Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264125AbTE0UwT (ORCPT ); Tue, 27 May 2003 16:52:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264146AbTE0UwT (ORCPT ); Tue, 27 May 2003 16:52:19 -0400 Received: from ppp-217-133-42-200.cust-adsl.tiscali.it ([217.133.42.200]:43931 "EHLO dualathlon.random") by vger.kernel.org with ESMTP id S264125AbTE0UwO (ORCPT ); Tue, 27 May 2003 16:52:14 -0400 Date: Tue, 27 May 2003 23:05:23 +0200 From: Andrea Arcangeli To: manish Cc: Marc-Christian Petersen , Marcelo Tosatti , linux-kernel@vger.kernel.org, Carl-Daniel Hailfinger , Christian Klose , William Lee Irwin III Subject: Re: 2.4.20: Proccess stuck in __lock_page ... Message-ID: <20030527210523.GT3767@dualathlon.random> References: <3ED2DE86.2070406@storadinc.com> <3ED3BDCE.4010200@storadinc.com> <20030527202047.GM3767@dualathlon.random> <200305272225.27720.m.c.p@wolk-project.de> <3ED3CDB8.3000500@storadinc.com> <20030527204743.GR3767@dualathlon.random> <3ED3CFAF.5040604@storadinc.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3ED3CFAF.5040604@storadinc.com> User-Agent: Mutt/1.4i X-GPG-Key: 1024D/68B9CB43 X-PGP-Key: 1024R/CB4660B9 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2440 Lines: 68 On Tue, May 27, 2003 at 01:50:55PM -0700, manish wrote: > Andrea Arcangeli wrote: > > >On Tue, May 27, 2003 at 01:42:32PM -0700, manish wrote: > > > >>Marc-Christian Petersen wrote: > >> > >>>On Tuesday 27 May 2003 22:20, Andrea Arcangeli wrote: > >>> > >>>Hi Andrea, > >>> > >>> > >>>>>1. Stock 2.4.20 > >>>>>2. 2.4.20 with the io_request_lock removed. > >>>>>The tests on the first one are still going. The tests on the second one > >>>>>showed processes getting stuck for long times (> 5 minutes) and not > >>>>>paused ... > >>>>> > >>>>sorry if it's a dumb question but what is the "io_request_lock removed" > >>>>thing? Hope you didn't delete any io_request_lock, if you did you can > >>>>get worse things than crashes (i.e. mm/fs corruption). the pausing bug > >>>>was a genuine race (quite innocent, if you could trigger a disk unplug > >>>>you could recover from it) > >>>> > >>>>Andrea > >>>> > >>>funny. I asked him the same ;) > >>> > >>>see his response: > >>> > >>>----------------------------------------------------------------------- > >>> > >>>>what is this io_request_lock patch you are talking about? > >>>> > >>>>ciao, Marc > >>>> > >>>We made some changes to the 2.4.20 kernel to remove the io_request_lock > >>>and replace with queue_lock and host_lock. > >>>----------------------------------------------------------------------- > >>> > >>>ciao, Marc > >>> > >>We made a change in the 2.4.20 kernel to remove the io_request_lock and > >>replace with the host_lock and the queue_lock. Probably, not a right > >>thing to do > >> > > > >right you are, but never mind, only remeber e2fsck the fs before > >booting the box so you don't risk fs corruption later with the solid > >kernels. > > > >Andrea > > > So, does it imply that we cannot remove the io_request_lock in 2.4 at all? io_request_lock can be at most made per-device in 2.4, this is just the case in my tree for istance. Locks are there for a reason, unless you redesign the code to work more scalar, you can't just drop them and expect stuff to work. But the io_request_lock has nothing to do with both the hangs and the delays, it only hurts scalability if you've lots of devices and lots of cpus. Andrea - 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/