Re: [RFC PATCH v2 3/7] sched/idle: Add poll before enter real idle path

[Quan Xu]

on 2017/9/1 13:57, Quan Xu wrote:
> on 2017/8/29 20:45, Peter Zijlstra wrote:
>
> > On Tue, Aug 29, 2017 at 11:46:37AM +0000, Yang Zhang wrote:
> > > Add poll in do_idle. For UP VM, if there are running task, it will not
> > > goes into idle path, so we only enable poll in SMP VM.
> > >
> > > Signed-off-by: Yang Zhang <yang.zhang.wz@xxxxxxxxx>
> > > Signed-off-by: Quan Xu <quan.xu0@xxxxxxxxx>
> > Broken SoB chain.
>  Peter, I can't follow 'Broken SoB chain'.. could you explain more 
> about it?
ÂÂÂ Peter, Ping..

Quan



> Â -Quan
>
> > > diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
> > > index 6c23e30..b374744 100644
> > > --- a/kernel/sched/idle.c
> > > +++ b/kernel/sched/idle.c
> > > @@ -74,6 +74,7 @@ static noinline int __cpuidle cpu_idle_poll(void)
> > > Â }
> > > Â Â /* Weak implementations for optional arch specific functions */
> > > +void __weak arch_cpu_idle_poll(void) { }
> > > Â void __weak arch_cpu_idle_prepare(void) { }
> > > Â void __weak arch_cpu_idle_enter(void) { }
> > And not a word on why we need a new arch hook. What's wrong with
> > arch_cpu_idle_enter() for instance?