From owner-freebsd-hackers Fri Aug 24 22:59:18 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from peter3.wemm.org (c1315225-a.plstn1.sfba.home.com [24.14.150.180]) by hub.freebsd.org (Postfix) with ESMTP id 6B20B37B410 for ; Fri, 24 Aug 2001 22:59:13 -0700 (PDT) (envelope-from peter@wemm.org) Received: from overcee.netplex.com.au (overcee.wemm.org [10.0.0.3]) by peter3.wemm.org (8.11.0/8.11.0) with ESMTP id f7P5xDM91881 for ; Fri, 24 Aug 2001 22:59:13 -0700 (PDT) (envelope-from peter@wemm.org) Received: from wemm.org (localhost [127.0.0.1]) by overcee.netplex.com.au (Postfix) with ESMTP id 1ED783810; Fri, 24 Aug 2001 22:59:13 -0700 (PDT) (envelope-from peter@wemm.org) X-Mailer: exmh version 2.3.1 01/18/2001 with nmh-1.0.4 To: Matt Dillon Cc: Julian Elischer , Alfred Perlstein , David Greenman , freebsd-hackers@FreeBSD.ORG Subject: Re: Possible race in i386/i386/pmap.c:pmap_copy() In-Reply-To: <200108250132.f7P1WfR03688@earth.backplane.com> Date: Fri, 24 Aug 2001 22:59:13 -0700 From: Peter Wemm Message-Id: <20010825055913.1ED783810@overcee.netplex.com.au> Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Matt Dillon wrote: > > : > :Thinking about this a bit more.... > :doesn't each process ahve it's own PTD?, so a process could sleep and > :another could run but it would have a differnt PTD > :so they could change that PTDE with impunity > :because when teh current process runs again it get's its own > :ptd back again.. > > Hmm. Ok, I think you are right. APTDpde is what is being loaded > and that points into the user page table directory page, which is > per-process. So APTDpde should be per-process. But it is! (sort-of) APTDpde was per-process but is now per-address-space with the advent of fork and RFMEM sharing (and KSE). When we context switch, PTD goes with the process^H^H^H^Haddress space, and APTD is merely mapped by the last entry in the per-process PTD (PTD[APTDPDTI] if memory serves correctly). Cheers, -Peter -- Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message