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Date: Thu, 27 Aug 2009 22:58:54 -0300
From: Glauber Costa <glommer@redhat.com>
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Subject: [Qemu-devel] Re: [PATCH v3] introduce on_vcpu
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To: Anthony Liguori <aliguori@us.ibm.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>, qemu-devel@nongnu.org, avi@redhat.com

On Thu, Aug 27, 2009 at 08:38:56PM -0500, Anthony Liguori wrote:
> Glauber Costa wrote:
>> qemu-kvm uses a TLS variable for that, to guarantee that we're in the same thread
>> as our calling context. I like this idea. if we have io-thread disabled, we're always
>> in the same thread, and will always execute the function directly as we used to do
>> before on_vcpu().
>>
>> I do however remember anthony bending towards issuing a gettid() instead of using
>> a TLS var. I'm fine with both. Anthony, avi, you guys have a word here?
>>   
>
> Since we already keep the tid in the vcpu structure, it seems to make  
> more sense to ask "am I this vcpu thread" by doing gettid() == env->tid  
> than by maintaining a new global tls variable.
Actually, we don't. qemu-kvm does, but not qemu.

There's, however, a 'host_tid' field used by linux-user that I intend to hijack
for that. It is one of the patches I have queued up.