sched/fair: fix idle balance when remaining tasks are all non-CFS tasks
PATCH 1/1 sched/fair: fix idle balance when remaining tasks are all non-CFS tasks
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(-)
kernel/sched/fair.c +1 -1
@@ -6197,7 +6197,7 @@ 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
kernel/sched/sched.h +2 -1
@@ -1271,7 +1271,8 @@ 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;
Signature · 1 line
1.9.1