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>
This commit is contained in:
Hugh Dickins 2009-12-14 17:58:48 -08:00 committed by Linus Torvalds
parent aaa468653b
commit 7509765a29

View File

@ -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 {