From mboxrd@z Thu Jan  1 00:00:00 1970
From: Valerie Aurora <vaurora@redhat.com>
Subject: Re: [PATCH 04/41] VFS: Remove unnecessary micro-optimization in cached_lookup()
Date: Thu, 10 Dec 2009 16:25:33 -0500
Message-ID: <20091210212533.GD10388@shell>
References: <1256152779-10054-5-git-send-email-vaurora@redhat.com> <200911300207.nAU27duL007220@agora.fsl.cs.sunysb.edu>
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Cc: Jan Blunck <jblunck@suse.de>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Christoph Hellwig <hch@infradead.org>,
	Andy Whitcroft <apw@canonical.com>,
	Scott James Remnant <scott@canonical.com>,
	Sandu Popa Marius <sandupopamarius@gmail.com>,
	Jan Rekorajski <baggins@sith.mimuw.edu.pl>,
	"J. R. Okajima" <hooanon05@yahoo.co.jp>,
	Arnd Bergmann <arnd@arndb.de>,
	Vladimir Dronnikov <dronnikov@gmail.com>,
	Felix Fietkau <nbd@openwrt.org>, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
To: Erez Zadok <ezk@cs.sunysb.edu>
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On Sun, Nov 29, 2009 at 09:07:39PM -0500, Erez Zadok wrote:
> In message <1256152779-10054-5-git-send-email-vaurora@redhat.com>, Valerie Aurora writes:
> > From: Jan Blunck <jblunck@suse.de>
> > 
> > d_lookup() takes rename_lock which is a seq_lock.  This is so cheap
> > it's not worth calling lockless __d_lookup() first from
> > cache_lookup().  Rename cached_lookup() to cache_lookup() while we're
> > there.
> 
> Val, this is another patch unrelated to union mounts, an
> optimization/simplification of the VFS code.  I think you need to try and
> push such VFS patches upstream more quickly, so as to reduce the set of UM
> patches you have to maintain.

I agree.  We posted them separately once and will do so again.

-VAL