On Fri, 2014-08-08 at 14:30 -0400, Waiman Long wrote: > I have 2 issues about this. First of all, the timing windows between > atomic_set() and mutex_has_owner() check is really small, I doubt it > will be that effective.
That is true, which is why I didn't bother showing any performance data in the changelog. However, more important than any performance, avoiding bogus wakeups is the _right_ thing to do when allowing lock stealing. > Secondly, I think you may need to call > mutex_release() and debug_mutex_unlock() to make the debugging code > work, but they seems to be called only under the wait_lock. So I think > there is more work that need to be done before this patch is ready. When !DEBUG both mutex_release() and debug_mutex_unlock() should be no-ops. So this allows us to do the mutex_has_owner() check *without* holding the wait_lock. When DEBUG is set, we don't even bother calling mutex_has_owner(), so nothing changes. I don't understand your concern. Thanks, Davidlohr -- 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/
