Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757662Ab1ELOIn (ORCPT ); Thu, 12 May 2011 10:08:43 -0400 Received: from one.firstfloor.org ([213.235.205.2]:50288 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757631Ab1ELOIk (ORCPT ); Thu, 12 May 2011 10:08:40 -0400 Date: Thu, 12 May 2011 16:08:32 +0200 From: Andi Kleen To: Milton Miller Cc: Andrew Morton , Nick Piggin , Benjamin Herrenschmidt , Anton Blanchard , Thomas Gleixner , Eric Dumazet , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Ingo Molnar , Linus Torvalds , Andi Kleen Subject: Re: [PATCH] seqlock: don't smp_rmb in seqlock reader spin loop Message-ID: <20110512140832.GK6008@one.firstfloor.org> References: <1304703767.3066.211.camel@edumazet-laptop> <20110506175051.GL11636@one.firstfloor.org> <1304710003.2821.0.camel@edumazet-laptop> <1304712267.2821.29.camel@edumazet-laptop> <1304713443.20980.124.camel@work-vm> <1304721004.2821.148.camel@edumazet-laptop> <1304722000.20980.130.camel@work-vm> <1304722835.2821.192.camel@edumazet-laptop> <1304724519.20980.139.camel@work-vm> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 528 Lines: 15 On Thu, May 12, 2011 at 04:13:54AM -0500, Milton Miller wrote: > > Move the smp_rmb after cpu_relax loop in read_seqlock and add > ACCESS_ONCE to make sure the test and return are consistent. > > A multi-threaded core in the lab didn't like the update Which core was that? -Andi -- 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/