One usecase is avoiding OOM hangs/livelocks. The reason these happen
is because the OOM killer is triggered by reclaim not being able to
free pages, but with fast flash devices there is *always* some clean
and uptodate cache to reclaim; the OOM killer never kicks in, even as
tasks spend 90% of the time thrashing the cache pages of their own
executables. There is no situation where this ever makes sense in
practice. We wrote a <100 line POC python script to monitor memory
pressure and kill stuff way before such pathological thrashing leads
to full system losses that require forcible hard resets.