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.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/alpha/kernel/perf_event.c

@@ -824,7 +824,6 @@ static void alpha_perf_event_irq_handler(unsigned long la_ptr,
 
 	idx = la_ptr;
 
-	perf_sample_data_init(&data, 0);
 	for (j = 0; j < cpuc->n_events; j++) {
 		if (cpuc->current_idx[j] == idx)
 			break;
@@ -848,7 +847,7 @@ static void alpha_perf_event_irq_handler(unsigned long la_ptr,
 
 	hwc = &event->hw;
 	alpha_perf_event_update(event, hwc, idx, alpha_pmu->pmc_max_period[idx]+1);
-	data.period = event->hw.last_period;
+	perf_sample_data_init(&data, 0, hwc->last_period);
 
 	if (alpha_perf_event_set_period(event, hwc, idx)) {
 		if (perf_event_overflow(event, &data, regs)) {

arch/arm/kernel/perf_event_v6.c

@@ -489,8 +489,6 @@ armv6pmu_handle_irq(int irq_num,
 	 */
 	armv6_pmcr_write(pmcr);
 
-	perf_sample_data_init(&data, 0);
-
 	cpuc = &__get_cpu_var(cpu_hw_events);
 	for (idx = 0; idx < cpu_pmu->num_events; ++idx) {
 		struct perf_event *event = cpuc->events[idx];
@@ -509,7 +507,7 @@ armv6pmu_handle_irq(int irq_num,
 
 		hwc = &event->hw;
 		armpmu_event_update(event, hwc, idx);
-		data.period = event->hw.last_period;
+		perf_sample_data_init(&data, 0, hwc->last_period);
 		if (!armpmu_event_set_period(event, hwc, idx))
 			continue;
 

arch/arm/kernel/perf_event_v7.c

@@ -1077,8 +1077,6 @@ static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev)
 	 */
 	regs = get_irq_regs();
 
-	perf_sample_data_init(&data, 0);
-
 	cpuc = &__get_cpu_var(cpu_hw_events);
 	for (idx = 0; idx < cpu_pmu->num_events; ++idx) {
 		struct perf_event *event = cpuc->events[idx];
@@ -1097,7 +1095,7 @@ static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev)
 
 		hwc = &event->hw;
 		armpmu_event_update(event, hwc, idx);
-		data.period = event->hw.last_period;
+		perf_sample_data_init(&data, 0, hwc->last_period);
 		if (!armpmu_event_set_period(event, hwc, idx))
 			continue;
 

arch/arm/kernel/perf_event_xscale.c

@@ -248,8 +248,6 @@ xscale1pmu_handle_irq(int irq_num, void *dev)
 
 	regs = get_irq_regs();
 
-	perf_sample_data_init(&data, 0);
-
 	cpuc = &__get_cpu_var(cpu_hw_events);
 	for (idx = 0; idx < cpu_pmu->num_events; ++idx) {
 		struct perf_event *event = cpuc->events[idx];
@@ -263,7 +261,7 @@ xscale1pmu_handle_irq(int irq_num, void *dev)
 
 		hwc = &event->hw;
 		armpmu_event_update(event, hwc, idx);
-		data.period = event->hw.last_period;
+		perf_sample_data_init(&data, 0, hwc->last_period);
 		if (!armpmu_event_set_period(event, hwc, idx))
 			continue;
 
@@ -588,8 +586,6 @@ xscale2pmu_handle_irq(int irq_num, void *dev)
 
 	regs = get_irq_regs();
 
-	perf_sample_data_init(&data, 0);
-
 	cpuc = &__get_cpu_var(cpu_hw_events);
 	for (idx = 0; idx < cpu_pmu->num_events; ++idx) {
 		struct perf_event *event = cpuc->events[idx];
@@ -603,7 +599,7 @@ xscale2pmu_handle_irq(int irq_num, void *dev)
 
 		hwc = &event->hw;
 		armpmu_event_update(event, hwc, idx);
-		data.period = event->hw.last_period;
+		perf_sample_data_init(&data, 0, hwc->last_period);
 		if (!armpmu_event_set_period(event, hwc, idx))
 			continue;
 

arch/mips/kernel/perf_event_mipsxx.c

@@ -1325,7 +1325,7 @@ static int mipsxx_pmu_handle_shared_irq(void)
 
 	regs = get_irq_regs();
 
