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SubjectRe: [this_cpu_xx V7 7/8] Module handling: Use this_cpu_xx to dynamically allocate counters
(Rusty Russell cc'd.)

On 12/15/2009 07:03 AM, Christoph Lameter wrote:
> @@ -479,15 +467,15 @@ static inline int try_module_get(struct
> int ret = 1;
>
> if (module) {
> - unsigned int cpu = get_cpu();
> if (likely(module_is_live(module))) {
> - local_inc(__module_ref_addr(module, cpu));
> + preempt_disable();
> + __this_cpu_inc(module->refptr->count);
> trace_module_get(module, _THIS_IP_,
> - local_read(__module_ref_addr(module, cpu)));
> + __this_cpu_read(module->refptr->count));
> + preempt_enable();
> }
> else
> ret = 0;
> - put_cpu();

I think you need preemption disabled while checking whether
module_is_live(). The state is protected by stop_machine or
synchronize_sched().

Thanks.

--
tejun


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