* [PATCH arm] Use common outgoing-CPU-notification code
@ 2019-06-11 19:24 Paul E. McKenney
2019-06-17 11:58 ` Mark Rutland
0 siblings, 1 reply; 5+ messages in thread
From: Paul E. McKenney @ 2019-06-11 19:24 UTC (permalink / raw)
To: linux, mark.rutland, dietmar.eggemann; +Cc: linux-kernel, linux-arm-kernel
This commit removes the open-coded CPU-offline notification with new
common code. In particular, this change avoids calling scheduler code
using RCU from an offline CPU that RCU is ignoring. This is a minimal
change. A more intrusive change might invoke the cpu_check_up_prepare()
and cpu_set_state_online() functions at CPU-online time, which would
allow onlining throw an error if the CPU did not go offline properly.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mark Rutland <mark.rutland@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index ebc53804d57b..8687d619260f 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -267,15 +267,13 @@ int __cpu_disable(void)
return 0;
}
-static DECLARE_COMPLETION(cpu_died);
-
/*
* called on the thread which is asking for a CPU to be shutdown -
* waits until shutdown has completed, or it is timed out.
*/
void __cpu_die(unsigned int cpu)
{
- if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
+ if (!cpu_wait_death(cpu, 5)) {
pr_err("CPU%u: cpu didn't die\n", cpu);
return;
}
@@ -322,7 +320,7 @@ void arch_cpu_idle_dead(void)
* this returns, power and/or clocks can be removed at any point
* from this CPU and its cache by platform_cpu_kill().
*/
- complete(&cpu_died);
+ (void)cpu_report_death();
/*
* Ensure that the cache lines associated with that completion are
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^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH arm] Use common outgoing-CPU-notification code
2019-06-11 19:24 [PATCH arm] Use common outgoing-CPU-notification code Paul E. McKenney
@ 2019-06-17 11:58 ` Mark Rutland
2019-06-17 13:06 ` Paul E. McKenney
0 siblings, 1 reply; 5+ messages in thread
From: Mark Rutland @ 2019-06-17 11:58 UTC (permalink / raw)
To: Paul E. McKenney; +Cc: linux, dietmar.eggemann, linux-arm-kernel, linux-kernel
On Tue, Jun 11, 2019 at 12:24:10PM -0700, Paul E. McKenney wrote:
> This commit removes the open-coded CPU-offline notification with new
> common code. In particular, this change avoids calling scheduler code
> using RCU from an offline CPU that RCU is ignoring. This is a minimal
> change. A more intrusive change might invoke the cpu_check_up_prepare()
> and cpu_set_state_online() functions at CPU-online time, which would
> allow onlining throw an error if the CPU did not go offline properly.
>
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: Russell King <linux@arm.linux.org.uk>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
FWIW:
Acked-by: Mark Rutland <mark.rutland@arm.com>
On the assumption that Russell is ok with this, I think this should be
dropped into the ARM patch system [1].
Paul, are you familiar with that, or would you prefer that someone else
submits the patch there? I can do so if you'd like.
Thanks,
Mark.
[1] https://www.armlinux.org.uk/developer/patches/info.php
>
> diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
> index ebc53804d57b..8687d619260f 100644
> --- a/arch/arm/kernel/smp.c
> +++ b/arch/arm/kernel/smp.c
> @@ -267,15 +267,13 @@ int __cpu_disable(void)
> return 0;
> }
>
> -static DECLARE_COMPLETION(cpu_died);
> -
> /*
> * called on the thread which is asking for a CPU to be shutdown -
> * waits until shutdown has completed, or it is timed out.
> */
> void __cpu_die(unsigned int cpu)
> {
> - if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
> + if (!cpu_wait_death(cpu, 5)) {
> pr_err("CPU%u: cpu didn't die\n", cpu);
> return;
> }
> @@ -322,7 +320,7 @@ void arch_cpu_idle_dead(void)
> * this returns, power and/or clocks can be removed at any point
> * from this CPU and its cache by platform_cpu_kill().
