On Dec 31, 2009, at 11:52 AM, Frank Zerangue wrote: > Help request -- Mutex(9) indicates that mutex replaces the spl(9) system. > > (1) When writing an interrupt handler, should the handler acquire a spin > mutex before modifying some IO that may be accessed also by a LWP?
Yes. and the mutex should be initialized to use IPL_VM. > (2) What happens when the interrupt handler cannot acquire the mutex? Will > the LWP that holds it ever be able to run again? That can't happen. The cpu will spin until the mutex is acquired. > (3) Will a LWP that holds a spin mutex be pre-empted by the scheduler? no.
