Re: [PATCH -V8 02/10] mm/numa: automatically generate node migration order

[Huang, Ying]

Dave Hansen <dave.hansen@xxxxxxxxx> writes:

> On 6/19/21 1:18 AM, Huang, Ying wrote:
>>>>  int next_demotion_node(int node)
>>>>  {
>>>> -	return node_demotion[node];
>>>> +	/*
>>>> +	 * node_demotion[] is updated without excluding
>>>> +	 * this function from running.  READ_ONCE() avoids
>>>> +	 * reading multiple, inconsistent 'node' values
>>>> +	 * during an update.
>>>> +	 */
>>>> +	return READ_ONCE(node_demotion[node]);
>>>>  }
>>> Is it necessary to have two separate patches to add node_demotion and
>>> next_demotion_node() then modify it immediately? Maybe merge Patch 1 into 2?
>>>
>>> Hmm, I just checked Patch 3 and it changes node_demotion again and uses RCU.
>>> I guess it might be much simpler to just introduce node_demotion with RCU
>>> in this patch and Patch 3 only takes care of hotplug events.
>> Hi, Dave,
>> 
>> What do you think about this?
>> 
>
> Squashing them seems like a good idea to me.

Sure.  Will do that.  How about move RCU from 3/10 to the squashed one?

Best Regards,
Huang, Ying