> */
> - complete(&cpu_died);
> + (void)cpu_report_death();
>
> /*
> * Ensure that the cache lines associated with that completion are
>
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH arm] Use common outgoing-CPU-notification code
2019-06-17 11:58 ` Mark Rutland
@ 2019-06-17 13:06 ` Paul E. McKenney
2019-06-26 16:42 ` Mark Rutland
0 siblings, 1 reply; 5+ messages in thread
From: Paul E. McKenney @ 2019-06-17 13:06 UTC (permalink / raw)
To: Mark Rutland; +Cc: linux, dietmar.eggemann, linux-arm-kernel, linux-kernel
On Mon, Jun 17, 2019 at 12:58:19PM +0100, Mark Rutland wrote:
> On Tue, Jun 11, 2019 at 12:24:10PM -0700, Paul E. McKenney wrote:
> > This commit removes the open-coded CPU-offline notification with new
> > common code. In particular, this change avoids calling scheduler code
> > using RCU from an offline CPU that RCU is ignoring. This is a minimal
> > change. A more intrusive change might invoke the cpu_check_up_prepare()
> > and cpu_set_state_online() functions at CPU-online time, which would
> > allow onlining throw an error if the CPU did not go offline properly.
> >
> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > Cc: linux-arm-kernel@lists.infradead.org
> > Cc: Russell King <linux@arm.linux.org.uk>
> > Cc: Mark Rutland <mark.rutland@arm.com>
> > Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
>
> FWIW:
>
> Acked-by: Mark Rutland <mark.rutland@arm.com>
>
> On the assumption that Russell is ok with this, I think this should be
> dropped into the ARM patch system [1].
>
> Paul, are you familiar with that, or would you prefer that someone else
> submits the patch there? I can do so if you'd like.
I never have used this system, so please do drop it in there! Let me
know when you have done so, and I will then drop it from -rcu.
Thanx, Paul
> Thanks,
> Mark.
>
> [1] https://www.armlinux.org.uk/developer/patches/info.php
>
> >
> > diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
> > index ebc53804d57b..8687d619260f 100644
> > --- a/arch/arm/kernel/smp.c
> > +++ b/arch/arm/kernel/smp.c
> > @@ -267,15 +267,13 @@ int __cpu_disable(void)
> > return 0;
> > }
> >
> > -static DECLARE_COMPLETION(cpu_died);
> > -
> > /*
> > * called on the thread which is asking for a CPU to be shutdown -
> > * waits until shutdown has completed, or it is timed out.
> > */
> > void __cpu_die(unsigned int cpu)
> > {
> > - if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
> > + if (!cpu_wait_death(cpu, 5)) {
> > pr_err("CPU%u: cpu didn't die\n", cpu);
> > return;
> > }
> > @@ -322,7 +320,7 @@ void arch_cpu_idle_dead(void)
> > * this returns, power and/or clocks can be removed at any point
> > * from this CPU and its cache by platform_cpu_kill().
> > */
> > - complete(&cpu_died);
> > + (void)cpu_report_death();
> >
> > /*
> > * Ensure that the cache lines associated with that completion are
> >
>
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH arm] Use common outgoing-CPU-notification code
2019-06-17 13:06 ` Paul E. McKenney
@ 2019-06-26 16:42 ` Mark Rutland
2019-06-26 17:49 ` Paul E. McKenney
0 siblings, 1 reply; 5+ messages in thread
From: Mark Rutland @ 2019-06-26 16:42 UTC (permalink / raw)
To: Paul E. McKenney; +Cc: linux, dietmar.eggemann, linux-arm-kernel, linux-kernel
On Mon, Jun 17, 2019 at 06:06:57AM -0700, Paul E. McKenney wrote:
> On Mon, Jun 17, 2019 at 12:58:19PM +0100, Mark Rutland wrote:
> > On Tue, Jun 11, 2019 at 12:24:10PM -0700, Paul E. McKenney wrote:
> > > This commit removes the open-coded CPU-offline notification with new
> > > common code. In particular, this change avoids calling scheduler code
> > > using RCU from an offline CPU that RCU is ignoring. This is a minimal
> > > change. A more intrusive change might invoke the cpu_check_up_prepare()
> > > and cpu_set_state_online() functions at CPU-online time, which would
> > > allow onlining throw an error if the CPU did not go offline properly.
