4
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
5
* Swap reorganised 29.12.95, Stephen Tweedie
8
#include <linux/slab.h>
9
#include <linux/smp_lock.h>
10
#include <linux/kernel_stat.h>
11
#include <linux/swap.h>
12
#include <linux/swapctl.h>
13
#include <linux/blkdev.h> /* for blk_size */
14
#include <linux/vmalloc.h>
15
#include <linux/pagemap.h>
16
#include <linux/shm.h>
18
#include <asm/pgtable.h>
20
spinlock_t swaplock = SPIN_LOCK_UNLOCKED;
21
unsigned int nr_swapfiles;
23
static int swap_overflow;
25
static const char Bad_file[] = "Bad swap file entry ";
26
static const char Unused_file[] = "Unused swap file entry ";
27
static const char Bad_offset[] = "Bad swap offset entry ";
28
static const char Unused_offset[] = "Unused swap offset entry ";
30
struct swap_list_t swap_list = {-1, -1};
32
struct swap_info_struct swap_info[MAX_SWAPFILES];
34
#define SWAPFILE_CLUSTER 256
36
static inline int scan_swap_map(struct swap_info_struct *si)
40
* We try to cluster swap pages by allocating them
41
* sequentially in swap. Once we've allocated
42
* SWAPFILE_CLUSTER pages this way, however, we resort to
43
* first-free allocation, starting a new cluster. This
44
* prevents us from scattering swap pages all over the entire
45
* swap partition, so that we reduce overall disk seek times
46
* between swap pages. -- sct */
48
while (si->cluster_next <= si->highest_bit) {
49
offset = si->cluster_next++;
50
if (si->swap_map[offset])
56
si->cluster_nr = SWAPFILE_CLUSTER;
58
/* try to find an empty (even not aligned) cluster. */
59
offset = si->lowest_bit;
61
if (offset+SWAPFILE_CLUSTER-1 <= si->highest_bit)
64
for (nr = offset; nr < offset+SWAPFILE_CLUSTER; nr++)
68
goto check_next_cluster;
70
/* We found a completly empty cluster, so start
75
/* No luck, so now go finegrined as usual. -Andrea */
76
for (offset = si->lowest_bit; offset <= si->highest_bit ; offset++) {
77
if (si->swap_map[offset])
79
si->lowest_bit = offset+1;
81
if (offset == si->lowest_bit)
83
if (offset == si->highest_bit)
85
if (si->lowest_bit > si->highest_bit) {
86
si->lowest_bit = si->max;
89
si->swap_map[offset] = 1;
91
si->cluster_next = offset+1;
94
si->lowest_bit = si->max;
99
swp_entry_t get_swap_page(void)
101
struct swap_info_struct * p;
102
unsigned long offset;
104
int type, wrapped = 0;
106
entry.val = 0; /* Out of memory */
108
type = swap_list.next;
111
if (nr_swap_pages <= 0)
115
p = &swap_info[type];
116
if ((p->flags & SWP_WRITEOK) == SWP_WRITEOK) {
118
offset = scan_swap_map(p);
119
swap_device_unlock(p);
121
entry = SWP_ENTRY(type,offset);
122
type = swap_info[type].next;
124
p->prio != swap_info[type].prio) {
125
swap_list.next = swap_list.head;
127
swap_list.next = type;
134
if (type < 0 || p->prio != swap_info[type].prio) {
135
type = swap_list.head;
140
goto out; /* out of swap space */
147
static struct swap_info_struct * swap_info_get(swp_entry_t entry)
149
struct swap_info_struct * p;
150
unsigned long offset, type;
154
type = SWP_TYPE(entry);
155
if (type >= nr_swapfiles)
157
p = & swap_info[type];
158
if (!(p->flags & SWP_USED))
160
offset = SWP_OFFSET(entry);
161
if (offset >= p->max)
163
if (!p->swap_map[offset])
166
if (p->prio > swap_info[swap_list.next].prio)
167
swap_list.next = type;
172
printk(KERN_ERR "swap_free: %s%08lx\n", Unused_offset, entry.val);
175
printk(KERN_ERR "swap_free: %s%08lx\n", Bad_offset, entry.val);
178
printk(KERN_ERR "swap_free: %s%08lx\n", Unused_file, entry.val);
181
printk(KERN_ERR "swap_free: %s%08lx\n", Bad_file, entry.val);
186
static void swap_info_put(struct swap_info_struct * p)
188
swap_device_unlock(p);
192
static int swap_entry_free(struct swap_info_struct *p, unsigned long offset)
194
int count = p->swap_map[offset];
196
if (count < SWAP_MAP_MAX) {
198
p->swap_map[offset] = count;
200
if (offset < p->lowest_bit)
201
p->lowest_bit = offset;
202
if (offset > p->highest_bit)
203
p->highest_bit = offset;
211
* Caller has made sure that the swapdevice corresponding to entry
212
* is still around or has not been recycled.
