| Message ID | 20240712102029.3697965-16-james.clark@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | coresight: Use per-sink trace ID maps for Perf sessions | expand |
On Fri, 12 Jul 2024 at 11:23, James Clark <james.clark@linaro.org> wrote: > > From: James Clark <james.clark@arm.com> > > Pending the release of IDs was a way of managing concurrent sysfs and > Perf sessions in a single global ID map. Perf may have finished while > sysfs hadn't, and Perf shouldn't release the IDs in use by sysfs and > vice versa. > > Now that Perf uses its own exclusive ID maps, pending release doesn't > result in any different behavior than just releasing all IDs when the > last Perf session finishes. As part of the per-sink trace ID change, we > would have still had to make the pending mechanism work on a per-sink > basis, due to the overlapping ID allocations, so instead of making that > more complicated, just remove it. > > Signed-off-by: James Clark <james.clark@arm.com> > Signed-off-by: James Clark <james.clark@linaro.org> > --- > .../hwtracing/coresight/coresight-etm-perf.c | 18 +++-- > .../hwtracing/coresight/coresight-trace-id.c | 67 +++++-------------- > .../hwtracing/coresight/coresight-trace-id.h | 31 ++++----- > include/linux/coresight.h | 6 +- > 4 files changed, 43 insertions(+), 79 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c > index 7fb55dafb639..70c99f0409b2 100644 > --- a/drivers/hwtracing/coresight/coresight-etm-perf.c > +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c > @@ -232,15 +232,21 @@ static void free_event_data(struct work_struct *work) > if (!(IS_ERR_OR_NULL(*ppath))) { > struct coresight_device *sink = coresight_get_sink(*ppath); > > - coresight_trace_id_put_cpu_id_map(cpu, &sink->perf_sink_id_map); > + /* > + * Mark perf event as done for trace id allocator, but don't call > + * coresight_trace_id_put_cpu_id_map() on individual IDs. Perf sessions > + * never free trace IDs to ensure that the ID associated with a CPU > + * cannot change during their and other's concurrent sessions. Instead, > + * a refcount is used so that the last event to call > + * coresight_trace_id_perf_stop() frees all IDs. > + */ > + coresight_trace_id_perf_stop(&sink->perf_sink_id_map); > + > coresight_release_path(*ppath); > } > *ppath = NULL; > } > > - /* mark perf event as done for trace id allocator */ > - coresight_trace_id_perf_stop(); > - > free_percpu(event_data->path); > kfree(event_data); > } > @@ -328,9 +334,6 @@ static void *etm_setup_aux(struct perf_event *event, void **pages, > sink = user_sink = coresight_get_sink_by_id(id); > } > > - /* tell the trace ID allocator that a perf event is starting up */ > - coresight_trace_id_perf_start(); > - > /* check if user wants a coresight configuration selected */ > cfg_hash = (u32)((event->attr.config2 & GENMASK_ULL(63, 32)) >> 32); > if (cfg_hash) { > @@ -411,6 +414,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages, > continue; > } > > + coresight_trace_id_perf_start(&sink->perf_sink_id_map); > *etm_event_cpu_path_ptr(event_data, cpu) = path; > } > > diff --git a/drivers/hwtracing/coresight/coresight-trace-id.c b/drivers/hwtracing/coresight/coresight-trace-id.c > index 8a777c0af6ea..bddaed3e5cf8 100644 > --- a/drivers/hwtracing/coresight/coresight-trace-id.c > +++ b/drivers/hwtracing/coresight/coresight-trace-id.c > @@ -18,12 +18,6 @@ static struct coresight_trace_id_map id_map_default = { > .cpu_map = &id_map_default_cpu_ids > }; > > -/* maintain a record of the pending releases per cpu */ > -static cpumask_t cpu_id_release_pending; > - > -/* perf session active counter */ > -static atomic_t