From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 22 May 2002 10:23:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 22 May 2002 10:23:18 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.101]:22725 "EHLO e1.ny.us.ibm.com") by vger.kernel.org with ESMTP id ; Wed, 22 May 2002 10:23:17 -0400 Date: Wed, 22 May 2002 09:19:34 -0500 From: Dave McCracken To: Linus Torvalds , Andi Kleen cc: linux-kernel@vger.kernel.org Subject: Re: [RFC] POSIX personality Message-ID: <13860000.1022077174@baldur.austin.ibm.com> In-Reply-To: X-Mailer: Mulberry/2.2.0 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --On Tuesday, May 21, 2002 04:08:52 PM -0700 Linus Torvalds wrote: >> >> One reason for it would be that it would be more efficient. All the >> various shared state needed for POSIX thread group emulation could be >> put into a single structure with a single reference count. > > Now, that's a separate issue - the issue of the exact _granularity_ of > the bits, and how you group things together. > > On that front, I don't have any strong feelings - but I suspect that it > almost always ends up being fairly obvious when it is "right" to group > things together, and when it isn't. > > For example, we probably could have had just one bit for (FS | FILES), > and the same is probably true of (SIGHAND | THREAD), but on the whole we > haven't really had any gray areas when it comes to the grouping. And I > don't see any coming up. > > Does that mean that we might have a CLONE_POSIXDAMAGE that just covers all > the strange POSIX stuff that make no sense anywhere else? Maybe. But I'd > want that to be just another bit with the same semantic behaviour as the > existing ones, _not_ be some external "POSIX personality". I've been thinking along those lines myself. At this point I'd suggest we implement them as separate, then if in the future no one ever uses them separately we can consider combining them. I know this can raise some backward compatibility issues but in theory if anyone cares we wouldn't do it. Dave McCracken ====================================================================== Dave McCracken IBM Linux Base Kernel Team 1-512-838-3059 dmccr@us.ibm.com T/L 678-3059