On Sun, 11 May 2014 18:35:31 +0200 Peter Zijlstra <[email protected]> wrote:
> So if the wait side has already observed cond==false, then without the > wakeup, which still potentially has ->on_rq == true, it would block. > Therefore the wakeup is a _real_ wakeup. > > We fundamentally cannot know, on the wake side, if the wait side has or > has not observed cond, and therefore the distinction you're trying to > make is a false one. I believe you may be misunderstanding Dongsheng. It has nothing to do with the wake condition. But the "success" is basically saying, "did I move the task on to the run queue?". That's a relevant piece of information that the wake up event isn't currently showing. Let me ask you this; with Donsheng's patch, will there ever be a sched_switch event when the wakeup event sees 'false' and the sched_switch event see the task with a state other than "R"? And if so, how did the task doing the wakeup event, wake up that task? -- Steve -- 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/
