Messages in this thread | | | Date | Sun, 05 Feb 2012 14:16:17 +0200 | From | Avi Kivity <> | Subject | Re: [v7 0/8] Reduce cross CPU IPI interference |
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On 02/02/2012 07:51 PM, Paul E. McKenney wrote: > On Thu, Feb 02, 2012 at 07:23:39PM +0200, Avi Kivity wrote: > > On 02/02/2012 07:01 PM, Paul E. McKenney wrote: > > > > > > > > It's not called (since the cpu is not idle). Instead we call > > > > rcu_virt_note_context_switch(). > > > > > > Frederic's work checks to see if there is only one runnable user task > > > on a given CPU. If there is only one, then the scheduling-clock interrupt > > > is turned off for that CPU, and RCU is told to ignore it while it is > > > executing in user space. Not sure whether this covers KVM guests. > > > > Conceptually it's the same. Maybe it needs adjustments, since kvm > > enters a guest in a different way than the kernel exits to userspace. > > > > > In any case, this is not yet in mainline. > > > > Let me know when it's in, and I'll have a look. > > Could you please touch base with Frederic Weisbecker to make sure that > what he is doing works for you? >
Looks like there are new rcu_user_enter() and rcu_user_exit() APIs which we can use. Hopefully they subsume rcu_virt_note_context_switch() so we only need one set of APIs.
-- error compiling committee.c: too many arguments to function
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