queue maintains a separate request pool per each cgroup when
CONFIG_BLK_CGROUP is enabled, and this parameter applies to each such
per-block-cgroup request pool. IOW, if there are N block cgroups,
-each request queue may have upto N request pools, each independently
+each request queue may have up to N request pools, each independently
regulated by nr_requests.
optimal_io_size (RO)