enqueue_task_fair jumps to enqueue_throttle label when cfs_rq_of(se) is throttled which means that se can't be NULL and we can skip the test.
Reviewed-by: Phil Auld <[email protected]> Signed-off-by: Vincent Guittot <[email protected]> --- v2 changes: - Remove useless if statement kernel/sched/fair.c | 39 ++++++++++++++++++++------------------- 1 file changed, 20 insertions(+), 19 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a0c690d57430..b51b12d63c39 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5513,28 +5513,29 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) list_add_leaf_cfs_rq(cfs_rq); } -enqueue_throttle: - if (!se) { - add_nr_running(rq, 1); - /* - * Since new tasks are assigned an initial util_avg equal to - * half of the spare capacity of their CPU, tiny tasks have the - * ability to cross the overutilized threshold, which will - * result in the load balancer ruining all the task placement - * done by EAS. As a way to mitigate that effect, do not account - * for the first enqueue operation of new tasks during the - * overutilized flag detection. - * - * A better way of solving this problem would be to wait for - * the PELT signals of tasks to converge before taking them - * into account, but that is not straightforward to implement, - * and the following generally works well enough in practice. - */ - if (flags & ENQUEUE_WAKEUP) - update_overutilized_status(rq); + /* At this point se is NULL and we are at root level*/ + add_nr_running(rq, 1); + + /* + * Since new tasks are assigned an initial util_avg equal to + * half of the spare capacity of their CPU, tiny tasks have the + * ability to cross the overutilized threshold, which will + * result in the load balancer ruining all the task placement + * done by EAS. As a way to mitigate that effect, do not account + * for the first enqueue operation of new tasks during the + * overutilized flag detection. + * + * A better way of solving this problem would be to wait for + * the PELT signals of tasks to converge before taking them + * into account, but that is not straightforward to implement, + * and the following generally works well enough in practice. + */ + if (flags & ENQUEUE_WAKEUP) + update_overutilized_status(rq); } +enqueue_throttle: if (cfs_bandwidth_used()) { /* * When bandwidth control is enabled; the cfs_rq_throttled() -- 2.17.1
