linux-kernel - Re: [PATCH 2/9] sched/fair: Add new cfs_rq.h_nr

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241128095643.GB24400@noisy.programming.kicks-ass.net>
Date: Thu, 28 Nov 2024 10:56:43 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: Vincent Guittot <vincent.guittot@...aro.org>
Cc: mingo@...hat.com, juri.lelli@...hat.com, dietmar.eggemann@....com,
	rostedt@...dmis.org, bsegall@...gle.com, mgorman@...e.de,
	vschneid@...hat.com, linux-kernel@...r.kernel.org,
	kprateek.nayak@....com, pauld@...hat.com, efault@....de,
	luis.machado@....com
Subject: Re: [PATCH 2/9] sched/fair: Add new cfs_rq.h_nr_enqueued

On Thu, Nov 28, 2024 at 10:27:43AM +0100, Vincent Guittot wrote:
> With delayed dequeued feature, a sleeping sched_entity remains enqueued
> in the rq until its lag has elapsed. As a result, it stays also visible
> in the statistics that are used to balance the system and in particular
> the field h_nr_running when the sched_entity is associated to a task.
> 
> Create a new h_nr_enqueued that tracks all enqueued tasks and restore the
> behavior of h_nr_running i.e. tracking the number of fair tasks that want
> to run.

Isn't h_nr_enqueued := h_nr_running - h_nr_delayed ? Does it really make
sense to have another variable that is so trivially computable?

Also naming; h_nr_enqueued isn't really adequate I feel, because the
whole problem is that the delayed tasks are still very much enqueued.