From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Subject: Re: [patch 1/2] fs: mnt_want_write speedup Date: Thu, 02 Apr 2009 11:37:20 -0700 Message-ID: <1238697440.8846.46.camel@nimitz> References: <20090310143718.GB15977@wotan.suse.de> <1236809477.30142.83.camel@nimitz> <20090312041334.GB1893@wotan.suse.de> <1237403623.8286.196.camel@nimitz> <20090402182210.GB17175@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Linux Kernel Mailing List , linux-fsdevel@vger.kernel.org, Andrew Morton To: Nick Piggin Return-path: Received: from e8.ny.us.ibm.com ([32.97.182.138]:44820 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756524AbZDBSh2 (ORCPT ); Thu, 2 Apr 2009 14:37:28 -0400 In-Reply-To: <20090402182210.GB17175@wotan.suse.de> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, 2009-04-02 at 20:22 +0200, Nick Piggin wrote: > On Wed, Mar 18, 2009 at 12:13:43PM -0700, Dave Hansen wrote: > > On Thu, 2009-03-12 at 05:13 +0100, Nick Piggin wrote: > > > On Wed, Mar 11, 2009 at 03:11:17PM -0700, Dave Hansen wrote: > > > > I'm feeling a bit better about these, although I am still honestly quite > > > > afraid of the barriers. I also didn't like all the #ifdefs much, but > > > > here's some help on that. > > > > > > FWIW, we have this in suse kernels because page fault performance was > > > so bad compared with SLES10. mnt_want_write & co was I think the 2nd > > > biggest offender for file backed mappings (after pvops). I think we're > > > around parity again even with pvops. > > > > Page faults themselves? Which path was that from? > > Yes. file_update_time. We should be able to use your mnt_clone_write() optimization separate from the mnt_want_write() speedup here, right? -- Dave