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From: Denys Vlasenko <vda.linux@googlemail.com>
To: Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH] xfs: reduce stack usage in xfs_bmap_btalloc()
Date: Sun, 27 Apr 2008 01:45:11 +0200
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Cc: David Chinner <dgc@sgi.com>, xfs@oss.sgi.com,
       Eric Sandeen <sandeen@sandeen.net>, Adrian Bunk <bunk@kernel.org>,
       linux-kernel@vger.kernel.org
References: <200804261651.02078.vda.linux@googlemail.com> <20080426200347.GA21021@infradead.org>
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On Saturday 26 April 2008 22:03, Christoph Hellwig wrote:
> On Sat, Apr 26, 2008 at 04:51:02PM +0200, Denys Vlasenko wrote:
> > Hi David,
> > 
> > This patch reduces xfs_bmap_btalloc() stack usage by 50 bytes
> > by moving part of its body into a helper function.
> > 
> > This results in some variables not taking stack space in
> > xfs_bmap_btalloc() anymore.
> 
> I think this is a good idea, although I'd rather split the function at
> a local boundary.  The patch below (which passes xfsqa) does that
> by splitting out the handling of the most complicated nullfb case
> out.  It probably won't help reducing stack useage as much as yours,
> but it helps beeing able to read the code a little better.

It saves only 16 bytes of stack.
--
vda