NFSD_STATS_DRC_MEM_USAGE
percpu_counter_sum_positive(&nn->counter[NFSD_STATS_DRC_MEM_USAGE]));
percpu_counter_add(&nn->counter[NFSD_STATS_DRC_MEM_USAGE], amount);
percpu_counter_sub(&nn->counter[NFSD_STATS_DRC_MEM_USAGE], amount);