Read Copy Update (RCU) is a portion of the kernel that handles mutual exclusion for a variety of subsystems in a lockless manner. There are a number of options that can be used to tune RCU in different ways:
RCU batch limit.
rcu.blimit=n
Set the maximum number of finished RCU callbacks to process in one batch.
RCU queue high level.
rcu.qhimark=n
Batch limiting is disabled when the number of queued RCU callbacks rises above n.
RCU queue low level.
rcu.qlowmark=n
Batch limiting is re-enabled when the number of queued RCU callbacks falls below n.
RCU callback queue length.
rcu.rsinterval=n
Set the number of additional RCU callbacks that should be queued before forcing a reschedule on all CPUs.