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>

15 files changed, 25 insertions, 43 deletions

diff --git a/arch/alpha/kernel/perf_event.c b/arch/alpha/kernel/perf_event.c
index 0dae252f7a33..d821b17047e0 100644
--- a/arch/alpha/kernel/perf_event.c
+++ b/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)) {
diff --git a/arch/arm/kernel/perf_event_v6.c b/arch/arm/kernel/perf_event_v6.c
index b78af0cc6ef3..ab627a740fa3 100644
--- a/arch/arm/kernel/perf_event_v6.c
+++ b/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;
 
diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c
index 00755d82e2f2..d3c536068162 100644
--- a/arch/arm/kernel/perf_event_v7.c
+++ b/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;
 
diff --git a/arch/arm/kernel/perf_event_xscale.c b/arch/arm/kernel/perf_event_xscale.c
index 71a21e6712f5..e34e7254e652 100644
--- a/arch/arm/kernel/perf_event_xscale.c
+++ b/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;
 
diff --git a/arch/mips/kernel/perf_event_mipsxx.c b/arch/mips/kernel/perf_event_mipsxx.c
index 811084f4e422..ab73fa2fb9b5 100644
--- a/arch/mips/kernel/perf_event_mipsxx.c
+++ b/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)                                               \
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 02aee03e713c..8f84bcba18da 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/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);
diff --git a/arch/powerpc/perf/core-fsl-emb.c b/arch/powerpc/perf/core-fsl-emb.c
index 0a6d2a9d569c..106c53354675 100644
--- a/arch/powerpc/perf/core-fsl-emb.c
+++ b/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);
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index 28559ce5eeb5..5713957dcb8a 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/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;
 
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index e33e9cf160eb..e049d6da0183 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 c8f69bea6624..2317228b5299 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 26b3e2fef104..166546ec6aef 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 7f64df19e7dd..5a3edc27f6e5 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 a2dfacfd7103..47124a73dd73 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);
         }
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index ddbb6a901f65..f32578634d9d 100644
--- a/include/linux/perf_event.h
+++ b/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,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 9789a56b7d54..00c58df9f4e2 100644
--- a/kernel/events/core.c
+++ b/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)) {