214
void swap_free(swp_entry_t entry)
216
struct swap_info_struct * p;
218
p = swap_info_get(entry);
220
swap_entry_free(p, SWP_OFFSET(entry));
226
* Check if we're the only user of a swap page,
227
* when the page is locked.
229
static int exclusive_swap_page(struct page *page)
232
struct swap_info_struct * p;
235
entry.val = page->index;
236
p = swap_info_get(entry);
238
/* Is the only swap cache user the cache itself? */
239
if (p->swap_map[SWP_OFFSET(entry)] == 1) {
240
/* Recheck the page count with the pagecache lock held.. */
241
spin_lock(&pagecache_lock);
242
if (page_count(page) - !!page->buffers == 2)
244
spin_unlock(&pagecache_lock);
252
* We can use this swap cache entry directly
253
* if there are no other references to it.
255
* Here "exclusive_swap_page()" does the real
256
* work, but we opportunistically check whether
257
* we need to get all the locks first..
259
int can_share_swap_page(struct page *page)
263
if (!PageLocked(page))
265
switch (page_count(page)) {
271
if (!PageSwapCache(page))
273
retval = exclusive_swap_page(page);
276
if (PageReserved(page))
284
* Work out if there are any other processes sharing this
285
* swap cache page. Free it if you can. Return success.
287
int remove_exclusive_swap_page(struct page *page)
290
struct swap_info_struct * p;
293
if (!PageLocked(page))
295
if (!PageSwapCache(page))
297
if (page_count(page) - !!page->buffers != 2) /* 2: us + cache */
300
entry.val = page->index;
301
p = swap_info_get(entry);
305
/* Is the only swap cache user the cache itself? */
307
if (p->swap_map[SWP_OFFSET(entry)] == 1) {
308
/* Recheck the page count with the pagecache lock held.. */
309
spin_lock(&pagecache_lock);
310
if (page_count(page) - !!page->buffers == 2) {
311
__delete_from_swap_cache(page);
315
spin_unlock(&pagecache_lock);
320
block_flushpage(page, 0);
322
page_cache_release(page);
329
* Free the swap entry like above, but also try to
330
* free the page cache entry if it is the last user.
332
void free_swap_and_cache(swp_entry_t entry)
334
struct swap_info_struct * p;
335
struct page *page = NULL;
337
p = swap_info_get(entry);
339
if (swap_entry_free(p, SWP_OFFSET(entry)) == 1)
340
page = find_trylock_page(&swapper_space, entry.val);
344
page_cache_get(page);
345
/* Only cache user (+us), or swap space full? Free it! */
346
if (page_count(page) - !!page->buffers == 2 || vm_swap_full()) {
347
delete_from_swap_cache(page);
351
page_cache_release(page);
356
* The swap entry has been read in advance, and we return 1 to indicate
357
* that the page has been used or is no longer needed.
