Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758320Ab0GTO04 (ORCPT ); Tue, 20 Jul 2010 10:26:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:2839 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757330Ab0GTO0z (ORCPT ); Tue, 20 Jul 2010 10:26:55 -0400 Date: Tue, 20 Jul 2010 10:26:48 -0400 From: Vivek Goyal To: Christoph Hellwig Cc: Jeff Moyer , Corrado Zoccolo , axboe@kernel.dk, Linux-Kernel Subject: Re: [PATCH 0/2] cfq-iosched: fixing RQ_NOIDLE handling. Message-ID: <20100720142647.GA8967@redhat.com> References: <20100713195650.GA21044@redhat.com> <20100713204236.GB21044@redhat.com> <20100720141102.GA6316@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100720141102.GA6316@infradead.org> User-Agent: Mutt/1.5.20 (2009-12-10) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1091 Lines: 24 On Tue, Jul 20, 2010 at 10:11:03AM -0400, Christoph Hellwig wrote: > Didn't you guys have a previous iteration of the fixes that gets > rid of REQ_NODILE by improving the heuristics inside cfq? That > would be much, much preffered from the filesystem point of view. Actually in this patch, I was thinking we can probably get rid of RQ_NOIDLE flag and just check for WRITE_SYNC. Any WRITE_SYNC queue gets served on sync-noidle tree. I am wondering will we not face jbd thread issues with direct writes also? If yes, then not special casing direct IO writes and treat them same as O_SYNC writes will make sense. I really wished that we had some blktrace of some standard workloads stored somewhere which we could simply replay using "btreplay" and come to some kind of conclusion whenever we are faced with taking such decisions. Thanks Vivek -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/