Re: [PATCH 6/9] sched/balancing: Update run_rebalance_domains() comments

From: Ingo Molnar <mingo@kernel.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Valentin Schneider <vschneid@redhat.com>,
	linux-kernel@vger.kernel.org,
	Shrikanth Hegde <sshegde@linux.ibm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 6/9] sched/balancing: Update run_rebalance_domains() comments
Date: Fri, 8 Mar 2024 11:15:45 +0100	[thread overview]
Message-ID: <ZerlUU4kAv580rLh@gmail.com> (raw)
In-Reply-To: <CAKfTPtCNnTVFdf85sRdJxPhdNZxc8qKcnHL3sznjg-KBVn8Bew@mail.gmail.com>

* Vincent Guittot <vincent.guittot@linaro.org> wrote:

> > """
> > The run_rebalance_domains() softirq handler is triggered via SCHED_SOFTIRQ
> > from two places:
> >
> > - directly from trigger_load_balance() in scheduler_tick(), for periodic
> >   load balance
> >
> > - indirectly from kick_ilb() (invoked down the scheduler_tick() too), which
> >   issues an SMP cross-call to nohz_csd_func() which will itself raise the
> >   softirq, for NOHZ idle balancing.
> 
> I'm not sure that we should provide too many details of the path as
> this might change in the future. What about the below ?
> 
>  - directly from the local scheduler_tick() for periodic load balance
> 
> - indirectly from a remote scheduler_tick() for NOHZ idle balancing
> through the SMP cross-call nohz_csd_func()

Okay - I updated it to:

  /*
   * This softirq handler is triggered via SCHED_SOFTIRQ from two places:
   *
   * - directly from the local scheduler_tick() for periodic load balancing
   *
   * - indirectly from a remote scheduler_tick() for NOHZ idle balancing
   *   through the SMP cross-call nohz_csd_func()
   */
  static __latent_entropy void run_rebalance_domains(struct softirq_action *h)

Does this work with everyone?

Thanks,

	Ingo