:
1780         /* If no-one else is actually using this page, avoid the copy
1781          * and just make the page writable */
1782         avoidcopy = (page_count(old_page) == 1);
1783         if (avoidcopy) {
1784                 set_huge_ptep_writable(vma, address, ptep);
1785                 return 0;
1786         }
1787
1788         /*
1789          * If the process that created a MAP_PRIVATE mapping is about to
1790          * perform a COW due to a shared page count, attempt to satisfy
1791          * the allocation without using the existing reserves. The pagecache
1792          * page is used to determine if the reserve at this address was
1793          * consumed or not. If reserves were used, a partial faulted mapping
1794          * at the time of fork() could consume its reserves on COW instead
1795          * of the full address range.
1796          */
1797         if (!(vma->vm_flags & VM_SHARED) &&
1798                         is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
1799                         old_page != pagecache_page)
1800                 outside_reserve = 1;
1801
1802         page_cache_get(old_page);
1803         new_page = alloc_huge_page(vma, address, outside_reserve);
1804
1805         if (IS_ERR(new_page)) {
1806                 page_cache_release(old_page);
1807
1808                 /*
1809                  * If a process owning a MAP_PRIVATE mapping fails to COW,
1810                  * it is due to references held by a child and an insufficient
1811                  * huge page pool. To guarantee the original mappers
1812                  * reliability, unmap the page from child processes. The child
1813                  * may get SIGKILLed if it later faults.
1814                  */
1815                 if (outside_reserve) {
1816                         BUG_ON(huge_pte_none(pte));
1817                         if (unmap_ref_private(mm, vma, old_page, address)) {
1818                                 BUG_ON(page_count(old_page) != 1);
1819                                 BUG_ON(huge_pte_none(pte));
1820                                 goto retry_avoidcopy;
1821                         }
1822                         WARN_ON_ONCE(1);
1823                 }
1824
1825                 return -PTR_ERR(new_page);
1826         }
1827
1828         spin_unlock(&mm->page_table_lock);
1829         copy_huge_page(new_page, old_page, address, vma);
1830         __SetPageUptodate(new_page);
1831         spin_lock(&mm->page_table_lock);
1832
1833         ptep = huge_pte_offset(mm, address & huge_page_mask(h));
1834         if (likely(pte_same(huge_ptep_get(ptep), pte))) {
1835                 /* Break COW */
1836                 huge_ptep_clear_flush(vma, address, ptep);
1837                 set_huge_pte_at(mm, address, ptep,
1838                                 make_huge_pte(vma, new_page, 1));
1839                 /* Make the old page be freed below */
1840                 new_page = old_page;
1841         }
1842         page_cache_release(new_page);
1843         page_cache_release(old_page);
1844         return 0;
1845 }
1846
1847 /* Return the pagecache page at a given address within a VMA */
1848 static struct page *hugetlbfs_pagecache_page(struct hstate *h,
1849                         struct vm_area_struct *vma, unsigned long address)
1850 {
1851         struct address_space *mapping;
1852         pgoff_t idx;
1853
1854         mapping = vma->vm_file->f_mapping;
1855         idx = vma_hugecache_offset(h, vma, address);
1856
1857         return find_lock_page(mapping, idx);
1858 }
1859
1860 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
1861                         unsigned long address, pte_t *ptep, int write_access)
1862 {
1863         struct hstate *h = hstate_vma(vma);
1864         int ret = VM_FAULT_SIGBUS;
1865         pgoff_t idx;
1866         unsigned long size;
1867         struct page *page;
1868         struct address_space *mapping;
1869         pte_t new_pte;
1870
1871         /*
1872          * Currently, we are forced to kill the process in the event the
1873          * original mapper has unmapped pages from the child due to a failed
1874          * COW. Warn that such a situation has occured as it may not be obvious
1875          */
1876         if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
1877                 printk(KERN_WARNING
1878                         "PID %d killed due to inadequate hugepage pool\n",
1879                         current->pid);
1880                 return ret;
1881         }
1882
1883         mapping = vma->vm_file->f_mapping;
1884         idx = vma_hugecache_offset(h, vma, address);
1885
1886         /*
1887          * Use page lock to guard against racing truncation
1888          * before we get page_table_lock.
