Commit 1eb52121 authored by Shaohua Li's avatar Shaohua Li Committed by Paul E. McKenney

rcu: Avoid unnecessary self-wakeup of per-CPU kthreads

There are a number of cases where the RCU can find additional work
for the per-CPU kthread within the context of that per-CPU kthread.
In such cases, the per-CPU kthread is already running, so attempting
to wake itself up does nothing except waste CPU cycles.  This commit
therefore checks to see if it is in the per-CPU kthread context,
omitting the wakeup in this case.
Signed-off-by: default avatarShaohua Li <shaohua.li@intel.com>
Signed-off-by: default avatarPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 1f288094
......@@ -1291,10 +1291,8 @@ static void invoke_rcu_callbacks_kthread(void)
local_irq_save(flags);
__this_cpu_write(rcu_cpu_has_work, 1);
if (__this_cpu_read(rcu_cpu_kthread_task) == NULL) {
local_irq_restore(flags);
return;
}
if (__this_cpu_read(rcu_cpu_kthread_task) != NULL &&
current != __this_cpu_read(rcu_cpu_kthread_task))
wake_up_process(__this_cpu_read(rcu_cpu_kthread_task));
local_irq_restore(flags);
}
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment