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From: Chris Down <chris@chrisdown.name>
To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Jakub Kicinski <kuba@kernel.org>,
	linux-mm@kvack.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH] mm, memcg: Do not high throttle allocators based on wraparound
Date: Tue, 31 Mar 2020 18:04:10 +0100	[thread overview]
Message-ID: <20200331170410.GB972283@chrisdown.name> (raw)
In-Reply-To: <20200331155752.GN30449@dhcp22.suse.cz>

Michal Hocko writes:
>I find this paragraph rather confusing. This is essentially an unsigned
>underflow when any of the memcg up the hierarchy is below the high
>limit, right?  There doesn't really seem anything complex in such a
>hierarchy.

The conditions to trigger the bug itself are easy, but having it obviously 
visible in tests requires a moderately complex hierarchy, since in the basic 
case ancestor_usage is "similar enough" to the test leaf cgroup's usage.


  reply	other threads:[~2020-03-31 17:04 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-31 15:24 Chris Down
2020-03-31 15:25 ` Chris Down
2020-03-31 15:57 ` Michal Hocko
2020-03-31 17:04   ` Chris Down [this message]
2020-03-31 19:00     ` Chris Down
2020-04-15  4:39 ` Johannes Weiner

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