From e418e1c2bf1a253916b569370653414eb28597b6 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Sun, 10 Dec 2006 02:20:23 -0800 Subject: [PATCH] [PATCH] sched: move idle status calculation into rebalance_tick() Perform the idle state determination in rebalance_tick. If we separate balancing from sched_tick then we also need to determine the idle state in rebalance_tick. V2->V3 Remove useless idlle != 0 check. Checking nr_running seems to be sufficient. Thanks Suresh. Signed-off-by: Christoph Lameter Cc: Peter Williams Cc: Nick Piggin Cc: Christoph Lameter Cc: "Siddha, Suresh B" Cc: "Chen, Kenneth W" Acked-by: Ingo Molnar Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sched.c | 37 ++++++++++++++++--------------------- 1 file changed, 16 insertions(+), 21 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 3c1b74a..14a8d90 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2867,10 +2867,16 @@ static void update_load(struct rq *this_rq) */ static void -rebalance_tick(int this_cpu, struct rq *this_rq, enum idle_type idle) +rebalance_tick(int this_cpu, struct rq *this_rq) { unsigned long interval; struct sched_domain *sd; + /* + * We are idle if there are no processes running. This + * is valid even if we are the idle process (SMT). + */ + enum idle_type idle = !this_rq->nr_running ? + SCHED_IDLE : NOT_IDLE; for_each_domain(this_cpu, sd) { if (!(sd->flags & SD_LOAD_BALANCE)) @@ -2902,37 +2908,26 @@ rebalance_tick(int this_cpu, struct rq *this_rq, enum idle_type idle) /* * on UP we do not need to balance between CPUs: */ -static inline void rebalance_tick(int cpu, struct rq *rq) -{ -} static inline void idle_balance(int cpu, struct rq *rq) { } -static inline void update_load(struct rq *this_rq) -{ -} #endif -static inline int wake_priority_sleeper(struct rq *rq) +static inline void wake_priority_sleeper(struct rq *rq) { - int ret = 0; - #ifdef CONFIG_SCHED_SMT if (!rq->nr_running) - return 0; + return; spin_lock(&rq->lock); /* * If an SMT sibling task has been put to sleep for priority * reasons reschedule the idle task to see if it can now run. */ - if (rq->nr_running) { + if (rq->nr_running) resched_task(rq->idle); - ret = 1; - } spin_unlock(&rq->lock); #endif - return ret; } DEFINE_PER_CPU(struct kernel_stat, kstat); @@ -3148,20 +3143,20 @@ void scheduler_tick(void) struct task_struct *p = current; int cpu = smp_processor_id(); struct rq *rq = cpu_rq(cpu); - enum idle_type idle = NOT_IDLE; update_cpu_clock(p, rq, now); rq->timestamp_last_tick = now; - if (p == rq->idle) { + if (p == rq->idle) /* Task on the idle queue */ - if (!wake_priority_sleeper(rq)) - idle = SCHED_IDLE; - } else + wake_priority_sleeper(rq); + else task_running_tick(rq, p); +#ifdef CONFIG_SMP update_load(rq); - rebalance_tick(cpu, rq, idle); + rebalance_tick(cpu, rq); +#endif } #ifdef CONFIG_SCHED_SMT -- 1.8.2.3