[pve-devel] balloon bug in qemu 2.1 ?

Andrew Thrift andrew at networklabs.co.nz
Fri Mar 6 09:17:07 CET 2015


Hi Alexandre,

Yes the affected VM seem to have "-machine type=pc-i440fx-2.1" in their KVM
parameters.

I found a bunch that have "machine: pc-i440fx-1.4" in the config, and KVM
parameters, and they output the full balloon stats e.g.:

# info balloon
balloon: actual=4096 max_mem=4096 total_mem=4095 free_mem=2221
mem_swapped_in=0 mem_swapped_out=0 major_page_faults=0
minor_page_faults=43 last_update=1425629742




On Fri, Mar 6, 2015 at 4:17 AM, Alexandre DERUMIER <aderumier at odiso.com>
wrote:

> ok,I speak too fast.
> It's not related to this patch.
>
>
> on current pve-qemu-kvm 2.1.
>
> balloon is working fine
> # info balloon
> balloon: actual=1024 max_mem=1024 total_mem=1002 free_mem=941
> mem_swapped_in=0 mem_swapped_out=0 major_page_faults=120
> minor_page_faults=215272 last_update=1425568324
>
>
> But if the vm (qemu 2.1) is started with
>  -machine type=pc-i440fx-2.1
> or
>  -machine type=pc-i440fx-2.0   (this is the case when you do a live
> migration)
>
> It's not working
>
> # info balloon
> balloon: actual=1024 max_mem=1024
>
>
>
> @Andrew, are your vm where you see the info balloon bug, have been
> migrated from old proxmox (without stop/start ?)
> can you check in ssh if the kvm process have -machine type in the command
> line ?
>
>
> ----- Mail original -----
> De: "aderumier" <aderumier at odiso.com>
> À: "Andrew Thrift" <andrew at networklabs.co.nz>
> Cc: "pve-devel" <pve-devel at pve.proxmox.com>
> Envoyé: Jeudi 5 Mars 2015 16:05:03
> Objet: Re: [pve-devel] balloon bug in qemu 2.1 ?
>
> I need to do more tests,
>
> but it seem that this commit (applied on qemu 2.2 but not on qemu 2.1)
>
> http://git.qemu.org/?p=qemu.git;a=commit;h=22644cd2c60151a964d9505f4c5f7baf845f20d8
>
> fix the problem with qemu 2.1.
> (I have tested with the patch, balloon works fine, I need to test without
> the patch to compare)
>
>
>
>
>
> ----- Mail original -----
> De: "aderumier" <aderumier at odiso.com>
> À: "Andrew Thrift" <andrew at networklabs.co.nz>
> Cc: "pve-devel" <pve-devel at pve.proxmox.com>
> Envoyé: Jeudi 5 Mars 2015 15:41:51
> Objet: Re: [pve-devel] balloon bug in qemu 2.1 ?
>
> in proxmox virtio-balloon-fix-query.patch,
>
> we have
>
> hw/virtio/virtio-balloon.c
>
> +
> + if (!(balloon_stats_enabled(dev) && balloon_stats_supported(dev) &&
> + dev->stats_last_update)) {
> + return;
> + }
> +
> + info->last_update = dev->stats_last_update;
> + info->has_last_update = true;
> +
> + info->mem_swapped_in = dev->stats[VIRTIO_BALLOON_S_SWAP_IN];
> + info->has_mem_swapped_in = info->mem_swapped_in >= 0 ? true : false;
> +
> + info->mem_swapped_out = dev->stats[VIRTIO_BALLOON_S_SWAP_OUT];
> + info->has_mem_swapped_out = info->mem_swapped_out >= 0 ? true : false;
> +
> + info->major_page_faults = dev->stats[VIRTIO_BALLOON_S_MAJFLT];
> + info->has_major_page_faults = info->major_page_faults >= 0 ? true :
> false;
> +
> + info->minor_page_faults = dev->stats[VIRTIO_BALLOON_S_MINFLT];
> + info->has_minor_page_faults = info->minor_page_faults >= 0 ? true :
> false;
> +
>
>
> so, that mean that in qemu 2.1
>
> + if (!(balloon_stats_enabled(dev) && balloon_stats_supported(dev) &&
> + dev->stats_last_update)) {
> + return;
> + }
>
> one of this 3 funtions is not working
>
>
> ----- Mail original -----
> De: "Andrew Thrift" <andrew at networklabs.co.nz>
> À: "aderumier" <aderumier at odiso.com>
> Cc: "pve-devel" <pve-devel at pve.proxmox.com>
> Envoyé: Jeudi 5 Mars 2015 15:17:58
> Objet: Re: [pve-devel] balloon bug in qemu 2.1 ?
>
> Hi Alexandre,
> This may be the cause of the crashes we have been experiencing. We
> reported them here:
>
>
> http://forum.proxmox.com/threads/21276-Kernel-Oops-Panic-on-3-10-5-and-3-10-7-Kernels
>
> These only started happening since we moved to qemu-2.1.x and we get the
> same output:
>
> # info balloon
> balloon: actual=16384 max_mem=16384
>
> and have noticed VM's with only 1-2GB usage in the guest reporting almost
> the entire amount of ram used to the host, even though we have the latest
> balloon driver loaded and the blnsvr.exe service running.
>
>
>
> On Thu, Mar 5, 2015 at 11:33 PM, Alexandre DERUMIER < aderumier at odiso.com
> > wrote:
>
>
> Hi,
>
> I have see a bug report here:
>
> http://forum.proxmox.com/threads/21111-RAM-Problem-since-Upgrade-to-3-4?p=108367&posted=1#post108367
>
> about balloon.
>
>
> on my qemu 2.2
>
> #info balloon
> balloon: actual=1024 max_mem=2048 total_mem=985 free_mem=895
> mem_swapped_in=0 mem_swapped_out=0 major_page_faults=301
> minor_page_faults=61411 last_update=1425550707
>
>
> same vm with qemu 2.2 + "-machine type=pc-i440fx-2.1"
> #info balloon
> balloon: actual=1024 max_mem=2048
>
>
>
> (Don't have true qemu 2.1 for test currently)
>
>
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