From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752817AbdBJOmV (ORCPT ); Fri, 10 Feb 2017 09:42:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55734 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751577AbdBJOmU (ORCPT ); Fri, 10 Feb 2017 09:42:20 -0500 From: Vitaly Kuznetsov To: Stephen Hemminger Cc: Thomas Gleixner , "x86\@kernel.org" , Andy Lutomirski , Ingo Molnar , "H. Peter Anvin" , "KY Srinivasan" , Haiyang Zhang , Dexuan Cui , "linux-kernel\@vger.kernel.org" , "devel\@linuxdriverproject.org" , "virtualization\@lists.linux-foundation.org" Subject: Re: [PATCH 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method References: <20170209141052.18694-1-vkuznets@redhat.com> <20170209141052.18694-3-vkuznets@redhat.com> Date: Fri, 10 Feb 2017 13:25:36 +0100 In-Reply-To: (Stephen Hemminger's message of "Thu, 9 Feb 2017 18:27:27 +0000") Message-ID: <87d1eqqlkv.fsf@vitty.brq.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Fri, 10 Feb 2017 12:25:40 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Stephen Hemminger writes: > Why not use existing seqlock's? > To be honest I don't quite understand how we could use it -- the sequence locking here is done against the page updated by the hypersior, we're not creating new structures (so I don't understand how we could use struct seqcount which we don't have) but I may be misunderstanding something. BTW, I just occured to me that I should've probably put the TSC reading code to mshyperv.h and use it from both vDSO and read_hv_clock_tsc() -- what do you thing? [snip] -- Vitaly