.

wcfs/client/wcfs.cpp

@@ -33,7 +33,14 @@
 // boundary. To support isolation efficiently, wcfs client uses wcfs/head/f
 // most of the time, but injects wcfs/@revX/f parts into mappings to maintain
 // f@at view driven by pin messages that wcfs server sends to client in
-// accordance with WCFS isolation protocol(*).
+// accordance to WCFS isolation protocol(*).
+//
+// Wcfs server sends pin messages synchronously triggered by access to mmaped
+// memory. That means that a client thread, that is accessing wcfs/head/f mmap,
+// is completely blocked while wcfs server sends pins and waits to receive acks
+// from all clients. In other words on-client handling of pins has to be done
+// in separate thread, because wcfs server can also send pins to client that
+// trigerred the access.
 //
 //
 //