From: Steven Rostedt (VMware) rostedt@goodmis.org
[ Upstream commit f447c196fe7a3a92c6396f7628020cb8d564be15 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/trace/trace_hwlat.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-)
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c index 5fe23f0ee7db6..158af5ddbc3aa 100644 --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -268,24 +268,13 @@ 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 @@ -302,7 +291,6 @@ 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;
@@ -332,12 +320,10 @@ 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(); @@ -368,13 +354,27 @@ 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);