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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 46BD8C04EB9 for ; Tue, 4 Dec 2018 01:08:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 141EF2146D for ; Tue, 4 Dec 2018 01:08:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 141EF2146D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=grimberg.me Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-block-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725983AbeLDBIs (ORCPT ); Mon, 3 Dec 2018 20:08:48 -0500 Received: from mail-ot1-f53.google.com ([209.85.210.53]:37404 "EHLO mail-ot1-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725976AbeLDBIs (ORCPT ); Mon, 3 Dec 2018 20:08:48 -0500 Received: by mail-ot1-f53.google.com with SMTP id 40so13591210oth.4 for ; Mon, 03 Dec 2018 17:08:47 -0800 (PST) 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=ZTkHp2a/CqnDWsjR4O4XvZkH8t+XMvF15FIYduNlo0s=; b=Y4nyZbtfIx2KBOXYqe1TQem/56AEyRzpACSNVHVGQlJDRUsvyDtre/6sDiWnRJ27rS kwLd2ANd4oBGVmBTk0rvWvJHMAZtbqQpVl4d7ZacLw50+gsk/UX9NIZavl3wv0XYvUai TFZxbbHkbLh68jq3Y1qxS+Jr5Z/zpfJn5GWQvXcC7dWrN8j1UG18JfRgM3fVyOvcPXIX 8Cr0Zv+8HYZbrVyO2J4tFT8pXaAfSNnafZgStKEHfqUir1VQIFYcimKym128O9U761Cu pWIFMB8f2jcd6WwwQEfBmVwFSW9/0nUsaJtBT89KUon65ze97gRC3WPNVqhIsF5WvHA9 3grw== X-Gm-Message-State: AA+aEWZgAM3SXVbMpdRzSm3gJk66zH3rpzDwj3X7EJQWBflNh0M8lq7G 0GIu1dM0bFSuFPoeTBqMDwy60YuR X-Google-Smtp-Source: AFSGD/VWtJn6tWKXvYx0NMX5vvBD6v6iyYIbotOjw09QdTW63gilCwVfRzFs4R3P/3GGFgArolvv7A== X-Received: by 2002:a9d:19eb:: with SMTP id k98mr10966275otk.205.1543885726432; Mon, 03 Dec 2018 17:08:46 -0800 (PST) Received: from ?IPv6:2600:1700:65a0:78e0:514:7862:1503:8e4d? ([2600:1700:65a0:78e0:514:7862:1503:8e4d]) by smtp.gmail.com with ESMTPSA id p203sm14800573oic.49.2018.12.03.17.08.44 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 03 Dec 2018 17:08:45 -0800 (PST) Subject: Re: [PATCH 08/13] nvme-pci: remove the CQ lock for interrupt driven queues To: Christoph Hellwig , Jens Axboe , Keith Busch Cc: Max Gurtovoy , linux-nvme@lists.infradead.org, linux-block@vger.kernel.org References: <20181202164628.1116-1-hch@lst.de> <20181202164628.1116-9-hch@lst.de> From: Sagi Grimberg Message-ID: <9c0d0bdf-cf47-ae54-8277-73ac608d99cd@grimberg.me> Date: Mon, 3 Dec 2018 17:08:44 -0800 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: <20181202164628.1116-9-hch@lst.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org > Now that we can't poll regular, interrupt driven I/O queues there > is almost nothing that can race with an interrupt. The only > possible other contexts polling a CQ are the error handler and > queue shutdown, and both are so far off in the slow path that > we can simply use the big hammer of disabling interrupts. > > With that we can stop taking the cq_lock for normal queues. Nice, Reviewed-by: Sagi Grimberg From mboxrd@z Thu Jan 1 00:00:00 1970 From: sagi@grimberg.me (Sagi Grimberg) Date: Mon, 3 Dec 2018 17:08:44 -0800 Subject: [PATCH 08/13] nvme-pci: remove the CQ lock for interrupt driven queues In-Reply-To: <20181202164628.1116-9-hch@lst.de> References: <20181202164628.1116-1-hch@lst.de> <20181202164628.1116-9-hch@lst.de> Message-ID: <9c0d0bdf-cf47-ae54-8277-73ac608d99cd@grimberg.me> > Now that we can't poll regular, interrupt driven I/O queues there > is almost nothing that can race with an interrupt. The only > possible other contexts polling a CQ are the error handler and > queue shutdown, and both are so far off in the slow path that > we can simply use the big hammer of disabling interrupts. > > With that we can stop taking the cq_lock for normal queues. Nice, Reviewed-by: Sagi Grimberg