Reviewed-by: Mike Leach mike.leach@linaro.org
On Fri, 12 Jul 2024 at 11:23, James Clark james.clark@linaro.org wrote:
From: James Clark james.clark@arm.com
Reduce contention on the lock by replacing the global lock with one for each map.
Signed-off-by: James Clark james.clark@arm.com Signed-off-by: James Clark james.clark@linaro.org
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 bddaed3e5cf8..d98e12cb30ec 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)
@@ -123,11 +121,11 @@ 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);}
@@ -136,7 +134,7 @@ 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);@@ -163,7 +161,7 @@ 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);@@ -180,12 +178,12 @@ 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);} @@ -195,10 +193,10 @@ 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);@@ -209,9 +207,9 @@ 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
-- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK