diff options
| -rw-r--r-- | kernel/rcutree_plugin.h | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index bbb43cad755..7082ea93566 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1986,12 +1986,19 @@ static void rcu_idle_count_callbacks_posted(void) #define RCU_IDLE_GP_DELAY 6 /* Roughly one grace period. */ #define RCU_IDLE_LAZY_GP_DELAY (6 * HZ) /* Roughly six seconds. */ +/* Loop counter for rcu_prepare_for_idle(). */ static DEFINE_PER_CPU(int, rcu_dyntick_drain); +/* If rcu_dyntick_holdoff==jiffies, don't try to enter dyntick-idle mode. */ static DEFINE_PER_CPU(unsigned long, rcu_dyntick_holdoff); +/* Timer to awaken the CPU if it enters dyntick-idle mode with callbacks. */ static DEFINE_PER_CPU(struct timer_list, rcu_idle_gp_timer); +/* Scheduled expiry time for rcu_idle_gp_timer to allow reposting. */ static DEFINE_PER_CPU(unsigned long, rcu_idle_gp_timer_expires); +/* Enable special processing on first attempt to enter dyntick-idle mode. */ static DEFINE_PER_CPU(bool, rcu_idle_first_pass); +/* Running count of non-lazy callbacks posted, never decremented. */ static DEFINE_PER_CPU(unsigned long, rcu_nonlazy_posted); +/* Snapshot of rcu_nonlazy_posted to detect meaningful exits from idle. */ static DEFINE_PER_CPU(unsigned long, rcu_nonlazy_posted_snap); /* @@ -2092,8 +2099,11 @@ static void rcu_idle_gp_timer_func(unsigned long cpu_in) */ static void rcu_prepare_for_idle_init(int cpu) { + per_cpu(rcu_dyntick_holdoff, cpu) = jiffies - 1; setup_timer(&per_cpu(rcu_idle_gp_timer, cpu), rcu_idle_gp_timer_func, cpu); + per_cpu(rcu_idle_gp_timer_expires, cpu) = jiffies - 1; + per_cpu(rcu_idle_first_pass, cpu) = 1; } /* @@ -2232,10 +2242,12 @@ static void rcu_prepare_for_idle(int cpu) } /* - * Keep a running count of callbacks posted so that rcu_prepare_for_idle() - * can detect when something out of the idle loop posts a callback. - * Of course, it had better do so either from a trace event designed to - * be called from idle or from within RCU_NONIDLE(). + * Keep a running count of the number of non-lazy callbacks posted + * on this CPU. This running counter (which is never decremented) allows + * rcu_prepare_for_idle() to detect when something out of the idle loop + * posts a callback, even if an equal number of callbacks are invoked. + * Of course, callbacks should only be posted from within a trace event + * designed to be called from idle or from within RCU_NONIDLE(). */ static void rcu_idle_count_callbacks_posted(void) { |