From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: pv clock: kvm is incompatible with xen :-( Date: Sat, 19 Apr 2008 08:23:41 +1000 Message-ID: <48091F6D.7030600@goop.org> References: <47FF1441.6010801@redhat.com> <47FF545C.3010107@qumranet.com> <47FF6B43.1070305@redhat.com> <47FFB5B9.2020904@goop.org> <4808AF8C.5010500@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel , Avi Kivity , Glauber de Oliveira Costa To: Gerd Hoffmann Return-path: In-Reply-To: <4808AF8C.5010500@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Gerd Hoffmann wrote: > I'm looking at the guest side of the issue right now, trying to identify > common code, and while doing so noticed that xen does the > version-check-loop in both get_time_values_from_xen(void) and > xen_clocksource_read(void), and I can't see any obvious reason for that. > The loop in xen_clocksource_read(void) is not needed IMHO. Can I drop it? > No. The get_nsec_offset() needs to be atomic with respect to the get_time_values() parameters. There could be a loopless __get_time_values() for use in this case, but given that it almost never loops, I don't think its worthwhile. J ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone