From owner-cvs-all Fri Oct 2 03:22:58 1998 Return-Path: Received: (from daemon@localhost) by hub.freebsd.org (8.8.8/8.8.8) id DAA29488 for cvs-all-outgoing; Fri, 2 Oct 1998 03:22:58 -0700 (PDT) (envelope-from owner-cvs-all) Received: from nlsystems.com (nlsys.demon.co.uk [158.152.125.33]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id DAA29474; Fri, 2 Oct 1998 03:22:46 -0700 (PDT) (envelope-from dfr@nlsystems.com) Received: from herring.nlsystems.com (herring.nlsystems.com [10.0.0.2]) by nlsystems.com (8.9.1/8.8.5) with SMTP id LAA06355; Fri, 2 Oct 1998 11:17:16 +0100 (BST) Date: Fri, 2 Oct 1998 11:17:16 +0100 (BST) From: Doug Rabson To: Garrett Wollman cc: Alex Nash , Poul-Henning Kamp , John Birrell , cvs-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/lib/libc_r/uthread uthread_gc.c Makefile.inc uthread_init.c uthread_find_thread.c uthread_kern.c uthread_create.c uthread_exit.c In-Reply-To: <199810011440.KAA20723@khavrinen.lcs.mit.edu> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-cvs-all@freebsd.org X-Loop: FreeBSD.org Precedence: bulk On Thu, 1 Oct 1998, Garrett Wollman wrote: > < said: > > > On Thu, Oct 01, 1998 at 10:02:06AM +0200, Poul-Henning Kamp wrote: > >> Alex, can we constrain ourselves to >actual< problems rather than > >> theoretically-possible-on-really-stupid-machines-problems ? > > > The atomicity of malloc_active++ is compiler dependent, not > > really-stupid-machine dependent. > > And, in particular, it may not be atomic on a three-operand RISC > machine. Imagine the following code sequence on an imaginary > processor: > > addil $malloc_active, %r0, %r1 > addl (%r1), %r0, %r2 > addil $1, %r2, %r3 > addl %r3, %r0, (%r1) I had to fix a whole stack of this kind of thing in the kernel before it would work reliably on the alpha. -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 181 951 1891 Fax: +44 181 381 1039