[PATCH 1/2] tracing/hwlat: Drop the duplicate assignment in start_kthread()

[PATCH 1/2] tracing/hwlat: Drop the duplicate assignment in start_kthread()

[Kevin Hao]

We have set 'current_mask' to '&save_cpumask' in its declaration,
so there is no need to assign again.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
---
 kernel/trace/trace_hwlat.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index e2be7bb7ef7e..ddb528a6cd51 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -371,7 +371,6 @@ static int start_kthread(struct trace_array *tr)
 		return 0;
 
 	/* Just pick the first CPU on first iteration */
-	current_mask = &save_cpumask;
 	get_online_cpus();
 	cpumask_and(current_mask, cpu_online_mask, tracing_buffer_mask);
 	put_online_cpus();
-- 
2.26.2

[PATCH 2/2] tracing/hwlat: Honor the tracing_cpumask

[Kevin Hao]

In calculation of the cpu mask for the hwlat kernel thread, the wrong
cpu mask is used instead of the tracing_cpumask, this causes the
tracing/tracing_cpumask useless for hwlat tracer. Fixes it.

Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs")
Signed-off-by: Kevin Hao <haokexin@gmail.com>
---
 kernel/trace/trace_hwlat.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index ddb528a6cd51..17873e5d0353 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -283,6 +283,7 @@ static bool disable_migrate;
 static void move_to_next_cpu(void)
 {
 	struct cpumask *current_mask = &save_cpumask;
+	struct trace_array *tr = hwlat_trace;
 	int next_cpu;
 
 	if (disable_migrate)
@@ -296,7 +297,7 @@ static void move_to_next_cpu(void)
 		goto disable;
 
 	get_online_cpus();
-	cpumask_and(current_mask, cpu_online_mask, tracing_buffer_mask);
+	cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask);
 	next_cpu = cpumask_next(smp_processor_id(), current_mask);
 	put_online_cpus();
 
@@ -372,7 +373,7 @@ static int start_kthread(struct trace_array *tr)
 
 	/* Just pick the first CPU on first iteration */
 	get_online_cpus();
-	cpumask_and(current_mask, cpu_online_mask, tracing_buffer_mask);
+	cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask);
 	put_online_cpus();
 	next_cpu = cpumask_first(current_mask);
 
-- 
2.26.2