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Date: Tue, 16 Apr 2013 10:12:40 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 4/5] virtio-blk: release reference to RAM's
	memoryRegion
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To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, Anthony Liguori <aliguori@us.ibm.com>, Jan Kiszka <jan.kiszka@siemens.com>, Marcelo Tosatti <mtosatti@redhat.com>, liu ping fan <qemulist@gmail.com>, qemu-devel@nongnu.org, Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>

Il 16/04/2013 09:57, Stefan Hajnoczi ha scritto:
> So it sounds like unplug will not block and there is no guarantee the
> memory is actually unplugged when the monitor command completes.  The
> memory region is only released when the last reference count holder lets
> go.
> 
> This means that pending I/O to a hung NFS mount can delay the actual
> unplug for unbounded time (by default the kernel NFS client keeps
> retrying and does not fail the I/O request).  The user will be able to
> issue additional monitor commands and see that memory is not yet
> unplugged?

I think "info mtree" would provide information.  We can add an event
too, similar to the recently added DEVICE_DELETED.

Paolo