359
* Always set the resulting pte to be nowrite (the same as COW pages
360
* after one process has exited). We don't know just how many PTEs will
361
* share this swap entry, so be cautious and let do_wp_page work out
362
* what to do if a write is requested later.
364
/* mmlist_lock and vma->vm_mm->page_table_lock are held */
365
static inline void unuse_pte(struct vm_area_struct * vma, unsigned long address,
366
pte_t *dir, swp_entry_t entry, struct page* page)
370
if (likely(pte_to_swp_entry(pte).val != entry.val))
372
if (unlikely(pte_none(pte) || pte_present(pte)))
375
set_pte(dir, pte_mkold(mk_pte(page, vma->vm_page_prot)));
380
/* mmlist_lock and vma->vm_mm->page_table_lock are held */
381
static inline void unuse_pmd(struct vm_area_struct * vma, pmd_t *dir,
382
unsigned long address, unsigned long size, unsigned long offset,
383
swp_entry_t entry, struct page* page)
395
pte = pte_offset(dir, address);
396
offset += address & PMD_MASK;
397
address &= ~PMD_MASK;
398
end = address + size;
402
unuse_pte(vma, offset+address-vma->vm_start, pte, entry, page);
403
address += PAGE_SIZE;
405
} while (address && (address < end));
408
/* mmlist_lock and vma->vm_mm->page_table_lock are held */
409
static inline void unuse_pgd(struct vm_area_struct * vma, pgd_t *dir,
410
unsigned long address, unsigned long size,
411
swp_entry_t entry, struct page* page)
414
unsigned long offset, end;
423
pmd = pmd_offset(dir, address);
424
offset = address & PGDIR_MASK;
425
address &= ~PGDIR_MASK;
426
end = address + size;
427
if (end > PGDIR_SIZE)
432
unuse_pmd(vma, pmd, address, end - address, offset, entry,
434
address = (address + PMD_SIZE) & PMD_MASK;
436
} while (address && (address < end));
439
/* mmlist_lock and vma->vm_mm->page_table_lock are held */
440
static void unuse_vma(struct vm_area_struct * vma, pgd_t *pgdir,
441
swp_entry_t entry, struct page* page)
443
unsigned long start = vma->vm_start, end = vma->vm_end;
448
unuse_pgd(vma, pgdir, start, end - start, entry, page);
449
start = (start + PGDIR_SIZE) & PGDIR_MASK;
451
} while (start && (start < end));
454
static void unuse_process(struct mm_struct * mm,
455
swp_entry_t entry, struct page* page)
457
struct vm_area_struct* vma;
460
* Go through process' page directory.
462
spin_lock(&mm->page_table_lock);
463
for (vma = mm->mmap; vma; vma = vma->vm_next) {
464
pgd_t * pgd = pgd_offset(mm, vma->vm_start);
465
unuse_vma(vma, pgd, entry, page);
467
XENO_flush_page_update_queue();
468
spin_unlock(&mm->page_table_lock);
473
* Scan swap_map from current position to next entry still in use.
474
* Recycle to start on reaching the end, returning 0 when empty.
476
static int find_next_to_unuse(struct swap_info_struct *si, int prev)
483
* No need for swap_device_lock(si) here: we're just looking
484
* for whether an entry is in use, not modifying it; false
485
* hits are okay, and sys_swapoff() has already prevented new
486
* allocations from this area (while holding swap_list_lock()).
495
* No entries in use at top of swap_map,
496
* loop back to start and recheck there.
502
count = si->swap_map[i];
503
if (count && count != SWAP_MAP_BAD)
510
* We completely avoid races by reading each swap page in advance,
511
* and then search for the process using it. All the necessary
512
* page table adjustments can then be made atomically.
