[PATCH 3/5] trace/osnoise: Use start/stop_per_cpu_kthreads() on osnoise_cpus_write()

From: Daniel Bristot de Oliveira
Date: Thu Aug 12 2021 - 10:44:53 EST


When writing a new CPU mask via osnoise/cpus, if the tracer is running,
the workload is restarted to follow the new cpumask. The restart is
currently done using osnoise_workload_start/stop(), which disables the
workload *and* the instrumentation. However, disabling the
instrumentation is not necessary.

Calling start/stop_per_cpu_kthreads() is enough to apply the new
osnoise/cpus config.

No functional change.

Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Tom Zanussi <zanussi@xxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: linux-trace-devel@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Daniel Bristot de Oliveira (Red Hat) <bristot@xxxxxxxxxx>
---
kernel/trace/trace_osnoise.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 9b283038fad2..9f95dbd5b19b 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -1678,9 +1678,6 @@ osnoise_cpus_read(struct file *filp, char __user *ubuf, size_t count,
return count;
}

-static int osnoise_workload_start(void);
-static void osnoise_workload_stop(void);
-
/*
* osnoise_cpus_write - Write function for "cpus" entry
* @filp: The active open file structure
@@ -1725,7 +1722,7 @@ osnoise_cpus_write(struct file *filp, const char __user *ubuf, size_t count,
mutex_lock(&trace_types_lock);
running = osnoise_busy;
if (running)
- osnoise_workload_stop();
+ stop_per_cpu_kthreads();

mutex_lock(&interface_lock);
/*
@@ -1739,7 +1736,7 @@ osnoise_cpus_write(struct file *filp, const char __user *ubuf, size_t count,
mutex_unlock(&interface_lock);

if (running)
- osnoise_workload_start();
+ start_per_cpu_kthreads();
mutex_unlock(&trace_types_lock);

free_cpumask_var(osnoise_cpumask_new);
--
2.31.1