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Subject: Re: [PATCH] net/mlx4_en: ensure rx_desc updating reaches HW before
 prod db updating
To:     Tariq Toukan <tariqt@mellanox.com>,
        Eric Dumazet <eric.dumazet@gmail.com>,
        Jason Gunthorpe <jgg@ziepe.ca>
Cc:     junxiao.bi@oracle.com, netdev@vger.kernel.org,
        linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
        Saeed Mahameed <saeedm@mellanox.com>
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From:   "jianchao.wang" <jianchao.w.wang@oracle.com>
Message-ID: <532b4d71-e2eb-35f3-894e-1c3288e7bc3f@oracle.com>
Date:   Thu, 25 Jan 2018 11:27:17 +0800
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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 ?

Thanks in advance
Jianchao