Re: [patch v3 -mm 1/3] memcg: integrate soft reclaim tighter withzone shrinking code

From: Tejun Heo
Date: Thu May 16 2013 - 18:12:17 EST


Sorry about the delay. Just getting back to memcg.

On Mon, May 13, 2013 at 09:46:10AM +0200, Michal Hocko wrote:
...
> during the first pass. Only groups which are over their soft limit or
> any of their parents up the hierarchy is over the limit are considered

ancestors?

> +static void shrink_zone(struct zone *zone, struct scan_control *sc)
> +{
> + bool do_soft_reclaim = mem_cgroup_should_soft_reclaim(sc);
> + unsigned long nr_scanned = sc->nr_scanned;
> +
> + __shrink_zone(zone, sc, do_soft_reclaim);
> +
> + /*
> + * No group is over the soft limit or those that are do not have
> + * pages in the zone we are reclaiming so we have to reclaim everybody
> + */
> + if (do_soft_reclaim && (sc->nr_scanned == nr_scanned)) {
> + __shrink_zone(zone, sc, false);
> + return;
> + }
> +}

Maybe the following is easier to follow?

if (mem_cgroup_should_soft_reclaim(sc)) {
__shrink_zone(zone, sc, true);
if (sc->nr_scanned == nr_scanned)
__shrink_zone(zone, sc, false);
} else {
__shrink_zone(zone, sc, false);
}

But it's a minor point, please feel free to ignore.

Reviewed-by: Tejun Heo <tj@xxxxxxxxxx>

Thanks.

--
tejun
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