Comment # 3 on bug 1196298 from Michal Koutn���

I have a theory how A/B/F can get protection of (MEMCG_SWAP_CLUSTER <<
sc->priority), which is numerically <= 128 KiB, however, the trace data in
comment 2 show that it can actually grow up to 10 MiB.
The reclaim in A/B/F with this unjustified protection causes the
memory.event:low increase.

I will look more into what's going on.