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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 C728DC43381 for ; Thu, 14 Feb 2019 05:57:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 94B2421934 for ; Thu, 14 Feb 2019 05:57:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="MBnrREsk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404354AbfBNF5s (ORCPT ); Thu, 14 Feb 2019 00:57:48 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:49062 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403946AbfBNF5r (ORCPT ); Thu, 14 Feb 2019 00:57:47 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x1E5rruP137725; Thu, 14 Feb 2019 05:57:37 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=VEHARTz3L96Isw/6vjmnriPs1HjxOK8/i9kYwu8JBec=; b=MBnrREsk0q+lBTRFgKVcKaxWq97r8BIHTjNEVo4Xztne+EcZkvUsAypGYX79dG8TzTJ0 Hyu/YdLmfeN2ZupDjaJBDTW3aUwD0fr5pa23JBzagwSYPbF6ybbx7YZTtbZClskoO7jt MeCfwdl+fo9+mVvwQ4emc7xkAcopdxJLMVk+2bf8eHE9aECFWfN+K9lAj1z1dhSVDPmL 9H9vOKImhT0rXd6RHu2PTC6wcdPki42wh203zwRMLH5Nc1Ju8k3ssbIzsXjXlIqaO2U0 Pa/vR7H5qzIiN7/vvZF37OTsQ4AS0eIAyGVT+NZUqWLEEHUMBGa3haNa6U6/WRM8cXAY oQ== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp2130.oracle.com with ESMTP id 2qhreknym0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 14 Feb 2019 05:57:37 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id x1E5vbJk004093 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 14 Feb 2019 05:57:37 GMT Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x1E5vaTO012111; Thu, 14 Feb 2019 05:57:36 GMT Received: from [172.20.10.5] (/223.104.212.152) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 14 Feb 2019 05:57:35 +0000 Subject: Re: [RFC PATCH v2 1/9] block: add nr_mirrors to request_queue To: "Theodore Y. Ts'o" Cc: linux-block@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, martin.petersen@oracle.com, shirley.ma@oracle.com, allison.henderson@oracle.com, david@fromorbit.com, darrick.wong@oracle.com, hch@infradead.org, adilger@dilger.ca References: <20190213095044.29628-1-bob.liu@oracle.com> <20190213095044.29628-2-bob.liu@oracle.com> <20190213160408.GW23000@mit.edu> From: Bob Liu Message-ID: <56d2dc78-01f8-9991-9199-372fe864d9f0@oracle.com> Date: Thu, 14 Feb 2019 13:57:20 +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: <20190213160408.GW23000@mit.edu> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9166 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1902140044 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2/14/19 12:04 AM, Theodore Y. Ts'o wrote: > On Wed, Feb 13, 2019 at 05:50:36PM +0800, Bob Liu wrote: >> @nr_mirrors is 1 by default which means only one copy, drivers e.g raid1 are >> responsible for setting the right value. The maximum value is >> BITS_PER_LONG which is 32 or 64. That should be big enough else retry lantency >> may be too high. > > This is admittedly bike-shedding, so feel free to ignore, but... > > In the case of Raid 6, "mirrors" will be a bit of a misnomer. Would > "nr_recovery" be better? > Now the initial/default value is 1 indicating only one copy of data. Would nr_copy be more accurate? > Thanks for working on this!! I would be interested in using this for > ext4 once it's available. > > - Ted >