From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: Re: [PATCH 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method Date: Fri, 10 Feb 2017 13:28:25 +0100 (CET) Message-ID: References: <20170209141052.18694-1-vkuznets@redhat.com> <20170209141052.18694-3-vkuznets@redhat.com> <87d1eqqlkv.fsf@vitty.brq.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <87d1eqqlkv.fsf@vitty.brq.redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Vitaly Kuznetsov Cc: Stephen Hemminger , Haiyang Zhang , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , Andy Lutomirski , Ingo Molnar , "H. Peter Anvin" , "devel@linuxdriverproject.org" , "virtualization@lists.linux-foundation.org" List-Id: virtualization@lists.linuxfoundation.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