From owner-freebsd-alpha Sun Jul 18 3:56:14 1999 Delivered-To: freebsd-alpha@freebsd.org Received: from herring.nlsystems.com (nlsys.demon.co.uk [158.152.125.33]) by hub.freebsd.org (Postfix) with ESMTP id BDDD21502C for ; Sun, 18 Jul 1999 03:56:09 -0700 (PDT) (envelope-from dfr@nlsystems.com) Received: from salmon.nlsystems.com (salmon.nlsystems.com [10.0.0.3]) by herring.nlsystems.com (8.9.3/8.8.8) with ESMTP id LAA31826; Sun, 18 Jul 1999 11:56:57 +0100 (BST) (envelope-from dfr@nlsystems.com) Date: Sun, 18 Jul 1999 11:56:57 +0100 (BST) From: Doug Rabson To: Bernd Walter Cc: freebsd-alpha@freebsd.org Subject: Re: 64bit address space on alpha In-Reply-To: <19990718123251.A88741@cicely8.cicely.de> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Sun, 18 Jul 1999, Bernd Walter wrote: > On Sun, Jul 18, 1999 at 09:27:14AM +0100, Doug Rabson wrote: > > On Sat, 17 Jul 1999, Bernd Walter wrote: > > > > > I would like to mmap a large file into a single process address space. > > > Is it save to increase MAXDSIZ to more than 4G? > > > If not is there already work in progress? > > > > It should be safe to increase MAXDSIZ. The maximum user address space is > > about 4T on FreeBSD/alpha. I have programs which mmap about 12G of device > > addresses. > Mmm 4T interesting... > My Documentation says that my 21066 is limited to 43Bit Vitual - which should > be something around 4T > Applys the 43Bit limit to modern alpha CPUs too or is FreeBSD limiting. I think 21264s can use larger address spaces but FreeBSD is currently limited to 43bit virtual (half for user, quarter for direct map physical->virtual and quarter for pte mapped kernel). Supporting 53bit addressing wouldn't be very hard. The main different is that it needs four levels of pagetables instead of three. -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 181 442 9037 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message