[PATCH V4 02/19] trace/osnoise: Split workload start from the tracer start

Daniel Bristot de Oliveira
2021-10-21T12:58:07Z

In preparation from supporting multiple trace instances, create
workload start/stop specific functions.

No functional change.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
---
kernel/trace/trace_osnoise.c | 53 ++++++++++++++++++++++--------------
1 file changed, 33 insertions(+), 20 deletions(-)

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 7b1f8187764c..0a04a9a4c85a 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -1545,7 +1545,7 @@ static int start_kthread(unsigned int cpu)
* This starts the kernel thread that will look for osnoise on many
* cpus.
*/
-static int start_per_cpu_kthreads(struct trace_array *tr)
+static int start_per_cpu_kthreads(void)
{
struct cpumask *current_mask = &save_cpumask;
int retval = 0;
@@ -1678,8 +1678,8 @@ osnoise_cpus_read(struct file *filp, char __user *ubuf, size_t count,
return count;
}

-static void osnoise_tracer_start(struct trace_array *tr);
-static void osnoise_tracer_stop(struct trace_array *tr);
+static int osnoise_workload_start(void);
+static void osnoise_workload_stop(void);

/*
* osnoise_cpus_write - Write function for "cpus" entry
@@ -1701,7 +1701,6 @@ static ssize_t
osnoise_cpus_write(struct file *filp, const char __user *ubuf, size_t count,
loff_t *ppos)
{
- struct trace_array *tr = osnoise_trace;
cpumask_var_t osnoise_cpumask_new;
int running, err;
char buf[256];
@@ -1726,7 +1725,7 @@ osnoise_cpus_write(struct file *filp, const char __user *ubuf, size_t count,
mutex_lock(&trace_types_lock);
running = osnoise_busy;
if (running)
- osnoise_tracer_stop(tr);
+ osnoise_workload_stop();

mutex_lock(&interface_lock);
/*
@@ -1740,7 +1739,7 @@ osnoise_cpus_write(struct file *filp, const char __user *ubuf, size_t count,
mutex_unlock(&interface_lock);

if (running)
- osnoise_tracer_start(tr);
+ osnoise_workload_start();
mutex_unlock(&trace_types_lock);

free_cpumask_var(osnoise_cpumask_new);
@@ -1921,7 +1920,10 @@ static int osnoise_hook_events(void)
return -EINVAL;
}

-static int __osnoise_tracer_start(struct trace_array *tr)
+/*
+ * osnoise_workload_start - start the workload and hook to events
+ */
+static int osnoise_workload_start(void)
{
int retval;

@@ -1936,7 +1938,7 @@ static int __osnoise_tracer_start(struct trace_array *tr)
barrier();
trace_osnoise_callback_enabled = true;

- retval = start_per_cpu_kthreads(tr);
+ retval = start_per_cpu_kthreads();
if (retval) {
unhook_irq_events();
return retval;
@@ -1947,6 +1949,26 @@ static int __osnoise_tracer_start(struct trace_array *tr)
return 0;
}

+/*
+ * osnoise_workload_stop - stop the workload and unhook the events
+ */
+static void osnoise_workload_stop(void)
+{
+ if (!osnoise_busy)
+ return;
+
+ trace_osnoise_callback_enabled = false;
+ barrier();
+
+ stop_per_cpu_kthreads();
+
+ unhook_irq_events();
+ unhook_softirq_events();
+ unhook_thread_events();
+
+ osnoise_busy = false;
+}
+
static void osnoise_tracer_start(struct trace_array *tr)
{
int retval;
@@ -1954,7 +1976,7 @@ static void osnoise_tracer_start(struct trace_array *tr)
if (osnoise_busy)
return;

- retval = __osnoise_tracer_start(tr);
+ retval = osnoise_workload_start();
if (retval)
pr_err(BANNER "Error starting osnoise tracer\n");

@@ -1965,16 +1987,7 @@ static void osnoise_tracer_stop(struct trace_array *tr)
if (!osnoise_busy)
return;

- trace_osnoise_callback_enabled = false;
- barrier();
-
- stop_per_cpu_kthreads();
-
- unhook_irq_events();
- unhook_softirq_events();
- unhook_thread_events();
-
- osnoise_busy = false;
+ osnoise_workload_stop();
}

static int osnoise_tracer_init(struct trace_array *tr)
@@ -2017,7 +2030,7 @@ static void timerlat_tracer_start(struct trace_array *tr)

osnoise_data.timerlat_tracer = 1;

- retval = __osnoise_tracer_start(tr);
+ retval = osnoise_workload_start();
if (retval)
goto out_err;

--
2.31.1