[ovirt-users] What is the purpose of memory deflation in oVirt memory ballooning?

Hi, guys Why does momd(ballooning manager in oVirt) explicitly deflate the balloon when host gets plenty of memory? as far as I know, momd is supporting memory ballooning with setMemory API to inflate/deflate the balloon in guest and I've just checked the memory change in the guest after inflating the balloon. as expected, memory(total, free, available) in the guest was reduced just after inflating the balloon, but it was "automatically" restored to its initial memory after a few seconds. So, here I'm wondering why deflation is additionally required even though it can be restored automatically just after seconds. Thanks.