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=-3.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 5FEB3C433E7 for ; Mon, 19 Oct 2020 16:19:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBCD6222E9 for ; Mon, 19 Oct 2020 16:19:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Ss4SzwO8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730404AbgJSQTj (ORCPT ); Mon, 19 Oct 2020 12:19:39 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:52050 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730190AbgJSQT3 (ORCPT ); Mon, 19 Oct 2020 12:19:29 -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 09JGEw47178885; Mon, 19 Oct 2020 16:19:24 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=content-type : mime-version : subject : from : in-reply-to : date : cc : content-transfer-encoding : message-id : references : to; s=corp-2020-01-29; bh=dMG+iodWtK8rRd3Qi1/hBHnO8Pu8b99TbSuHqVcnQl0=; b=Ss4SzwO86XOAuZw6CTDqz6pok3+Ok3mieav2J5ve6sPOQG5Y5IXRgJ0t9rE9uG4cgv90 J3UoUrAURJWV81CwFq3am+agYxGC9ThYTx96DJFd9QMVPOUiwjVqOMTSDWQ21OiykzXW DzL1p9opsZtx8BqApmwOWbBAV+tEr5p5jP7Pl0TQZxtOEu7FNG0HwkhoIdWZ+PGeuGNn aiKstbTsW5dcU1/OlLoQmp4vW+GvI0frFOpXbFzrBZxrVScHjWroJ/Ku/8b3skQPKbqX tRheKvd3FL3voCMQStCKjIqsn269+EeJt9hEYdQoHOnx8fexwUGq9EFH8HVUcp4iPDt6 /g== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by aserp2120.oracle.com with ESMTP id 347rjkpdha-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 19 Oct 2020 16:19:24 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09JGG9Bc059859; Mon, 19 Oct 2020 16:19:24 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3030.oracle.com with ESMTP id 348a6m39cy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 19 Oct 2020 16:19:24 +0000 Received: from abhmp0016.oracle.com (abhmp0016.oracle.com [141.146.116.22]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 09JGJNPO005052; Mon, 19 Oct 2020 16:19:23 GMT Received: from [20.15.0.8] (/73.88.28.6) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 19 Oct 2020 09:19:23 -0700 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.120.23.2.4\)) Subject: Re: [PATCH v3 05/17] scsi_transport_fc: Added a new rport state FC_PORTSTATE_MARGINAL From: Michael Christie In-Reply-To: <3803E6D0-68D6-407F-80AB-A17E7E0E69E3@oracle.com> Date: Mon, 19 Oct 2020 11:19:22 -0500 Cc: linux-scsi@vger.kernel.org, Hannes Reinecke , jsmart2021@gmail.com, emilne@redhat.com, mkumar@redhat.com Content-Transfer-Encoding: quoted-printable Message-Id: References: <1602732462-10443-1-git-send-email-muneendra.kumar@broadcom.com> <1602732462-10443-6-git-send-email-muneendra.kumar@broadcom.com> <5ca752c2-94e1-444a-7755-f48b09b38577@oracle.com> <3803E6D0-68D6-407F-80AB-A17E7E0E69E3@oracle.com> To: Muneendra Kumar M X-Mailer: Apple Mail (2.3608.120.23.2.4) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9779 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 mlxlogscore=999 bulkscore=0 spamscore=0 adultscore=0 suspectscore=0 mlxscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010190112 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9779 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 mlxlogscore=999 bulkscore=0 spamscore=0 priorityscore=1501 impostorscore=0 lowpriorityscore=0 phishscore=0 suspectscore=0 clxscore=1015 adultscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010190112 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org > On Oct 19, 2020, at 11:10 AM, Michael Christie = wrote: >=20 >=20 > So it=E2=80=99s not clear to me if you know the path is not optimal = and might hit > a timeout, and you are not going to use it once the existing IO = completes why > even try to send it? I mean in this setup, new commands that are = entering > the dm-multipath layer will not be sent to these marginal paths right? Oh yeah, to be clear I meant why try to send it on the marginal path = when you are setting up the path groups so they are not used and only the optimal = paths are used. When the driver/scsi layer fails the IO then the multipath layer will = make sure it goes on a optimal path right so you do not have to worry about hitting a = cmd timeout and firing off the scsi eh. However, one other question I had though, is are you setting up = multipathd so the marginal paths are used if the optimal ones were to fail (like the = optimal paths hit a link down, dev_loss_tmo or fast_io_fail fires, etc) or will they be = treated like failed paths? So could you end up with 3 groups: 1. Active optimal paths 2. Marginal 3. failed If the paths in 1 move to 3, then does multipathd handle it like a all = paths down or does multipathd switch to #2?