[{"id":1771891,"web_url":"http://patchwork.ozlabs.org/comment/1771891/","msgid":"<20170920140315.GR5788@mtr-leonro.local>","list_archive_url":null,"date":"2017-09-20T14:03:15","subject":"Re: [PATCH net-next 08/10] net/smc: introduce a delay","submitter":{"id":68852,"url":"http://patchwork.ozlabs.org/api/people/68852/","name":"Leon Romanovsky","email":"leon@kernel.org"},"content":"On Wed, Sep 20, 2017 at 01:58:11PM +0200, Ursula Braun wrote:\n> The number of outstanding work requests is limited. If all work\n> requests are in use, tx processing is postponed to another scheduling\n> of the tx worker. Switch to a delayed worker to have a gap for tx\n> completion queue events before the next retry.\n>\n\nHow will delay prevent and protect the resource exhausting?\n\nThanks","headers":{"Return-Path":"","X-Original-To":"patchwork-incoming@ozlabs.org","Delivered-To":"patchwork-incoming@ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=netdev-owner@vger.kernel.org;\n\treceiver=)","mail.kernel.org;\n\tdmarc=none (p=none dis=none) header.from=kernel.org","mail.kernel.org;\n\tspf=none smtp.mailfrom=leon@kernel.org"],"Received":["from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xy1fy4R7Kz9s82\n\tfor ;\n\tThu, 21 Sep 2017 00:03:22 +1000 (AEST)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1751554AbdITODU (ORCPT );\n\tWed, 20 Sep 2017 10:03:20 -0400","from mail.kernel.org ([198.145.29.99]:38366 \"EHLO mail.kernel.org\"\n\trhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP\n\tid S1751391AbdITODT (ORCPT );\n\tWed, 20 Sep 2017 10:03:19 -0400","from localhost (unknown [213.57.247.46])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256\n\tbits)) (No client certificate requested)\n\tby mail.kernel.org (Postfix) with ESMTPSA id F14A920C51;\n\tWed, 20 Sep 2017 14:03:17 +0000 (UTC)"],"DMARC-Filter":"OpenDMARC Filter v1.3.2 mail.kernel.org F14A920C51","Date":"Wed, 20 Sep 2017 17:03:15 +0300","From":"Leon Romanovsky ","To":"Ursula Braun ","Cc":"davem@davemloft.net, netdev@vger.kernel.org,\n\tlinux-rdma@vger.kernel.org, linux-s390@vger.kernel.org,\n\tjwi@linux.vnet.ibm.com, schwidefsky@de.ibm.com,\n\theiko.carstens@de.ibm.com, raspl@linux.vnet.ibm.com","Subject":"Re: [PATCH net-next 08/10] net/smc: introduce a delay","Message-ID":"<20170920140315.GR5788@mtr-leonro.local>","References":"<20170920115813.63745-1-ubraun@linux.vnet.ibm.com>\n\t<20170920115813.63745-9-ubraun@linux.vnet.ibm.com>","MIME-Version":"1.0","Content-Type":"multipart/signed; micalg=pgp-sha256;\n\tprotocol=\"application/pgp-signature\"; boundary=\"pleSNuEbvnUYtMxG\"","Content-Disposition":"inline","In-Reply-To":"<20170920115813.63745-9-ubraun@linux.vnet.ibm.com>","User-Agent":"Mutt/1.9.0 (2017-09-02)","Sender":"netdev-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"netdev@vger.kernel.org"}},{"id":1771929,"web_url":"http://patchwork.ozlabs.org/comment/1771929/","msgid":"","list_archive_url":null,"date":"2017-09-20T14:37:04","subject":"Re: [PATCH net-next 08/10] net/smc: introduce a delay","submitter":{"id":2266,"url":"http://patchwork.ozlabs.org/api/people/2266/","name":"Ursula Braun","email":"ubraun@linux.vnet.ibm.com"},"content":"On 09/20/2017 04:03 PM, Leon Romanovsky wrote:\n> On Wed, Sep 20, 2017 at 01:58:11PM +0200, Ursula Braun wrote:\n>> The number of outstanding work requests is limited. If all work\n>> requests are in use, tx processing is postponed to another scheduling\n>> of the tx worker. Switch to a delayed worker to have a gap for tx\n>> completion queue events before the next retry.\n>>\n> \n> How will delay prevent and protect the resource exhausting?\n> \n> Thanks\n> \n\nSMC runs with a fixed number of in-flight work requests per QP (constant\nSMC_WR_BUF_CNT) to prevent resource exhausting. If all work requests are\ncurrently in use, sending of another work request has to wait till some\noutstanding work request is confirmed via send completion queue. If sending\nis done in a context which is not allowed to wait, the tx_worker is\nscheduled instead.