Re: [Fake patch] Make sysfs_dirent.s_type an unsigned short

[Maneesh Soni <maneesh@in.ibm.com>]

On Fri, Dec 03, 2004 at 04:08:58AM +0000, Adam J. Richter wrote:
> 	Here is a fake patch against my heavily hacked sysfs tree
> to change sysfs_dirent.s_type from an int to an unsigned short.
> It appears next to another unsigned short (s_mode), so it should
> save 4 bytes per sysfs node.
> 
> 	Note that this patch will not apply to a pristine 2.6.10-rc2-bk15
> tree, because I've moved the declaration of struct sysfs_dirent
> from include/linux/sysfs.h to fs/sysfs/sysfs.h in a previous patch.
> 
> 	By the way, I have to sheepishly admit that somehow I previously
> underestimated the size of struct sysfs_dirent.  Only now
> with s_children and s_count removed and s_type shortened to 16 bits
> does sysfs_dirent occupy 32 bytes, according to /proc/slabinfo.
> This does not effect my previous statements about how much memory
> is saved by each of the patches that I've posted.  It just means
> the original amount of memory being used was more.
> 

Looks sane.

Thanks
Maneesh

> --- linux.prev/fs/sysfs/sysfs.h	2004-12-03 11:51:19.000000000 +0800
> +++ linux/fs/sysfs/sysfs.h	2004-12-03 00:51:44.000000000 +0800
> @@ -13,7 +13,7 @@
>  struct sysfs_dirent {
>  	struct list_head	s_sibling;
>  	void 			* s_element;
> -	int			s_type;
> +	unsigned short		s_type;
>  	umode_t			s_mode;
>  	struct dentry		* s_dentry;
>  };
> -

-- 
Maneesh Soni
Linux Technology Center, 
IBM India Software Labs,
Bangalore, India
email: maneesh@in.ibm.com
Phone: 91-80-25044990