From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752665AbdBJOFI (ORCPT ); Fri, 10 Feb 2017 09:05:08 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:60617 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752414AbdBJOEg (ORCPT ); Fri, 10 Feb 2017 09:04:36 -0500 Date: Fri, 10 Feb 2017 13:28:25 +0100 (CET) From: Thomas Gleixner To: Vitaly Kuznetsov cc: Stephen Hemminger , "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 In-Reply-To: <87d1eqqlkv.fsf@vitty.brq.redhat.com> Message-ID: References: <20170209141052.18694-1-vkuznets@redhat.com> <20170209141052.18694-3-vkuznets@redhat.com> <87d1eqqlkv.fsf@vitty.brq.redhat.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 10 Feb 2017, Vitaly Kuznetsov wrote: > 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. You can't use seqlock, but you might be able to use seqcount. Though I doubt it given the 0 check .... Thanks, tglx