- * Align the tail on cache line size to eliminate false-sharing
- * with head. Small note, however: the "qlen" field, kept for
- * debugging, will cause false-sharing between enqueue and
- * dequeue.
+ * We do not align head on a different cache-line than tail
+ * mainly because call_rcu callback-invocation threads use
+ * batching ("splice") to get an entire list of callbacks, which
+ * effectively empties the queue, and requires to touch the tail
+ * anyway.