Re: 答复: [PATCH] net: convert gro_count to bitmask

[David Miller <davem@davemloft.net>]

From: "Li,Rongqing" <lirongqing@baidu.com>
Date: Thu, 12 Jul 2018 03:03:51 +0000

> 
> 
>> -----邮件原件-----
>> 发件人: David Miller [mailto:davem@davemloft.net]
>> 发送时间: 2018年7月12日 10:49
>> 收件人: Li,Rongqing <lirongqing@baidu.com>
>> 抄送: netdev@vger.kernel.org
>> 主题: Re: [PATCH] net: convert gro_count to bitmask
>> 
>> From: Li RongQing <lirongqing@baidu.com>
>> Date: Wed, 11 Jul 2018 17:15:53 +0800
>> 
>> > +		clear_bit(index, &napi->gro_bitmask);
>> 
>> Please don't use atomics here, at least use __clear_bit().
>> 
> 
> Thanks, this is same as Eric's suggestion.
> 
> 
>> This is why I did the operations by hand in my version of the patch.
>> Also, if you are going to preempt my patch, at least retain the comment I
>> added around the GRO_HASH_BUCKETS definitions which warns the reader
>> about the limit.
>> 
> 
> I add BUILD_BUG_ON in netdev_init, so I think we need not to add comment

That's a good compile time check, but the person thinking about editing
the definition doesn't see the limit in the header file nor know why
the limit exists in the first place.