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Subject: Re: [PATCH v8 2/3] Documentation: add a isolation strategy sysfs node
 for uacce
To:     Greg KH <gregkh@linuxfoundation.org>
References: <20220902031304.37516-1-yekai13@huawei.com>
 <20220902031304.37516-3-yekai13@huawei.com> <Yxr5BpM+VIjKhVpZ@kroah.com>
 <45a50cf5-7416-4fcf-925b-ecca787425a5@huawei.com>
 <Yyg3ig+Y/w9eS6h0@kroah.com>
CC:     <herbert@gondor.apana.org.au>, <linux-crypto@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <wangzhou1@hisilicon.com>,
        <liulongfang@huawei.com>
From:   "yekai (A)" <yekai13@huawei.com>
Message-ID: <ff94b31b-7428-efbb-afa8-1b24f6afc02b@huawei.com>
Date:   Wed, 21 Sep 2022 11:04:41 +0800
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On 2022/9/19 17:34, Greg KH wrote:
> On Mon, Sep 19, 2022 at 11:21:30AM +0800, yekai (A) wrote:
>>
>> On 2022/9/9 16:27, Greg KH wrote:
>>> On Fri, Sep 02, 2022 at 03:13:03AM +0000, Kai Ye wrote:
>>>> Update documentation describing sysfs node that could help to
>>>> configure isolation strategy for users in the user space. And
>>>> describing sysfs node that could read the device isolated state.
>>>>
>>>> Signed-off-by: Kai Ye <yekai13@huawei.com>
>>>> ---
>>>>  Documentation/ABI/testing/sysfs-driver-uacce | 26 ++++++++++++++++++++
>>>>  1 file changed, 26 insertions(+)
>>>>
>>>> diff --git a/Documentation/ABI/testing/sysfs-driver-uacce b/Documentation/ABI/testing/sysfs-driver-uacce
>>>> index 08f2591138af..af5bc2f326d2 100644
>>>> --- a/Documentation/ABI/testing/sysfs-driver-uacce
>>>> +++ b/Documentation/ABI/testing/sysfs-driver-uacce
>>>> @@ -19,6 +19,32 @@ Contact:        linux-accelerators@lists.ozlabs.org
>>>>  Description:    Available instances left of the device
>>>>                  Return -ENODEV if uacce_ops get_available_instances is not provided
>>>>  
>>>> +What:           /sys/class/uacce/<dev_name>/isolate_strategy
>>>> +Date:           Sep 2022
>>>> +KernelVersion:  6.0
>>>> +Contact:        linux-accelerators@lists.ozlabs.org
>>>> +Description:    (RW) Configure the frequency size for the hardware error
>>>> +                isolation strategy. This size is a configured integer value.
>>>> +                The default is 0. The maximum value is 65535. This value is a
>>>> +                threshold based on your driver strategies.
>>> I do not understand what the units are here.
>>>
>>> How is anyone supposed to know what they are?
>> This unit is the number of times. Number of occurrences in a period, also means threshold.
>> If the number of device pci AER error exceeds the threshold in a time window, the device is
>> isolated. 
> Please document this very very well.
>
>>>> +                For example, in the hisilicon accelerator engine, first we will
>>>> +                time-stamp every slot AER error. Then check the AER error log
>>>> +                when the device AER error occurred. if the device slot AER error
>>>> +                count exceeds the preset the number of times in one hour, the
>>>> +                isolated state will be set to true. So the device will be
>>>> +                isolated. And the AER error log that exceed one hour will be
>>>> +                cleared. Of course, different strategies can be defined in
>>>> +                different drivers.
>>> So this file can contain values of different units depending on the
>>> different driver that creates it?  How is anyone supposed to know what
>>> it is and what it should be?
>>>
>>> This feels very loose, please define this much better so that it can be
>>> understood and maintained properly.
>>>
>>> thanks,
>>>
>>> greg k-h
>>> .
>>>
>> Yes,  We started out with the idea of not restricting the different drive,  only specifying the input and output.
>> Because we think different drivers require different processing  strategy.
> What different drivers?  You only have one!  And why do you need a
> framework for only one driver?  You should only add that when you have
> multiple users to ensure you got the framework correct otherwise you do
> not know how it will be used.
>
> thanks,
>
> greg k-h
> .
>
ok . I will move isolation strategy from qm to uacce in the next version. 

it can be understood and maintained properly.

thanks

Kai