Re: [PATCH v3 05/11] sched_ext: Add an event, SCX_EV_ENQ_SKIP_EXITING

[Tejun Heo]

On Fri, Jan 31, 2025 at 04:09:32PM +0900, Changwoo Min wrote:
> Add a core event, SCX_EV_ENQ_SKIP_EXITING, which represents how many
> times a task is enqueued to a local DSQ when exiting if
> SCX_OPS_ENQ_EXITING is not set.
> 
> __scx_add_event() is used since the caller holds an rq lock,
> so the preemption has already been disabled.
> 
> Signed-off-by: Changwoo Min <changwoo@xxxxxxxxxx>
> ---
>  kernel/sched/ext.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
> index 7147f730850b..37f86a84ac5d 100644
> --- a/kernel/sched/ext.c
> +++ b/kernel/sched/ext.c
> @@ -1461,6 +1461,12 @@ struct scx_event_stats {
>  	 * continued to run because there were no other tasks on the CPU.
>  	 */
>  	u64		SCX_EV_DISPATCH_KEEP_LAST;
> +
> +	/*
> +	 * If SCX_OPS_ENQ_EXITING is not set, the number of times that a task
> +	 * is dispatched to a local DSQ when exiting.
> +	 */
> +	u64		SCX_EV_ENQ_SKIP_EXITING;
>  };
>  
>  /*
> @@ -2068,8 +2074,10 @@ static void do_enqueue_task(struct rq *rq, struct task_struct *p, u64 enq_flags,
>  
>  	/* see %SCX_OPS_ENQ_EXITING */
>  	if (!static_branch_unlikely(&scx_ops_enq_exiting) &&
> -	    unlikely(p->flags & PF_EXITING))
> +	    unlikely(p->flags & PF_EXITING)) {
> +		__scx_add_event(SCX_EV_ENQ_SKIP_EXITING, 1);
>  		goto local;
> +	}
>  
>  	if (!SCX_HAS_OP(enqueue))
>  		goto global;
> @@ -4986,6 +4994,7 @@ static void scx_dump_state(struct scx_exit_info *ei, size_t dump_len)
>  	scx_dump_event(s, &events, SCX_EV_SELECT_CPU_FALLBACK);
>  	scx_dump_event(s, &events, SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE);
>  	scx_dump_event(s, &events, SCX_EV_DISPATCH_KEEP_LAST);
> +	scx_dump_event(s, &events, SCX_EV_ENQ_SKIP_EXITING);
>  
>  	if (seq_buf_has_overflowed(&s) && dump_len >= sizeof(trunc_marker))
>  		memcpy(ei->dump + dump_len - sizeof(trunc_marker),

Missing agg call?

-- 
tejun