K 10
svn:author
V 8
cperciva
K 8
svn:date
V 27
2011-01-04T15:55:15.638091Z
K 7
svn:log
V 498
Add hamfisted locking to the Xen/PV pmap code: Only allow one thread to
be in {pmap_pinit, pmap_copy, pmap_release} at a time.

This reduces the rate of panics when running 'make index' from ~0.6/hour
to ~0.02/hour (p < 10^-30).

At a later date this locking will be removed, and for this reason, it is
wrapped in #ifdef HAMFISTED_LOCKING; this temporary hack is being put in
place with the intention of shipping somewhat-stable Xen bits in FreeBSD
8.2-RELEASE.

PR:		kern/153672
MFC after:	3 days

END