diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2020-08-07 20:50:19 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-08-26 12:41:53 +0200 |
| commit | 1098582a0f6c4e8fd28da0a6305f9233d02c9c1d (patch) | |
| tree | bda70ef4f575f5c5e3d8e957cd5d88125dbddf9e /kernel | |
| parent | 49d9c5936314e44d314c605c39cce0fd947f9c3a (diff) | |
sched,idle,rcu: Push rcu_idle deeper into the idle path
Lots of things take locks, due to a wee bug, rcu_lockdep didn't notice
that the locking tracepoints were using RCU.
Push rcu_idle_{enter,exit}() as deep as possible into the idle paths,
this also resolves a lot of _rcuidle()/RCU_NONIDLE() usage.
Specifically, sched_clock_idle_wakeup_event() will use ktime which
will use seqlocks which will tickle lockdep, and
stop_critical_timings() uses lock.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200821085348.310943801@infradead.org
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/idle.c | 22 |
1 files changed, 8 insertions, 14 deletions
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 6bf34986f45c..ea3a0989dc4c 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -54,17 +54,18 @@ __setup("hlt", cpu_idle_nopoll_setup); static noinline int __cpuidle cpu_idle_poll(void) { + trace_cpu_idle(0, smp_processor_id()); + stop_critical_timings(); rcu_idle_enter(); - trace_cpu_idle_rcuidle(0, smp_processor_id()); local_irq_enable(); - stop_critical_timings(); while (!tif_need_resched() && - (cpu_idle_force_poll || tick_check_broadcast_expired())) + (cpu_idle_force_poll || tick_check_broadcast_expired())) cpu_relax(); - start_critical_timings(); - trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); + rcu_idle_exit(); + start_critical_timings(); + trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id()); return 1; } @@ -91,7 +92,9 @@ void __cpuidle default_idle_call(void) local_irq_enable(); } else { stop_critical_timings(); + rcu_idle_enter(); arch_cpu_idle(); + rcu_idle_exit(); start_critical_timings(); } } @@ -158,7 +161,6 @@ static void cpuidle_idle_call(void) if (cpuidle_not_available(drv, dev)) { tick_nohz_idle_stop_tick(); - rcu_idle_enter(); default_idle_call(); goto exit_idle; @@ -178,21 +180,17 @@ static void cpuidle_idle_call(void) u64 max_latency_ns; if (idle_should_enter_s2idle()) { - rcu_idle_enter(); entered_state = call_cpuidle_s2idle(drv, dev); if (entered_state > 0) goto exit_idle; - rcu_idle_exit(); - max_latency_ns = U64_MAX; } else { max_latency_ns = dev->forced_idle_latency_limit_ns; } tick_nohz_idle_stop_tick(); - rcu_idle_enter(); next_state = cpuidle_find_deepest_state(drv, dev, max_latency_ns); call_cpuidle(drv, dev, next_state); @@ -209,8 +207,6 @@ static void cpuidle_idle_call(void) else tick_nohz_idle_retain_tick(); - rcu_idle_enter(); - entered_state = call_cpuidle(drv, dev, next_state); /* * Give the governor an opportunity to reflect on the outcome @@ -226,8 +222,6 @@ exit_idle: */ if (WARN_ON_ONCE(irqs_disabled())) local_irq_enable(); - - rcu_idle_exit(); } /* |