From efa90a981bbc891efad96db2a75b5487e00852ca Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Mon, 14 Dec 2009 17:58:41 -0800 Subject: swap_info: change to array of pointers The swap_info_struct is only 76 or 104 bytes, but it does seem wrong to reserve an array of about 30 of them in bss, when most people will want only one. Change swap_info[] to an array of pointers. That does need a "type" field in the structure: pack it as a char with next type and short prio (aha, char is unsigned by default on PowerPC). Use the (admittedly peculiar) name "type" throughout for this index. /proc/swaps does not take swap_lock: I wouldn't want it to, but do take care with barriers when adding a new item to the array (never removed). Signed-off-by: Hugh Dickins Reviewed-by: KAMEZAWA Hiroyuki Acked-by: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/swap.h | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'include/linux/swap.h') diff --git a/include/linux/swap.h b/include/linux/swap.h index 82aa7e121c0..f1c248796fb 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -159,9 +159,10 @@ enum { * The in-memory structure used to track swap areas. */ struct swap_info_struct { - unsigned long flags; - int prio; /* swap priority */ - int next; /* next entry on swap list */ + unsigned long flags; /* SWP_USED etc: see above */ + 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 list_head extent_list; -- cgit v1.2.3-70-g09d2