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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 A32E8C43387 for ; Mon, 17 Dec 2018 01:27:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 728392084D for ; Mon, 17 Dec 2018 01:27:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731112AbeLQB1Z (ORCPT ); Sun, 16 Dec 2018 20:27:25 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57402 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731106AbeLQB1Z (ORCPT ); Sun, 16 Dec 2018 20:27:25 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7030F83F42; Mon, 17 Dec 2018 01:27:25 +0000 (UTC) Received: from ming.t460p (ovpn-8-20.pek2.redhat.com [10.72.8.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2D5245C1B4; Mon, 17 Dec 2018 01:27:14 +0000 (UTC) Date: Mon, 17 Dec 2018 09:27:09 +0800 From: Ming Lei To: Christoph Hellwig Cc: Jens Axboe , linux-block@vger.kernel.org, Jeff Moyer , Mike Snitzer Subject: Re: [PATCH 3/4] blk-mq: deal with shared queue mapping reliably Message-ID: <20181217012708.GE1223@ming.t460p> References: <20181216022517.26650-1-ming.lei@redhat.com> <20181216022517.26650-4-ming.lei@redhat.com> <20181216161650.GD9957@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181216161650.GD9957@lst.de> User-Agent: Mutt/1.9.1 (2017-09-22) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Mon, 17 Dec 2018 01:27:25 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Sun, Dec 16, 2018 at 05:16:50PM +0100, Christoph Hellwig wrote: > On Sun, Dec 16, 2018 at 10:25:16AM +0800, Ming Lei wrote: > > This patch sets map->nr_queues as zero explictly if there is zero > > queues for such queue type, then blk_mq_map_swqueue() can become > > more robust to deal with shared mappings. > > This looks a lot more clumsy than what we had before, can you explain > what additional robustnes it buys us? If there isn't one mapping type, its .nr_queues is set as zero explicitly, then we don't need to touch the related hctx/ctx which is retrieved via the shared mapping table. thanks, Ming