perf: Rework and fix the arch CPU-hotplug hooks

Remove the hw_perf_event_*() hotplug hooks in favour of per PMU hotplug
notifiers. This has the advantage of reducing the static weak interface
as well as exposing all hotplug actions to the PMU.

Use this to fix x86 hotplug usage where we did things in ONLINE which
should have been done in UP_PREPARE or STARTING.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: paulus@samba.org
Cc: eranian@google.com
Cc: robert.richter@amd.com
Cc: fweisbec@gmail.com
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
LKML-Reference: <20100305154128.736225361@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 6f8cd7da1a01..80acbf3d5de1 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -936,5 +936,21 @@ static inline void perf_event_disable(struct perf_event *event)		{ }
 #define perf_output_put(handle, x) \
         perf_output_copy((handle), &(x), sizeof(x))
 
+/*
+ * This has to have a higher priority than migration_notifier in sched.c.
+ */
+#define perf_cpu_notifier(fn)                                   \
+do {                                                            \
+        static struct notifier_block fn##_nb __cpuinitdata =    \
+                { .notifier_call = fn, .priority = 20 };        \
+        fn(&fn##_nb, (unsigned long)CPU_UP_PREPARE,             \
+                (void *)(unsigned long)smp_processor_id());     \
+        fn(&fn##_nb, (unsigned long)CPU_STARTING,               \
+                (void *)(unsigned long)smp_processor_id());     \
+        fn(&fn##_nb, (unsigned long)CPU_ONLINE,                 \
+                (void *)(unsigned long)smp_processor_id());     \
+        register_cpu_notifier(&fn##_nb);                        \
+} while (0)
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_PERF_EVENT_H */