Re: [patch 2/4] Configure out file locking features

From: Matthew Wilcox
Date: Tue Jul 29 2008 - 14:18:22 EST


On Tue, Jul 29, 2008 at 05:45:22PM +0200, Thomas Petazzoni wrote:
> This patch adds the CONFIG_FILE_LOCKING option which allows to remove
> support for advisory locks. With this patch enabled, the flock()
> system call, the F_GETLK, F_SETLK and F_SETLKW operations of fcntl()
> and NFS support are disabled. These features are not necessarly needed
> on embedded systems. It allows to save ~11 Kb of kernel code and data:
>
> text data bss dec hex filename
> 1125436 118764 212992 1457192 163c28 vmlinux.old
> 1114299 118564 212992 1445855 160fdf vmlinux
> -11137 -200 0 -11337 -2C49 +/-
>
> This patch has originally been written by Matt Mackall
> <mpm@xxxxxxxxxxx>, and is part of the Linux Tiny project.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>

In principle, I think this is a great idea.

> config NFS_FS
> tristate "NFS client support"
> - depends on INET
> + depends on INET && FILE_LOCKING
> select LOCKD
> select SUNRPC
> select NFS_ACL_SUPPORT if NFS_V3_ACL

I think this part is a little lazy. It should be possible to support
NFS without file locking. I suspect that's really not in-scope for the
linux-tiny tree as currently envisaged with the focus on embedded
devices that probably don't use NFS anyway. Do we want to care about
the situation of a machine with fixed workload, that doesn't need file
locking, but does use NFS?

--
Intel are signing my paycheques ... these opinions are still mine
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
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