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From: Chris Down <chris@chrisdown.name>
To: Yafang Shao <laoar.shao@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@kernel.org>,
	Vladimir Davydov <vdavydov.dev@gmail.com>,
	Linux MM <linux-mm@kvack.org>, Roman Gushchin <guro@fb.com>,
	stable@vger.kernel.org, Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH] mm, memcg: fix wrong mem cgroup protection
Date: Fri, 24 Apr 2020 14:05:54 +0100	[thread overview]
Message-ID: <20200424130554.GA1462690@chrisdown.name> (raw)
In-Reply-To: <CALOAHbAPkB4ryfQ1Lof+5REyC6KAD+WCz+sZqPb9tK3iZs+xnQ@mail.gmail.com>

I'm not debating whether your test case is correct or not, or whether the 
numbers are correct or not. The point is that 3 out of 4 people from mm list 
who have looked at this patch have no idea what it's trying to do, why it's 
important, or why these numbers *should* necessarily be wrong.

It's good that you have provided a way to demonstrate the effects of your 
changes, but one can't solve cognitive gaps with testing. If one could, then 
things like TDD would be effective on complex projects -- but they aren't[0].

We're really getting off in the weeds here, though. I just want to make it 
clear to you that if you think "more testing" is a solution to kernel ailments 
like this, you're going to be disappointed.

0: http://people.brunel.ac.uk/~csstmms/FucciEtAl_ESEM2016.pdf


  reply	other threads:[~2020-04-24 13:05 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-23  6:16 Yafang Shao
2020-04-23 15:33 ` Chris Down
2020-04-23 21:13   ` Roman Gushchin
2020-04-24  0:32     ` Yafang Shao
2020-04-24 10:40     ` Michal Hocko
2020-04-24 10:57       ` Yafang Shao
2020-04-24  0:49   ` Yafang Shao
2020-04-24 12:18     ` Chris Down
2020-04-24 12:44       ` Yafang Shao
2020-04-24 13:05         ` Chris Down [this message]
2020-04-24 13:10           ` Yafang Shao
2020-04-23 21:06 ` Roman Gushchin
2020-04-24  0:29   ` Yafang Shao
2020-04-24 13:14 ` Johannes Weiner
2020-04-24 13:44   ` Johannes Weiner
2020-04-24 14:33     ` Michal Hocko
2020-04-24 16:08     ` Yafang Shao
2020-04-24 14:29   ` Michal Hocko
2020-04-24 15:10     ` Johannes Weiner
2020-04-24 16:21       ` Michal Hocko
2020-04-24 16:51         ` Johannes Weiner
2020-04-27  8:25           ` Michal Hocko
2020-04-27  8:37             ` Yafang Shao
2020-04-27 16:52             ` Johannes Weiner
2020-04-24 16:21     ` Roman Gushchin
2020-04-24 16:30       ` Yafang Shao
2020-04-24 16:00   ` Yafang Shao

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