514
static int try_to_unuse(unsigned int type)
516
struct swap_info_struct * si = &swap_info[type];
517
struct mm_struct *start_mm;
518
unsigned short *swap_map;
519
unsigned short swcount;
524
int reset_overflow = 0;
528
* When searching mms for an entry, a good strategy is to
529
* start at the first mm we freed the previous entry from
530
* (though actually we don't notice whether we or coincidence
531
* freed the entry). Initialize this start_mm with a hold.
533
* A simpler strategy would be to start at the last mm we
534
* freed the previous entry from; but that would take less
535
* advantage of mmlist ordering (now preserved by swap_out()),
536
* which clusters forked address spaces together, most recent
537
* child immediately after parent. If we race with dup_mmap(),
538
* we very much want to resolve parent before child, otherwise
539
* we may miss some entries: using last mm would invert that.
542
atomic_inc(&init_mm.mm_users);
545
* Keep on scanning until all entries have gone. Usually,
546
* one pass through swap_map is enough, but not necessarily:
547
* mmput() removes mm from mmlist before exit_mmap() and its
548
* zap_page_range(). That's not too bad, those entries are
549
* on their way out, and handled faster there than here.
550
* do_munmap() behaves similarly, taking the range out of mm's
551
* vma list before zap_page_range(). But unfortunately, when
552
* unmapping a part of a vma, it takes the whole out first,
553
* then reinserts what's left after (might even reschedule if
554
* open() method called) - so swap entries may be invisible
555
* to swapoff for a while, then reappear - but that is rare.
557
while ((i = find_next_to_unuse(si, i))) {
559
* Get a page for the entry, using the existing swap
560
* cache page if there is one. Otherwise, get a clean
561
* page and read the swap into it.
563
swap_map = &si->swap_map[i];
564
entry = SWP_ENTRY(type, i);
565
page = read_swap_cache_async(entry);
568
* Either swap_duplicate() failed because entry
569
* has been freed independently, and will not be
570
* reused since sys_swapoff() already disabled
571
* allocation from here, or alloc_page() failed.
580
* Don't hold on to start_mm if it looks like exiting.
582
if (atomic_read(&start_mm->mm_users) == 1) {
585
atomic_inc(&init_mm.mm_users);
589
* Wait for and lock page. When do_swap_page races with
590
* try_to_unuse, do_swap_page can handle the fault much
591
* faster than try_to_unuse can locate the entry. This
592
* apparently redundant "wait_on_page" lets try_to_unuse
593
* defer to do_swap_page in such a case - in some tests,
594
* do_swap_page and try_to_unuse repeatedly compete.
600
* Remove all references to entry, without blocking.
601
* Whenever we reach init_mm, there's no address space
602
* to search, but use it as a reminder to search shmem.
607
flush_page_to_ram(page);
608
if (start_mm == &init_mm)
609
shmem = shmem_unuse(entry, page);
611
unuse_process(start_mm, entry, page);
614
int set_start_mm = (*swap_map >= swcount);
615
struct list_head *p = &start_mm->mmlist;
616
struct mm_struct *new_start_mm = start_mm;
617
struct mm_struct *mm;
619
spin_lock(&mmlist_lock);
620
while (*swap_map > 1 &&
621
(p = p->next) != &start_mm->mmlist) {
622
mm = list_entry(p, struct mm_struct, mmlist);
624
if (mm == &init_mm) {
626
spin_unlock(&mmlist_lock);
627
shmem = shmem_unuse(entry, page);
628
spin_lock(&mmlist_lock);
630
unuse_process(mm, entry, page);
631
if (set_start_mm && *swap_map < swcount) {
636
atomic_inc(&new_start_mm->mm_users);
637
spin_unlock(&mmlist_lock);
639
start_mm = new_start_mm;
643
* How could swap count reach 0x7fff when the maximum
644
* pid is 0x7fff, and there's no way to repeat a swap
645
* page within an mm (except in shmem, where it's the
646
* shared object which takes the reference count)?
647
* We believe SWAP_MAP_MAX cannot occur in Linux 2.4.
