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Date: Mon, 26 Mar 2018 18:58:23 +0800
From: Wei Wang <wei.w.wang@intel.com>
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Subject: Re: [Qemu-devel] [virtio-dev] Re: [PATCH v5 4/5] virtio-balloon:
 VIRTIO_BALLOON_F_FREE_PAGE_HINT
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org, quintela@redhat.com, dgilbert@redhat.com, pbonzini@redhat.com, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu0@gmail.com, nilal@redhat.com, riel@redhat.com

On 03/22/2018 11:13 AM, Wei Wang wrote:
>
> OK. I've tried to implement it this way: create an iothread via the 
> qemu cmdline option: --device 
> virtio-balloon,free-page-hint=true,iothread=iothread10, and schedule a 
> BH to run in the iothread context when free_page_start() is called.
>
> I think the drawback of this method is that the iothread exists during 
> the whole QEMU lifetime, which wastes CPU cycles (e.g. when live 
> migration isn't in progress). The method in v5 is like migration 
> thread, which comes only when the migration request is received and 
> goes when migration is done. Any thought?
>

Hi Michael,

Would it be acceptable to go with the thread creation method for now? I 
would prefer that method for the above reasons. If you are very 
confident about the iothread method, I can also send out the patches 
with that implementation. Hope we could finish this feature soon. Thanks.

Best,
Wei