| Date | Thu, 2 Dec 2021 22:02:21 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 01/11] sched: Trigger warning if ->migration_disabled counter underflows. |
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On Mon, Nov 29, 2021 at 06:46:44PM +0100, Sebastian Andrzej Siewior wrote: > If migrate_enable() is used more often than its counter part then it > remains undetected and rq::nr_pinned will underflow, too. > > Add a warning if migrate_enable() is attempted if without a matching a > migrate_disable(). > > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > --- > kernel/sched/core.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 76f9deeaa9420..02be3f6144e97 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -2171,6 +2171,8 @@ void migrate_enable(void) > if (p->migration_disabled > 1) { > p->migration_disabled--; > return;
Due to return there ^
> + } else if (WARN_ON_ONCE(p->migration_disabled == 0)) { > + return; > }
we can do away with else and simply write:
if (WARN_ON_ONCE(!p->migration_disabled)) return;
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