From mboxrd@z Thu Jan 1 00:00:00 1970 From: "jianchao.wang" Subject: Re: [PATCH] net/mlx4_en: ensure rx_desc updating reaches HW before prod db updating Date: Thu, 25 Jan 2018 14:25:04 +0800 Message-ID: <89066a75-43db-0f62-f171-70b0abaa8ea0@oracle.com> References: <1515728542-3060-1-git-send-email-jianchao.w.wang@oracle.com> <20180112163247.GB15974@ziepe.ca> <1515775567.131759.42.camel@gmail.com> <53b1ac4d-a294-eb98-149e-65d7954243da@oracle.com> <1516376999.3606.39.camel@gmail.com> <339a7156-9ef1-1f3c-30b8-3cc3558d124e@mellanox.com> <532b4d71-e2eb-35f3-894e-1c3288e7bc3f@oracle.com> <1516852543.3715.43.camel@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1516852543.3715.43.camel-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Content-Language: en-US Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Eric Dumazet , Tariq Toukan , Jason Gunthorpe Cc: junxiao.bi-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Saeed Mahameed List-Id: linux-rdma@vger.kernel.org Hi Eric Thanks for you kindly response and suggestion. That's really appreciated. Jianchao On 01/25/2018 11:55 AM, Eric Dumazet wrote: > On Thu, 2018-01-25 at 11:27 +0800, jianchao.wang wrote: >> Hi Tariq >> >> On 01/22/2018 10:12 AM, jianchao.wang wrote: >>>>> On 19/01/2018 5:49 PM, Eric Dumazet wrote: >>>>>> On Fri, 2018-01-19 at 23:16 +0800, jianchao.wang wrote: >>>>>>> Hi Tariq >>>>>>> >>>>>>> Very sad that the crash was reproduced again after applied the patch. >>>> >>>> Memory barriers vary for different Archs, can you please share more details regarding arch and repro steps? >>> The hardware is HP ProLiant DL380 Gen9/ProLiant DL380 Gen9, BIOS P89 12/27/2015 >>> The xen is installed. The crash occurred in DOM0. >>> Regarding to the repro steps, it is a customer's test which does heavy disk I/O over NFS storage without any guest. >>> >> >> What is the finial suggestion on this ? >> If use wmb there, is the performance pulled down ? > > Since https://urldefense.proofpoint.com/v2/url?u=https-3A__git.kernel.org_pub_scm_linux_kernel_git_davem_net-2Dnext.git_commit_-3Fid-3Ddad42c3038a59d27fced28ee4ec1d4a891b28155&d=DwICaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=7WdAxUBeiTUTCy8v-7zXyr4qk7sx26ATvfo6QSTvZyQ&m=c0oI8duFkyFBILMQYDsqRApHQrOlLY_2uGiz_utcd7s&s=E4_XKmSI0B63qB0DLQ1EX_fj1bOP78ZdeYADBf33B-k&e= > > we batch allocations, so mlx4_en_refill_rx_buffers() is not called that often. > > I doubt the additional wmb() will have serious impact there. > > -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751183AbeAYGZN (ORCPT ); Thu, 25 Jan 2018 01:25:13 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:42944 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750960AbeAYGZL (ORCPT ); Thu, 25 Jan 2018 01:25:11 -0500 Subject: Re: [PATCH] net/mlx4_en: ensure rx_desc updating reaches HW before prod db updating To: Eric Dumazet , Tariq Toukan , Jason Gunthorpe Cc: junxiao.bi@oracle.com, netdev@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, Saeed Mahameed References: <1515728542-3060-1-git-send-email-jianchao.w.wang@oracle.com> <20180112163247.GB15974@ziepe.ca> <1515775567.131759.42.camel@gmail.com> <53b1ac4d-a294-eb98-149e-65d7954243da@oracle.com> <1516376999.3606.39.camel@gmail.com> <339a7156-9ef1-1f3c-30b8-3cc3558d124e@mellanox.com> <532b4d71-e2eb-35f3-894e-1c3288e7bc3f@oracle.com> <1516852543.3715.43.camel@gmail.com> From: "jianchao.wang" Message-ID: <89066a75-43db-0f62-f171-70b0abaa8ea0@oracle.com> Date: Thu, 25 Jan 2018 14:25:04 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <1516852543.3715.43.camel@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8784 signatures=668655 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=807 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1801250088 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Eric Thanks for you kindly response and suggestion. That's really appreciated. Jianchao On 01/25/2018 11:55 AM, Eric Dumazet wrote: > On Thu, 2018-01-25 at 11:27 +0800, jianchao.wang wrote: >> Hi Tariq >> >> On 01/22/2018 10:12 AM, jianchao.wang wrote: >>>>> On 19/01/2018 5:49 PM, Eric Dumazet wrote: >>>>>> On Fri, 2018-01-19 at 23:16 +0800, jianchao.wang wrote: >>>>>>> Hi Tariq >>>>>>> >>>>>>> Very sad that the crash was reproduced again after applied the patch. >>>> >>>> Memory barriers vary for different Archs, can you please share more details regarding arch and repro steps? >>> The hardware is HP ProLiant DL380 Gen9/ProLiant DL380 Gen9, BIOS P89 12/27/2015 >>> The xen is installed. The crash occurred in DOM0. >>> Regarding to the repro steps, it is a customer's test which does heavy disk I/O over NFS storage without any guest. >>> >> >> What is the finial suggestion on this ? >> If use wmb there, is the performance pulled down ? > > Since https://urldefense.proofpoint.com/v2/url?u=https-3A__git.kernel.org_pub_scm_linux_kernel_git_davem_net-2Dnext.git_commit_-3Fid-3Ddad42c3038a59d27fced28ee4ec1d4a891b28155&d=DwICaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=7WdAxUBeiTUTCy8v-7zXyr4qk7sx26ATvfo6QSTvZyQ&m=c0oI8duFkyFBILMQYDsqRApHQrOlLY_2uGiz_utcd7s&s=E4_XKmSI0B63qB0DLQ1EX_fj1bOP78ZdeYADBf33B-k&e= > > we batch allocations, so mlx4_en_refill_rx_buffers() is not called that often. > > I doubt the additional wmb() will have serious impact there. > >