From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1052C00449 for ; Wed, 3 Oct 2018 06:14:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6F120205C9 for ; Wed, 3 Oct 2018 06:14:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6F120205C9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xmission.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726856AbeJCNBe (ORCPT ); Wed, 3 Oct 2018 09:01:34 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:33953 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726405AbeJCNBe (ORCPT ); Wed, 3 Oct 2018 09:01:34 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1g7aQg-0000QB-3B; Wed, 03 Oct 2018 00:14:38 -0600 Received: from [105.184.227.67] (helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1g7aQe-0005AX-LL; Wed, 03 Oct 2018 00:14:37 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Thomas Gleixner Cc: Arnd Bergmann , avagin@virtuozzo.com, dima@arista.com, Linux Kernel Mailing List , 0x7f454c46@gmail.com, adrian@lisas.de, Andy Lutomirski , Christian Brauner , gorcunov@openvz.org, "H. Peter Anvin" , Ingo Molnar , Jeff Dike , Oleg Nesterov , xemul@virtuozzo.com, Shuah Khan , containers@lists.linux-foundation.org, criu@openvz.org, Linux API , the arch/x86 maintainers , Alexey Dobriyan , linux-kselftest@vger.kernel.org References: <20180919205037.9574-1-dima@arista.com> <874lej6nny.fsf@xmission.com> <20180924205119.GA14833@outlook.office365.com> <874leezh8n.fsf@xmission.com> <20180925014150.GA6302@outlook.office365.com> <87zhw4rwiq.fsf@xmission.com> <87mus1ftb9.fsf@xmission.com> <877ej2xc23.fsf_-_@xmission.com> <87in2jskew.fsf@xmission.com> Date: Wed, 03 Oct 2018 08:14:25 +0200 In-Reply-To: (Thomas Gleixner's message of "Wed, 3 Oct 2018 07:25:35 +0200 (CEST)") Message-ID: <87in2jo8u6.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1g7aQe-0005AX-LL;;;mid=<87in2jo8u6.fsf@xmission.com>;;;hst=in02.mta.xmission.com;;;ip=105.184.227.67;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18EXT0eot4PmYqwIsbJFcW/UPiz6Fuc6mk= X-SA-Exim-Connect-IP: 105.184.227.67 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: Setting monotonic time? X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thomas Gleixner writes: > On Wed, 3 Oct 2018, Eric W. Biederman wrote: >> Direct access to hardware/drivers and not through an abstraction like >> the vfs (an abstraction over block devices) can legitimately be handled >> by hotplug events. I unplug one keyboard I plug in another. >> >> I don't know if the input layer is more of a general abstraction >> or more of a hardware device. I have not dug into it but my guess >> is abstraction from what I have heard. >> >> The scary difficulty here is if after restart input is reporting times >> in CLOCK_MONOTONIC and the applications in the namespace are talking >> about times in CLOCK_MONOTONIC_SYNC. Then there is an issue. As even >> with a fixed offset the times don't match up. >> >> So a time namespace absolutely needs to do is figure out how to deal >> with all of the kernel interfaces reporting times and figure out how to >> report them in the current time namespace. > > So you want to talk to Arnd who is leading the y2038 effort. He knowns how > many and which interfaces are involved aside of the obvious core timer > ones. It's quite an amount and the problem is that you really need to do > that at the interface level, because many of those time stamps are taken in > contexts which are completely oblivious of name spaces. Ditto for timeouts > and similar things which are handed in through these interfaces. Yep. That sounds right. Eric