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From: Andrew Morton <akpm@google.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Paul Menage <paul@paulmenage.org>, Li Zefan <lizf@cn.fujitsu.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Aditya Kali <adityakali@google.com>,
	Oleg Nesterov <oleg@redhat.com>,
	Kay Sievers <kay.sievers@vrfy.org>,
	Tim Hockin <thockin@hockin.org>, Tejun Heo <tj@kernel.org>,
	Containers <containers@lists.osdl.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 00/11 v5] cgroups: Task counter subsystem
Date: Tue, 13 Sep 2011 15:23:02 -0700	[thread overview]
Message-ID: <20110913152302.6c33ea6d.akpm@google.com> (raw)
In-Reply-To: <1315869091-18933-1-git-send-email-fweisbec@gmail.com>

On Tue, 13 Sep 2011 01:11:20 +0200
Frederic Weisbecker <fweisbec@gmail.com> wrote:

> No functional changes. Only documentation and comments added.
> Checkpatch.pl fixes, etc...
> 

What is the actual rationale for merging all of this?  For this amount
of complexity I do think we need to see significant end-user benefits. 
But all I'm seeing in this patchset is

       This is a step to be able to isolate a bit more a cgroup
       against the rest of the system and limit the global impact of a
       fork bomb inside a given cgroup.

which is really very thin.



Also, the changelogs don't appear to mention any testing results for
the fork-bomb-killer feature.

Is the fork-bomb-killer feature realistically useful?  As I understand
it, the problem with a fork-bomb is that it causes a huge swapstorm
while creating tasks very quickly.  The latency impact of the swapping
makes it very hard to regain control of the system so you can stop the
forking.  So to be effective, this feature would need to limit the
swapping?  Or something.  More substantiation, please.



Also, what is the relationship between this and RLIMIT_NPROC?  Given
that we have user namespaces, does that give us per-user,
per-namespace, per-container rlimits?  If it doesn't, should it?  Will
it?  If it does/will, how duplicative will that be?

  parent reply	other threads:[~2011-09-13 22:25 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-12 23:11 [PATCH 00/11 v5] cgroups: Task counter subsystem Frederic Weisbecker
2011-09-12 23:11 ` [PATCH 01/11] cgroups: Add res_counter_write_u64() API Frederic Weisbecker
2011-09-12 23:11 ` [PATCH 02/11] cgroups: New resource counter inheritance API Frederic Weisbecker
2011-09-12 23:11 ` [PATCH 03/11] cgroups: Add previous cgroup in can_attach_task/attach_task callbacks Frederic Weisbecker
2011-09-12 23:11 ` [PATCH 04/11] cgroups: New cancel_attach_task subsystem callback Frederic Weisbecker
2011-09-12 23:11 ` [PATCH 05/11] cgroups: Ability to stop res charge propagation on bounded ancestor Frederic Weisbecker
2011-09-12 23:11 ` [PATCH 06/11] cgroups: Add res counter common ancestor searching Frederic Weisbecker
2011-09-18 19:59   ` Kirill A. Shutemov
2011-09-30 12:42     ` Frederic Weisbecker
2011-10-01 15:07     ` Frederic Weisbecker
2011-10-01 15:19       ` Kirill A. Shutemov
2011-09-12 23:11 ` [PATCH 07/11] res_counter: Allow charge failure pointer to be null Frederic Weisbecker
2011-09-12 23:11 ` [PATCH 08/11] cgroups: Pull up res counter charge failure interpretation to caller Frederic Weisbecker
2011-09-12 23:11 ` [PATCH 09/11] cgroups: Add a task counter subsystem Frederic Weisbecker
2011-09-18 20:27   ` Kirill A. Shutemov
2011-09-30 12:54     ` Frederic Weisbecker
2011-09-30 21:03       ` Kirill A. Shutemov
2011-10-01 13:03         ` Frederic Weisbecker
2011-09-12 23:11 ` [PATCH 10/11] cgroups: Allow subsystems to cancel a fork Frederic Weisbecker
2011-09-12 23:11 ` [PATCH 11/11] cgroups: Convert task counter to use the subsys fork callback Frederic Weisbecker
2011-09-13 14:32 ` [PATCH 00/11 v5] cgroups: Task counter subsystem Peter Zijlstra
2011-09-13 14:37   ` Frederic Weisbecker
2011-09-13 14:49     ` Peter Zijlstra
2011-09-13 15:01       ` Frederic Weisbecker
2011-09-13 15:21 ` Frederic Weisbecker
2011-09-13 22:23 ` Andrew Morton [this message]
2011-09-15 13:56   ` Frederic Weisbecker

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