Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757487AbZDGTY7 (ORCPT ); Tue, 7 Apr 2009 15:24:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752569AbZDGTYt (ORCPT ); Tue, 7 Apr 2009 15:24:49 -0400 Received: from rtr.ca ([76.10.145.34]:38942 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752330AbZDGTYt (ORCPT ); Tue, 7 Apr 2009 15:24:49 -0400 Message-ID: <49DBA87F.6070501@rtr.ca> Date: Tue, 07 Apr 2009 15:24:47 -0400 From: Mark Lord Organization: Real-Time Remedies Inc. User-Agent: Thunderbird 2.0.0.21 (X11/20090318) MIME-Version: 1.0 To: Linus Torvalds Cc: Ray Lee , Hua Zhong , Theodore Tso , Jens Axboe , Linux Kernel Mailing List Subject: Re: [PATCH 0/8][RFC] IO latency/throughput fixes References: <1239022088-29002-1-git-send-email-jens.axboe@oracle.com> <20090406151054.GD5178@kernel.dk> <20090406183157.GD7376@mit.edu> <002501c9b6f3$f85b4910$e911db30$@com> <20090406211931.GB8586@mit.edu> <003001c9b6ff$a9259ce0$fb70d6a0$@com> <2c0942db0904061504l6504934bi446f7425fcd38470@mail.gmail.com> <49DB56B8.1060805@rtr.ca> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1513 Lines: 41 Linus Torvalds wrote: > > On Tue, 7 Apr 2009, Mark Lord wrote: >> What happens with ext3 "writeback", and ext4 "whatever", >> when one does the quickie reboot method: >> >> ALT-SYSRQ-S ALT-SYSRQ-U ALT-SYSRQ-S ALT-SYSRQ-B >> >> ??? > > Since 's' syncs (I think 'u' does too, as part of making things > read-only), the data blocks will be on disk after the boot regardless of > any other ordering. .. I was thinking more about delayed allocation in ext4, though. If it hasn't allocated the blocks, then sync() has nothing to write out. Or do they have hooks into the block layer to force alloc/commit when somebody does a sync() ?? > Of course, it will leave all your lock-files files alone, and I can almost > guarantee that some daemons (read: "NetworkManager") will then fail on the > next boot because they think they are already running. .. No, it behaves fine on reboot here. But actually, NM is one big reason why I end up having to use the ALT-SYSRQ-S/U/S/B. The Ubunutu reboot scripts seem broken at times w.r.t. NM -- it hangs the reboot sequence on some of my machines here for a very long time (during shutdown), because (I think) the scripts disable the interface before disabling NM.. Doh! Seems happy enough after rebooting though. Cheers -- 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/