This is actually useful, because it shows that the issue occurs even with Xen 4.6, which I think rules out a Xen side issue (otherwise we'd have had lots more reports from 4.4 through to 4.6) and points to a kernel side issue somewhere.But I checked logs more thoroughly and found it even on more recent kernels: 1) Lot of messages on 3.14-2-amd64 with xen-4.6, 13 domU's.Just to be clear, "Lots" here means "hundreds or thousands"? I think it is expected to see one or two around the time a VM is started or stopped, so with 13 domUs a couple of dozen messages wouldn't seem out of line to me.
pkg 3.14.15-2~1600 from last dmesg cleanup which was 23h ago, but all of them distributed in last 15h
2) 4.3.0-1-amd64 xen-4.6, only two messages shortly after boot, only 1 domU running: [ 12.473778] xen:balloon: Cannot add additional memory (-17) [ 21.673298] xen:balloon: Cannot add additional memory (-17) uptime 17 days. Previous on same machine was 4.2.0-1-amd64 with more (-17)'sWas it running xen-4.6 when it was running 4.2.0 or was that also older?
4.3.3-5 xen-4.6.0 and previous 4.2.6-1 xen-4.4.1
Also 4.2.0-1-amd64 is the ABI, not the package version. The package
versions is either in dpkg or you can find it in /proc/version:
Linux version 4.1.0-2-amd64 (debian-kernel@lists.debian.org) (gcc version 4.9.3 (Debian 4.9.3-3) ) #1 SMP Debian 4.1.6-1 (2015-08-23)
^^^ABI^^^^^^^ ^^^VERSION^^^^
Ok, if pkg versions is more important, then I updated all data with pkg versions in this post
3) 4.3.0-1-amd64, one month, several reboots, average 4 domU's, and no messagesAny idea which Xen?
kernel pkg 4.3.3-5 and 4.3.3-7 and xen-4.6.0
4) 3.16.0-4-amd64, xen-4.1, 22 domU's, uptime 188 days, in last month I see only Jan 7 14:12:08 Jan 7 14:12:08 Jan 7 14:12:08 Jan 7 14:12:08 Jan 7 14:27:47 Jan 7 14:27:47 Jan 7 14:27:47 Jan 7 14:27:48 and this is roughly the time last machine was created(started).
pkg 3.16.7-ckt7-1