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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY 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 4D4FAC35240 for ; Fri, 24 Jan 2020 01:59:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0C73B21835 for ; Fri, 24 Jan 2020 01:59:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="UtWNHzkp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730119AbgAXB7a (ORCPT ); Thu, 23 Jan 2020 20:59:30 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:37832 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728665AbgAXB7a (ORCPT ); Thu, 23 Jan 2020 20:59:30 -0500 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00O1wskm087187; Fri, 24 Jan 2020 01:59:27 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=to : cc : subject : from : references : date : in-reply-to : message-id : mime-version : content-type; s=corp-2019-08-05; bh=taQdrRdcpKgSpb6y35yA3R4kkotFmZIEdBjVF+7xJFA=; b=UtWNHzkp9LavK0w8BqruHzWK9jOg+iytTwVR5n79rOVo6f2yGQPq1lKCQPQuLcV9xKSt U9DWbtOPl5/kD/y6fZCU3dC44AVMJi9Cd5tmeUh84ovfG4VAVzJRo1viwpzGrVQ2O2Dc VgwQfShC80M+9T6X2+fWq1qbD3yITN44ClYF0MRvdMR/o6mfC+8LSmMZYwTKZ83+j3rr oxOcKzbCO4S5QpYh0OL/oOeoo0xTG7qDL9oVHMRPlYD/tgoHbUD8mbcwIR6Vdne6aHCc XSRWhxWS7L48cR5qESBkkrcvsw9E6xEEY+WXyUnOuVwm5JlLeqCSFuIY28MjWOetT68R pg== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2120.oracle.com with ESMTP id 2xktnrp3a8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 24 Jan 2020 01:59:27 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00O1xFSl190955; Fri, 24 Jan 2020 01:59:27 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3020.oracle.com with ESMTP id 2xqmwbjq4g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 24 Jan 2020 01:59:25 +0000 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 00O1wWRi027709; Fri, 24 Jan 2020 01:58:32 GMT Received: from ca-mkp.ca.oracle.com (/10.159.214.123) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 23 Jan 2020 17:58:32 -0800 To: Sumanesh Samanta Cc: linux-scsi@vger.kernel.org, "Martin K. Petersen" Subject: Re: [PATCH 5/6] scsi: core: don't limit per-LUN queue depth for SSD when HBA needs From: "Martin K. Petersen" Organization: Oracle Corporation References: <20200119071432.18558-1-ming.lei@redhat.com> <20200119071432.18558-6-ming.lei@redhat.com> Date: Thu, 23 Jan 2020 20:58:30 -0500 In-Reply-To: (Sumanesh Samanta's message of "Thu, 23 Jan 2020 17:01:47 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1.92 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9509 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001240012 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9509 signatures=668685 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=8.0.1-1911140001 definitions=main-2001240012 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Sumanesh, > The high-end controllers might expose a SCSI interface, but can have > all kind of devices (NVMe/SCSI/SATA) behind it, and has its own > capability to queue IO and feed to devices as needed. Those devices > should not be penalized with the overhead of the device_busy counter, > just because they chose to expose themselves has SCSI devices (for > historical and backward compatibility reasons). Please read what I proposed. megaraid VDs don't report QUEUE_FULL so you would not trigger the device_busy counter. -- Martin K. Petersen Oracle Linux Engineering