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Date: Tue, 03 Aug 2010 09:12:52 +0300
From: Avi Kivity <avi@redhat.com>
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Subject: [Qemu-devel] Re: [PATCH] QEMUFileBuffered: indicate that we're
 ready when the underlying file is ready
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To: Anthony Liguori <anthony@codemonkey.ws>, qemu-devel@nongnu.org

  On 07/07/2010 07:44 PM, Avi Kivity wrote:
> QEMUFileBuffered stops writing when the underlying QEMUFile is not ready,
> and tells its producer so.  However, when the underlying QEMUFile becomes
> ready, it neglects to pass that information along, resulting in stoppage
> of all data until the next tick (a tenths of a second).
>
> Usually this doesn't matter, because most QEMUFiles used with QEMUFileBuffered
> are almost always ready, but in the case of exec: migration this is not true,
> due to the small pipe buffers used to connect to the target process.  The
> result is very slow migration.
>
> Fix by detecting the readiness notification and propagating it.  The detection
> is a little ugly since QEMUFile overloads put_buffer() to send it, but that's
> the suject for a different patch.

Ping.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.