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From: Andrea Righi <arighi@nvidia.com>
To: Tejun Heo <tj@kernel.org>
Cc: David Vernet <void@manifault.com>,
	Changwoo Min <changwoo@igalia.com>,
	sched-ext@lists.linux.dev,
	Cheng-Yang Chou <yphbchou0911@gmail.com>,
	Emil Tsalapatis <emil@etsalapatis.com>,
	linux-kernel@vger.kernel.org,
	Ching-Chun Huang <jserv@ccns.ncku.edu.tw>,
	Chia-Ping Tsai <chia7712@gmail.com>
Subject: Re: [PATCH v3 sched_ext/for-7.2] sched_ext: add p->scx.tid and SCX_OPS_TID_TO_TASK lookup
Date: Sun, 19 Apr 2026 21:24:21 +0200	[thread overview]
Message-ID: <aeUr5XCd4c6tcVTE@gpd4> (raw)
In-Reply-To: <aeUpxKBfgvgA1AWO@slm.duckdns.org>

On Sun, Apr 19, 2026 at 09:15:16AM -1000, Tejun Heo wrote:
> Hello,
> 
> On Sun, Apr 19, 2026 at 09:02:11PM +0200, Andrea Righi wrote:
> > Hm... WARN_ON_ONCE() only fires once, it can be hard to catch subsequent errors,
> > especially in case of -ENOMEM.
> > 
> > How about triggering WARN_ON_ONCE(ret == -EEXIST), which should be considered a
> > real sched_ext core bug, and use scx_error() for insert failures (ENOMEM).
> > In this way the error is more obvious for the BPF scheduler and can immediately
> > exit if it happens (even if scx_error() is probably a bit of a semantic stretch
> > in this case)?
> 
> It can't fail with ENOMEM with insecure_elasticity set. It should never
> fail. If it ever triggers, it's a bug that we need to fix.

Oh I see, that's related to the other thread about restoring
insecure_elasticity. Ok, then I have no more complain. :)

Reviewed-by: Andrea Righi <arighi@nvidia.com>

Thanks,
-Andrea

  reply	other threads:[~2026-04-19 19:24 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-04-19 18:36 [PATCH v3 sched_ext/for-7.2] sched_ext: add p->scx.tid and SCX_OPS_TID_TO_TASK lookup Tejun Heo
2026-04-19 18:39 ` Cheng-Yang Chou
2026-04-19 19:02 ` Andrea Righi
2026-04-19 19:15   ` Tejun Heo
2026-04-19 19:24     ` Andrea Righi [this message]
2026-04-19 20:19 ` Tejun Heo

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