fs: remove 8 bytes of padding from block_device on 64bit builds

From: Richard Kennedy
Date: Mon Feb 14 2011 - 11:39:35 EST


Re-ordering struct block_inode to remove 8 bytes of padding on 64 bit
builds, which also shrinks bdev_inode by 8 bytes (776 -> 768) allowing
it to fit into one fewer cache lines.

Signed-off-by: Richard Kennedy <richard@xxxxxxxxxxxxxxx>
------
patch against v2.6.38-rc4
compiled & tested on x86_64

regards
Richard



diff --git a/include/linux/fs.h b/include/linux/fs.h
index bd32159..7c65780 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -658,9 +658,9 @@ struct address_space {

struct block_device {
dev_t bd_dev; /* not a kdev_t - it's a search key */
+ int bd_openers;
struct inode * bd_inode; /* will die */
struct super_block * bd_super;
- int bd_openers;
struct mutex bd_mutex; /* open/close mutex */
struct list_head bd_inodes;
void * bd_claiming;


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