[RFC 0/5] track memory used by balloon drivers

[Nico Pache <npache@redhat.com>]

This series introduces a way to track memory used by balloon drivers.

Add a NR_BALLOON_PAGES counter to track how many pages are reclaimed by the
balloon drivers. First add the accounting, then updates the balloon drivers
(virtio, Hyper-V, VMware, and Xen) to maintain this counter.

This makes the information visible in memory reporting interfaces like
/proc/meminfo, show_mem, and OOM reporting.

This provides admins visibility into their VM balloon sizes without
requiring different virtualization tooling. Furthermore, this information
is helpful when debugging an OOM inside a VM.

Tested: virtio_balloon, run stress-ng, inflate balloon, oom prints
Signed-off-by: Nico Pache <npache@redhat.com>

Nico Pache (5):
  meminfo: add a per node counter for balloon drivers
  virtio_balloon: update the NR_BALLOON_PAGES state
  hv_balloon: update the NR_BALLOON_PAGES state
  vmx_balloon: update the NR_BALLOON_PAGES state
  xen: balloon: update the NR_BALLOON_PAGES state

 drivers/hv/hv_balloon.c         | 2 ++
 drivers/misc/vmw_balloon.c      | 5 ++++-
 drivers/virtio/virtio_balloon.c | 4 ++++
 drivers/xen/balloon.c           | 4 ++++
 fs/proc/meminfo.c               | 2 ++
 include/linux/mmzone.h          | 1 +
 mm/memcontrol.c                 | 1 +
 mm/show_mem.c                   | 4 +++-
 mm/vmstat.c                     | 1 +
 9 files changed, 22 insertions(+), 2 deletions(-)

-- 
2.48.1