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Subject: Re: [PATCH 1/4] numa: introduce per-cgroup numa balancing locality,
 statistic
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, mcgrof@kernel.org, keescook@chromium.org,
        linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org,
        Mel Gorman <mgorman@suse.de>, riel@surriel.com
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 <3ac9b43a-cc80-01be-0079-df008a71ce4b@linux.alibaba.com>
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From:   =?UTF-8?B?546L6LSH?= <yun.wang@linux.alibaba.com>
Message-ID: <f8766405-70f3-71b0-60de-03425350189d@linux.alibaba.com>
Date:   Fri, 12 Jul 2019 11:15:41 +0800
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On 2019/7/11 下午9:43, Peter Zijlstra wrote:
> On Wed, Jul 03, 2019 at 11:28:10AM +0800, 王贇 wrote:
>> +#ifdef CONFIG_NUMA_BALANCING
>> +
>> +enum memcg_numa_locality_interval {
>> +	PERCENT_0_29,
>> +	PERCENT_30_39,
>> +	PERCENT_40_49,
>> +	PERCENT_50_59,
>> +	PERCENT_60_69,
>> +	PERCENT_70_79,
>> +	PERCENT_80_89,
>> +	PERCENT_90_100,
>> +	NR_NL_INTERVAL,
>> +};
> 
> That's just daft; why not make 8 equal sized buckets.
> 
>> +struct memcg_stat_numa {
>> +	u64 locality[NR_NL_INTERVAL];
>> +};
> 
>> +	if (remote || local) {
>> +		idx = ((local * 10) / (remote + local)) - 2;
> 
> 		idx = (NR_NL_INTERVAL * local) / (remote + local);

Make sense, we actually want to observe the situation rather than
the ratio itself, will be in next version.

Regards,
Michael Wang

> 
>> +	}
>> +
>> +	rcu_read_lock();
>> +	memcg = mem_cgroup_from_task(p);
>> +	if (idx != -1)
>> +		this_cpu_inc(memcg->stat_numa->locality[idx]);
>> +	rcu_read_unlock();
>> +}
>> +#endif