-	perf_sample_data_init(&data, 0);
+	perf_sample_data_init(&data, 0, 0);
 
 	switch (counters) {
 #define HANDLE_COUNTER(n)						\

arch/powerpc/perf/core-book3s.c

@@ -1299,8 +1299,7 @@ static void record_and_restart(struct perf_event *event, unsigned long val,
 	if (record) {
 		struct perf_sample_data data;
 
-		perf_sample_data_init(&data, ~0ULL);
-		data.period = event->hw.last_period;
+		perf_sample_data_init(&data, ~0ULL, event->hw.last_period);
 
 		if (event->attr.sample_type & PERF_SAMPLE_ADDR)
 			perf_get_data_addr(regs, &data.addr);

arch/powerpc/perf/core-fsl-emb.c

@@ -613,8 +613,7 @@ static void record_and_restart(struct perf_event *event, unsigned long val,
 	if (record) {
 		struct perf_sample_data data;
 
-		perf_sample_data_init(&data, 0);
-		data.period = event->hw.last_period;
+		perf_sample_data_init(&data, 0, event->hw.last_period);
 
 		if (perf_event_overflow(event, &data, regs))
 			fsl_emb_pmu_stop(event, 0);

arch/sparc/kernel/perf_event.c

@@ -1296,8 +1296,6 @@ static int __kprobes perf_event_nmi_handler(struct notifier_block *self,
 
 	regs = args->regs;
 
-	perf_sample_data_init(&data, 0);
-
 	cpuc = &__get_cpu_var(cpu_hw_events);
 
 	/* If the PMU has the TOE IRQ enable bits, we need to do a
@@ -1321,7 +1319,7 @@ static int __kprobes perf_event_nmi_handler(struct notifier_block *self,
 		if (val & (1ULL << 31))
 			continue;
 
-		data.period = event->hw.last_period;
+		perf_sample_data_init(&data, 0, hwc->last_period);
 		if (!sparc_perf_event_set_period(event, hwc, idx))
 			continue;
 

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;

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;

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 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
 		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;

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

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);
 	}

include/linux/perf_event.h

@@ -1132,11 +1132,14 @@ struct perf_sample_data {
 	struct perf_branch_stack	*br_stack;
 };
 
-static inline void perf_sample_data_init(struct perf_sample_data *data, u64 addr)
+static inline void perf_sample_data_init(struct perf_sample_data *data,
+					 u64 addr, u64 period)
 {
+	/* remaining struct members initialized in perf_prepare_sample() */
 	data->addr = addr;
 	data->raw  = NULL;
 	data->br_stack = NULL;
+	data->period	= period;
 }
 
 extern void perf_output_sample(struct perf_output_handle *handle,

kernel/events/core.c

@@ -4957,7 +4957,7 @@ void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
 	if (rctx < 0)
 		return;
 
-	perf_sample_data_init(&data, addr);
+	perf_sample_data_init(&data, addr, 0);
 
 	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
 
@@ -5215,7 +5215,7 @@ void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
 		.data = record,
 	};
 
-	perf_sample_data_init(&data, addr);
+	perf_sample_data_init(&data, addr, 0);
 	data.raw = &raw;
 
 	hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
@@ -5318,7 +5318,7 @@ void perf_bp_event(struct perf_event *bp, void *data)
 	struct perf_sample_data sample;
 	struct pt_regs *regs = data;
 
-	perf_sample_data_init(&sample, bp->attr.bp_addr);
+	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
 
 	if (!bp->hw.state && !perf_exclude_event(bp, regs))
 		perf_swevent_event(bp, 1, &sample, regs);
@@ -5344,8 +5344,7 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
 
 	event->pmu->read(event);
 
-	perf_sample_data_init(&data, 0);
-	data.period = event->hw.last_period;
+	perf_sample_data_init(&data, 0, event->hw.last_period);
 	regs = get_irq_regs();
 
 	if (regs && !perf_exclude_event(event, regs)) {