The following commit has been merged into the timers/urgent branch of tip:
Commit-ID: 40e97e42961f8c6cc7bd5fe67cc18417e02d78f1 Gitweb: https://git.kernel.org/tip/40e97e42961f8c6cc7bd5fe67cc18417e02d78f1 Author: Paul Gortmaker paul.gortmaker@windriver.com AuthorDate: Mon, 06 Dec 2021 09:59:50 -05:00 Committer: Thomas Gleixner tglx@linutronix.de CommitterDate: Sun, 10 Apr 2022 12:23:34 +02:00
tick/nohz: Use WARN_ON_ONCE() to prevent console saturation
While running some testing on code that happened to allow the variable tick_nohz_full_running to get set but with no "possible" NOHZ cores to back up that setting, this warning triggered:
if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE)) WARN_ON(tick_nohz_full_running);
The console was overwhemled with an endless stream of one WARN per tick per core and there was no way to even see what was going on w/o using a serial console to capture it and then trace it back to this.
Change it to WARN_ON_ONCE().
Fixes: 08ae95f4fd3b ("nohz_full: Allow the boot CPU to be nohz_full") Signed-off-by: Paul Gortmaker paul.gortmaker@windriver.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20211206145950.10927-3-paul.gortmaker@windriver.co...
--- kernel/time/tick-sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 2d76c91..3506f6e 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -188,7 +188,7 @@ static void tick_sched_do_timer(struct tick_sched *ts, ktime_t now) */ if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE)) { #ifdef CONFIG_NO_HZ_FULL - WARN_ON(tick_nohz_full_running); + WARN_ON_ONCE(tick_nohz_full_running); #endif tick_do_timer_cpu = cpu; }