lkml.org 
[lkml]   [2010]   [Jan]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH] fs: re-order super_block to remove 16 bytes of padding on 64bit builds
From
Date
re-order structure super_block to remove 16 bytes of alignment padding
on 64bit builds.

This shrinks the size of super_block from 712 to 696 bytes so requiring
one fewer 64 byte cache lines.

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>

-----
patch against 2.6.33-rc5
compiled & tested on x86_64 AMDX2 desktop machine.

I've been running with this patch applied for several weeks with no
problems.

regards
Richard



diff --git a/include/linux/fs.h b/include/linux/fs.h
index b1bcb27..a2f87ea 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1314,9 +1314,9 @@ extern spinlock_t sb_lock;
struct super_block {
struct list_head s_list; /* Keep this first */
dev_t s_dev; /* search index; _not_ kdev_t */
- unsigned long s_blocksize;
- unsigned char s_blocksize_bits;
unsigned char s_dirt;
+ unsigned char s_blocksize_bits;
+ unsigned long s_blocksize;
loff_t s_maxbytes; /* Max file size */
struct file_system_type *s_type;
const struct super_operations *s_op;
@@ -1357,16 +1357,16 @@ struct super_block {
void *s_fs_info; /* Filesystem private info */
fmode_t s_mode;

+ /* Granularity of c/m/atime in ns.
+ Cannot be worse than a second */
+ u32 s_time_gran;
+
/*
* The next field is for VFS *only*. No filesystems have any business
* even looking at it. You had been warned.
*/
struct mutex s_vfs_rename_mutex; /* Kludge */

- /* Granularity of c/m/atime in ns.
- Cannot be worse than a second */
- u32 s_time_gran;
-
/*
* Filesystem subtype. If non-empty the filesystem type field
* in /proc/mounts will be "type.subtype"



\
 
 \ /
  Last update: 2010-01-26 15:15    [W:0.021 / U:22.584 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site