lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Tue, 18 Aug 2020 12:26:16 +0200
From:   peterz@...radead.org
To:     Chris Down <chris@...isdown.name>
Cc:     Michal Hocko <mhocko@...e.com>, Waiman Long <longman@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Johannes Weiner <hannes@...xchg.org>,
        Vladimir Davydov <vdavydov.dev@...il.com>,
        Jonathan Corbet <corbet@....net>,
        Alexey Dobriyan <adobriyan@...il.com>,
        Ingo Molnar <mingo@...nel.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, cgroups@...r.kernel.org,
        linux-mm@...ck.org
Subject: Re: [RFC PATCH 0/8] memcg: Enable fine-grained per process memory
 control

On Tue, Aug 18, 2020 at 11:17:56AM +0100, Chris Down wrote:

> 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".

There is no feedback from the freeing rate, therefore it cannot be
correct in maintaining a maximum amount of pages.

0.5 pages / sec is still non-zero, and if the free rate is 0, you'll
crawl across whatever limit was set without any bounds. This is math
101.

It's true that I haven't been paying attention to mm in a while, but I
was one of the original authors of the I/O dirty balancing, I do think I
understand how these things work.

Powered by blists - more mailing lists