Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268086AbUJLXi0 (ORCPT ); Tue, 12 Oct 2004 19:38:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268089AbUJLXi0 (ORCPT ); Tue, 12 Oct 2004 19:38:26 -0400 Received: from gw02.applegatebroadband.net ([207.55.227.2]:37879 "EHLO data.mvista.com") by vger.kernel.org with ESMTP id S268086AbUJLXfZ (ORCPT ); Tue, 12 Oct 2004 19:35:25 -0400 Message-ID: <416C6A33.6030202@mvista.com> Date: Tue, 12 Oct 2004 16:35:15 -0700 From: George Anzinger Reply-To: george@mvista.com Organization: MontaVista Software User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4.2) Gecko/20040308 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Chris Friesen CC: Linux kernel Subject: Re: question about linux time change References: <4165AFBC.8010605@nortelnetworks.com> In-Reply-To: <4165AFBC.8010605@nortelnetworks.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1367 Lines: 36 Chris Friesen wrote: > > I have been asked to add the ability to notify userspace when the time > of day changes. The actual notification is the easy part. I'm having > issues with where exactly the time is really changed. Just what sort of time changes do you want to notify on? The ntp code "drifts" time a lot. Do you want to know about this? If it is only cases where there is a jump in time, you might do well to look at "clock_was_set()". It is in kernel/posix-timers.c and is called when ever do_settimeofday() is called AND on leap second calls. You will even find code in there to push the ladder out of the softirq context. > > do_settimeofday() is pretty straightforward. No problems there. > adjtimex() with ADJ_OFFSET_SINGLESHOT mode seems reasonable as well. > > adjtimex() with ADJ_OFFSET is a bit harder to follow. Can you give me > any pointers on what's going on with ADJ_OFFSET? > > Thanks, > > Chris > -- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml - 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/