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=-6.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 B5C46C388F7 for ; Thu, 29 Oct 2020 02:12:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5AB15206F7 for ; Thu, 29 Oct 2020 02:12:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="j+2ftmNx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388053AbgJ2CMZ (ORCPT ); Wed, 28 Oct 2020 22:12:25 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:45946 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726810AbgJ1VgZ (ORCPT ); Wed, 28 Oct 2020 17:36:25 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09SC55Wc136687; Wed, 28 Oct 2020 12:06:34 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2020-01-29; bh=3f8NAaZq9070x2DphUfx3HH/5T67COUGd9APGfKJakg=; b=j+2ftmNxgykWB94cTxmLulCIbcF9SmTqfT63NHitxkg8rKDUd1RLBl0s3jBP5Wjhljbj WdNiJebW8iUODjzqoSgC2d1H/9XnC2CJhpDED6rKdRUPPsO53EXQbRWRkzg11/kvIPjy ZLdLMz94jbKu0p608k8fplsurPzF+m5c5P0isbIB0snrABpe+nSlzF2+el9sKmb6Rehx ocZsX1t8/lDWfLm4iNx7LjZyPuyuRwLG3kBNpgclWShZ12XJSqT6g9VCCwyjHnSMBdbt knPbU1ZV/R8M7cr69T8BIusbMqOTwVPa6i+/Omn3AAgbJWVObLkfT0kozrNJWC3aXdiR ag== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2120.oracle.com with ESMTP id 34cc7ky1h4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 28 Oct 2020 12:06:34 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09SC6KuT155792; Wed, 28 Oct 2020 12:06:33 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3020.oracle.com with ESMTP id 34cx1rwbcg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 28 Oct 2020 12:06:33 +0000 Received: from abhmp0002.oracle.com (abhmp0002.oracle.com [141.146.116.8]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 09SC6VBs027451; Wed, 28 Oct 2020 12:06:32 GMT Received: from [192.168.1.102] (/39.109.231.106) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 28 Oct 2020 05:06:31 -0700 Subject: Re: [PATCH v9 0/3] readmirror feature (read_policy sysfs and in-memory only approach) To: dsterba@suse.cz, linux-btrfs@vger.kernel.org, josef@toxicpanda.com, dsterba@suse.com References: <20201023170403.GM6756@twin.jikos.cz> <31c3da05-2238-da84-509e-3b29835ec33a@oracle.com> <20201027180233.GF6756@twin.jikos.cz> From: Anand Jain Message-ID: Date: Wed, 28 Oct 2020 20:06:27 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20201027180233.GF6756@twin.jikos.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9787 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 phishscore=0 bulkscore=0 suspectscore=0 malwarescore=0 mlxlogscore=999 mlxscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010280083 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9787 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 lowpriorityscore=0 adultscore=0 malwarescore=0 spamscore=0 clxscore=1015 mlxscore=0 suspectscore=0 priorityscore=1501 impostorscore=0 bulkscore=0 phishscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010280083 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 28/10/20 2:02 am, David Sterba wrote: > On Tue, Oct 27, 2020 at 09:52:11AM +0800, Anand Jain wrote: >> >> >> On 24/10/20 1:04 am, David Sterba wrote: >>> On Thu, Oct 22, 2020 at 03:43:34PM +0800, Anand Jain wrote: >>>> v9: C coding style fixes in 1/3 and 3/3 >>> >>> So the point of adding the sysfs knobs is to allow testing various >>> mirror selection strategies, what exactly was discussed in the past. Do >>> you have patches for that as well? It does not need to be final and >>> polished but at least give us something to test. >>> >> >> Sure. I just sent out the patchset [1]. It provides read_policy: >> latency, device, and round-robin. >> >> [1] >> https://patchwork.kernel.org/project/linux-btrfs/list/?series=371023 > > Exporting more information from the devices would help us to decide but > is there anything we can do just with what we have? Or eventually add > our counters like for the in-flight requests or total bytes. The > intention is not to duplicate what block layer does as we need to > experiment with the stats and heuristics it's just for that purpose and > we don't have to rely on other subsystem patches. > I could rewrote the latency patch without export of any new block layer functions. Patchset v1 will soon be sent to the ML. I hope that shall address your concern. Thanks, Anand