From: Adrian Hunter Subject: Re: [PATCH 2/2] HACK: do I/O read requests while ext3 journal recovers Date: Wed, 15 Jul 2009 18:35:41 +0300 Message-ID: <4A5DF74D.7010100@nokia.com> References: <20090714140253.25993.64525.sendpatchset@ahunter-tower> <20090714140307.25993.26360.sendpatchset@ahunter-tower> <20090714212625.GE4829@webber.adilger.int> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: "Andrew.Morton.akpm@linux-foundation.org" , "Andreas.Dilger.adilger@sun.com" , "Stephen.Tweedie.sct@redhat.com" , "Bityutskiy Artem (Nokia-D/Helsinki)" , "linux-ext4@vger.kernel.org" To: Andreas Dilger Return-path: Received: from smtp.nokia.com ([192.100.122.230]:25775 "EHLO mgw-mx03.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755513AbZGOPgA (ORCPT ); Wed, 15 Jul 2009 11:36:00 -0400 In-Reply-To: <20090714212625.GE4829@webber.adilger.int> Sender: linux-ext4-owner@vger.kernel.org List-ID: Andreas Dilger wrote: > On Jul 14, 2009 17:03 +0300, Adrian Hunter wrote: >> The ext3 journal can take a long time to recover at mount >> time. That was partially fixed by placing a barrier into >> the I/O queue and then not waiting for the actual I/O to >> complete. > > Note that you can also reduce the journal recovery time by > reducing the size of the journal. Having a large journal > is needed for getting good performance with lots of updates > at high speeds. If you aren't doing a large amount of > filesystem IO (which I'd guess for an embedded device, assuming > you are using it for that), then you could reduce the size of > the journal to the minimum (1000 blocks) and this will also > reduce the recovery time correspondingly. Yes that may help, although the number of blocks involved is fairly small.