CVS commit: [netbsd-2-0] src/sys/arch/alpha/alpha

[Jeff Rizzo <riz%netbsd.org@localhost>]

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.