From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [rfc][patch] store-free path walking
Date: Mon, 12 Oct 2009 21:26:27 -0400
Message-ID: <20091013012627.GA19089@infradead.org>
References: <20091006064919.GB30316@wotan.suse.de> <20091006101414.GM5216@kernel.dk> <20091006122623.GE30316@wotan.suse.de> <20091006124941.GS5216@kernel.dk> <20091007085849.GN30316@wotan.suse.de> <20091007095657.GB8703@kernel.dk> <20091012035843.GC25882@wotan.suse.de>
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Cc: Jens Axboe <jens.axboe@oracle.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org,
	Ravikiran G Thirumalai <kiran@scalex86.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	samba-technical@lists.samba.org
To: Nick Piggin <npiggin@suse.de>
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On Mon, Oct 12, 2009 at 05:58:43AM +0200, Nick Piggin wrote:
> Tridge, Samba people: measuring vfs performance with dbench
> in my effort to improve Linux vfs scalability has shown up
> the statvfs syscall you make to be the final problematic
> issue for this workload. In particular reading /proc/mounts
> that glibc does to impement it. We could add complexity to
> the kernel to try improving it, or we could extend the
> statfs syscall so glibc can avoid the issue (requiring
> glibc upgrade). But I would like to know whether samba
> really uses statvfs() significantly?

Not sure if it's the reason why Samba uses it, but many portable
applications use statvfs because that is the standardizes one in
XPG / recent Posix while statfs is just a BSD extension Linux picked
up.  So making sure statvfs goes fast is a pretty essential thing.