Hi Rafael,
On Tue, Jun 23, 2020 at 07:57:59PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
> Subject: [PATCH] cpuidle: Rearrange s2idle-specific idle state entry code
>
> Implement call_cpuidle_s2idle() in analogy with call_cpuidle()
> for the s2idle-specific idle state entry and invoke it from
> cpuidle_idle_call() to make the s2idle-specific idle entry code
> path look more similar to the "regular" idle entry one.
>
> No intentional functional impact.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
> ---
> drivers/cpuidle/cpuidle.c | 6 +++---
> kernel/sched/idle.c | 15 +++++++++++----
> 2 files changed, 14 insertions(+), 7 deletions(-)
>
> Index: linux-pm/kernel/sched/idle.c
> ===================================================================
> --- linux-pm.orig/kernel/sched/idle.c
> +++ linux-pm/kernel/sched/idle.c
> @@ -96,6 +96,15 @@ void __cpuidle default_idle_call(void)
> }
> }
>
> +static int call_cpuidle_s2idle(struct cpuidle_driver *drv,
> + struct cpuidle_device *dev)
> +{
> + if (current_clr_polling_and_test())
> + return -EBUSY;
> +
> + return cpuidle_enter_s2idle(drv, dev);
> +}
> +
> static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device
> *dev,
> int next_state)
> {
> @@ -171,11 +180,9 @@ static void cpuidle_idle_call(void)
> if (idle_should_enter_s2idle()) {
> rcu_idle_enter();
>
> - entered_state = cpuidle_enter_s2idle(drv, dev);
> - if (entered_state > 0) {
> - local_irq_enable();
> + entered_state = call_cpuidle_s2idle(drv, dev);
I guess this changes the context a little bit that(comparing to [1/2 patch],
after this modification, when we found that TIF_NEED_RESCHED is set we can have
a second chance in the following call_cpuidle to do a second s2idle try. However
in [1/2 patch], it might exit the s2idle phase directly once when we see
TIF_NEED_RESCHED is set(because entered_state is postive we treat it as a
successful
s2idle). In summary I think the change (patch [2/2]) is more robust.
Acked-by: Chen Yu <yu.c.c...@intel.com>
Thanks,
Chenyu
