Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756680Ab0D0SAn (ORCPT ); Tue, 27 Apr 2010 14:00:43 -0400 Received: from claw.goop.org ([74.207.240.146]:38103 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756169Ab0D0SAi (ORCPT ); Tue, 27 Apr 2010 14:00:38 -0400 Message-ID: <4BD72643.7050200@goop.org> Date: Tue, 27 Apr 2010 11:00:35 -0700 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100330 Fedora/3.0.4-1.fc12 Lightning/1.0b2pre Thunderbird/3.0.4 MIME-Version: 1.0 To: Marcelo Tosatti CC: Glauber Costa , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, avi@redhat.com, Zachary Amsden Subject: Re: [PATCH 2/6] Add a global synchronization point for pvclock References: <1272303988-21929-1-git-send-email-glommer@redhat.com> <1272303988-21929-2-git-send-email-glommer@redhat.com> <1272303988-21929-3-git-send-email-glommer@redhat.com> <20100427132807.GB18410@amt.cnet> In-Reply-To: <20100427132807.GB18410@amt.cnet> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 579 Lines: 20 On 04/27/2010 06:28 AM, Marcelo Tosatti wrote: >> + last = atomic64_read(&last_value); >> + do { >> + if (ret < last) >> + return last; >> + last = atomic64_cmpxchg(&last_value, last, ret); >> + } while (unlikely(last != ret)); >> > Wraparound? > If the units nanoseconds, it's good for ~500,000 years of uptime. J -- 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/