linux-kernel - Re: [PATCH] sched: fair: drop useless cpumask_empty() in find_energy_efficient

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Message-ID: <34069a28-89e2-4881-a8a6-bb9d32c97191@web.de>
Date: Thu, 11 Sep 2025 16:00:35 +0200
From: Markus Elfring <Markus.Elfring@....de>
To: Yury Norov <yury.norov@...il.com>, kernel-janitors@...r.kernel.org,
 Ben Segall <bsegall@...gle.com>, Dietmar Eggemann
 <dietmar.eggemann@....com>, Ingo Molnar <mingo@...hat.com>,
 Juri Lelli <juri.lelli@...hat.com>, Mel Gorman <mgorman@...e.de>,
 Peter Zijlstra <peterz@...radead.org>, Steven Rostedt <rostedt@...dmis.org>,
 Valentin Schneider <vschneid@...hat.com>,
 Vincent Guittot <vincent.guittot@...aro.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
 K Prateek Nayak <kprateek.nayak@....com>,
 Madadi Vineeth Reddy <vineethr@...ux.ibm.com>
Subject: Re: [PATCH] sched: fair: drop useless cpumask_empty() in
 find_energy_efficient_cpu()

> cpumask_empty() call is O(N) and useless, because the previous
> cpumask_and() returns false for empty 'cpus'.

It seems to be more helpful to reuse a return value from a previous function call.
How do you think about to add any tags (like “Fixes” and “Cc”) accordingly?

See also:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.17-rc5#n94

Regards,
Markus