Re: [PATCH v3] net/ixgbe: add proper memory barriers for some Rx functions

[zhoumin <zhoumin@loongson.cn>]

Hi Thomas,

On Mon, June 12, 2023 at 8:44PM, Thomas Monjalon wrote:
> 12/06/2023 13:58, zhoumin:
>> On Mon, June 12, 2023 at 6:26PM, Thomas Monjalon wrote:
>>> 15/05/2023 04:10, Zhang, Qi Z:
>>>> From: Ruifeng Wang <Ruifeng.Wang@arm.com>
>>>>> From: Min Zhou <zhoumin@loongson.cn>
>>>>>> ---
>>>>>> v3:
>>>>>> - Use rte_smp_rmb() as the proper memory barrier instead of rte_rmb()
>>>>>> ---
>>>>>> v2:
>>>>>> - Make the calling of rte_rmb() for all platforms
>>>>>> ---
>>> [...]
>>>>> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
>>>> Applied to dpdk-next-net-intel.
>>>>
>>>> Thanks
>>>> Qi
>>>>
>>> Why ignoring checkpatch?
>>> It is saying:
>>> "
>>> Warning in drivers/net/ixgbe/ixgbe_rxtx.c:
>>> Using rte_smp_[r/w]mb
>>> "
>>
>> I'm sorry. Should we never use rte_smp_[r/w]mb in the driver's code?
> No we should avoid.
> It has been decided to slowly replace such barriers.
> By the way, I think it is not enough documented.
> You can find an explanation in doc/guides/rel_notes/deprecation.rst
Thank your for providing the reference documents. I have read this file. 
The explanation is clear and I get it.
> I think we should also add some notes to
> lib/eal/include/generic/rte_atomic.h
Yes, I do think so. The notes added at the definitions of 
rte_smp_[r/w]mb are better.
> Tyler, Honnappa, Ruifeng, Konstantin, what do you think?
>