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 <paul...@linux.vnet.ibm.com> > Cc: linux-arm-ker...@lists.infradead.org > Cc: Russell King <li...@arm.linux.org.uk> > Cc: Mark Rutland <mark.rutl...@arm.com> > Tested-by: Dietmar Eggemann <dietmar.eggem...@arm.com>
FWIW: Acked-by: Mark Rutland <mark.rutl...@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 >
