Messages in this thread | | | Date | Wed, 8 Aug 2007 12:20:56 +0200 | From | Andi Kleen <> | Subject | Re: allow non root users to set io priority "idle" ? |
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On Wed, Aug 08, 2007 at 01:51:32PM +0400, Sheplyakov Alexei wrote: > On Mon, Aug 06, 2007 at 01:11:01PM +0200, Andi Kleen wrote: > > > Very low priority can starve others when it holds some kernel resource > > needed by another task. > > Nevertheless ordinary users are permitted to lower priority ([re]nice)
Low priority as allowed by renice is ok -- the resource holder will run eventually and the system make progress.
> I don't quite understand. There are a lot of other ways to starve such > high-priority process: > 1. renice the low-priority process
That requires user action.
e.g. if you google a bit you can find a famous story where the NASA had to do that remotely to solve a PI problem on one of the Mars rovers. But I'm sure they weren't very pleased about it. And not everybody has a JPL control room to patch things up in the backhand.
> 2. send it a signal > 3. ptrace it
Only root can do these.
-Andi
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