The overload indicator is used for knowing when we can totally avoid load balancing to a cpu that is about to go idle. We can avoid load balancing when no cpu has cfs task and both rt and deadline have push/pull mechanism to do their own balancing.
However, rq->nr_running on behalf of the total number of each class tasks on the cpu, do idle balance when remaining tasks are all non-CFS tasks does not make any sense. This patch fix it by idle balance when there are still other CFS tasks in the rq's root domain. Signed-off-by: Wanpeng Li <[email protected]> --- kernel/sched/fair.c | 2 +- kernel/sched/sched.h | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a1c9267..8b7e131 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6192,7 +6192,7 @@ static inline void update_sg_lb_stats(struct lb_env *env, sgs->group_load += load; sgs->sum_nr_running += rq->cfs.h_nr_running; - if (rq->nr_running > 1) + if (rq->nr_running > 1 && rq->cfs.h_nr_running > 0) *overload = true; #ifdef CONFIG_NUMA_BALANCING diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 31f1e4d..f7dd978 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1269,7 +1269,8 @@ static inline void add_nr_running(struct rq *rq, unsigned count) rq->nr_running = prev_nr + count; - if (prev_nr < 2 && rq->nr_running >= 2) { + if (prev_nr < 2 && rq->nr_running >= 2 && + rq->cfs.h_nr_running > 0) { #ifdef CONFIG_SMP if (!rq->rd->overload) rq->rd->overload = true; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
