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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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