linux-kernel - Re: [PATCH] sched_ext: Remove unused code in the do_pick_task

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Message-Id: <DEYVTV95347Z.14PG6TGXWB4XE@etsalapatis.com>
Date: Mon, 15 Dec 2025 10:06:41 -0500
From: "Emil Tsalapatis" <emil@...alapatis.com>
To: "Emil Tsalapatis" <emil@...alapatis.com>, "Zqiang"
 <qiang.zhang@...ux.dev>, <tj@...nel.org>, <void@...ifault.com>,
 <arighi@...dia.com>, <changwoo@...lia.com>
Cc: <sched-ext@...ts.linux.dev>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] sched_ext: Remove unused code in the do_pick_task_scx()

On Mon Dec 15, 2025 at 10:05 AM EST, Emil Tsalapatis wrote:
> On Mon Dec 15, 2025 at 6:29 AM EST, Zqiang wrote:
>> The kick_idle variable is no longer used, this commit therefore remove
>> it and also remove associated code in the do_pick_task_scx().
>>
>> Fixes: 4c95380701f5 ("sched/ext: Fold balance_scx() into pick_task_scx()"),
>> Signed-off-by: Zqiang <qiang.zhang@...ux.dev>
>
> The change seems reasonable, but why is there a fixes up? This is
> followup cleanup, the original patch is perfectly fine.
>

Oh and of course tag aside:

Reviewed-by: Emil Tsalapatis <emil@...alapatis.com>

>> ---
>>  kernel/sched/ext.c | 8 ++------
>>  1 file changed, 2 insertions(+), 6 deletions(-)
>>
>> diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
>> index 695503a2f7d1..94164f2dec6d 100644
>> --- a/kernel/sched/ext.c
>> +++ b/kernel/sched/ext.c
>> @@ -2446,7 +2446,7 @@ static struct task_struct *
>>  do_pick_task_scx(struct rq *rq, struct rq_flags *rf, bool force_scx)
>>  {
>>  	struct task_struct *prev = rq->curr;
>> -	bool keep_prev, kick_idle = false;
>> +	bool keep_prev;
>>  	struct task_struct *p;
>>  
>>  	/* see kick_cpus_irq_workfn() */
>> @@ -2488,12 +2488,8 @@ do_pick_task_scx(struct rq *rq, struct rq_flags *rf, bool force_scx)
>>  			refill_task_slice_dfl(rcu_dereference_sched(scx_root), p);
>>  	} else {
>>  		p = first_local_task(rq);
>> -		if (!p) {
>> -			if (kick_idle)
>> -				scx_kick_cpu(rcu_dereference_sched(scx_root),
>> -					     cpu_of(rq), SCX_KICK_IDLE);
>> +		if (!p)
>>  			return NULL;
>> -		}
>>  
>>  		if (unlikely(!p->scx.slice)) {
>>  			struct scx_sched *sch = rcu_dereference_sched(scx_root);