On lun., 2016-02-29 at 07:54 -0800, Peter Hurley wrote: > The current kernel is HZ=250 but this would occur on HZ=1000 as well. Right. But the problem with HZ=100 and HZ=250 is that the detection can happens because jiffy granularity is too coarse, since msecs_to_jiffies(2) -> 1 Following patch might reduce the probability, but wont really fix your problem. Fact that ksoftirqd prio is not what you want is completely orthogonal. diff --git a/kernel/softirq.c b/kernel/softirq.c index 479e443..f7cc594 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -180,7 +180,7 @@ EXPORT_SYMBOL(__local_bh_enable_ip); /* * We restart softirq processing for at most MAX_SOFTIRQ_RESTART times, - * but break the loop if need_resched() is set or after 2 ms. + * but break the loop if need_resched() is set or after 2 ms/ticks. * The MAX_SOFTIRQ_TIME provides a nice upper bound in most cases, but in * certain cases, such as stop_machine(), jiffies may cease to * increment and so we need the MAX_SOFTIRQ_RESTART limit as @@ -191,7 +191,7 @@ EXPORT_SYMBOL(__local_bh_enable_ip); * we want to handle softirqs as soon as possible, but they * should not be able to lock up the box. */ -#define MAX_SOFTIRQ_TIME msecs_to_jiffies(2) +#define MAX_SOFTIRQ_TIME (1 + msecs_to_jiffies(2)) #define MAX_SOFTIRQ_RESTART 10 #ifdef CONFIG_TRACE_IRQFLAGS -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
