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

[Wei Yang]

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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