Re: [PATCH] mm/rmap.c: reuse mergeable anon_vma as parent when fork

From: Wei Yang
Date: Sat Oct 05 2019 - 08:35:33 EST


On Fri, Oct 04, 2019 at 06:15:54PM -0700, Matthew Wilcox wrote:
>On Sat, Oct 05, 2019 at 07:48:45AM +0800, Wei Yang wrote:
>> On Fri, Oct 04, 2019 at 09:11:20AM -0700, Matthew Wilcox wrote:
>> >On Sat, Oct 05, 2019 at 12:06:32AM +0800, Wei Yang wrote:
>> >> After this change, kernel build test reduces 20% anon_vma allocation.
>> >
>> >But does it have any effect on elapsed time or peak memory consumption?
>>
>> Do the same kernel build test and record time:
>>
>>
>> Origin
>>
>> real 2m50.467s
>> user 17m52.002s
>> sys 1m51.953s
>>
>> real 2m48.662s
>> user 17m55.464s
>> sys 1m50.553s
>>
>> real 2m51.143s
>> user 17m59.687s
>> sys 1m53.600s
>>
>>
>> Patched
>>
>> real 2m43.733s
>> user 17m25.705s
>> sys 1m41.791s
>>
>> real 2m47.146s
>> user 17m47.451s
>> sys 1m43.474s
>>
>> real 2m45.763s
>> user 17m38.230s
>> sys 1m42.102s
>>
>>
>> For time in sys, it reduced 8.5%.
>
>That's compelling!

Yep, looks good :-)

--
Wei Yang
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