649
* If that's wrong, then we should worry more about
650
* exit_mmap() and do_munmap() cases described above:
651
* we might be resetting SWAP_MAP_MAX too early here.
652
* We know "Undead"s can happen, they're okay, so don't
653
* report them; but do report if we reset SWAP_MAP_MAX.
655
if (*swap_map == SWAP_MAP_MAX) {
657
swap_device_lock(si);
660
swap_device_unlock(si);
666
* If a reference remains (rare), we would like to leave
667
* the page in the swap cache; but try_to_swap_out could
668
* then re-duplicate the entry once we drop page lock,
669
* so we might loop indefinitely; also, that page could
670
* not be swapped out to other storage meanwhile. So:
671
* delete from cache even if there's another reference,
672
* after ensuring that the data has been saved to disk -
673
* since if the reference remains (rarer), it will be
674
* read from disk into another page. Splitting into two
675
* pages would be incorrect if swap supported "shared
676
* private" pages, but they are handled by tmpfs files.
678
* Note shmem_unuse already deleted swappage from cache,
679
* unless corresponding filepage found already in cache:
680
* in which case it left swappage in cache, lowered its
681
* swap count to pass quickly through the loops above,
682
* and now we must reincrement count to try again later.
684
if ((*swap_map > 1) && PageDirty(page) && PageSwapCache(page)) {
685
rw_swap_page(WRITE, page);
688
if (PageSwapCache(page)) {
690
swap_duplicate(entry);
692
delete_from_swap_cache(page);
696
* So we could skip searching mms once swap count went
697
* to 1, we did not mark any present ptes as dirty: must
698
* mark page dirty so try_to_swap_out will preserve it.
702
page_cache_release(page);
705
* Make sure that we aren't completely killing
706
* interactive performance. Interruptible check on
707
* signal_pending() would be nice, but changes the spec?
709
if (current->need_resched)
714
if (reset_overflow) {
715
printk(KERN_WARNING "swapoff: cleared swap entry overflow\n");
721
asmlinkage long sys_swapoff(const char * specialfile)
723
struct swap_info_struct * p = NULL;
724
unsigned short *swap_map;
729
if (!capable(CAP_SYS_ADMIN))
732
err = user_path_walk(specialfile, &nd);
739
for (type = swap_list.head; type >= 0; type = swap_info[type].next) {
740
p = swap_info + type;
741
if ((p->flags & SWP_WRITEOK) == SWP_WRITEOK) {
742
if (p->swap_file == nd.dentry)
754
swap_list.head = p->next;
756
swap_info[prev].next = p->next;
758
if (type == swap_list.next) {
759
/* just pick something that's safe... */
760
swap_list.next = swap_list.head;
762
nr_swap_pages -= p->pages;
763
total_swap_pages -= p->pages;
767
err = try_to_unuse(type);
770
/* re-insert swap space back into swap_list */
772
for (prev = -1, i = swap_list.head; i >= 0; prev = i, i = swap_info[i].next)
773
if (p->prio >= swap_info[i].prio)
777
swap_list.head = swap_list.next = p - swap_info;
779
swap_info[prev].next = p - swap_info;
780
nr_swap_pages += p->pages;
781
total_swap_pages += p->pages;
782
p->flags = SWP_WRITEOK;
787
blkdev_put(p->swap_file->d_inode->i_bdev, BDEV_SWAP);
792
nd.mnt = p->swap_vfsmnt;
793
nd.dentry = p->swap_file;
794
p->swap_vfsmnt = NULL;
798
swap_map = p->swap_map;
801
swap_device_unlock(p);
813
int get_swaparea_info(char *buf)
815
char * page = (char *) __get_free_page(GFP_KERNEL);
816
struct swap_info_struct *ptr = swap_info;
817
int i, j, len = 0, usedswap;
822
len += sprintf(buf, "Filename\t\t\tType\t\tSize\tUsed\tPriority\n");
823
for (i = 0 ; i < nr_swapfiles ; i++, ptr++) {
824
if ((ptr->flags & SWP_USED) && ptr->swap_map) {
825
char * path = d_path(ptr->swap_file, ptr->swap_vfsmnt,
828
len += sprintf(buf + len, "%-31s ", path);
830
if (!ptr->swap_device)
831
len += sprintf(buf + len, "file\t\t");
833
len += sprintf(buf + len, "partition\t");
836
for (j = 0; j < ptr->max; ++j)
837
switch (ptr->swap_map[j]) {
844
len += sprintf(buf + len, "%d\t%d\t%d\n", ptr->pages << (PAGE_SHIFT - 10),
845
usedswap << (PAGE_SHIFT - 10), ptr->prio);
848
free_page((unsigned long) page);
852
int is_swap_partition(kdev_t dev) {
853
struct swap_info_struct *ptr = swap_info;
856
for (i = 0 ; i < nr_swapfiles ; i++, ptr++) {
857
if (ptr->flags & SWP_USED)
858
if (ptr->swap_device == dev)
865
* Written 01/25/92 by Simmule Turner, heavily changed by Linus.
