diff options
Diffstat (limited to 'kernel/sched/idle.c')
| -rw-r--r-- | kernel/sched/idle.c | 56 |
1 files changed, 42 insertions, 14 deletions
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index c47fce75e666..c0f307c4734c 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -7,6 +7,7 @@ #include <linux/tick.h> #include <linux/mm.h> #include <linux/stackprotector.h> +#include <linux/suspend.h> #include <asm/tlb.h> @@ -14,6 +15,16 @@ #include "sched.h" +/** + * sched_idle_set_state - Record idle state for the current CPU. + * @idle_state: State to record. + */ +void sched_idle_set_state(struct cpuidle_state *idle_state, int index) +{ + idle_set_state(this_rq(), idle_state); + idle_set_state_idx(this_rq(), index); +} + static int __read_mostly cpu_idle_force_poll; void cpu_idle_poll_ctrl(bool enable) @@ -104,24 +115,27 @@ static void cpuidle_idle_call(void) rcu_idle_enter(); /* - * Ask the cpuidle framework to choose a convenient idle state. - * Fall back to the default arch idle method on errors. + * Suspend-to-idle ("freeze") is a system state in which all user space + * has been frozen, all I/O devices have been suspended and the only + * activity happens here and in iterrupts (if any). In that case bypass + * the cpuidle governor and go stratight for the deepest idle state + * available. Possibly also suspend the local tick and the entire + * timekeeping to prevent timer interrupts from kicking us out of idle + * until a proper wakeup interrupt happens. */ - next_state = cpuidle_select(drv, dev); - if (next_state < 0) { -use_default: - /* - * We can't use the cpuidle framework, let's use the default - * idle routine. - */ - if (current_clr_polling_and_test()) - local_irq_enable(); - else - arch_cpu_idle(); - + if (idle_should_freeze()) { + cpuidle_enter_freeze(); + local_irq_enable(); goto exit_idle; } + /* + * Ask the cpuidle framework to choose a convenient idle state. + * Fall back to the default arch idle method on errors. + */ + next_state = cpuidle_select(drv, dev); + if (next_state < 0) + goto use_default; /* * The idle task must be scheduled, it is pointless to @@ -179,6 +193,19 @@ exit_idle: rcu_idle_exit(); start_critical_timings(); + return; + +use_default: + /* + * We can't use the cpuidle framework, let's use the default + * idle routine. + */ + if (current_clr_polling_and_test()) + local_irq_enable(); + else + arch_cpu_idle(); + + goto exit_idle; } /* @@ -199,6 +226,7 @@ static void cpu_idle_loop(void) */ __current_set_polling(); + quiet_vmstat(); tick_nohz_idle_enter(); while (!need_resched()) { |