> > >
> > > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > > Cc: linux-arm-kernel@lists.infradead.org
> > > Cc: Russell King <linux@arm.linux.org.uk>
> > > Cc: Mark Rutland <mark.rutland@arm.com>
> > > Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> >
> > FWIW:
> >
> > Acked-by: Mark Rutland <mark.rutland@arm.com>
> >
> > On the assumption that Russell is ok with this, I think this should be
> > dropped into the ARM patch system [1].
> >
> > Paul, are you familiar with that, or would you prefer that someone else
> > submits the patch there? I can do so if you'd like.
>
> I never have used this system, so please do drop it in there! Let me
> know when you have done so, and I will then drop it from -rcu.
After testing that multi_v7_defconfig built, I've just submitted this as
8872/1:
https://www.armlinux.org.uk/developer/patches/viewpatch.php?id=8872/1
Thanks,
Mark.
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH arm] Use common outgoing-CPU-notification code
2019-06-26 16:42 ` Mark Rutland
@ 2019-06-26 17:49 ` Paul E. McKenney
0 siblings, 0 replies; 5+ messages in thread
From: Paul E. McKenney @ 2019-06-26 17:49 UTC (permalink / raw)
To: Mark Rutland; +Cc: linux, dietmar.eggemann, linux-arm-kernel, linux-kernel
On Wed, Jun 26, 2019 at 05:42:00PM +0100, Mark Rutland wrote:
> On Mon, Jun 17, 2019 at 06:06:57AM -0700, Paul E. McKenney wrote:
> > On Mon, Jun 17, 2019 at 12:58:19PM +0100, Mark Rutland wrote:
> > > On Tue, Jun 11, 2019 at 12:24:10PM -0700, Paul E. McKenney wrote:
> > > > This commit removes the open-coded CPU-offline notification with new
> > > > common code. In particular, this change avoids calling scheduler code
> > > > using RCU from an offline CPU that RCU is ignoring. This is a minimal
> > > > change. A more intrusive change might invoke the cpu_check_up_prepare()
> > > > and cpu_set_state_online() functions at CPU-online time, which would
> > > > allow onlining throw an error if the CPU did not go offline properly.
> > > >
> > > > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > > > Cc: linux-arm-kernel@lists.infradead.org
> > > > Cc: Russell King <linux@arm.linux.org.uk>
> > > > Cc: Mark Rutland <mark.rutland@arm.com>
> > > > Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> > >
> > > FWIW:
> > >
> > > Acked-by: Mark Rutland <mark.rutland@arm.com>
> > >
> > > On the assumption that Russell is ok with this, I think this should be
> > > dropped into the ARM patch system [1].
> > >
> > > Paul, are you familiar with that, or would you prefer that someone else
> > > submits the patch there? I can do so if you'd like.
> >
> > I never have used this system, so please do drop it in there! Let me
> > know when you have done so, and I will then drop it from -rcu.
>
> After testing that multi_v7_defconfig built, I've just submitted this as
> 8872/1:
>
> https://www.armlinux.org.uk/developer/patches/viewpatch.php?id=8872/1
Very good, thank you! I will drop this from my -rcu tree.
Thanx, Paul
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^ permalink raw reply [flat|nested] 5+ messages in thread
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2019-06-11 19:24 [PATCH arm] Use common outgoing-CPU-notification code Paul E. McKenney
2019-06-17 11:58 ` Mark Rutland
2019-06-17 13:06 ` Paul E. McKenney
2019-06-26 16:42 ` Mark Rutland
2019-06-26 17:49 ` Paul E. McKenney
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