From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH 0/3] Convert libata pio task to slow-work Date: Fri, 28 Aug 2009 09:06:42 +0200 Message-ID: <20090828070641.GR12579@kernel.dk> References: <1251364122-9592-1-git-send-email-jens.axboe@oracle.com> <4A967DD7.20603@kernel.org> <20090827124927.GJ12579@kernel.dk> <4A96830F.9040805@kernel.org> <20090827184939.GK12579@kernel.dk> <4A9780EF.1030102@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from brick.kernel.dk ([93.163.65.50]:57081 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751964AbZH1HGk (ORCPT ); Fri, 28 Aug 2009 03:06:40 -0400 Content-Disposition: inline In-Reply-To: <4A9780EF.1030102@kernel.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, alan@lxorguk.ukuu.org.uk, jeff@garzik.org, dhowells@redhat.com On Fri, Aug 28 2009, Tejun Heo wrote: > >>> Care to post it? I know you don't think it's perfect yet, but it would > >>> make a lot more sense to throw effort into this rather than waste time > >>> on partial solutions. > >> I have this printed out code with full of red markings from proof > >> reading and flush implementation is mostly broken. Please give me a > >> couple of days. I'll post a rough unsplit version which at least > >> compiles with the planned changes applied by the end of the week. :-) > > > > Alright, fair enough. > > > > One question - do the 'exposed' workqueues (the ones that drivers > > allocate/create) sitting in front of the global cpu queue allow more > > than one thread per cpu, or is that property retained for the global cpu > > queue (where it is a necessity)? > > The exposed workqueues basically just play the gateway and don't have > threads associated with it, well, at least not the normal ones. It > may have single dedicated thread which usually isn't used but only > gets summoned when a queue stall is detected (new thread needs to be > created but blocks on allocation kind of situation). So, only the > global cpu queue has normal workers and there are multiple per cpu and > they're shared by all exported workqueues. Thanks for the clarification, it answers the question on what level of functionality is observed by the exported workqueues. Sounds good! -- Jens Axboe