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| author | Hugh Dickins <hugh.dickins@tiscali.co.uk> | 2009-12-14 17:58:48 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-15 08:53:16 -0800 |
| commit | 7509765a29cfb1a4c506c09b304aaf3b4111c653 (patch) | |
| tree | 1f2de5381e044b452653a3af0f32e403ffe51931 | |
| parent | aaa468653b4a0d11c603c48d716f765177a5a9e4 (diff) | |
| download | linux-7509765a29cfb1a4c506c09b304aaf3b4111c653.tar.gz linux-7509765a29cfb1a4c506c09b304aaf3b4111c653.tar.bz2 linux-7509765a29cfb1a4c506c09b304aaf3b4111c653.zip | |
swap_info: reorder its fields
Reorder (and comment) the fields of swap_info_struct, to make better
use of its cachelines: it's good for swap_duplicate() in particular
if unsigned int max and swap_map are near the start.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/swap.h | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index ac43d87b89b0..9f0ca325e30d 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -167,21 +167,21 @@ struct swap_info_struct { signed short prio; /* swap priority of this type */ signed char type; /* strange name for an index */ signed char next; /* next type on the swap list */ - struct file *swap_file; - struct block_device *bdev; - struct swap_extent first_swap_extent; - struct swap_extent *curr_swap_extent; - unsigned char *swap_map; - unsigned int lowest_bit; - unsigned int highest_bit; + unsigned int max; /* extent of the swap_map */ + unsigned char *swap_map; /* vmalloc'ed array of usage counts */ + unsigned int lowest_bit; /* index of first free in swap_map */ + unsigned int highest_bit; /* index of last free in swap_map */ + unsigned int pages; /* total of usable pages of swap */ + unsigned int inuse_pages; /* number of those currently in use */ + unsigned int cluster_next; /* likely index for next allocation */ + unsigned int cluster_nr; /* countdown to next cluster search */ unsigned int lowest_alloc; /* while preparing discard cluster */ unsigned int highest_alloc; /* while preparing discard cluster */ - unsigned int cluster_next; - unsigned int cluster_nr; - unsigned int pages; - unsigned int max; - unsigned int inuse_pages; - unsigned int old_block_size; + struct swap_extent *curr_swap_extent; + struct swap_extent first_swap_extent; + struct block_device *bdev; /* swap device or bdev of swap file */ + struct file *swap_file; /* seldom referenced */ + unsigned int old_block_size; /* seldom referenced */ }; struct swap_list_t { |