From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755041AbdKAQuv (ORCPT ); Wed, 1 Nov 2017 12:50:51 -0400 Received: from esa6.hgst.iphmx.com ([216.71.154.45]:55515 "EHLO esa6.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755024AbdKAQut (ORCPT ); Wed, 1 Nov 2017 12:50:49 -0400 X-IronPort-AV: E=Sophos;i="5.43,434,1503331200"; d="scan'208";a="61150038" From: Bart Van Assche To: "roman.penyaev@profitbricks.com" CC: "hch@lst.de" , "linux-kernel@vger.kernel.org" , "linux-block@vger.kernel.org" , "hare@suse.com" , "axboe@fb.com" Subject: Re: [PATCH 1/1] [RFC] blk-mq: fix queue stalling on shared hctx restart Thread-Topic: [PATCH 1/1] [RFC] blk-mq: fix queue stalling on shared hctx restart Thread-Index: AQHTR/sENmxK85jYyU6rqB1jXfMKp6LrdKyAgAEJ/gCAAK7tgIAEZT0AgA5AUwA= Date: Wed, 1 Nov 2017 16:50:45 +0000 Message-ID: <1509555044.2530.35.camel@wdc.com> References: <20171018102206.26020-1-roman.penyaev@profitbricks.com> <1508435243.2429.42.camel@wdc.com> <1508529929.3029.20.camel@wdc.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=Bart.VanAssche@wdc.com; x-originating-ip: [63.163.107.100] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;CY1PR0401MB1533;20:23TfRnjKQ30Qbdw2f2nmomOyWI6kUwiagc6WVOql+cVPpeZwstG35iweV3yTJusmJrImv0YCMQMWhoM1BrJEf3wA1fxTao2jSQtp+YCfclRB340Kf1zUMu1YbAi0CRvqm8g21t/0Rz1t3dJdkzofgdjZ9bl9ELAoYmLCw/hi3rA= x-ms-exchange-antispam-srfa-diagnostics: SSOS; x-ms-office365-filtering-correlation-id: 97eb35c0-d781-4224-1d9e-08d52148b259 x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(22001)(4534020)(4602075)(48565401081)(2017052603199);SRVR:CY1PR0401MB1533; x-ms-traffictypediagnostic: CY1PR0401MB1533: wdcipoutbound: EOP-TRUE x-exchange-antispam-report-test: UriScan:; x-microsoft-antispam-prvs: x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(100000700101)(100105000095)(100000701101)(100105300095)(100000702101)(100105100095)(6040450)(2401047)(5005006)(8121501046)(3231020)(100000703101)(100105400095)(10201501046)(93006095)(93001095)(3002001)(6055026)(6041248)(20161123560025)(20161123555025)(20161123564025)(201703131423075)(201702281528075)(201703061421075)(201703061406153)(20161123558100)(20161123562025)(6072148)(201708071742011)(100000704101)(100105200095)(100000705101)(100105500095);SRVR:CY1PR0401MB1533;BCL:0;PCL:0;RULEID:(100000800101)(100110000095)(100000801101)(100110300095)(100000802101)(100110100095)(100000803101)(100110400095)(100000804101)(100110200095)(100000805101)(100110500095);SRVR:CY1PR0401MB1533; x-forefront-prvs: 0478C23FE0 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(6009001)(39860400002)(346002)(376002)(189002)(24454002)(199003)(377424004)(316002)(6486002)(25786009)(189998001)(81156014)(81166006)(54906003)(8676002)(33646002)(101416001)(36756003)(14454004)(2900100001)(6436002)(6506006)(106356001)(93886005)(105586002)(3660700001)(3280700002)(103116003)(2950100002)(5640700003)(8936002)(76176999)(50986999)(54356999)(7736002)(2906002)(6916009)(77096006)(6246003)(4001150100001)(53546010)(2351001)(229853002)(68736007)(478600001)(305945005)(97736004)(72206003)(66066001)(5660300001)(2501003)(99286003)(575784001)(6512007)(4326008)(53936002)(102836003)(6116002)(86362001)(3846002);DIR:OUT;SFP:1102;SCL:1;SRVR:CY1PR0401MB1533;H:CY1PR0401MB1536.namprd04.prod.outlook.com;FPR:;SPF:None;PTR:InfoNoRecords;MX:1;A:1;LANG:en; spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="utf-8" Content-ID: <9FF6BE0764EAF54CA7D3C577A960455D@namprd04.prod.outlook.com> MIME-Version: 1.0 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-Network-Message-Id: 97eb35c0-d781-4224-1d9e-08d52148b259 X-MS-Exchange-CrossTenant-originalarrivaltime: 01 Nov 2017 16:50:45.4777 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY1PR0401MB1533 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id vA1GpGQ2015248 On Mon, 2017-10-23 at 17:12 +0200, Roman Penyaev wrote: > On Fri, Oct 20, 2017 at 10:05 PM, Bart Van Assche wrote: > > Commit 6d8c6c0f97ad is something I came up with to fix queue lockups in the > > SCSI and dm-mq drivers. > > You mean fairness? (some hctx get less amount of chances to be restarted). > That's why you need to restart them in RR fashion, right? Commit 6d8c6c0f97ad not only improved fairness but also fixed a lockup scenario. After a driver tag has been freed not only the hw queues of the request queue for which a request completed must be reexamined but also the hw queues associated with the other request queues that share the same tag set. Bart.