In both screenshots, it appears that the "buff/cache" value is very high.
Perhaps the balloon driver is reporting the "buff/cache" as in use to the host. Can you try running following commands to flush write buffers and free page cache? 1) sync 2) echo 3 > /proc/sys/vm/drop_caches After running the above, do you see that the "buff/cache" value decreases and does this result in the memory being reclaimed by Hyper-V? -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1584597 Title: Hyper-V Memory Ballooning re-broken in 16.04 Status in linux package in Ubuntu: Triaged Status in linux source package in Xenial: Triaged Bug description: Regression: #1294283 fixed memory ballooning in Hyper-V in 14.04, but the bug has returned in 16.04. Steps to reproduce: 1. Create Gen2 Hyper-V VM 2. Install Ubuntu 16.04 3. modprobe hv_balloon Memory usage according to Hyper-V Manager will not change This has been reproduced on 2 fresh Ubuntu Server 16.04 instances. I installed linux-generic-xenial on a 14.04 instance, rebooted, modprobe'd hv_balloon and memory usage in Hyper-V Manager reduced to the correct level. Environment: Host: Windows NanoServer 2016 Ubuntu Server 16.04 version_signature: `Ubuntu 4.4.0-21.37-generic 4.4.6` Ubuntu Server 14.04 version_signature: `Ubuntu 4.4.0-22.40~14.04.1-generic 4.4.8` To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1584597/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp