Re: [PATCH v10 10/11] arm64: idle: export arch_cpu_idle()

[Shuai Xue]

在 2025/2/19 05:33, Ankur Arora 写道:
> Needed for cpuidle-haltpoll.
>
> Acked-by: Will Deacon <will@xxxxxxxxxx>
> Signed-off-by: Ankur Arora <ankur.a.arora@xxxxxxxxxx>
> ---
>   arch/arm64/kernel/idle.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm64/kernel/idle.c b/arch/arm64/kernel/idle.c
> index 05cfb347ec26..b85ba0df9b02 100644
> --- a/arch/arm64/kernel/idle.c
> +++ b/arch/arm64/kernel/idle.c
> @@ -43,3 +43,4 @@ void __cpuidle arch_cpu_idle(void)
>   	 */
>   	cpu_do_idle();

Hi, Ankur,

With haltpoll_driver registered, arch_cpu_idle() on x86 can select
mwait_idle() in idle threads.

It use MONITOR sets up an effective address range that is monitored
for write-to-memory activities; MWAIT places the processor in
an optimized state (this may vary between different implementations)
until a write to the monitored address range occurs.

Should arch_cpu_idle() on arm64 also use the LDXR/WFE
to avoid wakeup IPI like x86 monitor/mwait?

Thanks.
Shuai