Re: [PATCH -mm] mm: more likely reclaim MADV_SEQUENTIAL mappings

From: KOSAKI Motohiro
Date: Sun Jul 20 2008 - 23:53:34 EST

Hi Andrew,

>> in my experience,
>> - page_referenced_one is performance critical point.
>> you should test some benchmark.
>> - its patch improved mmaped-copy performance about 5%.
>> (Of cource, you should test in current -mm. MM code was changed widely)
>> So, I'm looking for your test result :)
> The change seems logical and I queued it for 2.6.28.


> But yes, testing for what-does-this-improve is good and useful, but so
> is testing for what-does-this-worsen. How do we do that in this case?

In general, page_referenced_one is important for reclaim throuput.
if crap page_referenced_one changing happend,
system reclaim throuput become slow down.

Of cource, I don't think this patch cause performance regression :-)

So, any benchmark with memcgroup memory restriction is good choice.

maybe, I will able to post mamped-copy improve mesurement of Johannes's patch
after OLS.
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