Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753982AbYKGX4x (ORCPT ); Fri, 7 Nov 2008 18:56:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752069AbYKGX4p (ORCPT ); Fri, 7 Nov 2008 18:56:45 -0500 Received: from mx2.redhat.com ([66.187.237.31]:39938 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751449AbYKGX4o (ORCPT ); Fri, 7 Nov 2008 18:56:44 -0500 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <20081107052336.652868737@polymtl.ca> <20081107053349.861709786@polymtl.ca> <20081106220530.5b0e3a96.akpm@linux-foundation.org> <25298.1226055815@redhat.com> <20081107165112.GC22134@Krystal> To: Nicolas Pitre Cc: dhowells@redhat.com, Mathieu Desnoyers , Andrew Morton , Linus Torvalds , Ingo Molnar , Peter Zijlstra , linux-kernel@vger.kernel.org, Ralf Baechle , benh@kernel.crashing.org, paulus@samba.org, David Miller , Ingo Molnar , Thomas Gleixner , Steven Rostedt , linux-arch@vger.kernel.org Subject: Re: [RFC patch 08/18] cnt32_to_63 should use smp_rmb() Date: Fri, 07 Nov 2008 23:55:05 +0000 Message-ID: <9500.1226102105@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 760 Lines: 17 Nicolas Pitre wrote: > I explained several times already why I disagree. Preemption is not a > problem unless you're preempted away for long enough, or IOW if your > counter is too fast. That's my point. Say a nice -19 process gets preempted... what guarantees that it will resume within, the time it takes the counter to wrap? Even if the preempting process goes back to sleep, in that time a bunch of other processes could have woken up and could starve it for a long period of time. David -- 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/