2013/1/16 Preeti U Murthy <preeti@xxxxxxxxxxxxxxxxxx>: > > Yes.Thank you very much for the explanation :) But I dont see how the > context switching goes away with your patch.With your patch, when the > higher priority thread comes in when the lower priority thread is > running in the critical section,it will see the wait queue empty and > "continue its execution" without now wanting to enter the critical > section.So this means it will preempt the lower priority thread because > it is not waiting on a lock anyway.There is a context switch here right? > I dont see any problem in scheduling due to this,but I do think your > patch is essential. > I don't have a problem that there is a context switch to the high priority process: it has a higher priority, so it probably is more important. My problem is that even when the waitqueue is empty, the high priority thread has a risk to block on the spinlock needlessly (causing context switches to low priority task and back to the high priority task) Regards, Ivo Sieben -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
