• Dmitry Torokhov's avatar
    VMware Balloon driver · 453dc659
    Dmitry Torokhov authored
    This is a standalone version of VMware Balloon driver.  Ballooning is a
    technique that allows hypervisor dynamically limit the amount of memory
    available to the guest (with guest cooperation).  In the overcommit
    scenario, when hypervisor set detects that it needs to shuffle some
    memory, it instructs the driver to allocate certain number of pages, and
    the underlying memory gets returned to the hypervisor.  Later hypervisor
    may return memory to the guest by reattaching memory to the pageframes and
    instructing the driver to "deflate" balloon.
    
    We are submitting a standalone driver because KVM maintainer (Avi Kivity)
    expressed opinion (rightly) that our transport does not fit well into
    virtqueue paradigm and thus it does not make much sense to integrate with
    virtio.
    
    There were also some concerns whether current ballooning technique is the
    right thing.  If there appears a better framework to achieve this we are
    prepared to evaluate and switch to using it, but in the meantime we'd like
    to get this driver upstream.
    
    We want to get the driver accepted in distributions so that users do not
    have to deal with an out-of-tree module and many distributions have
    "upstream first" requirement.
    
    The driver has been shipping for a number of years and users running on
    VMware platform will have it installed as part of VMware Tools even if it
    will not come from a distribution, thus there should not be additional
    risk in pulling the driver into mainline.  The driver will only activate
    if host is VMware so everyone else should not be affected at all.
    Signed-off-by: default avatarDmitry Torokhov <dtor@vmware.com>
    Cc: Avi Kivity <avi@redhat.com>
    Cc: Jeremy Fitzhardinge <jeremy@goop.org>
    Cc: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    453dc659
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