perf_cs_etm_session_active = ATOMIC_INIT(0); > - > /* lock to protect id_map and cpu data */ > static DEFINE_SPINLOCK(id_map_lock); > > @@ -35,7 +29,6 @@ static void coresight_trace_id_dump_table(struct coresight_trace_id_map *id_map, > { > pr_debug("%s id_map::\n", func_name); > pr_debug("Used = %*pb\n", CORESIGHT_TRACE_IDS_MAX, id_map->used_ids); > - pr_debug("Pend = %*pb\n", CORESIGHT_TRACE_IDS_MAX, id_map->pend_rel_ids); > } > #define DUMP_ID_MAP(map) coresight_trace_id_dump_table(map, __func__) > #define DUMP_ID_CPU(cpu, id) pr_debug("%s called; cpu=%d, id=%d\n", __func__, cpu, id) > @@ -122,34 +115,18 @@ static void coresight_trace_id_free(int id, struct coresight_trace_id_map *id_ma > clear_bit(id, id_map->used_ids); > } > > -static void coresight_trace_id_set_pend_rel(int id, struct coresight_trace_id_map *id_map) > -{ > - if (WARN(!IS_VALID_CS_TRACE_ID(id), "Invalid Trace ID %d\n", id)) > - return; > - set_bit(id, id_map->pend_rel_ids); > -} > - > /* > - * release all pending IDs for all current maps & clear CPU associations > - * > - * This currently operates on the default id map, but may be extended to > - * operate on all registered id maps if per sink id maps are used. > + * Release all IDs and clear CPU associations. > */ > -static void coresight_trace_id_release_all_pending(void) > +static void coresight_trace_id_release_all(struct coresight_trace_id_map *id_map) > { > - struct coresight_trace_id_map *id_map = &id_map_default; > unsigned long flags; > - int cpu, bit; > + int cpu; > > spin_lock_irqsave(&id_map_lock, flags); > - for_each_set_bit(bit, id_map->pend_rel_ids, CORESIGHT_TRACE_ID_RES_TOP) { > - clear_bit(bit, id_map->used_ids); > - clear_bit(bit, id_map->pend_rel_ids); > - } > - for_each_cpu(cpu, &cpu_id_release_pending) { > - atomic_set(per_cpu_ptr(id_map_default.cpu_map, cpu), 0); > - cpumask_clear_cpu(cpu, &cpu_id_release_pending); > - } > + 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); > DUMP_ID_MAP(id_map); > } > @@ -164,7 +141,7 @@ static int _coresight_trace_id_get_cpu_id(int cpu, struct coresight_trace_id_map > /* check for existing allocation for this CPU */ > id = _coresight_trace_id_read_cpu_id(cpu, id_map); > if (id) > - goto get_cpu_id_clr_pend; > + goto get_cpu_id_out_unlock; > > /* > * Find a new ID. > @@ -185,11 +162,6 @@ static int _coresight_trace_id_get_cpu_id(int cpu, struct coresight_trace_id_map > /* allocate the new id to the cpu */ > atomic_set(per_cpu_ptr(id_map->cpu_map, cpu), id); > > -get_cpu_id_clr_pend: > - /* we are (re)using this ID - so ensure it is not marked for release */ > - cpumask_clear_cpu(cpu, &cpu_id_release_pending); > - clear_bit(id, id_map->pend_rel_ids); > - > get_cpu_id_out_unlock: > spin_unlock_irqrestore(&id_map_lock, flags); > > @@ -210,15 +182,8 @@ static void _coresight_trace_id_put_cpu_id(int cpu, struct coresight_trace_id_ma > > spin_lock_irqsave(&id_map_lock, flags); > > - if (atomic_read(&perf_cs_etm_session_active)) { > - /* set release at pending if perf still active */ > - coresight_trace_id_set_pend_rel(id, id_map); > - cpumask_set_cpu(cpu, &cpu_id_release_pending); > - } else { > - /* otherwise clear id */ > - coresight_trace_id_free(id, id_map); > - atomic_set(per_cpu_ptr(id_map->cpu_map, cpu), 0); > - } > + 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); > DUMP_ID_CPU(cpu, id); > @@ -302,17 +267,17 @@ void coresight_trace_id_put_system_id(int id) > } > EXPORT_SYMBOL_GPL(coresight_trace_id_put_system_id); > > -void coresight_trace_id_perf_start(void) > +void coresight_trace_id_perf_start(struct coresight_trace_id_map *id_map) > { > - atomic_inc(&perf_cs_etm_session_active); > - PERF_SESSION(atomic_read(&perf_cs_etm_session_active)); > + atomic_inc(&id_map->perf_cs_etm_session_active); > + PERF_SESSION(atomic_read(&id_map->perf_cs_etm_session_active)); > } > EXPORT_SYMBOL_GPL(coresight_trace_id_perf_start); > > -void coresight_trace_id_perf_stop(void) > +void coresight_trace_id_perf_stop(struct coresight_trace_id_map *id_map) > { > - if (!atomic_dec_return(&perf_cs_etm_session_active)) > - coresight_trace_id_release_all_pending(); > - PERF_SESSION(atomic_read(&perf_cs_etm_session_active)); > + if (!atomic_dec_return(&id_map->perf_cs_etm_session_active)) > + coresight_trace_id_release_all(id_map); > + PERF_SESSION(atomic_read(&id_map->perf_cs_etm_session_active)); > } > EXPORT_SYMBOL_GPL(coresight_trace_id_perf_stop); > diff --git a/drivers/hwtracing/coresight/coresight-trace-id.h b/drivers/hwtracing/coresight/coresight-trace-id.h > index 840babdd0794..9aae50a553ca 100644 > --- a/drivers/hwtracing/coresight/coresight-trace-id.h > +++ b/drivers/hwtracing/coresight/coresight-trace-id.h > @@ -17,9 +17,10 @@ > * released when done. > * > * In order to ensure that a consistent cpu / ID matching is maintained > - * throughout a perf cs_etm event session - a session in progress flag will > - * be maintained, and released IDs not cleared until the perf session is > - * complete. This allows the same CPU to be re-allocated its prior ID. > + * throughout a perf cs_etm event session - a session in progress flag will be > + * maintained for each sink, and IDs are cleared when all the perf sessions > + * complete. This allows the same CPU to be re-allocated its prior ID when > + * events are scheduled in and out. > * > * > * Trace ID maps will be created and initialised to prevent architecturally > @@ -66,11 +67,7 @@ int coresight_trace_id_get_cpu_id_map(int cpu, struct coresight_trace_id_map *id > /** > * Release an allocated trace ID associated with the CPU. > * > - * This will release the CoreSight trace ID associated with the CPU, > - * unless a perf session is in operation. > - * > - * If a perf session is in operation then the ID will be marked as pending > - * release. > + * This will release the CoreSight trace ID associated with the CPU. > * > * @cpu: The CPU index to release the associated trace ID. > */ > @@ -133,21 +130,21 @@ void coresight_trace_id_put_system_id(int id); > /** > * Notify the Trace ID allocator that a perf session is starting. > * > - * Increase the perf session reference count - called by perf when setting up > - * a trace event. > + * Increase the perf session reference count - called by perf when setting up a > + * trace event. > * > - * This reference count is used by the ID allocator to ensure that trace IDs > - * associated with a CPU cannot change or be released during a perf session. > + * Perf sessions never free trace IDs to ensure that the ID associated with a > + * CPU cannot change during their and other's concurrent sessions. Instead, > + * this refcount is used so that the last event to finish always frees all IDs. > */ > -void coresight_trace_id_perf_start(void); > +void coresight_trace_id_perf_start(struct coresight_trace_id_map *id_map); > > /** > * Notify the ID allocator that a perf session is stopping. > * > - * Decrease the perf session reference count. > - * if this causes the count to go to zero, then all Trace IDs marked as pending > - * release, will be released. > + * Decrease the perf session reference count. If this causes the count to go to > + * zero, then all Trace IDs will be released. > */ > -void coresight_trace_id_perf_stop(void); > +void coresight_trace_id_perf_stop(struct coresight_trace_id_map *id_map); > > #endif /* _CORESIGHT_TRACE_ID_H */ > diff --git a/include/linux/coresight.h b/include/linux/coresight.h > index 9c3067e2e38b..197949fd2c35 100644 > --- a/include/linux/coresight.h > +++ b/include/linux/coresight.h > @@ -227,14 +227,12 @@ struct coresight_sysfs_link { > * @used_ids: Bitmap to register available (bit = 0) and in use (bit = 1) IDs. > * Initialised so that the reserved IDs are permanently marked as > * in use. > - * @pend_rel_ids: CPU IDs that have been released by the trace source but not > - * yet marked as available, to allow re-allocation to the same > - * CPU during a perf session. > + * @perf_cs_etm_session_active: Number of Perf sessions using this ID map. > */ > struct coresight_trace_id_map { > DECLARE_BITMAP(used_ids, CORESIGHT_TRACE_IDS_MAX); > - DECLARE_BITMAP(pend_rel_ids, CORESIGHT_TRACE_IDS_MAX); > atomic_t __percpu *cpu_map; > + atomic_t perf_cs_etm_session_active; > }; > > /** > -- > 2.34.1 > Reviewed-by: Mike Leach <mike.leach@linaro.org> -- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 7fb55dafb639..70c99f0409b2 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -232,15 +232,21 @@ static void free_event_data(struct work_struct *work) if (!(IS_ERR_OR_NULL(*ppath))) { struct coresight_device *sink = coresight_get_sink(*ppath); - coresight_trace_id_put_cpu_id_map(cpu, &sink->perf_sink_id_map); + /* + * Mark perf event as done for trace id allocator, but don't call + * coresight_trace_id_put_cpu_id_map() on individual IDs. Perf sessions + * never free trace IDs to ensure that the ID associated with a CPU + * cannot change during their and other's concurrent sessions. Instead, + * a refcount is used so that the last event to call + * coresight_trace_id_perf_stop() frees all IDs. + */ + coresight_trace_id_perf_stop(&sink->perf_sink_id_map); + coresight_release_path(*ppath); } *ppath = NULL; } - /* mark perf event as done for trace id allocator */ - coresight_trace_id_perf_stop(); - free_percpu(event_data->path); kfree(event_data); } @@ -328,9 +334,6 @@ static void *etm_setup_aux(struct perf_event *event, void **pages, sink = user_sink = coresight_get_sink_by_id(id); } - /* tell the trace ID allocator that a perf event is starting up */ - coresight_trace_id_perf_start(); - /* check if user wants a coresight configuration selected */ cfg_hash = (u32)((event->attr.config2 & GENMASK_ULL(63, 32)) >> 32); if (cfg_hash) { @@ -411,6 +414,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages, continue; } + coresight_trace_id_perf_start(&sink->perf_sink_id_map); *etm_event_cpu_path_ptr(event_data, cpu) = path; } diff --git a/drivers/hwtracing/coresight/coresight-trace-id.c b/drivers/hwtracing/coresight/coresight-trace-id.c index 8a777c0af6ea..bddaed3e5cf8 100644 --- a/drivers/hwtracing/coresight/coresight-trace-id.c +++ b/drivers/hwtracing/coresight/coresight-trace-id.c @@ -18,12 +18,6 @@ static struct coresight_trace_id_map id_map_default = { .cpu_map = &id_map_default_cpu_ids }; -/* maintain a record of the pending releases per cpu */ -static cpumask_t cpu_id_release_pending; - -/* perf session active counter */ -static atomic_t perf_cs_etm_session_active = ATOMIC_INIT(0); - /* lock to protect id_map and cpu data */ static DEFINE_SPINLOCK(id_map_lock); @@ -35,7 +29,6 @@ static void coresight_trace_id_dump_table(struct coresight_trace_id_map *id_map, { pr_debug("%s id_map::\n", func_name); pr_debug("Used = %*pb\n", CORESIGHT_TRACE_IDS_MAX, id_map->used_ids); - pr_debug("Pend = %*pb\n", CORESIGHT_TRACE_IDS_MAX, id_map->pend_rel_ids); } #define DUMP_ID_MAP(map) coresight_trace_id_dump_table(map, __func__) #define DUMP_ID_CPU(cpu, id) pr_debug("%s