Re: [RFC 0/1] add support for reclaiming priorities per mem cgroup

[Tim Murray]

On Thu, Mar 30, 2017 at 12:40 PM, Tim Murray <timmurray@xxxxxxxxxx> wrote:
> The current critical vmpressure event
> hasn't been that successful in avoiding oom-killer (on 3.18, at
> least)--I've been able to get oom-killer to trigger without a
> vmpressure event.

Looked at this some more, and this is almost certainly because
vmpressure relies on workqueues. Scheduling delay from CFS workqueues
would explain vmpressure latency that results in oom-killer running
long before the critical vmpressure notification is received in
userspace, even if userspace is running as FIFO. We regularly see
10ms+ latency on workqueues, even when an Android device isn't heavily
loaded.