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coresight: Make trace ID map spinlock local to the map

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Reduce contention on the lock by replacing the global lock with one for
each map.

Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240722101202.26915-18-james.clark@linaro.org
This commit is contained in:
James Clark 2024-07-22 11:11:59 +01:00 committed by Suzuki K Poulose
parent 487eec8da8
commit 988d40a4d4
3 changed files with 14 additions and 14 deletions
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1
drivers/hwtracing/coresight/coresight-core.c
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@ -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);

26
drivers/hwtracing/coresight/coresight-trace-id.c
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@ -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);

1
include/linux/coresight.h
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@ -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;
};
/**