From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Bristot de Oliveira <bristot-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [RFC PATCH 0/2] x86: Fix missing core serialization on migration
Date: Tue, 14 Nov 2017 19:01:55 +0100
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To: Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, Mathieu Desnoyers <mathieu.desnoyers-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org>, Avi Kivity <avi-VrcmuVmyx1hWk0Htik3J/w@public.gmane.org>, Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, linux-kernel <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, linux-api <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "Paul E. McKenney" <paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>, Boqun Feng <boqun.feng-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Andrew Hunter <ahh-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, maged michael <maged.michael-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Benjamin Herrenschmidt <benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>, Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>, Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>, Dave Watson <davejwatson-b10kYP2dOMg@public.gmane.org>, Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>, Andrea Parri <parri.andrea-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, "Russell King, ARM Linux" <linux@armlinux.o>
List-Id: linux-api@vger.kernel.org

On 11/14/2017 06:40 PM, Peter Zijlstra wrote:
> On Tue, Nov 14, 2017 at 06:17:13PM +0100, Daniel Bristot de Oliveira wrote:
> 
>> IIRC, if the dest cpu is idle and the system is with idle=poll, no IPI
>> is fired as well, but that is not a very common case.
> 
> You're thinking about wake from idle? That is almost always without IPI,
> even without idle=poll.
> 

I meant the resched_curr(rq) of an rq on another CPU. If the dest is
idle && idle=poll, the IPI will not be send.

-- Daniel