Re: [PATCH] memcg: remove unneeded preempt_disable

Peter Zijlstra
2011-08-25T19:05:37Z

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.