From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Peter Zijlstra <peterz@infradead.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Borislav Petkov <bp@alien8.de>,
"the arch/x86 maintainers" <x86@kernel.org>,
Tony Luck <tony.luck@intel.com>, Len Brown <lenb@kernel.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
Linux PM <linux-pm@vger.kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Naresh Kamboju <naresh.kamboju@linaro.org>
Subject: Re: [RFC][PATCH 4/4] acpi: Take over RCU-idle for C3-BM idle
Date: Fri, 25 Sep 2020 17:24:03 +0200 [thread overview]
Message-ID: <CAJZ5v0g2sCth5nofpPt4ucjQC0W=aU3YmSPqSRp+OyFWgS6YxA@mail.gmail.com> (raw)
In-Reply-To: <20200925152000.GA171076@roeck-us.net>
On Fri, Sep 25, 2020 at 5:20 PM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On Tue, Sep 15, 2020 at 12:32:01PM +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>
>
> ia64:defconfig:
>
> ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined!
> ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined!
>
> I realize that this has already been reported more than a week ago, with
> no visible reaction. Another problem introduced in the same file, resulting
> in
>
> drivers/acpi/processor_idle.c: In function 'lapic_timer_needs_broadcast':
> drivers/acpi/processor_idle.c:179:1: warning:
> no return statement in function returning non-void
>
> may cause ia64 boot problems since a non-zero return value will trigger
> a function call. AFAICS that is not supposed to happen on ia64.
There are fixes for the above in my tree, they will go to Linus shortly.
Thanks!
next prev parent reply other threads:[~2020-09-25 15:24 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 ` [PATCH] rcu/tree: Export rcu_idle_{enter,exit} to module Borislav Petkov
2020-09-21 12:15 ` 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 [this message]
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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