called; cpu=%d, id=%d\n", __func__, cpu, id) @@ -122,34 +115,18 @@ static void coresight_trace_id_free(int id, struct coresight_trace_id_map *id_ma clear_bit(id, id_map->used_ids); } -static void coresight_trace_id_set_pend_rel(int id, struct coresight_trace_id_map *id_map) -{ - if (WARN(!IS_VALID_CS_TRACE_ID(id), "Invalid Trace ID %d\n", id)) - return; - set_bit(id, id_map->pend_rel_ids); -} - /* - * release all pending IDs for all current maps & clear CPU associations - * - * This currently operates on the default id map, but may be extended to - * operate on all registered id maps if per sink id maps are used. + * Release all IDs and clear CPU associations. */ -static void coresight_trace_id_release_all_pending(void) +static void coresight_trace_id_release_all(struct coresight_trace_id_map *id_map) { - struct coresight_trace_id_map *id_map = &id_map_default; unsigned long flags; - int cpu, bit; + int cpu; spin_lock_irqsave(&id_map_lock, flags); - for_each_set_bit(bit, id_map->pend_rel_ids, CORESIGHT_TRACE_ID_RES_TOP) { - clear_bit(bit, id_map->used_ids); - clear_bit(bit, id_map->pend_rel_ids); - } - for_each_cpu(cpu, &cpu_id_release_pending) { - atomic_set(per_cpu_ptr(id_map_default.cpu_map, cpu), 0); - cpumask_clear_cpu(cpu, &cpu_id_release_pending); - } + 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); DUMP_ID_MAP(id_map); } @@ -164,7 +141,7 @@ static int _coresight_trace_id_get_cpu_id(int cpu, struct coresight_trace_id_map /* check for existing allocation for this CPU */ id = _coresight_trace_id_read_cpu_id(cpu, id_map); if (id) - goto get_cpu_id_clr_pend; + goto get_cpu_id_out_unlock; /* * Find a new ID. @@ -185,11 +162,6 @@ static int _coresight_trace_id_get_cpu_id(int cpu, struct coresight_trace_id_map /* allocate the new id to the cpu */ atomic_set(per_cpu_ptr(id_map->cpu_map, cpu), id); -get_cpu_id_clr_pend: - /* we are (re)using this ID - so ensure it is not marked for release */ - cpumask_clear_cpu(cpu, &cpu_id_release_pending); - clear_bit(id, id_map->pend_rel_ids); - get_cpu_id_out_unlock: spin_unlock_irqrestore(&id_map_lock, flags); @@ -210,15 +182,8 @@ static void _coresight_trace_id_put_cpu_id(int cpu, struct coresight_trace_id_ma spin_lock_irqsave(&id_map_lock, flags); - if (atomic_read(&perf_cs_etm_session_active)) { - /* set release at pending if perf still active */ - coresight_trace_id_set_pend_rel(id, id_map); - cpumask_set_cpu(cpu, &cpu_id_release_pending); - } else { - /* otherwise clear id */ - coresight_trace_id_free(id, id_map); - atomic_set(per_cpu_ptr(id_map->cpu_map, cpu), 0); - } + 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); DUMP_ID_CPU(cpu, id); @@ -302,17 +267,17 @@ void coresight_trace_id_put_system_id(int id) } EXPORT_SYMBOL_GPL(coresight_trace_id_put_system_id); -void coresight_trace_id_perf_start(void) +void coresight_trace_id_perf_start(struct coresight_trace_id_map *id_map) { - atomic_inc(&perf_cs_etm_session_active); - PERF_SESSION(atomic_read(&perf_cs_etm_session_active)); + atomic_inc(&id_map->perf_cs_etm_session_active); + PERF_SESSION(atomic_read(&id_map->perf_cs_etm_session_active)); } EXPORT_SYMBOL_GPL(coresight_trace_id_perf_start); -void coresight_trace_id_perf_stop(void) +void coresight_trace_id_perf_stop(struct coresight_trace_id_map *id_map) { - if (!atomic_dec_return(&perf_cs_etm_session_active)) - coresight_trace_id_release_all_pending(); - PERF_SESSION(atomic_read(&perf_cs_etm_session_active)); + if (!atomic_dec_return(&id_map->perf_cs_etm_session_active)) + coresight_trace_id_release_all(id_map); + PERF_SESSION(atomic_read(&id_map->perf_cs_etm_session_active)); } EXPORT_SYMBOL_GPL(coresight_trace_id_perf_stop); diff --git a/drivers/hwtracing/coresight/coresight-trace-id.h b/drivers/hwtracing/coresight/coresight-trace-id.h index 840babdd0794..9aae50a553ca 100644 --- a/drivers/hwtracing/coresight/coresight-trace-id.h +++ b/drivers/hwtracing/coresight/coresight-trace-id.h @@ -17,9 +17,10 @@ * released when done. * * In order to ensure that a consistent cpu / ID matching is maintained - * throughout a perf cs_etm event session - a session in progress flag will - * be maintained, and released IDs not cleared until the perf session is - * complete. This allows the same CPU to be re-allocated its prior ID. + * throughout a perf cs_etm event session - a session in progress flag will be + * maintained for each sink, and IDs are cleared when all the perf sessions + * complete. This allows the same CPU to be re-allocated its prior ID when + * events are scheduled in and out. * * * Trace ID maps will be created and initialised to prevent architecturally @@ -66,11 +67,7 @@ int coresight_trace_id_get_cpu_id_map(int cpu, struct coresight_trace_id_map *id /** * Release an allocated trace ID associated with the CPU. * - * This will release the CoreSight trace ID associated with the CPU, - * unless a perf session is in operation. - * - * If a perf session is in operation then the ID will be marked as pending - * release. + * This will release the CoreSight trace ID associated with the CPU. * * @cpu: The CPU index to release the associated trace ID. */ @@ -133,21 +130,21 @@ void coresight_trace_id_put_system_id(int id); /** * Notify the Trace ID allocator that a perf session is starting. * - * Increase the perf session reference count - called by perf when setting up - * a trace event. + * Increase the perf session reference count - called by perf when setting up a + * trace event. * - * This reference count is used by the ID allocator to ensure that trace IDs - * associated with a CPU cannot change or be released during a perf session. + * Perf sessions never free trace IDs to ensure that the ID associated with a + * CPU cannot change during their and other's concurrent sessions. Instead, + * this refcount is used so that the last event to finish always frees all IDs. */ -void coresight_trace_id_perf_start(void); +void coresight_trace_id_perf_start(struct coresight_trace_id_map *id_map); /** * Notify the ID allocator that a perf session is stopping. * - * Decrease the perf session reference count. - * if this causes the count to go to zero, then all Trace IDs marked as pending - * release, will be released. + * Decrease the perf session reference count. If this causes the count to go to + * zero, then all Trace IDs will be released. */ -void coresight_trace_id_perf_stop(void); +void coresight_trace_id_perf_stop(struct coresight_trace_id_map *id_map); #endif /* _CORESIGHT_TRACE_ID_H */ diff --git a/include/linux/coresight.h b/include/linux/coresight.h index 9c3067e2e38b..197949fd2c35 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -227,14 +227,12 @@ struct coresight_sysfs_link { * @used_ids: Bitmap to register available (bit = 0) and in use (bit = 1) IDs. * Initialised so that the reserved IDs are permanently marked as * in use. - * @pend_rel_ids: CPU IDs that have been released by the trace source but not - * yet marked as available, to allow re-allocation to the same - * CPU during a perf session. + * @perf_cs_etm_session_active: Number of Perf sessions using this ID map. */ struct coresight_trace_id_map { DECLARE_BITMAP(used_ids, CORESIGHT_TRACE_IDS_MAX); - DECLARE_BITMAP(pend_rel_ids, CORESIGHT_TRACE_IDS_MAX); atomic_t __percpu *cpu_map; + atomic_t perf_cs_etm_session_active; }; /**