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Date: Tue, 25 Jun 2024 14:31:00 +0100
From: James Clark <james.clark@....com>
To: coresight@...ts.linaro.org,
suzuki.poulose@....com,
gankulkarni@...amperecomputing.com,
mike.leach@...aro.org,
leo.yan@...ux.dev,
anshuman.khandual@....com,
jszu@...dia.com,
bwicaksono@...dia.com
Cc: James Clark <james.clark@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
Alexandre Torgue <alexandre.torgue@...s.st.com>,
John Garry <john.g.garry@...cle.com>,
Will Deacon <will@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Jiri Olsa <jolsa@...nel.org>,
Ian Rogers <irogers@...gle.com>,
Adrian Hunter <adrian.hunter@...el.com>,
"Liang, Kan" <kan.liang@...ux.intel.com>,
linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-stm32@...md-mailman.stormreply.com,
linux-perf-users@...r.kernel.org
Subject: [PATCH v4 17/17] coresight: Make trace ID map spinlock local to the map
Reduce contention on the lock by replacing the global lock with one for
each map.
Signed-off-by: James Clark <james.clark@....com>
---
drivers/hwtracing/coresight/coresight-core.c | 1 +
.../hwtracing/coresight/coresight-trace-id.c | 26 +++++++++----------
include/linux/coresight.h | 1 +
3 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index c427e9344a84..ea38ecf26fcb 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -1164,6 +1164,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
+ spin_lock_init(&csdev->perf_sink_id_map.lock);
csdev->perf_sink_id_map.cpu_map = alloc_percpu(atomic_t);
if (!csdev->perf_sink_id_map.cpu_map) {
kfree(csdev);
diff --git a/drivers/hwtracing/coresight/coresight-trace-id.c b/drivers/hwtracing/coresight/coresight-trace-id.c
index 1e70892f5beb..82bb70c1ad73 100644
--- a/drivers/hwtracing/coresight/coresight-trace-id.c
+++ b/drivers/hwtracing/coresight/coresight-trace-id.c
@@ -15,12 +15,10 @@
/* Default trace ID map. Used in sysfs mode and for system sources */
static DEFINE_PER_CPU(atomic_t, id_map_default_cpu_ids) = ATOMIC_INIT(0);
static struct coresight_trace_id_map id_map_default = {
- .cpu_map = &id_map_default_cpu_ids
+ .cpu_map = &id_map_default_cpu_ids,
+ .lock = __SPIN_LOCK_UNLOCKED(id_map_default.lock)
};
-/* lock to protect id_map and cpu data */
-static DEFINE_SPINLOCK(id_map_lock);
-
/* #define TRACE_ID_DEBUG 1 */
#if defined(TRACE_ID_DEBUG) || defined(CONFIG_COMPILE_TEST)
@@ -124,11 +122,11 @@ static void coresight_trace_id_release_all(struct coresight_trace_id_map *id_map
unsigned long flags;
int cpu;
- spin_lock_irqsave(&id_map_lock, flags);
+ spin_lock_irqsave(&id_map->lock, flags);
bitmap_zero(id_map->used_ids, CORESIGHT_TRACE_IDS_MAX);
for_each_possible_cpu(cpu)
atomic_set(per_cpu_ptr(id_map->cpu_map, cpu), 0);
- spin_unlock_irqrestore(&id_map_lock, flags);
+ spin_unlock_irqrestore(&id_map->lock, flags);
DUMP_ID_MAP(id_map);
}
@@ -137,7 +135,7 @@ static int _coresight_trace_id_get_cpu_id(int cpu, struct coresight_trace_id_map
unsigned long flags;
int id;
- spin_lock_irqsave(&id_map_lock, flags);
+ spin_lock_irqsave(&id_map->lock, flags);
/* check for existing allocation for this CPU */
id = _coresight_trace_id_read_cpu_id(cpu, id_map);
@@ -164,7 +162,7 @@ static int _coresight_trace_id_get_cpu_id(int cpu, struct coresight_trace_id_map
atomic_set(per_cpu_ptr(id_map->cpu_map, cpu), id);
get_cpu_id_out_unlock:
- spin_unlock_irqrestore(&id_map_lock, flags);
+ spin_unlock_irqrestore(&id_map->lock, flags);
DUMP_ID_CPU(cpu, id);
DUMP_ID_MAP(id_map);
@@ -181,12 +179,12 @@ static void _coresight_trace_id_put_cpu_id(int cpu, struct coresight_trace_id_ma
if (!id)
return;
- spin_lock_irqsave(&id_map_lock, flags);
+ spin_lock_irqsave(&id_map->lock, flags);
coresight_trace_id_free(id, id_map);
atomic_set(per_cpu_ptr(id_map->cpu_map, cpu), 0);
- spin_unlock_irqrestore(&id_map_lock, flags);
+ spin_unlock_irqrestore(&id_map->lock, flags);
DUMP_ID_CPU(cpu, id);
DUMP_ID_MAP(id_map);
}
@@ -196,10 +194,10 @@ static int coresight_trace_id_map_get_system_id(struct coresight_trace_id_map *i
unsigned long flags;
int id;
- spin_lock_irqsave(&id_map_lock, flags);
+ spin_lock_irqsave(&id_map->lock, flags);
/* prefer odd IDs for system components to avoid legacy CPU IDS */
id = coresight_trace_id_alloc_new_id(id_map, 0, true);
- spin_unlock_irqrestore(&id_map_lock, flags);
+ spin_unlock_irqrestore(&id_map->lock, flags);
DUMP_ID(id);
DUMP_ID_MAP(id_map);
@@ -210,9 +208,9 @@ static void coresight_trace_id_map_put_system_id(struct coresight_trace_id_map *
{
unsigned long flags;
- spin_lock_irqsave(&id_map_lock, flags);
+ spin_lock_irqsave(&id_map->lock, flags);
coresight_trace_id_free(id, id_map);
- spin_unlock_irqrestore(&id_map_lock, flags);
+ spin_unlock_irqrestore(&id_map->lock, flags);
DUMP_ID(id);
DUMP_ID_MAP(id_map);
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index 197949fd2c35..c13342594278 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -233,6 +233,7 @@ struct coresight_trace_id_map {
DECLARE_BITMAP(used_ids, CORESIGHT_TRACE_IDS_MAX);
atomic_t __percpu *cpu_map;
atomic_t perf_cs_etm_session_active;
+ spinlock_t lock;
};
/**
--
2.34.1
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