[PATCH 4.9 06/39] tracing/hwlat: Honor the tracing_cpumask

Greg Kroah-Hartman
2020-08-24T09:28:30Z

From: Kevin Hao <haokexin@gmail.com>

[ Upstream commit 96b4833b6827a62c295b149213c68b559514c929 ]

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.

Link: https://lkml.kernel.org/r/20200730082318.42584-2-haokexin@gmail.com

Cc: Ingo Molnar <mingo@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs")
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 158af5ddbc3aa..d1e007c729235 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -271,6 +271,7 @@ 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)
@@ -284,7 +285,7 @@ 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();

@@ -361,7 +362,7 @@ static int start_kthread(struct trace_array *tr)
/* 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);
+ cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask);
put_online_cpus();
next_cpu = cpumask_first(current_mask);

--
2.25.1