Re: VIRTIO_BALLOON_F_FREE_PAGE_HINT

On 04.10.19 01:15, Tyler Sanderson wrote:

I was mistaken, the problem with overcommit accounting is not fixed by
the change to shrinker interface.
This means that large allocations are stopped even if they could succeed
by deflating the balloon.

Please note that some people use the balloon for actual memory unplug -
so initiating to deflate the balloon under any circumstances is
undesired. It's different with "VIRTIO_BALLOON_F_DEFLATE_ON_OOM" being
set - however that is barely the case (at least in the setups I know :) ).

So yes, free page reporting is a different thing, because it really is
used to "hint" and not to "agree to unplug" in any scenario.

-- 

Thanks,

David / dhildenb