I have a couple of questions regarding cond_resched(). The first one is: what's the motivation to introduce this function? The comments in the source code says it is want to reduce latency. But why not simply invoke schedule()? A possible reason might be that, cond_resched() invokes schedule() only when the NEED_RESCHED flag is set. But my understanding is if that flag is set, the process must be in the status of preemption disabled, and in this case, in my opinion, a cond_resched() does not do anything more than preempt_enable(). The second question is, why the cond_resched() have PREEMPT_ACTIVE flag set before calling schedule()? The comments seems to say it is to prevent a second (recursive?) call of cond_resched(), but I can not see any recursive call in the source code. Did I miss anything? -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
