The following reply was made to PR port-alpha/25599; it has been noted by GNATS.

From: Jeff Rizzo <riz@netbsd.org>
To: gnats-bugs@netbsd.org
Cc: 
Subject: PR/25599 CVS commit: [netbsd-2-0] src/sys/arch/alpha/alpha
Date: Sun,  7 Aug 2005 15:08:16 +0000 (UTC)

 Module Name:	src
 Committed By:	riz
 Date:		Sun Aug  7 15:08:16 UTC 2005
 
 Modified Files:
 	src/sys/arch/alpha/alpha [netbsd-2-0]: pmap.c
 
 Log Message:
 Pull up revision 1.211 (requested by thorpej in ticket #5528):
 1. Disable the lazy allocation of lev1map in pmap_enter(), instead
 doing
 it in pmap_create(), and freeing the lev1map in pmap_destroy().
 This
 means that pm_lev1map is consistent for the life of the pmap.
 2. pmap_extract() now uses vtophys() for the kernel pmap.  This avoids
 having to lock the kernel pmap, since kernel PT pages are never
 freed.
 3. Because of (1), pmap_asn_alloc() no longer needs to operate on a
 locked
 pmap; pm_lev1map will never change over the life of the pmap,
 and all
 other access to the pmap is done in per-CPU fields or with atomic
 operations.
 4. Because of (3), pmap_activate() no longer needs to lock the pmap
 to do its work, thus eliminating the deadlock with sched_lock
 described
 in PR port-alpha/25599.  This is safe because we are guaranteed
 that
 the pmap is still alive, since by definition an LWP that uses
 that it
 is about to run.
 Thanks to Michael Hitch for the analysis, and Michael and Ragge for
 testing.
 
 
 To generate a diff of this commit:
 cvs rdiff -r1.207 -r1.207.2.1 src/sys/arch/alpha/alpha/pmap.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.