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Date: Tue, 26 Aug 2014 15:45:50 +0800
From: Fam Zheng <famz@redhat.com>
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	<201408261531174782867@sangfor.com>
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Subject: Re: [Qemu-devel] [PATCH v6 0/3] linux-aio: introduce submit I/O asa
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To: Zhang Haoyu <zhanghy@sangfor.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, "Michael S. Tsirkin" <mst@redhat.com>, Stefan Hajnoczi <stefanha@gmail.com>, Ming Lei <ming.lei@canonical.com>, qemu-devel <qemu-devel@nongnu.org>, Stefan Hajnoczi <stefanha@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>

On Tue, 08/26 15:31, Zhang Haoyu wrote:
> Can we use the queued io data as caches, 
> io write will directly return and tell the guest the io is completed after the io is enqueued, 
> better user experience for burst io,
> and io-read will firstly search the io queue, if matched data found, directly get the data from the queue, 
> if not, then read the data from the disk or host page cache.
> Any ideas?

Guest kernel already has a page cache that exactly does this, also keeping a
copy of guest request data in qemu may hurt the bandwidth in some cases.

Fam