From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 559EFC4646B for ; Tue, 25 Jun 2019 02:14:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 247EE20652 for ; Tue, 25 Jun 2019 02:14:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729450AbfFYCOf (ORCPT ); Mon, 24 Jun 2019 22:14:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57528 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727835AbfFYCOf (ORCPT ); Mon, 24 Jun 2019 22:14:35 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C410B81F1B; Tue, 25 Jun 2019 02:14:27 +0000 (UTC) Received: from ming.t460p (ovpn-8-21.pek2.redhat.com [10.72.8.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C1F3C600CD; Tue, 25 Jun 2019 02:14:17 +0000 (UTC) Date: Tue, 25 Jun 2019 10:14:12 +0800 From: Ming Lei To: Thomas Gleixner Cc: Weiping Zhang , axboe@kernel.dk, Tejun Heo , Christoph Hellwig , bvanassche@acm.org, keith.busch@intel.com, minwoo.im.dev@gmail.com, linux-block@vger.kernel.org, cgroups@vger.kernel.org, linux-nvme@lists.infradead.org, LKML Subject: Re: [PATCH v3 4/5] genirq/affinity: allow driver's discontigous affinity set Message-ID: <20190625021411.GD23777@ming.t460p> References: <1ead341c6d603cf138aed62e31091f257cb19981.1561385989.git.zhangweiping@didiglobal.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 25 Jun 2019 02:14:35 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi Thomas, On Mon, Jun 24, 2019 at 05:42:39PM +0200, Thomas Gleixner wrote: > On Mon, 24 Jun 2019, Weiping Zhang wrote: > > > The driver may implement multiple affinity set, and some of > > are empty, for this case we just skip them. > > Why? What's the point of creating empty sets? Just because is not a real > good justification. Patch 5 will add 4 new sets for supporting NVMe's weighted round robin arbitration. It can be a headache to manage so many irq sets(now the total sets can become 6) dynamically since size of anyone in the new 4 sets can be zero, so each particular set is assigned one static index for avoiding the management trouble, then empty set will be seen by irq_create_affinity_masks(). So looks skipping the empty set makes sense because the API will become easier to use than before. Thanks, Ming