perf: Pass last sampling period to perf_sample_data_init()

We always need to pass the last sample period to
perf_sample_data_init(), otherwise the event distribution will be
wrong. Thus, modifiyng the function interface with the required period
as argument. So basically a pattern like this:

        perf_sample_data_init(&data, ~0ULL);
        data.period = event->hw.last_period;

will now be like that:

        perf_sample_data_init(&data, ~0ULL, event->hw.last_period);

Avoids unininitialized data.period and simplifies code.

Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1333390758-10893-3-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

5 files changed, 8 insertions, 15 deletions

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index e33e9cf..e049d6d 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1183,8 +1183,6 @@ int x86_pmu_handle_irq(struct pt_regs *regs)
 	int idx, handled = 0;
 	u64 val;
 
-	perf_sample_data_init(&data, 0);
-
 	cpuc = &__get_cpu_var(cpu_hw_events);
 
 	/*
@@ -1219,7 +1217,7 @@ int x86_pmu_handle_irq(struct pt_regs *regs)
 		 * event overflow
 		 */
 		handled++;
-		data.period	= event->hw.last_period;
+		perf_sample_data_init(&data, 0, event->hw.last_period);
 
 		if (!x86_perf_event_set_period(event))
 			continue;
diff --git a/arch/x86/kernel/cpu/perf_event_amd_ibs.c b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
index c8f69be..2317228 100644
--- a/arch/x86/kernel/cpu/perf_event_amd_ibs.c
+++ b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
@@ -398,8 +398,7 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
 	}
 
 	perf_ibs_event_update(perf_ibs, event, config);
-	perf_sample_data_init(&data, 0);
-	data.period = event->hw.last_period;
+	perf_sample_data_init(&data, 0, hwc->last_period);
 
 	if (event->attr.sample_type & PERF_SAMPLE_RAW) {
 		ibs_data.caps = ibs_caps;
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 26b3e2f..166546e 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -1027,8 +1027,6 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
 	u64 status;
 	int handled;
 
-	perf_sample_data_init(&data, 0);
-
 	cpuc = &__get_cpu_var(cpu_hw_events);
 
 	/*
@@ -1082,7 +1080,7 @@ again:
 		if (!intel_pmu_save_and_restart(event))
 			continue;
 
-		data.period = event->hw.last_period;
+		perf_sample_data_init(&data, 0, event->hw.last_period);
 
 		if (has_branch_stack(event))
 			data.br_stack = &cpuc->lbr_stack;
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 7f64df1..5a3edc2 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -316,8 +316,7 @@ int intel_pmu_drain_bts_buffer(void)
 
 	ds->bts_index = ds->bts_buffer_base;
 
-	perf_sample_data_init(&data, 0);
-	data.period = event->hw.last_period;
+	perf_sample_data_init(&data, 0, event->hw.last_period);
 	regs.ip     = 0;
 
 	/*
@@ -564,8 +563,7 @@ static void __intel_pmu_pebs_event(struct perf_event *event,
 	if (!intel_pmu_save_and_restart(event))
 		return;
 
-	perf_sample_data_init(&data, 0);
-	data.period = event->hw.last_period;
+	perf_sample_data_init(&data, 0, event->hw.last_period);
 
 	/*
 	 * We use the interrupt regs as a base because the PEBS record
diff --git a/arch/x86/kernel/cpu/perf_event_p4.c b/arch/x86/kernel/cpu/perf_event_p4.c
index a2dfacf..47124a7 100644
--- a/arch/x86/kernel/cpu/perf_event_p4.c
+++ b/arch/x86/kernel/cpu/perf_event_p4.c
@@ -1005,8 +1005,6 @@ static int p4_pmu_handle_irq(struct pt_regs *regs)
 	int idx, handled = 0;
 	u64 val;
 
-	perf_sample_data_init(&data, 0);
-
 	cpuc = &__get_cpu_var(cpu_hw_events);
 
 	for (idx = 0; idx < x86_pmu.num_counters; idx++) {
@@ -1034,10 +1032,12 @@ static int p4_pmu_handle_irq(struct pt_regs *regs)
 		handled += overflow;
 
 		/* event overflow for sure */
-		data.period = event->hw.last_period;
+		perf_sample_data_init(&data, 0, hwc->last_period);
 
 		if (!x86_perf_event_set_period(event))
 			continue;
+
+
 		if (perf_event_overflow(event, &data, regs))
 			x86_pmu_stop(event, 0);
 	}