On Mon, 8 Jan 2007 22:14:46 -0500 Mathieu Desnoyers <[EMAIL PROTECTED]> wrote:
> +* How to use local atomic operations > + > +#include <linux/percpu.h> > +#include <asm/local.h> > + > +static DEFINE_PER_CPU(local_t, counters) = LOCAL_INIT(0); > + > + > +* Counting > + > +In preemptible context, use get_cpu_var() and put_cpu_var() around local > atomic > +operations : it makes sure that preemption is disabled around write access to > +the per cpu variable. For instance : > + > + local_inc(&get_cpu_var(counters)); > + put_cpu_var(counters); Confused. The whole point behind local_t is that we can do atomic-wrt-interrupts inc and dec on them. Consequently, as atomic-wrt-interrupts means atomic-wrt-preemption, there is no need to do a preempt_disable() around local_inc() and local_dec(). - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/