On 08/16/2017 02:59 PM, Steven Rostedt wrote: > On Wed, 16 Aug 2017 14:46:42 -0400 > Waiman Long <longman@xxxxxxxxxx> wrote: > > >> I haven't been thinking about RT tasks. You are right that it can be a >> problem in this case. I think I will have to revert back to use >> mutex_lock() if a RT task is running. Though in this case, the lock >> inversion problem will still be there. However, it is highly unlikely >> that a RT task will need to read write the block trace sysfs files. > And it is highly unlikely that the lock inversion will happen. But That is true too:-) > let's not switch one bug with another. And with PREEMPT_RT coming, that > can boost tasks into being RT, it can make the likelihood of RT tasks > running normally non RT tasks higher. > > -- Steve I am thinking about maybe letting a RT task to sleep a tiny amount of time instead of calling schedule(). Hopefully, that will allow a lower-priority task to make forward progress. Cheers, Longman
