Trivial(?) reorganization of topology lock in geom_event

[Marius Nünnerich]

Hi,

while working on the DTrace probes for geom I noticed that
g_topology_lock() is called 20 times per second from the g_event
thread, even though the thread only runs 10 times per second when
idle. Maybe it is possible to change the locking like in this patch? I
also changed the position of one unlocking of g_eventlock.

Patch (relative to src/sys):
http://nuenneri.ch/freebsd/geom_tl.patch


As a side note:
Do all the msleep calls have to have a timeout? Why is this so?

Kind regards
Marius