On Mon, Feb 08, 2021 at 03:45:50PM +0100, Peter Zijlstra wrote:
On Mon, Feb 01, 2021 at 12:05:45AM +0100, Frederic Weisbecker wrote:
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 305727ea0677..b601a3aa2152 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -55,6 +55,7 @@ __setup("hlt", cpu_idle_nopoll_setup); static noinline int __cpuidle cpu_idle_poll(void) { trace_cpu_idle(0, smp_processor_id());
- rcu_nocb_flush_deferred_wakeup(); stop_critical_timings(); rcu_idle_enter(); local_irq_enable();
@@ -173,6 +174,8 @@ static void cpuidle_idle_call(void) struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); int next_state, entered_state;
- rcu_nocb_flush_deferred_wakeup();
- /*
- Check if the idle task must be rescheduled. If it is the
- case, exit the function after re-enabling the local irq.
Ok if I do this instead?
--- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -55,7 +55,6 @@ __setup("hlt", cpu_idle_nopoll_setup); static noinline int __cpuidle cpu_idle_poll(void) { trace_cpu_idle(0, smp_processor_id());
- rcu_nocb_flush_deferred_wakeup(); stop_critical_timings(); rcu_idle_enter(); local_irq_enable();
@@ -174,8 +173,6 @@ static void cpuidle_idle_call(void) struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); int next_state, entered_state;
- rcu_nocb_flush_deferred_wakeup();
- /*
- Check if the idle task must be rescheduled. If it is the
- case, exit the function after re-enabling the local irq.
@@ -288,6 +285,7 @@ static void do_idle(void) } arch_cpu_idle_enter();
rcu_nocb_flush_deferred_wakeup();/* * In poll mode we reenable interrupts and spin. Also if we
Right, I think that should work. Nothing should call_rcu() before the need_resched() call. And if it does, we still have the nocb_timer to do the deferred wakeup in the worst case.
Thanks.