On Thu, Jul 18, 2019 at 12:03:23PM -0400, Nitesh Narayan Lal wrote: > >>>> For example we allocate pages until shrinker kicks in. > >>>> Fair enough but in fact many it would be better to > >>>> do the reverse: trigger shrinker and then send as many > >>>> free pages as we can to host. > >>> I'm not sure I understand this last part. > >> Oh basically what I am saying is this: one of the reasons to use page > >> hinting is when host is short on memory. In that case, why don't we use > >> shrinker to ask kernel drivers to free up memory? Any memory freed could > >> then be reported to host. > > Didn't the balloon driver already have a feature like that where it > > could start shrinking memory if the host was under memory pressure? > If you are referring to auto-ballooning (I don't think it is merged). It > has its own set of disadvantages such as it could easily lead to OOM, > memory corruption and so on. Right. So what I am saying is: we could have a flag that triggers a shrinker once before sending memory hints. Worth considering. -- MST
