On Thu, Apr 17, 2014 at 12:53:28PM -0500, Christoph Lameter wrote:
> On Thu, 17 Apr 2014, Paul E. McKenney wrote:
>
> > Fair enough! I resent the patch with your Ack to Tejun.
>
> Also note that you may want to use
>
> this_cpu_inc
>
> instead of raw_cpu_inc.
>
> this_cpu_inc will not disable preemption or anything on x86 but just
> create a single instruction using instruction atomicity to avoid the
> preempt on/off sequence.
>
>
> On platforms that cannot emit such an instruction it will fallback to
> disable interrupts for the sequence of instructions that increments the
> value.
>
> With such an approach incrementing the counter should be much safer. If
> the other arch want to avoid irq on/off sequences then they can override
> the fallback to use atomics or whatever the processor architecture permits
> to avoid the overhead of interrupt on / off.
Fair enough, but in this case I don't need it to be safe.
Thanx, Paul
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