867
* The swapon system call
869
asmlinkage long sys_swapon(const char * specialfile, int swap_flags)
871
struct swap_info_struct * p;
873
struct inode * swap_inode;
877
static int least_priority = 0;
878
union swap_header *swap_header = 0;
879
int swap_header_version;
880
int nr_good_pages = 0;
881
unsigned long maxpages = 1;
883
struct block_device *bdev = NULL;
884
unsigned short *swap_map;
886
if (!capable(CAP_SYS_ADMIN))
891
for (type = 0 ; type < nr_swapfiles ; type++,p++)
892
if (!(p->flags & SWP_USED))
895
if (type >= MAX_SWAPFILES) {
899
if (type >= nr_swapfiles)
900
nr_swapfiles = type+1;
903
p->swap_vfsmnt = NULL;
909
p->sdev_lock = SPIN_LOCK_UNLOCKED;
911
if (swap_flags & SWAP_FLAG_PREFER) {
913
(swap_flags & SWAP_FLAG_PRIO_MASK)>>SWAP_FLAG_PRIO_SHIFT;
915
p->prio = --least_priority;
918
error = user_path_walk(specialfile, &nd);
922
p->swap_file = nd.dentry;
923
p->swap_vfsmnt = nd.mnt;
924
swap_inode = nd.dentry->d_inode;
927
if (S_ISBLK(swap_inode->i_mode)) {
928
kdev_t dev = swap_inode->i_rdev;
929
struct block_device_operations *bdops;
932
if (is_mounted(dev)) {
937
p->swap_device = dev;
938
set_blocksize(dev, PAGE_SIZE);
940
bd_acquire(swap_inode);
941
bdev = swap_inode->i_bdev;
942
de = devfs_get_handle_from_inode(swap_inode);
943
bdops = devfs_get_ops(de); /* Increments module use count */
944
if (bdops) bdev->bd_op = bdops;
946
error = blkdev_get(bdev, FMODE_READ|FMODE_WRITE, 0, BDEV_SWAP);
947
devfs_put_ops(de);/*Decrement module use count now we're safe*/
950
set_blocksize(dev, PAGE_SIZE);
952
if (!dev || (blk_size[MAJOR(dev)] &&
953
!blk_size[MAJOR(dev)][MINOR(dev)]))
956
if (blk_size[MAJOR(dev)])
957
swapfilesize = blk_size[MAJOR(dev)][MINOR(dev)]
958
>> (PAGE_SHIFT - 10);
959
} else if (S_ISREG(swap_inode->i_mode))
960
swapfilesize = swap_inode->i_size >> PAGE_SHIFT;
965
for (i = 0 ; i < nr_swapfiles ; i++) {
966
struct swap_info_struct *q = &swap_info[i];
967
if (i == type || !q->swap_file)
969
if (swap_inode->i_mapping == q->swap_file->d_inode->i_mapping)
973
swap_header = (void *) __get_free_page(GFP_USER);
975
printk("Unable to start swapping: out of memory :-)\n");
980
lock_page(virt_to_page(swap_header));
981
rw_swap_page_nolock(READ, SWP_ENTRY(type,0), (char *) swap_header);
983
if (!memcmp("SWAP-SPACE",swap_header->magic.magic,10))
984
swap_header_version = 1;
985
else if (!memcmp("SWAPSPACE2",swap_header->magic.magic,10))
986
swap_header_version = 2;
988
printk("Unable to find swap-space signature\n");
993
switch (swap_header_version) {
995
memset(((char *) swap_header)+PAGE_SIZE-10,0,10);
999
for (i = 1 ; i < 8*PAGE_SIZE ; i++) {
1000
