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

[Quan Xu]

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 more about it?

 -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)
> >   }
> >   
> >   /* Weak implementations for optional arch specific functions */
> > +void __weak arch_cpu_idle_poll(void) { }
> >   void __weak arch_cpu_idle_prepare(void) { }
> >   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?