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Re: [Qemu-devel] [PATCH v2 0/3] fix bug about balloon working incorrectl
From: |
zhanghailiang |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/3] fix bug about balloon working incorrectly when hotplug memeory |
Date: |
Mon, 17 Nov 2014 20:25:14 +0800 |
User-agent: |
Mozilla/5.0 (Windows NT 6.1; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 |
On 2014/11/17 18:53, zhanghailiang wrote:
On 2014/11/17 18:39, Michael S. Tsirkin wrote:
On Mon, Nov 17, 2014 at 01:11:07PM +0800, zhanghailiang wrote:
Hi,
Patch 1 and 2 mainly fix bug about balloon not working correctly when we do
hotplug memory. It takes 'ram_size' as VM's real RAM size which is wrong
after we hotplug memory.
This bug exists since we begin to support hotplug memory, and it is better
to fix it.
Patch 3 add some trace events, it helps debugging balloon. If it is unnecessary,
pls feel free to remove it.
Thanks,
zhanghailiang
What about other users of ram_size?
Are they all incorrect?
pc-dimm is only supported in x86 target now, and i am not quite sure if hotplug
memory will break migration. I'll look into it. Thanks.
Hi Michael,
I have made a global search in qemu code, ram_size is used mostly for VM's
startup initialization, I think it's all OK except virtio-balloon and
function vmport_cmd_ram_size (I'm not sure about this place :( ).
But, Unfortunately, hotplug memory action breaks migration. :(
I have made a simple test about this:
Source:
# start VM
# hotplug memory:
object_add memory-backend-ram,id=ram1,size=1024M,host-nodes=0,policy=bind
device_add pc-dimm,id=dimm1,memdev=ram1
# migrate VM to Destination
Destination:
# qemu-system-x86_64: Unknown ramblock "ram1", cannot accept migration
qemu: warning: error while loading state for instance 0x0 of device 'ram'
qemu-system-x86_64: load of migration failed: Invalid argument
*further test*:
hot-add CPU also break migration and reports error in destination:
'Unknown savevm section or instance 'cpu_common' 4
qemu-system-x86_64: load of migration failed: Invalid argument'
I think we should support migration after hotplug memory/CPU action,
what's your opinion? ;)
I will try to fix these two problems.
Thanks,
zhanghailiang
v2:
- fix compiling break for other targets that don't support pc-dimm
zhanghailiang (3):
pc-dimm: add a function to calculate VM's current RAM size
virtio-balloon: Fix balloon not working correctly when hotplug memory
virtio-balloon: Add some trace events
hw/mem/pc-dimm.c | 26 ++++++++++++++++++++++++++
hw/virtio/virtio-balloon.c | 21 +++++++++++++++------
include/exec/cpu-common.h | 1 +
stubs/qmp_pc_dimm_device_list.c | 5 +++++
trace-events | 4 ++++
5 files changed, 51 insertions(+), 6 deletions(-)
--
1.7.12.4
.
- [Qemu-devel] [PATCH v2 0/3] fix bug about balloon working incorrectly when hotplug memeory, zhanghailiang, 2014/11/17
- [Qemu-devel] [PATCH v2 2/3] virtio-balloon: Fix balloon not working correctly when hotplug memory, zhanghailiang, 2014/11/17
- [Qemu-devel] [PATCH v2 3/3] virtio-balloon: Add some trace events, zhanghailiang, 2014/11/17
- [Qemu-devel] [PATCH v2 1/3] pc-dimm: add a function to calculate VM's current RAM size, zhanghailiang, 2014/11/17
- Re: [Qemu-devel] [PATCH v2 0/3] fix bug about balloon working incorrectly when hotplug memeory, Michael S. Tsirkin, 2014/11/17
- Re: [Qemu-devel] [PATCH v2 0/3] fix bug about balloon working incorrectly when hotplug memeory, Michael S. Tsirkin, 2014/11/17
Re: [Qemu-devel] [PATCH v2 0/3] fix bug about balloon working incorrectly when hotplug memeory, zhanghailiang, 2014/11/19