K 10
svn:author
V 7
glebius
K 8
svn:date
V 27
2017-10-09T20:51:58.977191Z
K 7
svn:log
V 513
In mb_dupcl() don't copy full m_ext, to avoid cache miss.  Respectively,
in mb_free_ext() always use fields from the original refcount holding
mbuf (see. r296242) mbuf.  Cuts another cache miss from mb_free_ext().

However, treat EXT_EXTREF mbufs differently, since they are different -
they don't have a refcount holding mbuf.

Provide longer comments in m_ext declaration to explain this change
and change from r296242.

In collaboration with:	gallatin
Differential Revision:	https://reviews.freebsd.org/D12615

END