Messages in this thread | | | Date | Wed, 21 Jul 2004 15:14:23 -0700 | Subject | Re: [linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch | From | Bill Huey (hui) <> |
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On Wed, Jul 21, 2004 at 11:18:26PM +0200, Ingo Molnar wrote: > trying to make softirqs preemptible surely wont fly for 2.6 and it will > also overly complicate the softirq model. What's so terminally wrong > about adding preemption checks to the softirq paths? It should solve the > preemption problem for good. The unbound softirq paths are well-known > (mostly in the networking code) and already have preemption-alike > checks.
These folks are tring to make the entire kernel fully preemptable, possibly, to handle arbitrary preemption at any point during the execution. It's a noble task to make the kernel preemptable in that way, but what I've seen is that the use of non-preemptive critical sections commits all locks below it in the call/lock graph to also be non-preemptive critical sections and therefore forcing the use of traditional lock-break and other techniques to lower latency.
Adding preemption points helps with the problems, but isn't something that can be guaranteed to have a certain latency within N numbers of context switches and some rescheduling computations, etc...
IMO, this is something that the Linux community should think about being friendly to or have some kind of consideration for the possibility of this.
bill
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