The problem is that userland has to be really clever because of overcommit... that's what the whole thread is about! The reason people want complex things like fsync and barriers is that the OOM killer has normalized the bad idea that applications should behave well when suddenly SIGKILL'd, and this is way harder than looking at the return value from malloc. When a program I write has elevated permissions, which fortunately is often, I will always write -1000 into my oom_score_adj, but not everyone has this luxury.