# Re: \[PATCH v2 04/11\] sched: Simplify wake\_up\_\*idle\*()

- From: Qian Cai \<hidden\>
- Date: 2021-10-19 15:32:27 
- List: live-patching
- Page: https://ratatoskr.run/live-patching/2021/10/1547277
- Thread: https://ratatoskr.run/live-patching/2021/09/1525995/t.md

```text


On 10/19/2021 5:10 AM, Peter Zijlstra wrote:
> Here, hows this then?
> 
> ---
> diff --git a/kernel/smp.c b/kernel/smp.c
> index ad0b68a3a3d3..61ddc7a3bafa 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -1170,14 +1170,12 @@ void wake_up_all_idle_cpus(void)
>  {
>  	int cpu;
>  
> -	cpus_read_lock();
> -	for_each_online_cpu(cpu) {
> -		if (cpu == raw_smp_processor_id())
> -			continue;
> -
> -		wake_up_if_idle(cpu);
> +	for_each_cpu(cpu) {
> +		preempt_disable();
> +		if (cpu != smp_processor_id() && cpu_online(cpu))
> +			wake_up_if_idle(cpu);
> +		preempt_enable();
>  	}
> -	cpus_read_unlock();
>  }
>  EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus);

This does not compile.

kernel/smp.c:1173:18: error: macro "for_each_cpu" requires 2 arguments, but only 1 given
```