> +/*
> + * Anonymous LRU management is a waste if there is
> + * ultimately no way to reclaim the memory.
> + */
> +bool anon_should_be_aged(struct lruvec *lruvec)
> +{
> + struct pglist_data *pgdat = lruvec_pgdat(lruvec);
> +
> + /* Aging the anon LRU is valuable if swap is present: */
> + if (total_swap_pages > 0)
> + return true;
> +
> + /* Also valuable if anon pages can be demoted: */
> + if (next_demotion_node(pgdat->node_id) >= 0)
> + return true;
> +
> + /* No way to reclaim anon pages. Should not age anon LRUs: */
> + return false;
> +}
anon_should_be_aged() doesn't really need "lruvec". It essentially
answers whether the pages of the given node can be swapped or demoted.
So it would be clearer and less confusing if anon_should_be_aged()
takes "pgdat" instead of "lruvec" as the argument. The call to
mem_cgroup_lruvec(NULL, pgdat) in age_active_anon() can then be removed
as well.
