Crap, you're right, either notify_cpu_starting() is done too early or
smp_store_cpu_info() is done too late.
Since smp_store_cpu_info() relies on the result of calibrate_delay() we
can't easily change that order, but since there really isn't any other
CPU_STARTING user in tree (I appear to have created the first?!) we can
easily move that notifier thing later.
(What's up with that IRQ-enable over calibrate_delay(), can't we simply
enable the NMI watchdog later?)
So I guess something like the below should work:
---
arch/x86/kernel/smpboot.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 06d98ae..6808b93 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -242,8 +242,6 @@ static void __cpuinit smp_callin(void)
end_local_APIC_setup();
map_cpu_to_logical_apicid();
- notify_cpu_starting(cpuid);
-
/*
* Need to setup vector mappings before we enable interrupts.
*/
@@ -264,6 +262,8 @@ static void __cpuinit smp_callin(void)
*/
smp_store_cpu_info(cpuid);
+ notify_cpu_starting(cpuid);
+
/*
* Allow the master to continue.
*/
Which then allows us to write something like:
---
arch/x86/kernel/cpu/perf_event.c | 8 ++-
arch/x86/kernel/cpu/perf_event_amd.c | 69 ++++++++++++++++++---------------
2 files changed, 43 insertions(+), 34 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index f571f51..4db6eaf 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -209,7 +209,7 @@ struct x86_pmu {
struct event_constraint *event_constraints;
void (*quirks)(void);
- void (*cpu_prepare)(int cpu);
+ int (*cpu_prepare)(int cpu);
void (*cpu_starting)(int cpu);
void (*cpu_dying)(int cpu);
void (*cpu_dead)(int cpu);
@@ -1330,11 +1330,12 @@ static int __cpuinit
x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
{
...
