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SubjectRe: [PATCH 1/4] x86: set cpu masks before calling CPU_STARTING notifiers
On Thu, Nov 18, 2010 at 12:52:33PM +0100, Thomas Gleixner wrote:
> On Thu, 18 Nov 2010, Andi Kleen wrote:
>
> > From: Andi Kleen <ak@linux.intel.com>
> >
> > When booting up a CPU set the various topology masks before
> > calling the CPU_STARTING notifier. This way the notifier
> > can actually use the masks.
> >
> > This is needed for a perf change.
> >
> > Signed-off-by: Andi Kleen <ak@linux.intel.com>
> > ---
> > arch/x86/kernel/smpboot.c | 8 ++++----
> > 1 files changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> > index 083e99d..9d2980e 100644
> > --- a/arch/x86/kernel/smpboot.c
> > +++ b/arch/x86/kernel/smpboot.c
> > @@ -281,6 +281,10 @@ static void __cpuinit smp_callin(void)
> > */
> > smp_store_cpu_info(cpuid);
> >
> > + /* This must be done before setting cpu_online_mask */
>
> Can we please fix up that comment to match that change ?

Here's an updated patch.

x86: set cpu masks before calling CPU_STARTING notifiers

When booting up a CPU set the various topology masks before
calling the CPU_STARTING notifier. This way the notifier
can actually use the masks.

This is needed for a perf change.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 083e99d..c019c03 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -281,6 +281,13 @@ static void __cpuinit smp_callin(void)
*/
smp_store_cpu_info(cpuid);

+ /*
+ * This must be done before setting cpu_online_mask
+ * or calling notify_cpu_starting.
+ */
+ set_cpu_sibling_map(raw_smp_processor_id());
+ wmb();
+
notify_cpu_starting(cpuid);

/*
@@ -322,10 +329,6 @@ notrace static void __cpuinit start_secondary(void *unused)
legacy_pic->unmask(0);
}

- /* This must be done before setting cpu_online_mask */
- set_cpu_sibling_map(raw_smp_processor_id());
- wmb();
-
/*
* We need to hold call_lock, so there is no inconsistency
* between the time smp_call_function() determines number of

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