From mboxrd@z Thu Jan 1 00:00:00 1970 From: jianhai luan Subject: Re: [Xen-devel] [PATCH net] xen-netback: add the scenario which now beyond the range time_after_eq(). Date: Wed, 23 Oct 2013 16:02:14 +0800 Message-ID: <52678286.6000802@oracle.com> References: <1381944167-24918-1-git-send-email-jianhai.luan@oracle.com> <525FBB4F02000078000FBB30@nat28.tlf.novell.com> <525FA79F.8060601@oracle.com> <525FC98002000078000FBBB5@nat28.tlf.novell.com> <52601274.5010008@oracle.com> <526102DE02000078000FBFBB@nat28.tlf.novell.com> <5260EDD8.4020608@oracle.com> <52610CD202000078000FC00B@nat28.tlf.novell.com> <20131018112417.GA20185@zion.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Jan Beulich , annie li , david.vrabel@citrix.com, ian.campbell@citrix.com, xen-devel@lists.xenproject.org, netdev@vger.kernel.org To: Wei Liu , David Laight Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:48275 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752126Ab3JWICj (ORCPT ); Wed, 23 Oct 2013 04:02:39 -0400 In-Reply-To: <20131018112417.GA20185@zion.uk.xensource.com> Sender: netdev-owner@vger.kernel.org List-ID: On 2013-10-18 19:24, Wei Liu wrote: > On Fri, Oct 18, 2013 at 09:40:33AM +0100, David Laight wrote: >>>> My understanding is this patch does not simply double the span, it is >>>> just stricter than the original one. Please check my previous comments, >>>> I paste it here. >>> No, the code (on a 32-bit arch) just _can't_ handle jiffies differences >>> beyond 2^32, no matter how cleverly you use the respective macros. >>> All arithmetic there is done modulo 2^32. >> I haven't followed this discussion very closely but it might be possible >> to arrange that the 'incorrect lack of credit' only occurs for a few >> seconds every time 'jiffies' wraps - instead of half of the time. >> Then you'd have to be extremely unlucky to hit the timing window. >> > As I understand it, this is the idea of this patch -- to narrow down the > timing window. Jan, do you agree the idea or have better suggestion to me. Thanks, Jason > > Wei. > >> David >> >> >> >> -- >> To unsubscribe from this list: send the line "unsubscribe netdev" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html