kernel-packages team mailing list archive

[Alex Ng <alexng@xxxxxxxxxxxxx>]

Hi Jason,

As Josh mentioned, the screenshot shows that demand as seen by Hyper-V
is still quite high compared to what is displayed inside the guest. If
this number doesn't settle, then Hyper-V would have no reason to reclaim
memory. Does the Hyper-V memory demand number ever settle after some
time?

With the "free" command, you should be seeing the following if memory is
being returned to the host successfully:

- Because Linux guests return memory via ballooning instead of hot-
unplug; you'll never see the "total" memory decrease (i.e. it'll always
reflect the spike)

- Instead, you should see that "used" memory increases and "free" memory
decreases. This indicates the kernel allocated some memory so no one can
use it, and that Hyper-V has reclaimed this memory. (i.e. the used
memory should increase by roughly the amount that the host has
reclaimed)

-- 
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`

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