Return-Path: Received: from mail-wy0-f174.google.com ([74.125.82.174]:46818 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752956Ab1IULvF (ORCPT ); Wed, 21 Sep 2011 07:51:05 -0400 Received: by wyg34 with SMTP id 34so1799758wyg.19 for ; Wed, 21 Sep 2011 04:51:03 -0700 (PDT) Message-ID: <4E79CFA3.4090403@tonian.com> Date: Wed, 21 Sep 2011 14:50:59 +0300 From: Benny Halevy To: Boaz Harrosh CC: tao.peng@emc.com, Trond.Myklebust@netapp.com, linux-nfs@vger.kernel.org, honey@citi.umich.edu, rees@umich.edu Subject: Re: [PATCH 2/3] pnfs: introduce pnfs private workqueue References: <1316488728-24912-1-git-send-email-rees@umich.edu> <1316488728-24912-3-git-send-email-rees@umich.edu> <1316558461.15093.4.camel@lade.trondhjem.org> <20110921002917.GA30770@merit.edu> <2E1EB2CF9ED1CB4AA966F0EB76EAB4430B480226@SACMVEXC2-PRD.hq.netapp.com> <4E798C93.40409@tonian.com> <4E79C2F0.30303@tonian.com> <4E79CA34.3060602@tonian.com> <4E79CD8F.6050901@panasas.com> In-Reply-To: <4E79CD8F.6050901@panasas.com> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On 2011-09-21 14:42, Boaz Harrosh wrote: > On 09/21/2011 02:27 PM, Benny Halevy wrote: >>> Unless we do following: >>> 1. preallocate memory for extent state convertion >>> 2. use nfsiod/rpciod to handle bl_write_cleanup >>> 3. for pnfs error case, create a kthread to recollapse and resend to MDS >>> I don't quite understand. How do you use nfs state manager to do other tasks? >> >> You need to keep a list of things to do hanging off of the nfs client structure >> and set a bit in cl_state telling the state manager it has work to do >> and wake it up. It then needs to go over the list of, say nfs_inodes >> and call into the layout driver to handle the errors. >> >> Benny > > Good god, Is it not already too complicated? > > The LD is out of the picture. You all seemed to agree that > the LD has reported an io_done on the nfsiod/rpciod, and in the error case > Generic layer needs to do it's coalescing on some other thread. So > your description above is not correct, the LD is out of the picture. > True, if the ld cleanup on io_done is sufficient. > It all looks too complicated for me. A pnfs workqueue for both 2 and 3 > above is very good. Specially since the workqueue also shares global > pool threads, No? I like it that there is a preallocated thread for > the error-case, think about it. I'm fine too with using a workqueue for the error case. But I'd rather have the common case done path do only lightweight, wait free processing. Benny > > Thanks > Boaz > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html