[PATCH 0/2] sched/nohz: disallow non-existent cores from nohz-full

Paul Gortmaker
2021-12-06T16:00:21Z

A couple months back I sent a fix to reconcile rcu_nocbs= input
restrictions with nohz_full= input restrictions; with the latter being
more restrictive than the former.

However, in relaxing the nohz_full restrictions, I made it possible to
boot with a nohz_full= parameter that contains nothing but nonexistent
and not-possible cores - which will trigger a WARN.

This fixes the original reconcile commit by explicitly coding our
allowed values just like RCU does, and changes the WARN_ON to a
WARN_ON_ONCE, since it needlessly rendered the machine unusable.

---

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>

Paul Gortmaker (2):
sched/isolation: really align nohz_full with rcu_nocbs
tick/nohz: WARN_ON --> WARN_ON_ONCE to prevent console saturation

kernel/sched/isolation.c | 12 ++++++++++++
kernel/time/tick-sched.c | 2 +-
2 files changed, 13 insertions(+), 1 deletion(-)

--
2.17.1