\nWith this patch a small delay is added to avoid too many unsuccessful send\nretries due to a still ongoing \"all work requests in use\" condition.","headers":{"Return-Path":"","X-Original-To":"patchwork-incoming@ozlabs.org","Delivered-To":"patchwork-incoming@ozlabs.org","Authentication-Results":"ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=netdev-owner@vger.kernel.org;\n\treceiver=)","Received":["from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xy2QB51YFz9sNr\n\tfor ;\n\tThu, 21 Sep 2017 00:37:22 +1000 (AEST)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1751635AbdITOhT (ORCPT );\n\tWed, 20 Sep 2017 10:37:19 -0400","from mx0b-001b2d01.pphosted.com ([148.163.158.5]:53344 \"EHLO\n\tmx0a-001b2d01.pphosted.com\" rhost-flags-OK-OK-OK-FAIL)\n\tby vger.kernel.org with ESMTP id S1751507AbdITOhS (ORCPT\n\t); Wed, 20 Sep 2017 10:37:18 -0400","from pps.filterd (m0098417.ppops.net [127.0.0.1])\n\tby mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id\n\tv8KEYYNX041727\n\tfor ; Wed, 20 Sep 2017 10:37:18 -0400","from e06smtp10.uk.ibm.com (e06smtp10.uk.ibm.com [195.75.94.106])\n\tby mx0a-001b2d01.pphosted.com with ESMTP id 2d3su8sxng-1\n\t(version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT)\n\tfor ; Wed, 20 Sep 2017 10:37:17 -0400","from localhost\n\tby e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use\n\tOnly! Violators will be prosecuted\n\tfor from ;\n\tWed, 20 Sep 2017 15:37:15 +0100","from b06cxnps4074.portsmouth.uk.ibm.com (9.149.109.196)\n\tby e06smtp10.uk.ibm.com (192.168.101.140) with IBM ESMTP SMTP\n\tGateway: Authorized Use Only! Violators will be prosecuted; \n\tWed, 20 Sep 2017 15:37:13 +0100","from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com\n\t[9.149.105.62])\n\tby b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with\n\tESMTP id v8KEbCYm23724246; Wed, 20 Sep 2017 14:37:12 GMT","from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1])\n\tby IMSVA (Postfix) with ESMTP id 725D9AE04D;\n\tWed, 20 Sep 2017 15:32:05 +0100 (BST)","from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1])\n\tby IMSVA (Postfix) with ESMTP id 0AB5CAE045;\n\tWed, 20 Sep 2017 15:32:05 +0100 (BST)","from oc0447013845.ibm.com (unknown [9.152.222.28])\n\tby d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP;\n\tWed, 20 Sep 2017 15:32:04 +0100 (BST)"],"Subject":"Re: [PATCH net-next 08/10] net/smc: introduce a delay","To":"Leon Romanovsky ","Cc":"davem@davemloft.net, netdev@vger.kernel.org,\n\tlinux-rdma@vger.kernel.org, linux-s390@vger.kernel.org,\n\tjwi@linux.vnet.ibm.com, schwidefsky@de.ibm.com,\n\theiko.carstens@de.ibm.com, raspl@linux.vnet.ibm.com","References":"<20170920115813.63745-1-ubraun@linux.vnet.ibm.com>\n\t<20170920115813.63745-9-ubraun@linux.vnet.ibm.com>\n\t<20170920140315.GR5788@mtr-leonro.local>","From":"Ursula Braun ","Date":"Wed, 20 Sep 2017 16:37:04 +0200","User-Agent":"Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101\n\tThunderbird/52.3.0","MIME-Version":"1.0","In-Reply-To":"<20170920140315.GR5788@mtr-leonro.local>","Content-Type":"multipart/signed; micalg=pgp-sha1;\n\tprotocol=\"application/pgp-signature\";\n\tboundary=\"gkd84svHUA67ToIcEcsqtjfc0Dii1QHOK\"","X-TM-AS-GCONF":"00","x-cbid":"17092014-0040-0000-0000-000003DBB3B0","X-IBM-AV-DETECTION":"SAVI=unused REMOTE=unused XFE=unused","x-cbparentid":"17092014-0041-0000-0000-000025DCE9BD","Message-Id":"","X-Proofpoint-Virus-Version":"vendor=fsecure engine=2.50.10432:, ,\n\tdefinitions=2017-09-20_04:, , signatures=0","X-Proofpoint-Spam-Details":"rule=outbound_notspam policy=outbound score=0\n\tspamscore=0 suspectscore=0\n\tmalwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam\n\tadjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000\n\tdefinitions=main-1709200199","Sender":"netdev-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"netdev@vger.kernel.org"}}]