• David Vrabel's avatar
    xen/balloon: use hotplugged pages for foreign mappings etc. · 1cf6a6c8
    David Vrabel authored
    alloc_xenballooned_pages() is used to get ballooned pages to back
    foreign mappings etc.  Instead of having to balloon out real pages,
    use (if supported) hotplugged memory.
    This makes more memory available to the guest and reduces
    fragmentation in the p2m.
    This is only enabled if the xen.balloon.hotplug_unpopulated sysctl is
    set to 1.  This sysctl defaults to 0 in case the udev rules to
    automatically online hotplugged memory do not exist.
    Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
    Reviewed-by: default avatarDaniel Kiper <daniel.kiper@oracle.com>
    - Add xen.balloon.hotplug_unpopulated sysctl to enable use of hotplug
      for unpopulated pages.