From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Thumshirn Subject: Re: [LSF/MM TOPIC][LSF/MM ATTEND] NAPI polling for block drivers Date: Wed, 18 Jan 2017 16:16:43 +0100 Message-ID: <20170118151643.GJ3514@linux-x5ow.site> References: <8b47ca34-d2ff-26dc-721e-2cb1e18f1efc@grimberg.me> <499af528-7810-f82d-1f11-cbf8f3a5b21c@grimberg.me> <53a3fb6c-c75a-519a-f669-2bcab404e01d@grimberg.me> <20170117162752.GE6067@linux-x5ow.site> <6df6bf6a-7cd3-1700-2b0a-e140325ebf47@grimberg.me> <20170118135156.GG3514@linux-x5ow.site> <20170118145816.GI3514@linux-x5ow.site> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:55630 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750907AbdARPQr (ORCPT ); Wed, 18 Jan 2017 10:16:47 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Sagi Grimberg Cc: Jens Axboe , Christoph Hellwig , Linux-scsi@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, Keith Busch , "lsf-pc@lists.linux-foundation.org" On Wed, Jan 18, 2017 at 05:14:36PM +0200, Sagi Grimberg wrote: > > >Hannes just spotted this: > >static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx, > > const struct blk_mq_queue_data *bd) > >{ > >[...] > > __nvme_submit_cmd(nvmeq, &cmnd); > > nvme_process_cq(nvmeq); > > spin_unlock_irq(&nvmeq->q_lock); > > return BLK_MQ_RQ_QUEUE_OK; > >out_cleanup_iod: > > nvme_free_iod(dev, req); > >out_free_cmd: > > nvme_cleanup_cmd(req); > > return ret; > >} > > > >So we're draining the CQ on submit. This of cause makes polling for > >completions in the IRQ handler rather pointless as we already did in the > >submission path. > > I think you missed: > http://git.infradead.org/nvme.git/commit/49c91e3e09dc3c9dd1718df85112a8cce3ab7007 I indeed did, thanks. -- Johannes Thumshirn Storage jthumshirn@suse.de +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850