if (test_bit(i,(char *) swap_header)) {
1009
p->swap_map = vmalloc(maxpages * sizeof(short));
1014
for (i = 1 ; i < maxpages ; i++) {
1015
if (test_bit(i,(char *) swap_header))
1018
p->swap_map[i] = SWAP_MAP_BAD;
1023
/* Check the swap header's sub-version and the size of
1024
the swap file and bad block lists */
1025
if (swap_header->info.version != 1) {
1027
"Unable to handle swap header version %d\n",
1028
swap_header->info.version);
1034
maxpages = SWP_OFFSET(SWP_ENTRY(0,~0UL)) - 1;
1035
if (maxpages > swap_header->info.last_page)
1036
maxpages = swap_header->info.last_page;
1037
p->highest_bit = maxpages - 1;
1040
if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES)
1043
/* OK, set up the swap map and apply the bad block list */
1044
if (!(p->swap_map = vmalloc(maxpages * sizeof(short)))) {
1050
memset(p->swap_map, 0, maxpages * sizeof(short));
1051
for (i=0; i<swap_header->info.nr_badpages; i++) {
1052
int page = swap_header->info.badpages[i];
1053
if (page <= 0 || page >= swap_header->info.last_page)
1056
p->swap_map[page] = SWAP_MAP_BAD;
1058
nr_good_pages = swap_header->info.last_page -
1059
swap_header->info.nr_badpages -
1060
1 /* header page */;
1065
if (swapfilesize && maxpages > swapfilesize) {
1067
"Swap area shorter than signature indicates\n");
1071
if (!nr_good_pages) {
1072
printk(KERN_WARNING "Empty swap-file\n");
1076
p->swap_map[0] = SWAP_MAP_BAD;
1078
swap_device_lock(p);
1080
p->flags = SWP_WRITEOK;
1081
p->pages = nr_good_pages;
1082
nr_swap_pages += nr_good_pages;
1083
total_swap_pages += nr_good_pages;
1084
printk(KERN_INFO "Adding Swap: %dk swap-space (priority %d)\n",
1085
nr_good_pages<<(PAGE_SHIFT-10), p->prio);
1087
/* insert swap space into swap_list: */
1089
for (i = swap_list.head; i >= 0; i = swap_info[i].next) {
1090
if (p->prio >= swap_info[i].prio) {
1097
swap_list.head = swap_list.next = p - swap_info;
1099
swap_info[prev].next = p - swap_info;
1101
swap_device_unlock(p);
1107
blkdev_put(bdev, BDEV_SWAP);
1110
swap_map = p->swap_map;
1111
nd.mnt = p->swap_vfsmnt;
1112
nd.dentry = p->swap_file;
1114
p->swap_file = NULL;
1115
p->swap_vfsmnt = NULL;
1118
if (!(swap_flags & SWAP_FLAG_PREFER))
1126
free_page((long) swap_header);
1131
void si_swapinfo(struct sysinfo *val)
1134
unsigned long nr_to_be_unused = 0;
1137
for (i = 0; i < nr_swapfiles; i++) {
1139
if (swap_info[i].flags != SWP_USED)
1141
for (j = 0; j < swap_info[i].max; ++j) {
1142
switch (swap_info[i].swap_map[j]) {
1151
val->freeswap = nr_swap_pages + nr_to_be_unused;
1152
val->totalswap = total_swap_pages + nr_to_be_unused;
1157
* Verify that a swap entry is valid and increment its swap map count.
