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From: Glauber Costa <glommer@redhat.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, avi@redhat.com
Subject: Re: [PATCH 1/6] Enable pvclock flags in vcpu_time_info structure
Date: Mon, 26 Apr 2010 15:45:10 -0300	[thread overview]
Message-ID: <20100426184510.GF16166@mothafucka.localdomain> (raw)
In-Reply-To: <4BD5D76D.9020601@goop.org>

On Mon, Apr 26, 2010 at 11:11:57AM -0700, Jeremy Fitzhardinge wrote:
> On 04/26/2010 10:46 AM, Glauber Costa wrote:
> > This patch removes one padding byte and transform it into a flags
> > field. New versions of guests using pvclock will query these flags
> > upon each read.
> >   
> 
> Is this necessary?  Why not just make the pvclock driver maintain a
> local flag set, and have the HV backend call into it to update it.  Why
> does it need to be part of the pvclock structure?
Because it is already there, and we have plenty of space left?

There are obvious other ways, but I don't see any of them being simpler.
If we go by the method you suggested, we'd have, for instance, to register
the memory area where this flags lives. Which is a duplication of the
infrastructure already present in kvmclock.



  reply	other threads:[~2010-04-26 18:45 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-26 17:46 [PATCH 0/6] pvclock fixes Glauber Costa
2010-04-26 17:46 ` [PATCH 1/6] Enable pvclock flags in vcpu_time_info structure Glauber Costa
2010-04-26 17:46   ` [PATCH 2/6] Add a global synchronization point for pvclock Glauber Costa
2010-04-26 17:46     ` [PATCH 3/6] change msr numbers for kvmclock Glauber Costa
2010-04-26 17:46       ` [PATCH 4/6] export new cpuid KVM_CAP Glauber Costa
2010-04-26 17:46         ` [PATCH 5/6] Try using new kvm clock msrs Glauber Costa
2010-04-26 17:46           ` [PATCH 6/6] don't compute pvclock adjustments if we trust the tsc Glauber Costa
2010-04-27 13:40             ` Marcelo Tosatti
2010-04-27 15:11               ` Glauber Costa
2010-04-27 18:03               ` Avi Kivity
2010-04-27 18:57                 ` Glauber Costa
2010-04-27 13:35           ` [PATCH 5/6] Try using new kvm clock msrs Marcelo Tosatti
2010-04-27 13:30         ` [PATCH 4/6] export new cpuid KVM_CAP Marcelo Tosatti
2010-04-27 15:09           ` Glauber Costa
2010-04-27 16:55           ` Glauber Costa
2010-04-27 18:12         ` Avi Kivity
2010-04-27 19:09           ` Glauber Costa
2010-04-27 19:20             ` Avi Kivity
2010-04-27 13:28     ` [PATCH 2/6] Add a global synchronization point for pvclock Marcelo Tosatti
2010-04-27 18:00       ` Jeremy Fitzhardinge
2010-04-26 18:11   ` [PATCH 1/6] Enable pvclock flags in vcpu_time_info structure Jeremy Fitzhardinge
2010-04-26 18:45     ` Glauber Costa [this message]
2010-04-27 18:07   ` Avi Kivity
2010-04-27 19:09     ` Glauber Costa
2010-04-27  2:21 ` [PATCH 0/6] pvclock fixes Zachary Amsden

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