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

Quan Xu
2017-09-01T05:58:02Z

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@gmail.com>
>> Signed-off-by: Quan Xu <quan.xu0@gmail.com>
> 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?