On Tue, 2012-05-15 at 17:43 +0200, Jan Kara wrote:
> +void fprop_fraction_percpu(struct fprop_global *p,
> + struct fprop_local_percpu *pl,
> + unsigned long *numerator, unsigned long *denominator)
> +{
> + unsigned int seq;
> + s64 den;
> +
> + do {
> + seq = read_seqcount_begin(&p->sequence);
> + fprop_reflect_period_percpu(p, pl);
> + *numerator = percpu_counter_read_positive(&pl->events);
> + den = percpu_counter_read(&p->events);
> + if (den <= 0)
> + den = percpu_counter_sum(&p->events);
> + *denominator = den;
> + } while (read_seqcount_retry(&p->sequence, seq));
> +}
why not use percpu_counter_read_positive(&p->events) and ditch
percpu_counter_sum()? That sum can be terribly expensive..
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