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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2017-01-31 16:48:23 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2017-01-31 16:48:23 -0500
commitf447c196fe7a3a92c6396f7628020cb8d564be15 (patch)
treea8bf323602e0e299a8e361d4b23ae6b4d120fa2b /kernel
parent79c6f448c8b79c321e4a1f31f98194e4f6b6cae7 (diff)
downloadlinux-f447c196fe7a3a92c6396f7628020cb8d564be15.tar.gz
tracing: Clean up the hwlat binding code
Instead of initializing the affinity of the hwlat kthread in the thread itself, simply set up the initial affinity at thread creation. This simplifies the code. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_hwlat.c34
1 files changed, 17 insertions, 17 deletions
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index af344a1b..75fb54a 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -266,24 +266,13 @@ out:
static struct cpumask save_cpumask;
static bool disable_migrate;
-static void move_to_next_cpu(bool initmask)
+static void move_to_next_cpu(void)
{
- static struct cpumask *current_mask;
+ struct cpumask *current_mask = &save_cpumask;
int next_cpu;
if (disable_migrate)
return;
-
- /* Just pick the first CPU on first iteration */
- if (initmask) {
- current_mask = &save_cpumask;
- get_online_cpus();
- cpumask_and(current_mask, cpu_online_mask, tracing_buffer_mask);
- put_online_cpus();
- next_cpu = cpumask_first(current_mask);
- goto set_affinity;
- }
-
/*
* If for some reason the user modifies the CPU affinity
* of this thread, than stop migrating for the duration
@@ -300,7 +289,6 @@ static void move_to_next_cpu(bool initmask)
if (next_cpu >= nr_cpu_ids)
next_cpu = cpumask_first(current_mask);
- set_affinity:
if (next_cpu >= nr_cpu_ids) /* Shouldn't happen! */
goto disable;
@@ -330,12 +318,10 @@ static void move_to_next_cpu(bool initmask)
static int kthread_fn(void *data)
{
u64 interval;
- bool initmask = true;
while (!kthread_should_stop()) {
- move_to_next_cpu(initmask);
- initmask = false;
+ move_to_next_cpu();
local_irq_disable();
get_sample();
@@ -366,13 +352,27 @@ static int kthread_fn(void *data)
*/
static int start_kthread(struct trace_array *tr)
{
+ struct cpumask *current_mask = &save_cpumask;
struct task_struct *kthread;
+ int next_cpu;
+
+ /* 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);
+ put_online_cpus();
+ next_cpu = cpumask_first(current_mask);
kthread = kthread_create(kthread_fn, NULL, "hwlatd");
if (IS_ERR(kthread)) {
pr_err(BANNER "could not start sampling thread\n");
return -ENOMEM;
}
+
+ cpumask_clear(current_mask);
+ cpumask_set_cpu(next_cpu, current_mask);
+ sched_setaffinity(kthread->pid, current_mask);
+
hwlat_kthread = kthread;
wake_up_process(kthread);