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Commit b3b77736 authored by Kevin Hao's avatar Kevin Hao Committed by Greg Kroah-Hartman
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tracing/hwlat: Honor the tracing_cpumask 

commit 96b4833b6827a62c295b149213c68b559514c929 upstream.

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: 0330f7aa ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs")
Signed-off-by: default avatarKevin Hao <haokexin@gmail.com>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 46c9d392

kernel/trace/trace_hwlat.c

+3 −2
Original line number Diff line number Diff line
@@ -270,6 +270,7 @@ 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)
@@ -283,7 +284,7 @@ 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();
@@ -360,7 +361,7 @@ 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);