[Ocfs2-devel] [PATCH] Reoganize data elements to reduce memory footprint

[Joel Becker <Joel.Becker@oracle.com>]

On Wed, Jun 09, 2010 at 05:45:10PM -0700, Joel Becker wrote:
> 	I think you should change l_type, l_action, l_requested,
> l_blocking, and l_level to unsigned char.  While the enums that set them

	I missed l_unlock_action.  That one too.

> should be not modified, they do not have more than 256 values.  All the
> functions around them can use the enum type in their arguments.  Just
> the ocfs2_lock_res itself stores them in unsigned char.
> 	This would potentially save us 15 bytes per ocfs2_lock_res,
> 45 per inode.  More realistic is probably 12 per lock_res and 36 per
> inode, but still!

	So that's 18 bytes per ocfs2_lock_res, 54 per inode.  Of course,
alignment probably costs us 2 per lock_res, so call it 48 per inode of
real savings.  Nice!

Joel

[Thanks to Tao for noticing I missed l_unlock_action]

-- 

"Here's a nickle -- get yourself a better X server."
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Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127