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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 C51E1C10F0E for ; Mon, 15 Apr 2019 09:51:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9367F2070D for ; Mon, 15 Apr 2019 09:51:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727146AbfDOJvr (ORCPT ); Mon, 15 Apr 2019 05:51:47 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:45168 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725939AbfDOJvr (ORCPT ); Mon, 15 Apr 2019 05:51:47 -0400 Received: from [5.158.153.52] (helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1hFyHA-0004FB-7H; Mon, 15 Apr 2019 11:51:44 +0200 Date: Mon, 15 Apr 2019 11:51:38 +0200 (CEST) From: Thomas Gleixner To: Huw Davies cc: linux kernel , Andy Lutomirski , Vincenzo Frascino Subject: Re: [PATCH 2/3] x86/vdso: Allow clock specific mult and shift values In-Reply-To: <20190415093042.GA21726@merlot.physics.ox.ac.uk> Message-ID: References: <20190411101205.10006-1-huw@codeweavers.com> <20190411101205.10006-3-huw@codeweavers.com> <20190415093042.GA21726@merlot.physics.ox.ac.uk> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 15 Apr 2019, Huw Davies wrote: > On Sun, Apr 14, 2019 at 12:53:32PM +0200, Thomas Gleixner wrote: > > So it stays in the same cache line, but as we move the VDSO to generic > > code, the mask field needs to stay and this will make basetime[CLOCK_MONOTONIC] > > overlap into the next cache line. > > Thanks for the great review; this is a good point. > > > See https://lkml.kernel.org/r/alpine.DEB.2.21.1902231727060.1666@nanos.tec.linutronix.de > > for an alternate solution to this problem, which avoids this and just gives > > CLOCK_MONOTONIC_RAW a separate storage space alltogether. > > I can certainly do this for the x86 vdso. Would that be useful or > should I wait for Vincenzo's work on the generic vdso first? Depends. If Vincenzo comes along with his new version soon, then you might get this for free :) Vincenzo, what's the state of your work? Thanks, tglx