linux-kernel - [PATCHv2 1/2] trace/hwlat: Do not wipe the contents of per-cpu thread data

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Date:   Fri, 10 Mar 2023 12:04:50 +0200
From:   Tero Kristo <tero.kristo@...ux.intel.com>
To:     rostedt@...dmis.org, bristot@...nel.org, mhiramat@...nel.org
Cc:     linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org
Subject: [PATCHv2 1/2] trace/hwlat: Do not wipe the contents of per-cpu thread data

Do not wipe the contents of the per-cpu kthread data when starting the
tracer, as this will completely forget about already running instances
and can later start new additional per-cpu threads.

Signed-off-by: Tero Kristo <tero.kristo@...ux.intel.com>
---
v2:
  * split into separate patch

 kernel/trace/trace_hwlat.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index d440ddd5fd8b..edc26dc22c3f 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -584,9 +584,6 @@ static int start_per_cpu_kthreads(struct trace_array *tr)
 	 */
 	cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask);
 
-	for_each_online_cpu(cpu)
-		per_cpu(hwlat_per_cpu_data, cpu).kthread = NULL;
-
 	for_each_cpu(cpu, current_mask) {
 		retval = start_cpu_kthread(cpu);
 		if (retval)
-- 
2.25.1