1889          */
1890 retry:
1891         page = find_lock_page(mapping, idx);
1892         if (!page) {
1893                 size = i_size_read(mapping->host) >> huge_page_shift(h);
1894                 if (idx >= size)
1895                         goto out;
1896                 page = alloc_huge_page(vma, address, 0);
1897                 if (IS_ERR(page)) {
1898                         ret = -PTR_ERR(page);
1899                         goto out;
1900                 }
1901                 clear_huge_page(page, address, huge_page_size(h));
1902                 __SetPageUptodate(page);
1903
1904                 if (vma->vm_flags & VM_SHARED) {
1905                         int err;
1906                         struct inode *inode = mapping->host;
1907
1908                         err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
1909                         if (err) {
1910                                 put_page(page);
1911                                 if (err == -EEXIST)
1912                                         goto retry;
1913                                 goto out;
1914                         }
1915
1916                         spin_lock(&inode->i_lock);
1917                         inode->i_blocks += blocks_per_huge_page(h);
1918                         spin_unlock(&inode->i_lock);
1919                 } else
1920                         lock_page(page);
1921         }
1922
1923         spin_lock(&mm->page_table_lock);
1924         size = i_size_read(mapping->host) >> huge_page_shift(h);
1925         if (idx >= size)
1926                 goto backout;
1927
1928         ret = 0;
1929         if (!huge_pte_none(huge_ptep_get(ptep)))
1930                 goto backout;
1931
1932         new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
1933                                 && (vma->vm_flags & VM_SHARED)));
1934         set_huge_pte_at(mm, address, ptep, new_pte);
1935
1936         if (write_access && !(vma->vm_flags & VM_SHARED)) {
1937                 /* Optimization, do the COW without a second fault */
1938                 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
1939         }
1940
1941         spin_unlock(&mm->page_table_lock);
1942         unlock_page(page);
1943 out:
1944         return ret;
1945
1946 backout:
1947         spin_unlock(&mm->page_table_lock);
1948         unlock_page(page);
1949         put_page(page);
1950         goto out;
1951 }
1952
1953 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
1954                         unsigned long address, int write_access)
1955 {
1956         pte_t *ptep;
1957         pte_t entry;
1958         int ret;
1959         static DEFINE_MUTEX(hugetlb_instantiation_mutex);
1960         struct hstate *h = hstate_vma(vma);
1961
1962         ptep = huge_pte_alloc(mm, address, huge_page_size(h));
1963         if (!ptep)
1964                 return VM_FAULT_OOM;
1965
1966         /*
1967          * Serialize hugepage allocation and instantiation, so that we don't
1968          * get spurious allocation failures if two CPUs race to instantiate
1969          * the same page in the page cache.
1970          */
1971         mutex_lock(&hugetlb_instantiation_mutex);
1972         entry = huge_ptep_get(ptep);
1973         if (huge_pte_none(entry)) {
1974                 ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
1975                 mutex_unlock(&hugetlb_instantiation_mutex);
1976                 return ret;
1977         }
1978
1979         ret = 0;
1980
1981         spin_lock(&mm->page_table_lock);
1982         /* Check for a racing update before calling hugetlb_cow */
1983         if (likely(pte_same(entry, huge_ptep_get(ptep))))
1984                 if (write_access && !pte_write(entry)) {
1985                         struct page *page;
1986                         page = hugetlbfs_pagecache_page(h, vma, address);
1987                         ret = hugetlb_cow(mm, vma, address, ptep, entry, page);
1988                         if (page) {
1989                                 unlock_page(page);
1990                                 put_page(page);
1991                         }
1992                 }
1993         spin_unlock(&mm->page_table_lock);
1994         mutex_unlock(&hugetlb_instantiation_mutex);
1995
1996         return ret;
1997 }
1998
1999 /* Can be overriden by architectures */
2000 __attribute__((weak)) struct page *
2001 follow_huge_pud(struct mm_struct *mm, unsigned long address,
2002                pud_t *pud, int write)
2003 {
2004         BUG();
2005         return NULL;
2006 }
2007
2008 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
2009                         struct page **pages, struct vm_area_struct **vmas,
2010                         unsigned long *position, int *length, int i,
2011                         int write)
2012 {
2013         unsigned long pfn_offset;
2014         unsigned long vaddr = *position;
2015         int remainder = *length;
2016         struct hstate *h = hstate_vma(vma);
2017
2018         spin_lock(&mm->page_table_lock);
2019         while (vaddr < vma->vm_end && remainder) {
2020                 pte_t *pte;
2021                 struct page *page;
2022
2023                 /*
2024                  * Some archs (sparc64, sh*) have multiple pte_ts to
2025                  * each hugepage.  We have to make * sure we get the
2026                  * first, for the page indexing below to work.
