From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: kvm-devel@lists.sourceforge.net, Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [ RfC / patch ] kvmclock fixes
Date: Mon, 21 Apr 2008 23:38:19 +1000 [thread overview]
Message-ID: <480C98CB.4000209@goop.org> (raw)
In-Reply-To: <480C9011.7080507@redhat.com>
Gerd Hoffmann wrote:
> +cycle_t pvclock_clocksource_read(struct kvm_vcpu_time_info *src)
> +{
> + struct pvclock_shadow_time *shadow;
> + cycle_t ret;
> + unsigned version;
> +
> + shadow = &get_cpu_var(shadow_time);
> + do {
> + version = pvclock_get_time_values(shadow, src);
> + barrier();
> + ret = shadow->system_timestamp + pvclock_get_nsec_offset(shadow);
> + barrier();
>
Is barrier() strong enough? Does kvm guarantee that the per-cpu time
parameters are only ever updated by that cpu? I'm pretty sure Xen does,
so that's OK.
J
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next prev parent reply other threads:[~2008-04-21 13:38 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-07 11:53 paravirt clock stil causing hangs in kvm-65 Nikola Ciprich
2008-04-07 21:34 ` Marcelo Tosatti
2008-04-08 1:18 ` Marcelo Tosatti
2008-04-08 5:59 ` Nikola Ciprich
2008-04-19 15:29 ` Marcelo Tosatti
2008-04-19 16:22 ` Glauber Costa
2008-04-19 16:49 ` Marcelo Tosatti
2008-04-21 7:15 ` Gerd Hoffmann
2008-04-21 8:33 ` [ RfC / patch ] kvmclock fixes Gerd Hoffmann
2008-04-21 9:57 ` Jeremy Fitzhardinge
2008-04-21 13:01 ` Gerd Hoffmann
2008-04-21 13:38 ` Jeremy Fitzhardinge [this message]
2008-04-24 13:20 ` paravirt clock stil causing hangs in kvm-65 Glauber Costa
2008-04-26 14:24 ` extmaillist
2008-04-19 16:29 ` Marcelo Tosatti
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