This patch moves the condition before entering idle into the cpuidle main function located in idle.c. That simplify the idle mainloop functions and increase the readibility of the conditions to enter truly idle.
This patch is code reorganization and does not change the behavior of the function.
Signed-off-by: Daniel Lezcano daniel.lezcano@linaro.org Cc: Peter Zijlstra peterz@infradead.org ---
V4: * took into account clockevents_notify(ENTER) could fail * removed an extra current_clr_polling_and_test added in V3 V3: * reorganized cpuidle_idle_call function as Suggested by Peter Zijlstra https://lkml.org/lkml/2014/2/24/492
--- kernel/sched/idle.c | 84 +++++++++++++++++++++++++++++----------------------- 1 file changed, 47 insertions(+), 37 deletions(-)
Index: cpuidle-next/kernel/sched/idle.c =================================================================== --- cpuidle-next.orig/kernel/sched/idle.c +++ cpuidle-next/kernel/sched/idle.c @@ -76,44 +76,59 @@ static int cpuidle_idle_call(void) int next_state, entered_state, ret; bool broadcast;
+ if (current_clr_polling_and_test()) { + local_irq_enable(); + __current_set_polling(); + return 0; + } + stop_critical_timings(); rcu_idle_enter();
ret = cpuidle_enabled(drv, dev); - if (ret < 0) { - arch_cpu_idle(); - goto out; - }
- /* ask the governor for the next state */ - next_state = cpuidle_select(drv, dev); + if (!ret) { + /* ask the governor for the next state */ + next_state = cpuidle_select(drv, dev); + + if (current_clr_polling_and_test()) { + dev->last_residency = 0; + entered_state = next_state; + local_irq_enable(); + } else { + broadcast = !!(drv->states[next_state].flags & + CPUIDLE_FLAG_TIMER_STOP); + + if (broadcast) + ret = clockevents_notify( + CLOCK_EVT_NOTIFY_BROADCAST_ENTER, + &dev->cpu); + + if (!ret) { + trace_cpu_idle_rcuidle(next_state, dev->cpu); + + entered_state = cpuidle_enter(drv, dev, + next_state); + + trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, + dev->cpu); + + if (broadcast) + clockevents_notify( + CLOCK_EVT_NOTIFY_BROADCAST_EXIT, + &dev->cpu);
- if (need_resched()) { - dev->last_residency = 0; - /* give the governor an opportunity to reflect on the outcome */ - cpuidle_reflect(dev, next_state); - local_irq_enable(); - goto out; + /* give the governor an opportunity to reflect on the outcome */ + cpuidle_reflect(dev, entered_state); + } + } }
- broadcast = !!(drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP); - - if (broadcast && - clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu)) - return -EBUSY; - - trace_cpu_idle_rcuidle(next_state, dev->cpu); - - entered_state = cpuidle_enter(drv, dev, next_state); - - trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); + if (ret) + arch_cpu_idle();
- if (broadcast) - clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu); + __current_set_polling();
- /* give the governor an opportunity to reflect on the outcome */ - cpuidle_reflect(dev, entered_state); -out: if (WARN_ON_ONCE(irqs_disabled())) local_irq_enable();
@@ -150,16 +165,11 @@ static void cpu_idle_loop(void) * know that the IPI is going to arrive right * away */ - if (cpu_idle_force_poll || tick_check_broadcast_expired()) { + if (cpu_idle_force_poll || tick_check_broadcast_expired()) cpu_idle_poll(); - } else { - if (!current_clr_polling_and_test()) { - cpuidle_idle_call(); - } else { - local_irq_enable(); - } - __current_set_polling(); - } + else + cpuidle_idle_call(); + arch_cpu_idle_exit(); }