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 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 To: Eric Dumazet , Tariq Toukan , Jason Gunthorpe 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 List-Id: netdev.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