> We often have a case where a driver wants to access its data structure > in process context as well as in interrupt context (in its ISR). In > such scenarios, we generally use spin_lock_irqsave() to grab the lock > as well as disable all the local interrupts. AFAIK, disabling of local > interrupts is required so as to avoid running your ISR (which needs > the lock) while process context is holding the lock. However, this > also disables any other ISRs (which DO NOT need the lock) on the local > processor. > > Isn't this sub-optimal? Shouldn't there be a finer grained locking? actually it's optimal. It's fastest to delay the interrupts a little and be done with what you want to do under the lock quickly, and THEN take the interrupt. This means the lock hold time is short, which significantly reduces contention on this lock...
So on the same lines, if a data structure is accessed in both process context and in a (single) driver ISR, should a driver use spin_lock_irqsave() to get the lock in ISR? Or will a simple spin_lock() suffice? Thanks, Rajat -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
