rculfhash: document add lock-freedom

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/rculfhash.c b/rculfhash.c
index 64875f6a57ba96025d076319f35772f6b0ca96a2..15f56ef80caab5156414a648e5808607ab99da25 100644 (file)
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -77,6 +77,11 @@
  *   that is does not contain the "removed" node anymore, even if
  *   concurrent delete/add operations are changing the structure of the
  *   list concurrently.
+ * - The add operation performs gargage collection of buckets if it
+ *   encounters nodes with removed flag set in the bucket where it wants
+ *   to add its new node. This ensures lock-freedom of add operation by
+ *   helping the remover unlink nodes from the list rather than to wait
+ *   for it do to so.
  * - A RCU "order table" indexed by log2(hash index) is copied and
  *   expanded by the resize operation. This order table allows finding
  *   the "dummy node" tables.