Re: [PATCH 14/16] KVM-GST: KVM Steal time registration

From: Rik van Riel
Date: Mon Jan 24 2011 - 20:27:12 EST


On 01/24/2011 08:25 PM, Glauber Costa wrote:
On Mon, 2011-01-24 at 18:31 -0500, Rik van Riel wrote:
On 01/24/2011 01:06 PM, Glauber Costa wrote:
Register steal time within KVM. Everytime we sample the steal time
information, we update a local variable that tells what was the
last time read. We then account the difference.

Signed-off-by: Glauber Costa<glommer@xxxxxxxxxx>
CC: Rik van Riel<riel@xxxxxxxxxx>
CC: Jeremy Fitzhardinge<jeremy.fitzhardinge@xxxxxxxxxx>
CC: Peter Zijlstra<peterz@xxxxxxxxxxxxx>
CC: Avi Kivity<avi@xxxxxxxxxx>

On second thought - how does this deal with cpu hotplug and
hot unplug?

Do you allocate a new one of these structs every time a cpu
is hot unplugged and then hotplugged, leaking the old one?

Will leaving the old value around confuse the steal time
calculation?

If you look closely, there are no allocations happening at all,
it's all static.

In that case, does the per-cpu steal area need to be
reinitialized at hotplug time?

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