perf, x86: Use helper function in x86_pmu_enable_all()

Use helper function in x86_pmu_enable_all() to minimize access to
x86_pmu.eventsel in the fast path. The counter's msr address is now
calculated using struct hw_perf_event. Later we add code that
calculates the msr addresses with a table lookup which shouldn't be
done in the fast path.

Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1296664860-10886-2-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/cpu/perf_event.c

@@ -642,21 +642,24 @@ static void x86_pmu_disable(struct pmu *pmu)
 	x86_pmu.disable_all();
 }
 
+static inline void __x86_pmu_enable_event(struct hw_perf_event *hwc,
+					  u64 enable_mask)
+{
+	wrmsrl(hwc->config_base + hwc->idx, hwc->config | enable_mask);
+}
+
 static void x86_pmu_enable_all(int added)
 {
 	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
 	int idx;
 
 	for (idx = 0; idx < x86_pmu.num_counters; idx++) {
-		struct perf_event *event = cpuc->events[idx];
-		u64 val;
+		struct hw_perf_event *hwc = &cpuc->events[idx]->hw;
 
 		if (!test_bit(idx, cpuc->active_mask))
 			continue;
 
-		val = event->hw.config;
-		val |= ARCH_PERFMON_EVENTSEL_ENABLE;
-		wrmsrl(x86_pmu.eventsel + idx, val);
+		__x86_pmu_enable_event(hwc, ARCH_PERFMON_EVENTSEL_ENABLE);
 	}
 }
 
@@ -915,12 +918,6 @@ static void x86_pmu_enable(struct pmu *pmu)
 	x86_pmu.enable_all(added);
 }
 
-static inline void __x86_pmu_enable_event(struct hw_perf_event *hwc,
-					  u64 enable_mask)
-{
-	wrmsrl(hwc->config_base + hwc->idx, hwc->config | enable_mask);
-}
-
 static inline void x86_pmu_disable_event(struct perf_event *event)
 {
 	struct hw_perf_event *hwc = &event->hw;