2027                  */
2028                 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
2029
2030                 if (!pte || huge_pte_none(huge_ptep_get(pte)) ||
2031                     (write && !pte_write(huge_ptep_get(pte)))) {
2032                         int ret;
2033
2034                         spin_unlock(&mm->page_table_lock);
2035                         ret = hugetlb_fault(mm, vma, vaddr, write);
2036                         spin_lock(&mm->page_table_lock);
2037                         if (!(ret & VM_FAULT_ERROR))
2038                                 continue;
2039
2040                         remainder = 0;
2041                         if (!i)
2042                                 i = -EFAULT;
2043                         break;
2044                 }
2045
2046                 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
2047                 page = pte_page(huge_ptep_get(pte));
2048 same_page:
2049                 if (pages) {
2050                         get_page(page);
2051                         pages[i] = page + pfn_offset;
2052                 }
2053
2054                 if (vmas)
2055                         vmas[i] = vma;
2056
2057                 vaddr += PAGE_SIZE;
2058                 ++pfn_offset;
2059                 --remainder;
2060                 ++i;
2061                 if (vaddr < vma->vm_end && remainder &&
2062                                 pfn_offset < pages_per_huge_page(h)) {
2063                         /*
2064                          * We use pfn_offset to avoid touching the pageframes
2065                          * of this compound page.
2066                          */
2067                         goto same_page;
2068                 }
2069         }
2070         spin_unlock(&mm->page_table_lock);
2071         *length = remainder;
2072         *position = vaddr;
2073
2074         return i;
2075 }
2076
2077 void hugetlb_change_protection(struct vm_area_struct *vma,
2078                 unsigned long address, unsigned long end, pgprot_t newprot)
2079 {
2080         struct mm_struct *mm = vma->vm_mm;
2081         unsigned long start = address;
2082         pte_t *ptep;
2083         pte_t pte;
2084         struct hstate *h = hstate_vma(vma);
2085
2086         BUG_ON(address >= end);
2087         flush_cache_range(vma, address, end);
2088
2089         spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
2090         spin_lock(&mm->page_table_lock);
2091         for (; address < end; address += huge_page_size(h)) {
2092                 ptep = huge_pte_offset(mm, address);
2093                 if (!ptep)
2094                         continue;
2095                 if (huge_pmd_unshare(mm, &address, ptep))
2096                         continue;
2097                 if (!huge_pte_none(huge_ptep_get(ptep))) {
2098                         pte = huge_ptep_get_and_clear(mm, address, ptep);
2099                         pte = pte_mkhuge(pte_modify(pte, newprot));
2100                         set_huge_pte_at(mm, address, ptep, pte);
2101                 }
2102         }
2103         spin_unlock(&mm->page_table_lock);
2104         spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
2105
2106         flush_tlb_range(vma, start, end);
2107 }
2108
2109 int hugetlb_reserve_pages(struct inode *inode,
2110                                         long from, long to,
2111                                         struct vm_area_struct *vma)
2112 {
2113         long ret, chg;
2114         struct hstate *h = hstate_inode(inode);
2115
2116         if (vma && vma->vm_flags & VM_NORESERVE)
2117                 return 0;
2118
2119         /*
2120          * Shared mappings base their reservation on the number of pages that
2121          * are already allocated on behalf of the file. Private mappings need
2122          * to reserve the full area even if read-only as mprotect() may be
2123          * called to make the mapping read-write. Assume !vma is a shm mapping
2124          */
2125         if (!vma || vma->vm_flags & VM_SHARED)
2126                 chg = region_chg(&inode->i_mapping->private_list, from, to);
2127         else {
2128                 struct resv_map *resv_map = resv_map_alloc();
2129                 if (!resv_map)
2130                         return -ENOMEM;
2131
2132                 chg = to - from;
2133
2134                 set_vma_resv_map(vma, resv_map);
2135                 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
2136         }
2137
2138         if (chg < 0)
2139                 return chg;
2140
2141         if (hugetlb_get_quota(inode->i_mapping, chg))
2142                 return -ENOSPC;
2143         ret = hugetlb_acct_memory(h, chg);
2144         if (ret < 0) {
2145                 hugetlb_put_quota(inode->i_mapping, chg);
2146                 return ret;
2147         }
2148         if (!vma || vma->vm_flags & VM_SHARED)
2149                 region_add(&inode->i_mapping->private_list, from, to);
2150         return 0;
2151 }
2152
2153 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
2154 {
2155         struct hstate *h = hstate_inode(inode);
2156         long chg = region_truncate(&inode->i_mapping->private_list, offset);
2157
2158         spin_lock(&inode->i_lock);
2159         inode->i_blocks -= blocks_per_huge_page(h);
2160         spin_unlock(&inode->i_lock);
2161
2162         hugetlb_put_quota(inode->i_mapping, (chg - freed));
2163         hugetlb_acct_memory(h, -(chg - freed));
2164 }