Re: [PATCH 010 of 11] knfsd: make rpc threads pools numa aware

From: Andrew Morton
Date: Mon Jul 31 2006 - 00:12:53 EST


On Mon, 31 Jul 2006 10:42:34 +1000
NeilBrown <neilb@xxxxxxx> wrote:

> +static int
> +svc_pool_map_init_percpu(struct svc_pool_map *m)
> +{
> + unsigned int maxpools = num_possible_cpus();
> + unsigned int pidx = 0;
> + unsigned int cpu;
> + int err;
> +
> + err = svc_pool_map_alloc_arrays(m, maxpools);
> + if (err)
> + return err;
> +
> + for_each_online_cpu(cpu) {
> + BUG_ON(pidx > maxpools);
> + m->to_pool[cpu] = pidx;
> + m->pool_to[pidx] = cpu;
> + pidx++;
> + }

That isn't right - it assumes that cpu_possible_map is not sparse. If it
is sparse, we allocate undersized pools and then overindex them.
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