Re: [RFC][Patch v8 0/7] KVM: Guest Free Page Hinting

[Michael S. Tsirkin]

On Sat, Feb 16, 2019 at 10:40:15AM +0100, David Hildenbrand wrote:
> It would be worth a try. My feeling is that a synchronous report after
> e.g. 512 frees should be acceptable, as it seems to be acceptable on
> s390x. (basically always enabled, nobody complains).

What slips under the radar on an arch like s390 might
raise issues for a popular arch like x86. My fear would be
if it's only a problem e.g. for realtime. Then you get
a condition that's very hard to trigger and affects
worst case latencies.

But really what business has something that is supposedly
an optimization blocking a VCPU? We are just freeing up
lots of memory why is it a good idea to slow that
process down?

-- 
MST