The vm_page lock is not needed around the call to vm_page_insert().

Submitted by:	alc
MFC after:	1 week
When auto-sizing the buffer cache, limit the amount of physical memory
used as the estimation of size, to 32GB.  This provides around 100K of
buffer headers and corresponding KVA for buffer map at the peak.
Sizing the cache larger is not useful, also resulting in the wasting
and exhausting of KVA for large machines.

Reported and tested by:	bdrewery
Sponsored by:	The FreeBSD Foundation
MFamd64: when printing the trap information, show the %esp value.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week