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From: "Michal Koutný" <mkoutny@suse.com>
To: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>, Michal Hocko <mhocko@suse.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	Shakeel Butt <shakeelb@google.com>,
	Muchun Song <songmuchun@bytedance.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
	linux-mm@kvack.org, Chris Down <chris@chrisdown.name>
Subject: Re: [PATCH] mm/memcontrol: Don't increase effective low/min if no protection needed
Date: Tue, 18 Oct 2022 00:46:24 +0200	[thread overview]
Message-ID: <Y03bQJcK4o4Po1v2@blackbook> (raw)
In-Reply-To: <Y0WiIDmPPXYZuHpX@slm.duckdns.org>

On Tue, Oct 11, 2022 at 07:04:32AM -1000, Tejun Heo <tj@kernel.org> wrote:
> Wouldn't it make sense to fix the test? With recursive_prot on, the cgroup
> actually is under low protection and it seems like the correct behavior is
> to report the low events accordingly.

It depends whether the there is a residual protection that the
memory.low=0 sibling can use (with memory_recursiveprot).

In the discussed LTP test, there should be no residual protection that
would justify the apparently misreported memory.low events. I.e. the
test is correct, the failure points to a subtle issue with distributing
residual protection among siblings.

Been there, (haven't) done that:
1) https://bugzilla.suse.com/show_bug.cgi?id=1196298
2) https://lore.kernel.org/r/20220325103118.GC2828@blackbody.suse.cz/

HTH,
Michal


      parent reply	other threads:[~2022-10-17 22:46 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-11 14:30 Waiman Long
2022-10-11 15:39 ` Michal Hocko
2022-10-11 17:00   ` Waiman Long
2022-10-11 17:04     ` Tejun Heo
2022-10-11 17:14       ` Waiman Long
2022-10-11 19:01       ` Michal Hocko
2022-10-17 22:46       ` Michal Koutný [this message]

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