[PATCH v4 08/40] perf/arm: use atomic find_bit() API

Yury Norov
2024-06-20T17:57:32Z

Simplify subsystem by use atomic find_bit() or atomic API where
applicable.

CC: Will Deacon <will@kernel.org>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
drivers/perf/arm-cci.c | 25 +++++++------------------
drivers/perf/arm-ccn.c | 11 +++--------
drivers/perf/arm_dmc620_pmu.c | 10 +++-------
drivers/perf/arm_pmuv3.c | 9 +++------
4 files changed, 16 insertions(+), 39 deletions(-)

diff --git a/drivers/perf/arm-cci.c b/drivers/perf/arm-cci.c
index c76bac668dea..4c5d23942352 100644
--- a/drivers/perf/arm-cci.c
+++ b/drivers/perf/arm-cci.c
@@ -4,6 +4,7 @@
// Author: Punit Agrawal <punit.agrawal@arm.com>, Suzuki Poulose <suzuki.poulose@arm.com>

#include <linux/arm-cci.h>
+#include <linux/find_atomic.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/module.h>
@@ -318,12 +319,9 @@ static int cci400_get_event_idx(struct cci_pmu *cci_pmu,
return CCI400_PMU_CYCLE_CNTR_IDX;
}

- for (idx = CCI400_PMU_CNTR0_IDX; idx <= CCI_PMU_CNTR_LAST(cci_pmu); ++idx)
- if (!test_and_set_bit(idx, hw->used_mask))
- return idx;
-
- /* No counters available */
- return -EAGAIN;
+ idx = find_and_set_next_bit(hw->used_mask, CCI_PMU_CNTR_LAST(cci_pmu) + 1,
+ CCI400_PMU_CNTR0_IDX);
+ return idx < CCI_PMU_CNTR_LAST(cci_pmu) + 1 ? idx : -EAGAIN;
}

static int cci400_validate_hw_event(struct cci_pmu *cci_pmu, unsigned long hw_event)
@@ -792,13 +790,8 @@ static int pmu_get_event_idx(struct cci_pmu_hw_events *hw, struct perf_event *ev
if (cci_pmu->model->get_event_idx)
return cci_pmu->model->get_event_idx(cci_pmu, hw, cci_event);

- /* Generic code to find an unused idx from the mask */
- for (idx = 0; idx <= CCI_PMU_CNTR_LAST(cci_pmu); idx++)
- if (!test_and_set_bit(idx, hw->used_mask))
- return idx;
-
- /* No counters available */
- return -EAGAIN;
+ idx = find_and_set_bit(hw->used_mask, CCI_PMU_CNTR_LAST(cci_pmu) + 1);
+ return idx < CCI_PMU_CNTR_LAST(cci_pmu) + 1 ? idx : -EAGAIN;
}

static int pmu_map_event(struct perf_event *event)
@@ -851,12 +844,8 @@ static void pmu_free_irq(struct cci_pmu *cci_pmu)
{
int i;

- for (i = 0; i < cci_pmu->nr_irqs; i++) {
- if (!test_and_clear_bit(i, &cci_pmu->active_irqs))
- continue;
-
+ for_each_test_and_clear_bit(i, &cci_pmu->active_irqs, cci_pmu->nr_irqs)
free_irq(cci_pmu->irqs[i], cci_pmu);
- }
}

static u32 pmu_read_counter(struct perf_event *event)
diff --git a/drivers/perf/arm-ccn.c b/drivers/perf/arm-ccn.c
index 86ef31ac7503..bd66d90dfda6 100644
--- a/drivers/perf/arm-ccn.c
+++ b/drivers/perf/arm-ccn.c
@@ -5,6 +5,7 @@
*/

#include <linux/ctype.h>
+#include <linux/find_atomic.h>
#include <linux/hrtimer.h>
#include <linux/idr.h>
#include <linux/interrupt.h>
@@ -580,15 +581,9 @@ static const struct attribute_group *arm_ccn_pmu_attr_groups[] = {

static int arm_ccn_pmu_alloc_bit(unsigned long *bitmap, unsigned long size)
{
- int bit;
-
- do {
- bit = find_first_zero_bit(bitmap, size);
- if (bit >= size)
- return -EAGAIN;
- } while (test_and_set_bit(bit, bitmap));
+ int bit = find_and_set_bit(bitmap, size);

- return bit;
+ return bit < size ? bit : -EAGAIN;
}

/* All RN-I and RN-D nodes have identical PMUs */
diff --git a/drivers/perf/arm_dmc620_pmu.c b/drivers/perf/arm_dmc620_pmu.c
index 7e5f1d4fca0f..f41cc2ee9564 100644
--- a/drivers/perf/arm_dmc620_pmu.c
+++ b/drivers/perf/arm_dmc620_pmu.c
@@ -16,6 +16,7 @@
#include <linux/cpumask.h>
#include <linux/device.h>
#include <linux/errno.h>
+#include <linux/find_atomic.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
@@ -303,13 +304,8 @@ static int dmc620_get_event_idx(struct perf_event *event)
end_idx = DMC620_PMU_MAX_COUNTERS;
}

- for (idx = start_idx; idx < end_idx; ++idx) {
- if (!test_and_set_bit(idx, dmc620_pmu->used_mask))
- return idx;
- }
-
- /* The counters are all in use. */
- return -EAGAIN;
+ idx = find_and_set_next_bit(dmc620_pmu->used_mask, end_idx, start_idx);
+ return idx < end_idx ? idx : -EAGAIN;
}

static inline
diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c
index 23fa6c5da82c..f3b20a3b1d9c 100644
--- a/drivers/perf/arm_pmuv3.c
+++ b/drivers/perf/arm_pmuv3.c
@@ -17,6 +17,7 @@
#include <linux/acpi.h>
#include <linux/bitfield.h>
#include <linux/clocksource.h>
+#include <linux/find_atomic.h>
#include <linux/of.h>
#include <linux/perf/arm_pmu.h>
#include <linux/perf/arm_pmuv3.h>
@@ -903,13 +904,9 @@ static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu)
static int armv8pmu_get_single_idx(struct pmu_hw_events *cpuc,
struct arm_pmu *cpu_pmu)
{
- int idx;
+ int idx = find_and_set_next_bit(cpuc->used_mask, cpu_pmu->num_events, ARMV8_IDX_COUNTER0);

- for (idx = ARMV8_IDX_COUNTER0; idx < cpu_pmu->num_events; idx++) {
- if (!test_and_set_bit(idx, cpuc->used_mask))
- return idx;
- }
- return -EAGAIN;
+ return idx < cpu_pmu->num_events ? idx : -EAGAIN;
}

static int armv8pmu_get_chain_idx(struct pmu_hw_events *cpuc,
--
2.43.0