Re: [RFC] simple_lmk: Introduce Simple Low Memory Killer for Android

From: Matthew Wilcox
Date: Tue Mar 12 2019 - 11:25:48 EST

On Tue, Mar 12, 2019 at 09:05:32AM +0100, Michal Hocko wrote:
> On Mon 11-03-19 15:15:35, Suren Baghdasaryan wrote:
> > Yeah, killing speed is a well-known problem which we are considering
> > in LMKD. For example the recent LMKD change to assign process being
> > killed to a cpuset cgroup containing big cores cuts the kill time
> > considerably. This is not ideal and we are thinking about better ways
> > to expedite the cleanup process.
> If you design is relies on the speed of killing then it is fundamentally
> flawed AFAICT. You cannot assume anything about how quickly a task dies.
> It might be blocked in an uninterruptible sleep or performin an
> operation which takes some time. Sure, oom_reaper might help here but
> still.

Many UNINTERRUPTIBLE sleeps can be converted to KILLABLE sleeps. It just
needs someone to do the work.