linux-kernel - Re: [PATCH] mm/rmap.c: reuse mergeable anon

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Date:   Sat, 5 Oct 2019 07:48:45 +0800
From:   Wei Yang <richardw.yang@...ux.intel.com>
To:     Matthew Wilcox <willy@...radead.org>
Cc:     Wei Yang <richardw.yang@...ux.intel.com>,
        akpm@...ux-foundation.org, kirill.shutemov@...ux.intel.com,
        jglisse@...hat.com, mike.kravetz@...cle.com, riel@...riel.com,
        khlebnikov@...dex-team.ru, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm/rmap.c: reuse mergeable anon_vma as parent when fork

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%.

-- 
Wei Yang
Help you, Help me