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From: Simon <wei.guo.simon@gmail.com>
To: qemu-devel@nongnu.org
Subject: Does memory hotplug work when VFIO device already attached
Date: Sun, 17 May 2020 11:47:06 +0800	[thread overview]
Message-ID: <CAB3_kSXU1FUMuTD1ibo88hV0ja+PCmFTCB+JX6dXWoNORR-EYQ@mail.gmail.com> (raw)

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Hi,

I am trying do memory hotplug(add new memory DIMM)  in an VM attached with
VFIO device (host running with 4.9 kernel). What I observed is weird:
If my original VM is 10G (already occupies 10G RSS at host), and hotplug
add 30G DIMM to qemu,  the RSS of qemu keeps growing until nearly 39G and
suddenly drops down to 10G or ever lower. Then the RSS grows again towards
40G. The free of host keeps decreasing and it triggers OOM at last.

My question is: is this scenario valid and ever supported? (maybe some bugs
in my environment).  Is there any known problem to Qemu memory hotplug
(attached VFIO device)?

Thanks,
- Simon

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                 reply	other threads:[~2020-05-17  3:48 UTC|newest]

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