From: Theodore Tso Subject: Re: [PATCH 1/3] block_write_full_page: Use synchronous writes for WBC_SYNC_ALL writebacks Date: Wed, 8 Apr 2009 11:25:41 -0400 Message-ID: <20090408152541.GA14895@mit.edu> References: <1238185471-31152-2-git-send-email-tytso@mit.edu> <20090406232141.ebdb426a.akpm@linux-foundation.org> <20090406235052.1ea47513.akpm@linux-foundation.org> <20090407070835.GM5178@kernel.dk> <20090407002313.fcdd1da0.akpm@linux-foundation.org> <20090407075732.GO5178@kernel.dk> <20090407190913.GA31723@mit.edu> <20090407193239.GE5178@kernel.dk> <20090407214421.GA7031@mit.edu> <20090408055853.GJ5178@kernel.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andrew Morton , Linux Kernel Developers List , Ext4 Developers List , jack@suse.cz To: Jens Axboe Return-path: Received: from thunk.org ([69.25.196.29]:47143 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755750AbZDHPZy (ORCPT ); Wed, 8 Apr 2009 11:25:54 -0400 Content-Disposition: inline In-Reply-To: <20090408055853.GJ5178@kernel.dk> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Apr 08, 2009 at 07:58:54AM +0200, Jens Axboe wrote: > > I'm not even sure what is documented about this sort of thing in biodoc, > but it's actually somewhat outside the realm of block layer > documentation. The block layer should document that you need to call > unplug if you are going to be waiting for that IO. How the vm code does > it is implementation detail mostly, the important thing is that it gets > done :-) Fair enough; I agree a lot of the problem is the page writeback subsystem isn't well documented at all, and is crying out for a review for possible refactorization and cleanup.... - Ted