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Re: [Qemu-devel] When AioHandler->is_external=true?
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From: |
Fam Zheng |
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Subject: |
Re: [Qemu-devel] When AioHandler->is_external=true? |
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Date: |
Wed, 21 Nov 2018 13:39:23 +0800 |
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User-agent: |
Mutt/1.10.1 (2018-07-13) |
On Tue, 11/20 20:34, Dongli Zhang wrote:
> Hi,
>
> Would you please help explain in which case AioHandler->is_external is true,
> and
> when it is false?
>
> I read about iothread and mainloop and I am little bit confused about it.
VirtIO's ioeventfd is an example of is_external == true. It means the events
handler on this fd may initiate more I/O, such as read/write on virtual storage
backend, so are specially taken care of at certain points when we won't want
more I/O requests to be processed, such as when a block job is completing, or in
the middle of a QMP transaction.
Fam