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Commit 270ba5f7 authored by Richard Kennedy's avatar Richard Kennedy Committed by Al Viro
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fs: re-order super_block to remove 16 bytes of padding on 64bit builds 



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: default avatarRichard 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
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent f1771ffa

include/linux/fs.h

+6 −6
Original line number Diff line number Diff line
@@ -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"