On Mon, 2002-03-04 at 00:18, sridharv@ufl.edu wrote:
> I have a question related to spin locking on UP systems.Before that I would
> like to point out my understanding of the background stuff
> 1. spinlocks shud be used in intr handlers
> 2. interrupts can preempt kernel code
> 3. spinlocks are turned to empty when kernel is compiled without SMP support.
This is right.
> If a particular driver is running( not the intr handler part) and at this time
> an interrupt occurs. The handler has to be invoked now. Won't the preemption
> cause race conditions/inconsistencies? Is any other mechanism used?
> Pl correct me if I have not understood any part of this correctly
> -sridhar
Right, that is why you would use a spin_lock ! :)
Further, you would want to use a spin_lock_irq and related friends. The
irq disable prevents the race wrt interrupts and the spin_lock prevents
racing wrt SMP.
Robert Love
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This archive was generated by hypermail 2b29 : Thu Mar 07 2002 - 21:00:31 EST