Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755320AbZJRWwk (ORCPT ); Sun, 18 Oct 2009 18:52:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751450AbZJRWwj (ORCPT ); Sun, 18 Oct 2009 18:52:39 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:60168 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750840AbZJRWwj (ORCPT ); Sun, 18 Oct 2009 18:52:39 -0400 Date: Mon, 19 Oct 2009 00:52:35 +0200 From: Pavel Machek To: Mathieu Desnoyers Cc: Pierre-Marc Fournier , Jan Blunck , Steven Munroe , rp@svcs.cs.pdx.edu, Josh Triplett , linux-kernel@vger.kernel.org, ltt-dev@lists.casi.polymtl.ca, Pierre Habouzit , Jon Bernard , "Paul E. McKenney" , Bert Wesarg Subject: Re: [rp] Userspace RCU 0.2.3 Message-ID: <20091018225234.GA9164@elf.ucw.cz> References: <20091014223657.GC6458@Krystal> <20091015000225.GG6763@linux.vnet.ibm.com> <20091015023925.GA27959@Krystal> <20091015090042.GA7677@feather> <4AD75EA6.8080809@polymtl.ca> <20091017171615.GD1526@ucw.cz> <20091018220243.GA32405@Krystal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091018220243.GA32405@Krystal> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1635 Lines: 39 On Sun 2009-10-18 18:02:43, Mathieu Desnoyers wrote: > * Pavel Machek (pavel@ucw.cz) wrote: > > On Thu 2009-10-15 13:40:54, Pierre-Marc Fournier wrote: > > > Josh Triplett wrote: > > > > > > > > Even Debian has given up on real 386 systems at this point, primarily > > > > because system libraries like glibc have; 486 and better represents the > > > > bare minimum required at this point. I don't know of any distributions > > > > supporting real 386 systems at this point, and doing so would represent > > > > a major undertaking. > > > > > > > > > > What about embedded systems? Anyone know if some 386 chips, perhaps even > > > in smp configurations, are still in use in those? > > > > smp 386: definitely not. > > Hrm, so for UP 386, I wonder what's the best approach. > > One would be to encapsulate all write accesses to the RCU pointers. If > we detect that the architecture lacks cmpxchg, _all_ update operations > (rcu_assign_pointer, rcu_xchg_pointer and rcu_cmpxchg_pointer) would > have to use the signal-disabled+mutex fall-back. > > Does it make sense ? Yep, but it sounds expensive. Another option is to ignore the issue and see how many people still have 386s :-). Few embedded systems may be affected, but... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/