parent_dmemcs
if (!parent_dmemcs(limit_pool->cs))
struct dmemcg_state *parent = parent_dmemcs(dmemcs);
for (p = dmemcs; p; p = parent_dmemcs(p)) {
for (p = dmemcs, pp = parent_dmemcs(dmemcs); pp; p = pp, pp = parent_dmemcs(p)) {