On Tue, Apr 13, 2021 at 09:18:42PM +0800, qianjun.ker...@gmail.com wrote:
> From: jun qian <qianjun.ker...@gmail.com>
>
> If it has been determined that the current cpu need resched in the
> early stage of for_each_sched_entity, then there is no need to check
> preempt in the subsequent se->parent entity_tick.
Right, but does it actually do anything, except increase linecount?
> Signed-off-by: jun qian <qianjun.ker...@gmail.com>
> ---
> kernel/sched/fair.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 1a68a0536add..c0d135100d54 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4352,8 +4352,13 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct
> sched_entity *curr)
> {
> unsigned long ideal_runtime, delta_exec;
> struct sched_entity *se;
> + struct rq *rq = rq_of(cfs_rq);
> s64 delta;
>
> + /* If the TIF_NEED_RESCHED has been set, it is no need to check again */
> + if (test_tsk_need_resched(rq->curr))
> + return;
> +
> ideal_runtime = sched_slice(cfs_rq, curr);
> delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
> if (delta_exec > ideal_runtime) {
Also, I think that's placed wrong; this way we can mis clear_buddies().
