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SubjectRe: [RFC][PATCH] page reclaim throttle take2
KOSAKI Motohiro wrote:
> Hi
>
>>> I don't think so.
>>> all modern many cpu machine stand on NUMA.
>>> it mean following,
>>> - if cpu increases, then zone increases, too.
>>>
>>> if default value increase by #cpus, lock contension dramatically increase
>>> on large numa.
>>>
>>> Have I overlooked anything?
>>>
>> How about adding something like..
>> ==
>> CONFIG_SIMULTANEOUS_PAGE_RECLAIMERS
>> int
>> default 3
>> depends on DEBUG
>> help
>> This value determines the number of threads which can do page reclaim
>> in a zone simultaneously. If this is too big, performance under heavy memory
>> pressure will decrease.
>> If unsure, use default.
>> ==
>>
>> Then, you can get performance reports from people interested in this
>> feature in test cycle.
>
> hm, intersting.
> but sysctl parameter is more better, i think.
>
> OK, I'll add it at next post.

I think sysctl should be interesting. The config option provides good
documentation, but it is static in nature (requires reboot to change). I wish we
could have the best of both worlds.

--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL


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