linux-kernel - Question about a8ea6fc9b089 ("sched: Stop PF_NO_SETAFFINITY from being inherited by various init system threads")

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Message-ID: <20210610170435.GA2187550@paulmck-ThinkPad-P17-Gen-1>
Date:   Thu, 10 Jun 2021 10:04:35 -0700
From:   "Paul E. McKenney" <paulmck@...nel.org>
To:     frederic@...nel.org
Cc:     linux-kernel@...r.kernel.org
Subject: Question about a8ea6fc9b089 ("sched: Stop PF_NO_SETAFFINITY from
 being inherited by various init system threads")

Hello, Frederic,

This commit works well, but has the unfortunate side-effect of making
smp_processor_id() complain when used in a preemptible region even
though the kthread has been pinned onto a single CPU by a call to
set_cpus_allowed_ptr().  (Which did return success.)

This isn't a big deal -- I can easily switch to raw_smp_processor_id(),
which is arguably a better choice anyway because it prevents the
complaints from flooding out any real warnings due to error returns
from set_cpus_allowed_ptr() or something else unpinning the kthread.
Which I am in the process of doing:

516e52e9f5ec ("scftorture: Avoid excess warnings")
475d6d49f21d ("refscale: Avoid excess warnings in ref_scale_reader()")

But I figured that I should check to see if this change was in fact
intentional.

							Thanx, Paul