On Wed, 2011-01-05 at 01:12 +0800, Hillf Danton wrote: > On Wed, Jan 5, 2011 at 1:08 AM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote: > > On Wed, 2011-01-05 at 00:51 +0800, Hillf Danton wrote: > >> Where is the yield_to callback in the patch for RT schedule class? > >> If @p is RT, what could you do? > > > > RT guests are a pipe dream, you first need to get the hypervisor (kvm in > > this case) to be RT, which it isn't. Then you either need to very > > statically set-up the host and the guest scheduling constraints (not > > possible with RR/FIFO) or have a complete paravirt RT scheduler which > > communicates its requirements to the host. > > > Even guest is not RT, you could not prevent it from being preempted by > RT task which has nothing to do guests. Sure, but yield_to() being a NOP for RT tasks is perfectly fine. Pretty much all yield*() usage is a bug anyway. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