1159
* Note: if swap_map[] reaches SWAP_MAP_MAX the entries are treated as
1160
* "permanent", but will be reclaimed by the next swapoff.
1162
int swap_duplicate(swp_entry_t entry)
1164
struct swap_info_struct * p;
1165
unsigned long offset, type;
1168
type = SWP_TYPE(entry);
1169
if (type >= nr_swapfiles)
1171
p = type + swap_info;
1172
offset = SWP_OFFSET(entry);
1174
swap_device_lock(p);
1175
if (offset < p->max && p->swap_map[offset]) {
1176
if (p->swap_map[offset] < SWAP_MAP_MAX - 1) {
1177
p->swap_map[offset]++;
1179
} else if (p->swap_map[offset] <= SWAP_MAP_MAX) {
1180
if (swap_overflow++ < 5)
1181
printk(KERN_WARNING "swap_dup: swap entry overflow\n");
1182
p->swap_map[offset] = SWAP_MAP_MAX;
1186
swap_device_unlock(p);
1191
printk(KERN_ERR "swap_dup: %s%08lx\n", Bad_file, entry.val);
1196
* Prior swap_duplicate protects against swap device deletion.
1198
void get_swaphandle_info(swp_entry_t entry, unsigned long *offset,
1199
kdev_t *dev, struct inode **swapf)
1202
struct swap_info_struct *p;
1204
type = SWP_TYPE(entry);
1205
if (type >= nr_swapfiles) {
1206
printk(KERN_ERR "rw_swap_page: %s%08lx\n", Bad_file, entry.val);
1210
p = &swap_info[type];
1211
*offset = SWP_OFFSET(entry);
1212
if (*offset >= p->max && *offset != 0) {
1213
printk(KERN_ERR "rw_swap_page: %s%08lx\n", Bad_offset, entry.val);
1216
if (p->swap_map && !p->swap_map[*offset]) {
1217
printk(KERN_ERR "rw_swap_page: %s%08lx\n", Unused_offset, entry.val);
1220
if (!(p->flags & SWP_USED)) {
1221
printk(KERN_ERR "rw_swap_page: %s%08lx\n", Unused_file, entry.val);
1225
if (p->swap_device) {
1226
*dev = p->swap_device;
1227
} else if (p->swap_file) {
1228
*swapf = p->swap_file->d_inode;
1230
printk(KERN_ERR "rw_swap_page: no swap file or device\n");
1236
* swap_device_lock prevents swap_map being freed. Don't grab an extra
1237
* reference on the swaphandle, it doesn't matter if it becomes unused.
1239
int valid_swaphandles(swp_entry_t entry, unsigned long *offset)
1241
int ret = 0, i = 1 << page_cluster;
1243
struct swap_info_struct *swapdev = SWP_TYPE(entry) + swap_info;
1245
if (!page_cluster) /* no readahead */
1247
toff = (SWP_OFFSET(entry) >> page_cluster) << page_cluster;
1248
if (!toff) /* first page is swap header */
1252
swap_device_lock(swapdev);
1254
/* Don't read-ahead past the end of the swap area */
1255
if (toff >= swapdev->max)
1257
/* Don't read in free or bad pages */
1258
if (!swapdev->swap_map[toff])
1260
if (swapdev->swap_map[toff] == SWAP_MAP_BAD)
1265
swap_device_unlock(swapdev);
added
removed
xenolinux-2.4.25-sparse/mm/swapfile.c
