linux-kernel - Re: [RFC 1/4] memcg: provide root figures from system totals

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, 2 Oct 2012 13:15:43 +0400
From:	Glauber Costa <glommer@...allels.com>
To:	Michal Hocko <mhocko@...e.cz>
CC:	<linux-kernel@...r.kernel.org>, <cgroups@...r.kernel.org>,
	<linux-mm@...ck.org>, <devel@...nvz.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Kamezawa Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Mel Gorman <mgorman@...e.de>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [RFC 1/4] memcg: provide root figures from system totals

On 10/01/2012 09:00 PM, Michal Hocko wrote:
> On Tue 25-09-12 12:52:50, Glauber Costa wrote:
>> > For the root memcg, there is no need to rely on the res_counters.
> This is true only if there are no children groups but once there is at
> least one we have to move global statistics into root res_counter and
> start using it since then. This is a tricky part because it has to be
> done atomically so that we do not miss anything.
> 
Why can't we shortcut it all the time?

It makes a lot of sense to use the root cgroup as the sum of everything,
IOW, global counters. Otherwise you are left in a situation where you
had global statistics, and all of a sudden, when a group is created, you
start having just a subset of that, excluding the tasks in root.

If we can always assume root will have the sum of *all* tasks, including
the ones in root, we should never need to rely on root res_counters.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/