From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965284AbbI2O0S (ORCPT ); Tue, 29 Sep 2015 10:26:18 -0400 Received: from mga11.intel.com ([192.55.52.93]:53265 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965055AbbI2O0J (ORCPT ); Tue, 29 Sep 2015 10:26:09 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,608,1437462000"; d="scan'208";a="815342380" Date: Tue, 29 Sep 2015 14:26:07 +0000 (UTC) From: Keith Busch X-X-Sender: vmware@localhost.lm.intel.com To: Ming Lei cc: Jens Axboe , linux-kernel@vger.kernel.org, Keith Busch , Matthew Wilcox , linux-nvme@lists.infradead.org, Christoph Hellwig Subject: Re: [PATCH 0/3] blk-mq & nvme: introduce .map_changed In-Reply-To: <1443496857-26887-1-git-send-email-tom.leiming@gmail.com> Message-ID: References: <1443496857-26887-1-git-send-email-tom.leiming@gmail.com> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 28 Sep 2015, Ming Lei wrote: > This patchset introduces .map_changed callback into 'struct blk_mq_ops', > and use this callback to get NVMe notified about the mapping changed event, > then NVMe can update the irq affinity hint for its queues. I think this is going the wrong direction. Shouldn't we provide blk-mq the vectors in the tag set so that layer can manage the irq hints? This could lead to more cpu-queue assignment optimizations from using that information. For example, two h/w contexts sharing the same vector shouldn't be assigned to cpus on different NUMA nodes. > Also the 'cpumask' in 'struct blk_mq_tags' isn't needed any more, so remove > that and related kernel interface. It was added to the tags because the cpu mask is an artifact of the tags rather that duplicating it across all the h/w contexts sharing the same set. It also doesn't let a h/w context from one namespace overwrite another's cpu affinity mask when they share the same vector.