On Thu, 2011-08-25 at 13:46 -0500, Christoph Lameter wrote:

RISC cpus have instruction to construct complex atomic actions by the cpu
as I have shown before for ARM. 

Also, I thought this_cpu thing's were at best locally atomic. If you
make them full blown atomic ops then even __this_cpu ops will have to be
full atomic ops, otherwise:


CPU0			CPU(1)

this_cpu_inc(&foo);	preempt_disable();
			__this_cpu_inc(&foo);
			preempt_enable();

might step on each other's toes.