From: Borislav Petkov <bp@alien8.de>
To: Sven Joachim <svenjoac@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
rjw@rjwysocki.net, x86@kernel.org, tony.luck@intel.com,
lenb@kernel.org, daniel.lezcano@linaro.org,
linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
linux-pm@vger.kernel.org, ulf.hansson@linaro.org,
paulmck@kernel.org, tglx@linutronix.de,
naresh.kamboju@linaro.org, Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
rcu@vger.kernel.org
Subject: [PATCH] rcu/tree: Export rcu_idle_{enter,exit} to module
Date: Mon, 21 Sep 2020 12:37:41 +0200 [thread overview]
Message-ID: <20200921103741.GC5901@zn.tnic> (raw)
In-Reply-To: <87wo0npk72.fsf@turtle.gmx.de>
Lemme add whatever get_maintainer spits, to Cc.
On Mon, Sep 21, 2020 at 11:12:33AM +0200, Sven Joachim wrote:
> On 2020-09-15 12:32 +0200, Peter Zijlstra wrote:
>
> > The C3 BusMaster idle code takes lock in a number of places, some deep
> > inside the ACPI code. Instead of wrapping it all in RCU_NONIDLE, have
> > the driver take over RCU-idle duty and avoid flipping RCU state back
> > and forth a lot.
> >
> > ( by marking 'C3 && bm_check' as RCU_IDLE, we _must_ call enter_bm() for
> > that combination, otherwise we'll loose RCU-idle, this requires
> > shuffling some code around )
> >
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>
> I got modpost errors in 5.9-rc6 after this patch:
>
> ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined!
> ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined!
>
> Reverting commit 1fecfdbb7acc made them go away. Notably my
> configuration had CONFIG_ACPI_PROCESSOR=m, changing that
> to CONFIG_ACPI_PROCESSOR=y let the build succeed as well.
I guess this. Running randconfigs on it for a while, to see what else
breaks.
---
From: Borislav Petkov <bp@suse.de>
Date: Mon, 21 Sep 2020 12:31:36 +0200
Fix this link error:
ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined!
ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined!
when CONFIG_ACPI_PROCESSOR is built as module. PeterZ says that in light
of ARM needing those soon too, they should simply be exported.
Fixes: 1fecfdbb7acc ("ACPI: processor: Take over RCU-idle for C3-BM idle")
Reported-by: Sven Joachim <svenjoac@gmx.de>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
---
kernel/rcu/tree.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8ce77d9ac716..f78ee759af9c 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -673,6 +673,7 @@ void rcu_idle_enter(void)
lockdep_assert_irqs_disabled();
rcu_eqs_enter(false);
}
+EXPORT_SYMBOL_GPL(rcu_idle_enter);
#ifdef CONFIG_NO_HZ_FULL
/**
@@ -886,6 +887,7 @@ void rcu_idle_exit(void)
rcu_eqs_exit(false);
local_irq_restore(flags);
}
+EXPORT_SYMBOL_GPL(rcu_idle_exit);
#ifdef CONFIG_NO_HZ_FULL
/**
--
2.21.0
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-09-21 10:37 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-15 10:31 [RFC][PATCH 0/4] Fix up ACPI processor idle vs RCU Peter Zijlstra
2020-09-15 10:31 ` [RFC][PATCH 1/4] acpi: Use CPUIDLE_FLAG_TIMER_STOP Peter Zijlstra
2020-09-15 16:26 ` Rafael J. Wysocki
2020-09-16 15:42 ` peterz
2020-09-16 16:01 ` Borislav Petkov
2020-09-16 17:38 ` Rafael J. Wysocki
2020-09-16 17:38 ` Rafael J. Wysocki
2020-09-22 3:26 ` Guenter Roeck
2020-09-22 19:03 ` Rafael J. Wysocki
2020-09-15 10:31 ` [RFC][PATCH 2/4] acpi: Use CPUIDLE_FLAG_TLB_FLUSHED Peter Zijlstra
2020-09-15 10:32 ` [RFC][PATCH 3/4] cpuidle: Allow cpuidle drivers to take over RCU-idle Peter Zijlstra
2020-09-15 13:20 ` Ulf Hansson
2020-09-15 10:32 ` [RFC][PATCH 4/4] acpi: Take over RCU-idle for C3-BM idle Peter Zijlstra
2020-09-21 9:12 ` Sven Joachim
2020-09-21 10:37 ` Borislav Petkov [this message]
2020-09-21 12:15 ` [PATCH] rcu/tree: Export rcu_idle_{enter,exit} to module Rafael J. Wysocki
2020-09-21 13:32 ` Paul E. McKenney
2020-09-21 13:38 ` Rafael J. Wysocki
2020-09-25 15:20 ` [RFC][PATCH 4/4] acpi: Take over RCU-idle for C3-BM idle Guenter Roeck
2020-09-25 15:24 ` Rafael J. Wysocki
2020-09-25 15:29 ` Paul E. McKenney
2020-09-15 18:31 ` [RFC][PATCH 0/4] Fix up ACPI processor idle vs RCU Borislav Petkov
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