On 09/10/2013 06:08 AM, Peter Zijlstra wrote: > In order to combine the preemption and need_resched test we need to > fold the need_resched information into the preempt_count value. > > We keep the existing TIF_NEED_RESCHED infrastructure in place but at 3 > sites test it and fold its value into preempt_count; namely: > > - resched_task() when setting TIF_NEED_RESCHED on the current task > - scheduler_ipi() when resched_task() sets TIF_NEED_RESCHED on a > remote task it follows it up with a reschedule IPI > and we can modify the cpu local preempt_count from > there. > - cpu_idle_loop() for when resched_task() found tsk_is_polling().
It looks like the intel_idle code can get confused if TIF_NEED_RESCHED is set but the preempt resched bit is not -- the need_resched call between monitor and mwait won't notice TIF_NEED_RESCHED. Is this condition possible? --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
