[PATCH 12/49] perf: replace bitmap_weight with bitmap_empty where appropriate

Yury Norov
2022-02-10T23:19:56Z

In some places, drivers/perf code calls bitmap_weight() to check if any
bit of a given bitmap is set. It's better to use bitmap_empty() in that
case because bitmap_empty() stops traversing the bitmap as soon as it
finds first set bit, while bitmap_weight() counts all bits unconditionally.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
drivers/perf/arm-cci.c | 2 +-
drivers/perf/arm_pmu.c | 4 ++--
drivers/perf/hisilicon/hisi_uncore_pmu.c | 2 +-
drivers/perf/xgene_pmu.c | 2 +-
4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/perf/arm-cci.c b/drivers/perf/arm-cci.c
index 54aca3a62814..96e09fa40909 100644
--- a/drivers/perf/arm-cci.c
+++ b/drivers/perf/arm-cci.c
@@ -1096,7 +1096,7 @@ static void cci_pmu_enable(struct pmu *pmu)
{
struct cci_pmu *cci_pmu = to_cci_pmu(pmu);
struct cci_pmu_hw_events *hw_events = &cci_pmu->hw_events;
- int enabled = bitmap_weight(hw_events->used_mask, cci_pmu->num_cntrs);
+ bool enabled = !bitmap_empty(hw_events->used_mask, cci_pmu->num_cntrs);
unsigned long flags;

if (!enabled)
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 295cc7952d0e..a31b302b0ade 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -524,7 +524,7 @@ static void armpmu_enable(struct pmu *pmu)
{
struct arm_pmu *armpmu = to_arm_pmu(pmu);
struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
- int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events);
+ bool enabled = !bitmap_empty(hw_events->used_mask, armpmu->num_events);

/* For task-bound events we may be called on other CPUs */
if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
@@ -785,7 +785,7 @@ static int cpu_pm_pmu_notify(struct notifier_block *b, unsigned long cmd,
{
struct arm_pmu *armpmu = container_of(b, struct arm_pmu, cpu_pm_nb);
struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
- int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events);
+ bool enabled = !bitmap_empty(hw_events->used_mask, armpmu->num_events);

if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
return NOTIFY_DONE;
diff --git a/drivers/perf/hisilicon/hisi_uncore_pmu.c b/drivers/perf/hisilicon/hisi_uncore_pmu.c
index a738aeab5c04..358e4e284a62 100644
--- a/drivers/perf/hisilicon/hisi_uncore_pmu.c
+++ b/drivers/perf/hisilicon/hisi_uncore_pmu.c
@@ -393,7 +393,7 @@ EXPORT_SYMBOL_GPL(hisi_uncore_pmu_read);
void hisi_uncore_pmu_enable(struct pmu *pmu)
{
struct hisi_pmu *hisi_pmu = to_hisi_pmu(pmu);
- int enabled = bitmap_weight(hisi_pmu->pmu_events.used_mask,
+ bool enabled = !bitmap_empty(hisi_pmu->pmu_events.used_mask,
hisi_pmu->num_counters);

if (!enabled)
diff --git a/drivers/perf/xgene_pmu.c b/drivers/perf/xgene_pmu.c
index 5283608dc055..0c32dffc7ede 100644
--- a/drivers/perf/xgene_pmu.c
+++ b/drivers/perf/xgene_pmu.c
@@ -867,7 +867,7 @@ static void xgene_perf_pmu_enable(struct pmu *pmu)
{
struct xgene_pmu_dev *pmu_dev = to_pmu_dev(pmu);
struct xgene_pmu *xgene_pmu = pmu_dev->parent;
- int enabled = bitmap_weight(pmu_dev->cntr_assign_mask,
+ bool enabled = !bitmap_empty(pmu_dev->cntr_assign_mask,
pmu_dev->max_counters);

if (!enabled)
--
2.32.0