Hi, > I think the main idea spinlock disables preemption is,
> the other process that's spinning on the lock can acquire lock. > but in some implementations of spinlock, like qspinlock in x86 (or mcs lock), > I think there's no need to disable preemption. because processes > waiting for lock cannot acquire the lock before the lock holder hand > over to other process. Are you talking about disabling local irq(ex. spin_lock_irqsave)? If so, think about the situation that a process holding the lock is preempted by interrupt. And that interrupt handler tries to grab the spinlock. It will lead to deadlock.
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
