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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 6AE84C3A589 for ; Tue, 20 Aug 2019 18:48:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A32022DA7 for ; Tue, 20 Aug 2019 18:48:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730515AbfHTSsB (ORCPT ); Tue, 20 Aug 2019 14:48:01 -0400 Received: from relay9-d.mail.gandi.net ([217.70.183.199]:44597 "EHLO relay9-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729351AbfHTSsB (ORCPT ); Tue, 20 Aug 2019 14:48:01 -0400 X-Originating-IP: 90.65.161.137 Received: from localhost (lfbn-1-1545-137.w90-65.abo.wanadoo.fr [90.65.161.137]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay9-d.mail.gandi.net (Postfix) with ESMTPSA id E0D24FF802; Tue, 20 Aug 2019 18:47:55 +0000 (UTC) Date: Tue, 20 Aug 2019 20:47:55 +0200 From: Alexandre Belloni To: Thomas Gleixner Cc: Karel Zak , Lennart Poettering , Arnd Bergmann , "Theodore Y. Ts'o" , Linus Torvalds , Linux Kernel Mailing List , John Stultz , Stephen Boyd , Florian Weimer , "H. Peter Anvin" , Palmer Dabbelt , Alistair Francis , GNU C Library , OGAWA Hirofumi Subject: Re: New kernel interface for sys_tz and timewarp? Message-ID: <20190820184755.GP3545@piout.net> References: <20190814000622.GB20365@mit.edu> <20190814090936.GB10516@gardel-login> <20190814093208.GG3600@piout.net> <20190819110903.if3dzhvfnlqutn6s@ws.net.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/08/2019 15:43:03+0200, Thomas Gleixner wrote: > On Mon, 19 Aug 2019, Karel Zak wrote: > > On Wed, Aug 14, 2019 at 11:32:08AM +0200, Alexandre Belloni wrote: > > > On 14/08/2019 11:09:36+0200, Lennart Poettering wrote: > > > > On Mi, 14.08.19 10:31, Arnd Bergmann (arnd@arndb.de) wrote: > > > > > > > > > - glibc stops passing the caller timezone argument to the kernel > > > > > - the distro kernel disables CONFIG_RTC_HCTOSYS, > > > > > CONFIG_RTC_SYSTOHC and CONFIG_GENERIC_CMOS_UPDATE > > > > > > > > What's the benefit of letting userspace do this? It sounds a lot more > > > > fragile to leave this syncing to userspace if the kernel can do this > > > > trivially on its own. > > > > Good point, why CONFIG_RTC_SYSTOHC has been added to the kernel? > > 023f333a99ce ("NTP: Add a CONFIG_RTC_SYSTOHC configuration") This answers only half the question. The follow up is then why do we need update_persistent_clock? -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com