Re: [PATCH 04/10] cpuidle, psci: Push RCU-idle into driver

[Geert Uytterhoeven]

Hi Cheng,

On Fri, Mar 3, 2023 at 10:35 AM Cheng-Jui Wang
<cheng-jui.wang@xxxxxxxxxxxx> wrote:
> From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
>
> commit e038f7b8028a1d1bc8ac82351c71ea538f19a879 upstream.
>
> Doing RCU-idle outside the driver, only to then temporarily enable it
> again, at least twice, before going idle is suboptimal.
>
> Notably once implicitly through the cpu_pm_*() calls and once
> explicitly doing ct_irq_*_irqon().
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
> Tested-by: Kajetan Puchalski <kajetan.puchalski@xxxxxxx>
> Tested-by: Tony Lindgren <tony@xxxxxxxxxxx>
> Tested-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
> Reviewed-by: Guo Ren <guoren@xxxxxxxxxx>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Link: https://lore.kernel.org/r/20230112195539.760296658@xxxxxxxxxxxxx
> Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
> Signed-off-by: Cheng-Jui Wang <cheng-jui.wang@xxxxxxxxxxxx>

Given this patch introduced a so far unresolved regression upstream,
I think it's premature to backport this to stable.

https://lore.kernel.org/all/ff338b9f-4ab0-741b-26ea-7b7351da156@xxxxxxxxxxxxxx

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds