Hi ..... On Fri, Oct 9, 2009 at 12:08 PM, Daniel Rodrick <daniel.rodrick@xxxxxxxxx> wrote: > Firstly, Does preempt_disable() disable the preemption on all the > processors or on just the local processor? Just the local processor AFAIK. > Secondly, a preempt_disable() a suffifient synchronization technique > to guard a data that is shared only among process context code on a > Uni-processor? And on SMP? Well, if you're sure this data structure is shared *only* between process (including kernel thread), then I am quite sure preempt_disable is enough in Uni Processor. However, in SMP situation, as you can predict by yourself, it's not > Lastly, is it allowable to schedule / sleep immediately after a call > to preempt_disable()? You shall hit "scheduling while atomic" bug. Check schedule() function, there you'll see it's calling schedule_debug. Eventually, it will check whether the current preempt variable is >=0 or not. If it is, stack is dumped. -- regards, Mulyadi Santosa Freelance Linux trainer blog: the-hydra.blogspot.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
