linux-kernel - Re: [PATCH] ACPI: processor/idle: Annotate more functions to live in cpuidle section

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Date:   Thu, 9 Jun 2022 20:44:53 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     "Guilherme G. Piccoli" <gpiccoli@...lia.com>
Cc:     ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Rafael Wysocki <rafael.j.wysocki@...el.com>,
        kernel@...ccoli.net, kernel-dev@...lia.com,
        Len Brown <lenb@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>
Subject: Re: [PATCH] ACPI: processor/idle: Annotate more functions to live in
 cpuidle section

On Wed, Jun 8, 2022 at 12:25 AM Guilherme G. Piccoli
<gpiccoli@...lia.com> wrote:
>
> Commit 6727ad9e206c ("nmi_backtrace: generate one-line reports for idle cpus")
> introduced a new text section called cpuidle; with that, we have a mechanism
> to add idling functions in such section and skip them from nmi_backtrace
> output, since they're useless and potentially flooding for such report.
>
> Happens that inlining might cause some real idle functions to end-up
> outside of such section; this is currently the case of ACPI processor_idle
> driver; the functions acpi_idle_enter_* do inline acpi_idle_do_entry(),
> hence they stay out of the cpuidle section.
> Fix that by marking such functions to also live in the cpuidle section.
>
> Fixes: 6727ad9e206c ("nmi_backtrace: generate one-line reports for idle cpus")
> Cc: Len Brown <lenb@...nel.org>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Rafael J. Wysocki <rafael@...nel.org>
> Signed-off-by: Guilherme G. Piccoli <gpiccoli@...lia.com>
> ---
>
> Hi folks, this was tested on top of v5.19-rc1, with sysrq-l.
>
> An alternative for this approach would be to mark acpi_idle_do_entry()
> as noinline, but I'd risk to say that's a bit worse performance-wise.
> Let me know your preference, I can rework the patch if you prefer =)
>
> Thanks in advance for reviews,
>
>
> Guilherme
>
>
>  drivers/acpi/processor_idle.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index 6a5572a1a80c..13200969ccf3 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -607,7 +607,7 @@ static DEFINE_RAW_SPINLOCK(c3_lock);
>   * @cx: Target state context
>   * @index: index of target state
>   */
> -static int acpi_idle_enter_bm(struct cpuidle_driver *drv,
> +static int __cpuidle acpi_idle_enter_bm(struct cpuidle_driver *drv,
>                                struct acpi_processor *pr,
>                                struct acpi_processor_cx *cx,
>                                int index)
> @@ -664,7 +664,7 @@ static int acpi_idle_enter_bm(struct cpuidle_driver *drv,
>         return index;
>  }
>
> -static int acpi_idle_enter(struct cpuidle_device *dev,
> +static int __cpuidle acpi_idle_enter(struct cpuidle_device *dev,
>                            struct cpuidle_driver *drv, int index)
>  {
>         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
> @@ -693,7 +693,7 @@ static int acpi_idle_enter(struct cpuidle_device *dev,
>         return index;
>  }
>
> -static int acpi_idle_enter_s2idle(struct cpuidle_device *dev,
> +static int __cpuidle acpi_idle_enter_s2idle(struct cpuidle_device *dev,
>                                   struct cpuidle_driver *drv, int index)
>  {
>         struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
> --

Applied as 5.20 material, thanks!