Le jeudi 28 avril 2011 Ã 17:48 +0200, Eric Dumazet a Ãcrit :
> uld add a seqcount (shared), and increment it each time one cpu
> changes global count.
>
> _sum() could get an additional parameter, the max number of allowed
> changes during _sum() run.
>
> If _sum() notices seqcount was changed too much, restart the loop.
>
> s64 __percpu_counter_sum(struct percpu_counter *fbc, unsigned maxfuzzy)
> {
> s64 ret;
> unsigned int oldseq, newseq;
> int cpu;
> restart:
> oldseq = fbc->seqcount;
> smp_rmb();
> ret = fbc->count;
> for_each_online_cpu(cpu) {
> s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
> ret += *pcount;
> }
> smp_rmb()
> newseq = fbc->count;
Sorry, it should be :
newseq = fbc->seqcount
> if (newseq - oldseq >= maxfuzzy)
> goto restart;
> return ret;
> }
>
>
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