Re: [PATCH] arm64: smp: Update the topology masks before calling CPU_STARTING notifiers

[Rohit Vaswani]

On 8/15/2014 3:43 AM, Will Deacon wrote:
> On Wed, Aug 13, 2014 at 02:11:09AM +0100, Rohit Vaswani wrote:
> > Currently, the CPU_STARTING notifiers would observe an incorrect sibling
> > mask since the notifier chain is called before the topology masks are updated
> > for the new cpu.
> > Update the topology masks before calling the notifier chain to fix this
> > problem.
> >
> > Signed-off-by: Rohit Vaswani <rvaswani@xxxxxxxxxxxxxx>
> > ---
> >   arch/arm/kernel/smp.c   | 4 ++--
> >   arch/arm64/kernel/smp.c | 4 ++--
> >   2 files changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
> > index 7c4fada..0e2237c 100644
> > --- a/arch/arm/kernel/smp.c
> > +++ b/arch/arm/kernel/smp.c
> > @@ -363,12 +363,12 @@ asmlinkage void secondary_start_kernel(void)
> >   	if (smp_ops.smp_secondary_init)
> >   		smp_ops.smp_secondary_init(cpu);
> >   
> > +	smp_store_cpu_info(cpu);
> > +
> >   	notify_cpu_starting(cpu);
> >   
> >   	calibrate_delay();
> >   
> > -	smp_store_cpu_info(cpu);
> > -
> Hmm, smp_store_cpu_info takes a copy of loops_per_jiffy. Are you sure it's
> safe to move the call before calibrate_delay?

Right! - I had looked at the arm64 version .  I checked for arm32 now 
and I think we should be
safe to move calibrate_delay before the smp_store_cpu_info and I can 
push a v2 version if
there are no concerns. I did not see calibrate_delay having any 
dependency for cpu_starting notifiers.

-Rohit
> Will


Thanks,
Rohit Vaswani

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