linux-kernel - Re: [RFC/PATCH] Add sysfs control to modify a user's cpu share

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]

Message-ID: <20071003040939.GI5724@linux.vnet.ibm.com>
Date:	Wed, 3 Oct 2007 09:39:39 +0530
From:	Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>
To:	Eric St-Laurent <ericstl34@...patico.ca>
Cc:	Ingo Molnar <mingo@...e.hu>,
	Dhaval Giani <dhaval@...ux.vnet.ibm.com>,
	Mike Galbraith <efault@....de>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Dmitry Adamushko <dmitry.adamushko@...il.com>,
	lkml <linux-kernel@...r.kernel.org>, maneesh@...ux.vnet.ibm.com,
	Andrew Morton <akpm@...ux-foundation.org>,
	Sudhir Kumar <skumar@...ux.vnet.ibm.com>
Subject: Re: [RFC/PATCH] Add sysfs control to modify a user's cpu share

On Tue, Oct 02, 2007 at 06:12:39PM -0400, Eric St-Laurent wrote:
> While a sysfs interface is OK and somewhat orthogonal to the interface
> proposed the containers patches, I think maybe a new syscall should be
> considered.

We had discussed syscall vs filesystem based interface for resource
management [1] and there was a heavy bias favoring filesystem based interface,
based on which the container (now "cgroup") filesystem evolved.

Where we already have one interface defined, I would be against adding 
an equivalent syscall interface.

Note that this "fair-user" scheduling can in theory be accomplished
using the same cgroup based interface, but requires some extra setup in
userspace (either to run a daemon which moves tasks to appropriate
control groups/containers upon their uid change OR to modify initrd to mount 
cgroup filesystem at early bootup time). I expect most distros to enable
CONFIG_FAIR_CGROUP_SCHED (control group based fair group scheduler) and not 
CONFIG_FAIR_USER_SHCED (user id based fair group scheduler). The only
reason why we are providing CONFIG_FAIR_USER_SCHED and the associated
sysfs interface is to help test group scheduler w/o requiring knowledge
of cgroup filesystem.

Reference:

1. http://marc.info/?l=linux-kernel&m=116231242201300&w=2

-- 
Regards,
vatsa
-
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/