Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932522AbVJaSC3 (ORCPT ); Mon, 31 Oct 2005 13:02:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932525AbVJaSC3 (ORCPT ); Mon, 31 Oct 2005 13:02:29 -0500 Received: from ns.virtualhost.dk ([195.184.98.160]:52246 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S932522AbVJaSC3 (ORCPT ); Mon, 31 Oct 2005 13:02:29 -0500 Date: Mon, 31 Oct 2005 19:03:15 +0100 From: Jens Axboe To: Linus Torvalds Cc: Tejun Heo , Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org Subject: Re: [PATCH][noop-iosched] don't reuse a freed request Message-ID: <20051031180314.GZ19267@suse.de> References: <20051031023024.GC5632@mandriva.com> <20051031074022.GN19267@suse.de> <4365D01D.2040406@gmail.com> <20051031082354.GO19267@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3094 Lines: 76 On Mon, Oct 31 2005, Linus Torvalds wrote: > > > On Mon, 31 Oct 2005, Jens Axboe wrote: > > > > So either we disable merging for noop by setting REQ_NOMERGE in > > elevator_noop_add_request(), or we add a noop_list and do the > > dispatching like in the other io schedulers. I'd prefer the latter, > > merging is still beneficial for noop (and it has always done it). > > > > For now, we should add the former. > > > > Signed-off-by: Jens Axboe > > Btw, Jens, I appreciate seeing the discussion history when applying a > patch, but at the same time I do _not_ want to use it as a commit message, > it's just too confusing and worthless in that context. > > And yet, your final comments don't much make sense without the background, > so I can't just use them either. > > So, I rewrote the explanation. Which is fine, but I wish people who sent > patches would think more about what message they want to have in the > commit logs, so that (a) Lazy-Linus doesn't have to write his own message > and (b) so that the message is correct when Lazy-and-Stupid-Linus > sometimes doesn't necessarily see/understand all the problems it fixes. > > Btw, the email-patch-sending protocol still allows for putting all the > ugly history in for my (and the mailing lists) pleasure: that's what the > "---" marker after the explanation is for. So you can _both_ have a nice > clean commit message _and_ give more of a historical background for the > patch. My bad, I know I'm a little bad at describing patches sometimes (Andrew has been on my case in the past as well), I will make a conscious effort to describe them better. > Anyway, in this case, the commit message ended up looking like this:: > > commit 581c1b14394aee60aff46ea67d05483261ed6527 > Author: Jens Axboe > Date: Mon Oct 31 09:23:54 2005 +0100 > > [PATCH] noop-iosched: avoid corrupted request merging > > Tejun Heo notes: > > "I'm currently debugging this. The problem is that we are using the > generic dispatch queue directly in the noop sched and merging is NOT > allowed on dispatch queues but generic handling of last_merge tries > to merge requests. I'm still trying to verify this, so I'll be back > with results soon." > > In the meantime, disable merging for noop by setting REQ_NOMERGE in > elevator_noop_add_request(). > > Eventually, we should add a noop_list and do the dispatching like in the > other io schedulers. Merging is still beneficial for noop (and it has > always done it). > > Signed-off-by: Jens Axboe > Signed-off-by: Linus Torvalds > > which is basically your email cleaned up and compressed into a readable > commit message. Indeed, looks good, thanks for writing it up! -- Jens Axboe - 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/