Re: [PATCH] [request for inclusion] Realtime LSM

Peter Williams
2005-03-08T05:41:57Z

Andrew Morton wrote:
> Matt Mackall <mpm@selenic.com> wrote:
>
>>I think Chris Wright's last rlimit patch is more sensible and ready to
>> go.
>
>
> I must say that I like rlimits - very straightforward, although somewhat
> awkward to use from userspace due to shortsighted shell design.
>
> Does anyone have serious objections to this approach?

I don't object to rlimits per se and I think that they are useful but
not as a sole solution to this problem. Being able to give a task
preferential treatment is a permissions issue and should be solved as one.

Having RT cpu usage limits on tasks is a useful tool to have when
granting normal users the privilege of running tasks as RT tasks so that
you can limit the damage that they can do BUT the presence of a limit on
a task is not a very good criterion for granting that privilege.

The granting of the ability to switch to and from RT mode should require
a means to specify which users it applies to and also which programs it
applies to. The RT rlimits mechanism doesn't meet these criteria.

In summary, IMHO you should put them both in but modify the RT rlimits
patch so that it plays no part in the decision as to whether the task is
allowed to run as RT or not.

Peter
--
Peter Williams pwil3058@bigpond.net.au

"Learning, n. The kind of ignorance distinguishing the studious."
-- Ambrose Bierce