Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754589AbYKGRFw (ORCPT ); Fri, 7 Nov 2008 12:05:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752765AbYKGRFk (ORCPT ); Fri, 7 Nov 2008 12:05:40 -0500 Received: from mx2.redhat.com ([66.187.237.31]:52439 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751016AbYKGRFj (ORCPT ); Fri, 7 Nov 2008 12:05:39 -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: <20081107164758.GB22134@Krystal> References: <20081107164758.GB22134@Krystal> <20081107003816.9b0f947a.akpm@linux-foundation.org> <20081107052336.652868737@polymtl.ca> <20081107053349.861709786@polymtl.ca> <20081106220530.5b0e3a96.akpm@linux-foundation.org> <25363.1226056819@redhat.com> To: Mathieu Desnoyers Cc: dhowells@redhat.com, Andrew Morton , Nicolas Pitre , 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 17:04:57 +0000 Message-ID: <8481.1226077497@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 775 Lines: 20 Mathieu Desnoyers wrote: > First off, using this macro with get_cycles() is simply buggy, because the > macro expects _perfect_ order of timestamps, no skew whatsoever, or > otherwise time could jump. Erm... Why can't I pass it get_cycles()? Are you saying that sched_clock() in MN10300 is wrong for it's use of get_cycles() with cnt32_to_63()? > __x.lo = readl(cnt_lo); /* mmio read */ readl() might insert an extra barrier instruction. Not only that, io_addr must be unsigned long. 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/