From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Mackall Subject: Re: [patch 2/4] Configure out file locking features Date: Tue, 29 Jul 2008 13:57:55 -0500 Message-ID: <1217357875.15724.167.camel@calx> References: <20080729154520.728594017@free-electrons.com> > <20080729154747.872888047@free-electrons.com> <20080729181751.GA24924@parisc-linux.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080729181751.GA24924@parisc-linux.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Matthew Wilcox Cc: Thomas Petazzoni , linux-kernel@vger.kernel.org, linux-embedded@vger.kernel.org, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org On Tue, 2008-07-29 at 12:17 -0600, Matthew Wilcox wrote: > 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 > > , and is part of the Linux Tiny project. > > > > Signed-off-by: Thomas Petazzoni > > 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? I would lean towards no, but if someone comes along who cares, they're welcome to try it. This stuff all has to strike a balance between savings and effort/complexity/maintainability, so any time the submitter is too lazy to cover a less common use case, it's probably a good sign they're approaching that tipping point. On the other hand, if you think it's trivial to do a locking-ectomy on NFS, I'd be happy to see it. The typical embedded NFS-based devices are NAS servers and media players and are going to be more concerned about things like page cache balancing. -- Mathematics is the supreme nostalgia of our time.