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

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Date:   Tue,  7 Jun 2022 19:24:58 -0300
From:   "Guilherme G. Piccoli" <gpiccoli@...lia.com>
To:     linux-acpi@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        rafael.j.wysocki@...el.com, kernel@...ccoli.net,
        kernel-dev@...lia.com,
        "Guilherme G. Piccoli" <gpiccoli@...lia.com>,
        Len Brown <lenb@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>
Subject: [PATCH] ACPI: processor/idle: Annotate more functions to live in cpuidle section

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);
-- 
2.36.0