On 2018/08/02 19:32, Wei Wang wrote: > On 08/01/2018 07:34 PM, Michal Hocko wrote: >> Do you have any numbers for how does this work in practice? > > It works in this way: for example, we can set the parameter, balloon_pages_to_shrink, > to shrink 1GB memory once shrink scan is called. Now, we have a 8GB guest, and we balloon > out 7GB. When shrink scan is called, the balloon driver will get back 1GB memory and give > them back to mm, then the ballooned memory becomes 6GB. Since shrinker might be called concurrently (am I correct?), the balloon might deflate far more than needed if it releases such much memory. If shrinker is used, releasing 256 pages might be sufficient.
