Re: [Qemu-devel] [PATCH 2/4] vnc: allow the Buffer to shrink again

[Peter Lieven <pl@kamp.de>]

Am 27.08.2015 um 12:39 schrieb Daniel P. Berrange:
> On Thu, Aug 27, 2015 at 12:18:52PM +0200, Peter Lieven wrote:
>> currently the Buffer can only grow. This increases Qemu memory footprint
>> dramatically since normally the biggest VNC updates are at connection time.
>> But also after a VNC session has terminated there is one persistent buffer
>> in queue->buffer which I have seen to increase to over 100MB and it is never
>> getting smaller again.
> Do you have any idea what caused the buffer to increase to 100MB in size
> in the first place ? I would expect a full screen update would cause the
> biggest buffer usage, and even for a 1920x1140 screen that should not
> be anywhere near 100MB in size. IOW, i'm wondering if the 100MB usage
> is symptomatic of a more serious bug somewhere else in the VNC code
> that you're just masking you reducing buffer size afterwards.

Maybe my commit message was a bit unclear. The memory usage of all buffers
went up to 100MB. The issue with the Buffer is that its not shrinking and that
the date is effectivly in 3 Buffers before its transferred on the wire. Plus depending
on the encoding used there are even more internal buffers.

Peter