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Date:   Tue, 18 Aug 2020 11:17:56 +0100
From:   Chris Down <chris@chrisdown.name>
To:     peterz@infradead.org
Cc:     Michal Hocko <mhocko@suse.com>, Waiman Long <longman@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Ingo Molnar <mingo@kernel.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org,
        linux-mm@kvack.org
Subject: Re: [RFC PATCH 0/8] memcg: Enable fine-grained per process memory
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peterz@infradead.org writes:
>But then how can it run-away like Waiman suggested?

Probably because he's not running with that commit at all. We and others use 
this to prevent runaway allocation on a huge range of production and desktop 
use cases and it works just fine.

>/me goes look... and finds MEMCG_MAX_HIGH_DELAY_JIFFIES.
>
>That's a fail... :-(

I'd ask that you understand a bit more about the tradeoffs and intentions of 
the patch before rushing in to declare its failure, considering it works just 
fine :-)

Clamping the maximal time allows the application to take some action to 
remediate the situation, while still being slowed down significantly. 2 seconds 
per allocation batch is still absolutely plenty for any use case I've come 
across. If you have evidence it isn't, then present that instead of vague 
notions of "wrongness".