From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chandra Seetharaman Subject: Re: [dm-devel] [PATCH 2/3] scsi_dh: Remove the workqueue usedforactivate Date: Thu, 07 May 2009 22:25:34 -0700 Message-ID: <1241760334.17612.3.camel@chandra-ubuntu> References: <20090428025230.11108.88559.sendpatchset@chandra-ubuntu> <20090428025242.11108.43024.sendpatchset@chandra-ubuntu> <4A02565B.9060105@cs.wisc.edu><1241742949.27327.1.camel@chandra-ubuntu> <4A03A278.2080105@cs.wisc.edu> Reply-To: sekharan@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from e37.co.us.ibm.com ([32.97.110.158]:37290 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751228AbZEHFZO (ORCPT ); Fri, 8 May 2009 01:25:14 -0400 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e37.co.us.ibm.com (8.13.1/8.13.1) with ESMTP id n485OepJ012730 for ; Thu, 7 May 2009 23:24:40 -0600 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n485PEsx208948 for ; Thu, 7 May 2009 23:25:14 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n485PDJE008170 for ; Thu, 7 May 2009 23:25:14 -0600 In-Reply-To: <4A03A278.2080105@cs.wisc.edu> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: device-mapper development Cc: linux-scsi@vger.kernel.org On Thu, 2009-05-07 at 22:09 -0500, Mike Christie wrote: > Chandra Seetharaman wrote: > > On Wed, 2009-05-06 at 22:32 -0500, Mike Christie wrote: > >> Chandra Seetharaman wrote: > >>> Since scsi_dh_activate() has become an asynchronous function, > >>> we do not need a workqueue for submitting scsi_dh_activate(). > >>> > >>> This patch just removes the workqueue that submits scsi_dh_activate(). > >>> > >> Before this is merged, we need to convert the other device handlers to > >> use blk_execute_rq_nowait or use their own workqueue_struct right? > > > > If we want those modules also behave async, then yes. > > > > But, this set of 3 patches would work fine as I made the relevant > > changes to those modules so that they work properly. > > > > What was the point of the workqueue? > > I think if you merged the patch and left the other modules as is you > would hit a problem where the multipathd work queue struct thread is > busy waiting on activate commands when it should be routing IO to paths > that do not need a activate. I am sorry for not being clear. As I mentioned in my original posting, I am working on making the other modules also async. WIll be posting those patches in a day or two. May be I will resubmit this set (with your suggestion for GFP_NOIO) along with those. In my reply (above), I was just trying to say that these set of patches work (with the caveat you noted). > > -- > dm-devel mailing list > dm-devel@redhat.com > https://www.redhat.com/mailman/listinfo/dm-devel