Messages in this thread | | | Subject | Re: [patch] cpusets, cgroups: disallow attaching kthreadd | From | Peter Zijlstra <> | Date | Tue, 11 Oct 2011 16:08:07 +0200 |
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On Mon, 2011-10-10 at 09:43 -0700, Tejun Heo wrote:
> Yes, I think we need something like this. wq workers were using > PF_THREAD_BOUND to prevent diddling from userland which made some > unhappy.
But that can be properly fixed.
> Maybe we need a flag to properly indicate "don't diddle with > this thread from userland"? But, then, mainline kernel wouldn't need > the current PF_THREAD_BOUND at all. Peter, Steven, what do you think?
Strict per-cpu affinity that is needed for correctness and disallows sched_setaffinity() is something entirely different from not being allowed to put something in a cgroup.
As to not allowing to put in a cgroup thing, is there anything other than kthreadd for which we need to enforce that? So far I've mostly treated it like: root can do stupid things, this is one of them, don't do that then.
I don't think its horribly bad to change the affinity mask of kthreadd, if a sibling kthread needs a specific affinity it should set that and override whatever it inherits. If it runs with the default, its a neat way of setting that.
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