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authorHugh Dickins <hugh@veritas.com>2005-09-03 18:54:34 -0400
committerLinus Torvalds <torvalds@evo.osdl.org>2005-09-05 03:05:40 -0400
commit53092a7402f227151a681b0c92ec8598c5618b1a (patch)
treeea482a18567c8b3b1778331ee3c4864e2f4dae6f /mm
parent11d31886dbcb61039ed3789e583d21c6e70960fd (diff)
[PATCH] swap: show span of swap extents
The "Adding %dk swap" message shows the number of swap extents, as a guide to how fragmented the swapfile may be. But a useful further guide is what total extent they span across (sometimes scarily large). And there's no need to keep nr_extents in swap_info: it's unused after the initial message, so save a little space by keeping it on stack. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/swapfile.c44
1 files changed, 30 insertions, 14 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 73521d39e985..d4da84ee3925 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -854,7 +854,6 @@ static void destroy_swap_extents(struct swap_info_struct *sis)
854 list_del(&se->list); 854 list_del(&se->list);
855 kfree(se); 855 kfree(se);
856 } 856 }
857 sis->nr_extents = 0;
858} 857}
859 858
860/* 859/*
@@ -893,8 +892,7 @@ add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
893 new_se->start_block = start_block; 892 new_se->start_block = start_block;
894 893
895 list_add_tail(&new_se->list, &sis->extent_list); 894 list_add_tail(&new_se->list, &sis->extent_list);
896 sis->nr_extents++; 895 return 1;
897 return 0;
898} 896}
899 897
900/* 898/*
@@ -928,7 +926,7 @@ add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
928 * This is extremely effective. The average number of iterations in 926 * This is extremely effective. The average number of iterations in
929 * map_swap_page() has been measured at about 0.3 per page. - akpm. 927 * map_swap_page() has been measured at about 0.3 per page. - akpm.
930 */ 928 */
931static int setup_swap_extents(struct swap_info_struct *sis) 929static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span)
932{ 930{
933 struct inode *inode; 931 struct inode *inode;
934 unsigned blocks_per_page; 932 unsigned blocks_per_page;
@@ -936,11 +934,15 @@ static int setup_swap_extents(struct swap_info_struct *sis)
936 unsigned blkbits; 934 unsigned blkbits;
937 sector_t probe_block; 935 sector_t probe_block;
938 sector_t last_block; 936 sector_t last_block;
937 sector_t lowest_block = -1;
938 sector_t highest_block = 0;
939 int nr_extents = 0;
939 int ret; 940 int ret;
940 941
941 inode = sis->swap_file->f_mapping->host; 942 inode = sis->swap_file->f_mapping->host;
942 if (S_ISBLK(inode->i_mode)) { 943 if (S_ISBLK(inode->i_mode)) {
943 ret = add_swap_extent(sis, 0, sis->max, 0); 944 ret = add_swap_extent(sis, 0, sis->max, 0);
945 *span = sis->pages;
944 goto done; 946 goto done;
945 } 947 }
946 948
@@ -985,19 +987,28 @@ static int setup_swap_extents(struct swap_info_struct *sis)
985 } 987 }
986 } 988 }
987 989
990 first_block >>= (PAGE_SHIFT - blkbits);
991 if (page_no) { /* exclude the header page */
992 if (first_block < lowest_block)
993 lowest_block = first_block;
994 if (first_block > highest_block)
995 highest_block = first_block;
996 }
997
988 /* 998 /*
989 * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks 999 * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
990 */ 1000 */
991 ret = add_swap_extent(sis, page_no, 1, 1001 ret = add_swap_extent(sis, page_no, 1, first_block);
992 first_block >> (PAGE_SHIFT - blkbits)); 1002 if (ret < 0)
993 if (ret)
994 goto out; 1003 goto out;
1004 nr_extents += ret;
995 page_no++; 1005 page_no++;
996 probe_block += blocks_per_page; 1006 probe_block += blocks_per_page;
997reprobe: 1007reprobe:
998 continue; 1008 continue;
999 } 1009 }
1000 ret = 0; 1010 ret = nr_extents;
1011 *span = 1 + highest_block - lowest_block;
1001 if (page_no == 0) 1012 if (page_no == 0)
1002 page_no = 1; /* force Empty message */ 1013 page_no = 1; /* force Empty message */
1003 sis->max = page_no; 1014 sis->max = page_no;
@@ -1265,6 +1276,8 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
1265 union swap_header *swap_header = NULL; 1276 union swap_header *swap_header = NULL;
1266 int swap_header_version; 1277 int swap_header_version;
1267 int nr_good_pages = 0; 1278 int nr_good_pages = 0;
1279 int nr_extents;
1280 sector_t span;
1268 unsigned long maxpages = 1; 1281 unsigned long maxpages = 1;
1269 int swapfilesize; 1282 int swapfilesize;
1270 unsigned short *swap_map; 1283 unsigned short *swap_map;
@@ -1300,7 +1313,6 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
1300 nr_swapfiles = type+1; 1313 nr_swapfiles = type+1;
1301 INIT_LIST_HEAD(&p->extent_list); 1314 INIT_LIST_HEAD(&p->extent_list);
1302 p->flags = SWP_USED; 1315 p->flags = SWP_USED;
1303 p->nr_extents = 0;
1304 p->swap_file = NULL; 1316 p->swap_file = NULL;
1305 p->old_block_size = 0; 1317 p->old_block_size = 0;
1306 p->swap_map = NULL; 1318 p->swap_map = NULL;
@@ -1477,9 +1489,11 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
1477 p->swap_map[0] = SWAP_MAP_BAD; 1489 p->swap_map[0] = SWAP_MAP_BAD;
1478 p->max = maxpages; 1490 p->max = maxpages;
1479 p->pages = nr_good_pages; 1491 p->pages = nr_good_pages;
1480 error = setup_swap_extents(p); 1492 nr_extents = setup_swap_extents(p, &span);
1481 if (error) 1493 if (nr_extents < 0) {
1494 error = nr_extents;
1482 goto bad_swap; 1495 goto bad_swap;
1496 }
1483 nr_good_pages = p->pages; 1497 nr_good_pages = p->pages;
1484 } 1498 }
1485 if (!nr_good_pages) { 1499 if (!nr_good_pages) {
@@ -1494,9 +1508,11 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
1494 p->flags = SWP_ACTIVE; 1508 p->flags = SWP_ACTIVE;
1495 nr_swap_pages += nr_good_pages; 1509 nr_swap_pages += nr_good_pages;
1496 total_swap_pages += nr_good_pages; 1510 total_swap_pages += nr_good_pages;
1497 printk(KERN_INFO "Adding %dk swap on %s. Priority:%d extents:%d\n", 1511
1498 nr_good_pages<<(PAGE_SHIFT-10), name, 1512 printk(KERN_INFO "Adding %dk swap on %s. "
1499 p->prio, p->nr_extents); 1513 "Priority:%d extents:%d across:%lluk\n",
1514 nr_good_pages<<(PAGE_SHIFT-10), name, p->prio,
1515 nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10));
1500 1516
1501 /* insert swap space into swap_list: */ 1517 /* insert swap space into swap_list: */
1502 prev = -1; 1518 prev = -1;