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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8895BC433F5 for ; Thu, 4 Nov 2021 11:35:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 664DC611F2 for ; Thu, 4 Nov 2021 11:35:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229705AbhKDLhv (ORCPT ); Thu, 4 Nov 2021 07:37:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229505AbhKDLhu (ORCPT ); Thu, 4 Nov 2021 07:37:50 -0400 Received: from mail-io1-xd32.google.com (mail-io1-xd32.google.com [IPv6:2607:f8b0:4864:20::d32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7DF69C061714 for ; Thu, 4 Nov 2021 04:35:12 -0700 (PDT) Received: by mail-io1-xd32.google.com with SMTP id c206so4983695iof.2 for ; Thu, 04 Nov 2021 04:35:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=sjvI3JmU6GmecRTvKr1vVa+DLj/A99mNyYw8EjZN+Tw=; b=qk3RBgocGZJS4wMhgYC7vlpo4hPoPXoEr7IYSA58MVsgHl5aDa/N4HaisWa2SGo7KP +yDHGbmXrVxPqprW/tTP2beHfr3edZOG5A3Ws8t1dT4mBntOS2JpcIqC0vu9RzcTL7Kz dWoZXJH32/DwxuADjW0t8egTtzmLRT866NS3xZeUgirqrZ46cdlYglCw4E+7bcASS1aa kM4aSonNOMMppXNY+C2H7e2OfBAhk/T1WXsMzIVrr8V+CaHiMjkAW6rqboGd2w4bHrv2 Cl/uXPwGwgXML3eVkkr7ePfov0jdsehVc4184oP1xEnwZiBeIBxuEpTtOOZp8dIbmjGy kSuQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=sjvI3JmU6GmecRTvKr1vVa+DLj/A99mNyYw8EjZN+Tw=; b=XIN2K2Rr2KzkAkpG4lLDeC899+1lTJlXhmIKgv9dsT0yHu9LfnE/v2pjoQQLEKG3KP qGXu7EzZXYsw5oh8PNdNcxPg5KBIoyT2p1O7CVxipc+nevn5czpcysYsI4kntIhPhrEi 7VEhzYEyUXp1H10b+/4VEsBL0AJQvcCTNqmQZ9pWaTNDCXUCitetmHRcJolpzc3ADBDR HwOcZN8X3YpUJlU03yZrVGVqtA2uJNT3DHne1jEjwKnrHbmWXwWuDE67rBcr1Dvez6af V8p994+VsWwtI3tIUC+mCNYUVADmTvBp7XOiZTthw3gc7wx+AYNcmueldqAN65v5/LTr t0NA== X-Gm-Message-State: AOAM531Zoa1WyTtZSTonq9yjDkzTmWO1wcnPWcIAOqtIGA5WEC4ocV7Q J/PMTfS1OuJmHA/p1XkthTPy9gO9n4Mtvg== X-Google-Smtp-Source: ABdhPJwpSh28ro/oqrEwr/kUoNYqmk2NPeZO/dkZ9S/OBpmpDcV2XD9RSQiiS8ObPHapz8MFIPH8UQ== X-Received: by 2002:a5d:8b94:: with SMTP id p20mr34853014iol.146.1636025711599; Thu, 04 Nov 2021 04:35:11 -0700 (PDT) Received: from [192.168.1.116] ([66.219.217.159]) by smtp.gmail.com with ESMTPSA id j3sm1207267ilu.64.2021.11.04.04.35.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 04 Nov 2021 04:35:11 -0700 (PDT) Subject: Re: [PATCH 4/4] block: move plug rq alloc into helper and ensure queue match To: Christoph Hellwig Cc: linux-block@vger.kernel.org References: <20211103183222.180268-1-axboe@kernel.dk> <20211103183222.180268-5-axboe@kernel.dk> From: Jens Axboe Message-ID: Date: Thu, 4 Nov 2021 05:35:10 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 11/4/21 3:17 AM, Christoph Hellwig wrote: > On Wed, Nov 03, 2021 at 12:32:22PM -0600, Jens Axboe wrote: >> + if (plug && !rq_list_empty(plug->cached_rq)) { >> + rq = rq_list_peek(&plug->cached_rq); > > No need for the empty check plus peek. This could be simplified > down to: > > if (!plug) > return NULL; > rq = rq_list_peek(&plug->cached_rq); > if (!rq || rq->q != q) > return NULL; > > rq_qos_throttle(q, bio); > plug->cached_rq = rq_list_next(rq); > INIT_LIST_HEAD(&rq->queuelist); > return rq; I tend to prefer having logic flow from the expected conditions. And since we need to check if the plug is valid anyway, I prefer the current logic. -- Jens Axboe