On 2019/7/11 下午9:47, Peter Zijlstra wrote:
[snip]
>> +    rcu_read_lock();
>> +    memcg = mem_cgroup_from_task(p);
>> +    if (idx != -1)
>> +            this_cpu_inc(memcg->stat_numa->locality[idx]);
> 
> I thought cgroups were supposed to be hierarchical. That is, if we have:
> 
>           R
>        / \
>        A
>       /\
>         B
>         \
>          t1
> 
> Then our task t1 should be accounted to B (as you do), but also to A and
> R.

I get the point but not quite sure about this...

Not like pages there are no hierarchical limitation on locality, also tasks
running in a particular group have no influence to others, not to mention the
extra overhead, does it really meaningful to account the stuff hierarchically?

Regards,
Michael Wang

> 
>> +    rcu_read_unlock();
>> +}
>> +#endif

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