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From: sashiko-bot@kernel.org
To: "Tao Cui" <cui.tao@linux.dev>
Cc: bpf@vger.kernel.org, sched-ext@lists.linux.dev
Subject: Re: [PATCH] sched_ext: don't deliver duplicate ops.cgroup_set_idle() for same value
Date: Tue, 01 Sep 2026 03:22:40 +0000	[thread overview]
Message-ID: <20260901032240.929AA1F000E9@smtp.kernel.org> (raw)
In-Reply-To: <20260901031101.731943-1-cui.tao@linux.dev>

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The patch references a non-existent struct member `tg->scx.sched_idle`, which causes a build failure.
--

commit b3dc4baced455427fac828517318398556404ffa
Author: Tao Cui <cuitao@kylinos.cn>

sched_ext: don't deliver duplicate ops.cgroup_set_idle() for same value

This commit modifies scx_group_set_idle() to prevent delivering duplicate
cgroup transition callbacks to the BPF scheduler. It checks if the new idle
value differs from the existing value before invoking the callback.

Link: https://lore.kernel.org/r/b53c61a1-4d7d-4232-941f-d48b0563d4ed

> diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c
> index c539d15cda637..c72d9780830b8 100644
> --- a/kernel/sched/ext/ext.c
> +++ b/kernel/sched/ext/ext.c
> @@ -4930,7 +4930,8 @@ void scx_group_set_idle(struct task_group *tg, bool idle)
>  	percpu_down_read(&scx_cgroup_ops_rwsem);
>  	sch = scx_tg_knob_sched(tg);
>  
> -	if (scx_cgroup_enabled && sch && SCX_HAS_OP(sch, cgroup_set_idle))
> +	if (scx_cgroup_enabled && sch && SCX_HAS_OP(sch, cgroup_set_idle) &&
> +	    tg->scx.sched_idle != idle)

[Severity: Low]
Does this code build successfully when CONFIG_EXT_GROUP_SCHED is enabled?
It appears tg->scx.sched_idle is referencing a non-existent member in
struct scx_task_group.

Looking at include/linux/sched/ext.h, the scx_task_group struct defines
the field simply as idle:

struct scx_task_group {
    ...
    bool idle;
    ...
};

Should this condition check tg->scx.idle != idle instead?

>  		SCX_CALL_OP(sch, cgroup_set_idle, NULL, tg_cgrp(tg), idle);
>  
>  	/* Update the task group's idle state */

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901031101.731943-1-cui.tao@linux.dev?part=1

  reply	other threads:[~2026-09-01  3:22 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-01  3:11 [PATCH] sched_ext: don't deliver duplicate ops.cgroup_set_idle() for same value Tao Cui
2026-09-01  3:22 ` sashiko-bot [this message]
2026-09-01  7:25 ` Andrea Righi
2026-09-01 12:35   ` Tao Cui

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