mq_notify(SIGEV_THREAD) must be implemented in user space. If an event 
is triggered, the kernel must send a notification to user space, and 
then glibc must create the thread with the requested attributes for the 
notification callback. The current implementation in Andrew's -mm tree 
uses single shot file descriptor - it works, but it's resource hungry.

Attached is a new proposal:
- split netlink_unicast into separate substeps
- use an AF_NETLINK socket for the message queue notification

What do you think?

--
    Manfred