perf_event: x86: Deduplicate the disable code

Share the meat of the x86_pmu_disable() code with hw_perf_enable().

Also remove the barrier() from that code, since I could not convince
myself we actually need it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index fdbe248..07fa0c2 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1401,6 +1401,8 @@ static inline void x86_assign_hw_event(struct perf_event *event,
        }
 }
 
+static void __x86_pmu_disable(struct perf_event *event, struct cpu_hw_events *cpuc);
+
 void hw_perf_enable(void)
 {
        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
@@ -1426,13 +1428,7 @@ void hw_perf_enable(void)
                        if (hwc->idx == -1 || hwc->idx == cpuc->assign[i])
                                continue;
 
-                       x86_pmu.disable(hwc, hwc->idx);
-
-                       clear_bit(hwc->idx, cpuc->active_mask);
-                       barrier();
-                       cpuc->events[hwc->idx] = NULL;
-
-                       x86_perf_event_update(event, hwc, hwc->idx);
+                       __x86_pmu_disable(event, cpuc);
 
                        hwc->idx = -1;
                }
@@ -1822,11 +1818,10 @@ static void intel_pmu_drain_bts_buffer(struct cpu_hw_events *cpuc)
        event->pending_kill = POLL_IN;
 }
 
-static void x86_pmu_disable(struct perf_event *event)
+static void __x86_pmu_disable(struct perf_event *event, struct cpu_hw_events *cpuc)
 {
-       struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
        struct hw_perf_event *hwc = &event->hw;
-       int i, idx = hwc->idx;
+       int idx = hwc->idx;
 
        /*
         * Must be done before we disable, otherwise the nmi handler
@@ -1836,12 +1831,6 @@ static void x86_pmu_disable(struct perf_event *event)
        x86_pmu.disable(hwc, idx);
 
        /*
-        * Make sure the cleared pointer becomes visible before we
-        * (potentially) free the event:
-        */
-       barrier();
-
-       /*
         * Drain the remaining delta count out of a event
         * that we are disabling:
         */
@@ -1852,6 +1841,14 @@ static void x86_pmu_disable(struct perf_event *event)
                intel_pmu_drain_bts_buffer(cpuc);
 
        cpuc->events[idx] = NULL;
+}
+
+static void x86_pmu_disable(struct perf_event *event)
+{
+       struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+       int i;
+
+       __x86_pmu_disable(event, cpuc);
 
        for (i = 0; i < cpuc->n_events; i++) {
                if (event == cpuc->event_list[i]) {