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=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 9BBFAC43441 for ; Mon, 12 Nov 2018 17:10:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5FCA322503 for ; Mon, 12 Nov 2018 17:10:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="kmXb/r+T" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5FCA322503 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729968AbeKMDEa (ORCPT ); Mon, 12 Nov 2018 22:04:30 -0500 Received: from mail-pg1-f194.google.com ([209.85.215.194]:32882 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727659AbeKMDEa (ORCPT ); Mon, 12 Nov 2018 22:04:30 -0500 Received: by mail-pg1-f194.google.com with SMTP id z11so1709094pgu.0 for ; Mon, 12 Nov 2018 09:10:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=ej2zWVNDkKDNwVA+EVbiOGWXtvZFOLaPlACrw1hHV7k=; b=kmXb/r+TPkHme/w723MEjEX1OmHpW0Rzgx7MIqmYbImnpm7bgEJJFyKtMTgh+aQVte agicwsN632siixG/62KiWdGhoU46apMOF1brZjdXFJo2mgEK9HrjoOb55+V8JJPKQmj0 ti08t693wG1g4M5YwSIPIqIQXBzq19GG4j+OuLtRXOqn8/2oFn6SXOcXh7HdYqVFD6bE AdtKnoNSsJQvNP62bXDvoSRh+lDcqpKt+ZzoR9M/j+dq5gnYH3mDLtkgblIsxSZnPV2u V6hUZaKHXLAgEDKbb2CvJvv2WW+Ae9xaNC5/NUMBNMzk9qsdXXHHfZZeVRzZ5WfOyAeP 9QrQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=ej2zWVNDkKDNwVA+EVbiOGWXtvZFOLaPlACrw1hHV7k=; b=AC86VS2LTVlmIFq81GDbE/SMsb8EGtodLl3/D5js0+KaNC0Vx2OSA12b9QC9W/Ltoh PQitud9ok3tS42Kor2AbP7vMTxEIDyewINs0WZqx8r/mY+4cKCocFvx9oqjnIPvPXyVL b84sLTfqPbdK7eUP3Mn995tw/+kO6Bacx7l+Q6Yb/tallp9o+0QOXaPmTxpmuTZeX9y7 iRUCtAGrfpgQolZOEtMwtEy3sJKs5cAN/vn8hX065n36Am+oDmUi6sODamh44OQO/TBZ wXT5wbHEI2aJcafvr6ihCacYu8shVxSLrl0Gj4oNgS5pJXd69PLnjU/YYnK5NwcBXZ5e 74Uw== X-Gm-Message-State: AGRZ1gLwHMLD99iYJvYBlaW2n5eI+pUSSoIQ3raGz3SxSV0l/CLnBLaX mNMrQiODF4JSWcz6kLZp1QnQPARp3bA= X-Google-Smtp-Source: AJdET5fNMpBXSVwTARCXCIhhgisnHkPzwszZOFeYF6eVG46zcK2imqa2HIyMDB12ukhRBLBV8biyIg== X-Received: by 2002:a62:3a82:: with SMTP id v2mr1661841pfj.174.1542042620858; Mon, 12 Nov 2018 09:10:20 -0800 (PST) Received: from [192.168.1.121] (66.29.188.166.static.utbb.net. [66.29.188.166]) by smtp.gmail.com with ESMTPSA id u82-v6sm204925pfj.131.2018.11.12.09.10.18 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 12 Nov 2018 09:10:19 -0800 (PST) Subject: Re: [PATCH V5 1/6] blk-mq: make __blk_mq_issue_directly be able to accept NULL cookie pointer To: Jianchao Wang Cc: ming.lei@redhat.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <1542014609-1769-1-git-send-email-jianchao.w.wang@oracle.com> <1542014609-1769-2-git-send-email-jianchao.w.wang@oracle.com> From: Jens Axboe Message-ID: <01bd2f70-cc78-9bfd-aa30-b73c44eaa9bb@kernel.dk> Date: Mon, 12 Nov 2018 10:10:16 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <1542014609-1769-2-git-send-email-jianchao.w.wang@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/12/18 2:23 AM, Jianchao Wang wrote: > Make __blk_mq_issue_directly be able to accept a NULL cookie pointer > and remove the dummy unused_cookie in blk_mq_request_issue_directly. What's the reasoning behind this? Seems faster to store the cookie always, instead of introducing a branch to the hot path. -- Jens Axboe