linux-kernel - Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

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Message-ID: <6d155f79-8ba2-b322-4e92-311e7be98f79@linux.alibaba.com>
Date:   Wed, 4 Mar 2020 15:06:48 +0800
From:   Alex Shi <alex.shi@...ux.alibaba.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     cgroups@...r.kernel.org, mgorman@...hsingularity.net,
        tj@...nel.org, hughd@...gle.com, khlebnikov@...dex-team.ru,
        daniel.m.jordan@...cle.com, yang.shi@...ux.alibaba.com,
        willy@...radead.org, hannes@...xchg.org, lkp@...el.com,
        Michal Hocko <mhocko@...nel.org>,
        Vladimir Davydov <vdavydov.dev@...il.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Rong Chen <rong.a.chen@...el.com>
Subject: Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU



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