From: Chris Metcalf <[email protected]> Running watchdog can be a helpful debugging feature on regular cores, but it's incompatible with nohz_full, since it forces regular scheduling events. Accordingly, just exit out immediately from any nohz_full core.
An alternate approach would be to add a flags field or function to smp_hotplug_thread to control on which cores the percpu threads are created, but it wasn't clear that much mechanism was useful. Signed-off-by: Chris Metcalf <[email protected]> --- kernel/watchdog.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 3174bf8e3538..8a46d9d8a66f 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -19,6 +19,7 @@ #include <linux/sysctl.h> #include <linux/smpboot.h> #include <linux/sched/rt.h> +#include <linux/tick.h> #include <asm/irq_regs.h> #include <linux/kvm_para.h> @@ -431,6 +432,10 @@ static void watchdog_enable(unsigned int cpu) hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); hrtimer->function = watchdog_timer_fn; + /* nohz_full cpus do not do watchdog checking. */ + if (tick_nohz_full_cpu(cpu)) + do_exit(0); + /* Enable the perf event */ watchdog_nmi_enable(cpu); -- 2.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
