Messages in this thread | | | Date | Mon, 17 Jun 2019 06:06:57 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH arm] Use common outgoing-CPU-notification code |
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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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