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Re: [Xen-devel] [PATCH] Yield to VCPU hcall, spinlock yielding

To: "Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Yield to VCPU hcall, spinlock yielding
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Sat, 4 Jun 2005 07:55:25 +0100
Cc: Bryan Rosenburg <rosnbrg@xxxxxxxxxx>, Orran Krieger <okrieg@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, Michael Hohnbaum <hohnbaum@xxxxxxxxxx>, Ryan Harper <ryanh@xxxxxxxxxx>
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On 3 Jun 2005, at 23:06, Ian Pratt wrote:

It's been a while since I looked at Xen's boot_vcpu code (which could do
with a bit of refactoring between common and arch anyhow), but I don't
recall there being anything in there that looked particularly expensive.
Having said that, it's only holding down a couple of KB of memory, so
maybe we just need up/down/add.

You can't do a full remove without auditing the whole of Xen and adding a reference count to the vcpu structure. We're probably best off lazily allocating vcpus but then destroy them all when the domain finally is destructed.

 -- Keir

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