From owner-freebsd-commit  Mon Oct 23 00:27:07 1995
Return-Path: owner-commit
Received: (from root@localhost)
          by freefall.freebsd.org (8.6.12/8.6.6) id AAA25109
          for freebsd-commit-outgoing; Mon, 23 Oct 1995 00:27:07 -0700
Received: (from root@localhost)
          by freefall.freebsd.org (8.6.12/8.6.6) id AAA25097
          for cvs-all-outgoing; Mon, 23 Oct 1995 00:27:00 -0700
Received: (from root@localhost)
          by freefall.freebsd.org (8.6.12/8.6.6) id AAA25087
          for cvs-sys-outgoing; Mon, 23 Oct 1995 00:26:58 -0700
Received: from godzilla.zeta.org.au (godzilla.zeta.org.au [203.2.228.19])
          by freefall.freebsd.org (8.6.12/8.6.6) with ESMTP id AAA25081
          ; Mon, 23 Oct 1995 00:26:52 -0700
Received: (from bde@localhost) by godzilla.zeta.org.au (8.6.9/8.6.9) id RAA17572; Mon, 23 Oct 1995 17:23:09 +1000
Date: Mon, 23 Oct 1995 17:23:09 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199510230723.RAA17572@godzilla.zeta.org.au>
To: bde@zeta.org.au, davidg@Root.COM
Subject: Re: cvs commit: src/sys/vm vm_glue.c vm_map.c vm_page.c vm_pageout.c
Cc: CVS-commiters@freefall.freebsd.org, cvs-sys@freefall.freebsd.org
Sender: owner-commit@FreeBSD.org
Precedence: bulk

>   NBPG _should_ refer to the hardware page size. PAGE_SIZE should refer to
>the "software" page size - the size that the independant portion of the VM
>system uses. CLBYTES is a historical thing that should probably go away.
>   NBPG should probably only be used in the machine-dependant portion of the
>sources on architectures where NBPG != PAGE_SIZE...in the case of the i386, I
>personally would prefer that PAGE_SIZE be used everywhere - especially when
>it's not clear what is 'managed' by the higher VM system layer.

The VM layer currently seems to manage bothe PAGE_SIZE and NBPG.  I think it
should manage only higher level pages but don't like the name `PAGE_SIZE'
since it's not clear whether that means a hardware page size, a software
page size, or the size of a cluster of hardware pages (actually it clearly
doesn't mean the cluster size, but it should be thought of as a cluster
size in the clustering layer.  OTOH, the i386 code should be aware that
the software page size is the same as the hardware pages size and have a
null clustering layer.  I think it should still use NBPG for h/w pages and
PAGE_SIZE as little as possible.

Bruce