From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andi Kleen <ak@linux.intel.com>
Subject: Re: [patch 1/2] fs: cleanup files_lock
Date: Tue, 16 Mar 2010 07:41:16 -0700
Message-ID: <4B9F988C.6090008@linux.intel.com>
References: <20100316094423.GM2869@laptop>
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Cc: Al Viro <viro@ZenIV.linux.org.uk>,
	Frank Mayhar <fmayhar@google.com>,
	John Stultz <johnstul@us.ibm.com>,
	linux-fsdevel@vger.kernel.org, Greg Kroah-Hartman <gregkh@suse.de>,
	Alan Cox <alan@lxorguk.ukuu.org.uk>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Linus Torvalds <torvalds@linux-foundation.org>
To: Nick Piggin <npiggin@suse.de>
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, Nick Piggin wrote:
> I would like to start sending bits of vfs scalability improvements to
> be reviewed and hopefully merged.
>
> I will start with files_lock. Last time this one came up, it was
> criticised because some hoped to get rid of files list, and because
> it didn't have enough justification of the scalability improvement.
>
> For the first criticism, it isn't any more difficult to rip out if
> we are ever able to remove files list. For the second, I have gathered
> some statistics and written better justification. Andi I believe is
> finding kbuild is becoming limited by files lock on larger systems.

Yes we're seeing files_list lock as the major bottleneck on a 32 CPU Threads
kernel build.

I did a quick review of the patch and it looks good to me.

Acked-by: Andi Kleen <ak@linux.intel.com>

-Andi