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Subject: Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU
To:     Andrew Morton <akpm@linux-foundation.org>
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        tj@kernel.org, hughd@google.com, khlebnikov@yandex-team.ru,
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        Michal Hocko <mhocko@kernel.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
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        Rong Chen <rong.a.chen@intel.com>
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From:   Alex Shi <alex.shi@linux.alibaba.com>
Message-ID: <6d155f79-8ba2-b322-4e92-311e7be98f79@linux.alibaba.com>
Date:   Wed, 4 Mar 2020 15:06:48 +0800
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在 2020/3/4 上午8:46, Andrew Morton 写道:
> 
> Well, any difference would be small and the numbers did get a bit
> lower, albeit probably within the margin of error.
> 
> But you know, if someone were to send a patch which micro-optimized
> some code by replacing 'TestClearXXX()' with `if PageXXX()
> ClearPageXXX()', I would happily merge it!
> 
> Is this change essential to the overall patchset?  If not, I'd be
> inclined to skip it?
> 

Hi Andrew,

Thanks a lot for comments!
Yes, this patch is essential for all next.

Consider the normal memory testing would focus on user page, that probabably with PageLRU. 

Fengguang's vm-scalibicase-small-allocs which used a lots vm_area_struct slab, which may
got some impact. 0day/Cheng Rong is working on the test. In my roughly testing, it may drop 5% on my
96threads/394GB machine.

Thanks
Alex