Re: [patch, 2.6.11-rc2] sched: /proc/sys/kernel/rt_cpu_limit tunable

[Chris Wright <chrisw@osdl.org>]

* Ingo Molnar (mingo@elte.hu) wrote:
> * Chris Wright <chrisw@osdl.org> wrote:
> > * Ingo Molnar (mingo@elte.hu) wrote:
> > > well, there's setrlimit, so you could add a jackd client callback that
> > > instructs all clients to change their RT_CPU_RATIO rlimit. In theory we
> > > could try to add a new rlimit syscall that changes another task's rlimit
> > > (right now the syscalls only allow the changing of the rlimit of the
> > > current task) - that would enable utilities to change the rlimit of all
> > > tasks in the system, achieving the equivalent of a global sysctl.
> > 
> > We've talked about smth. similar in another thread.  I'm not opposed
> > to the idea.
> 
> did that thread go into technical details? There are some rlimit users
> that might not be prepared to see the rlimit change under them. The
> RT_CPU_RATIO one ought to be safe, but generally i'm not so sure.

Not really.   I mentioned the above, as well as the security concern.
Right now, at least the task_setrlimit hook would have to change to take
into account the task.  And I never convinced myself that async changes
would be safe for each rlimit.

thanks,
-chris
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