Re: [PATCH] mm, memcg: Do not high throttle allocators based on wraparound

[Chris Down]

Michal Hocko writes:
> I find this paragraph rather confusing. This is essentially an unsigned
> underflow when any of the memcg up the hierarchy is below the high
> limit, right?  There doesn't really seem anything complex in such a
> hierarchy.

The conditions to trigger the bug itself are easy, but having it obviously 
visible in tests requires a moderately complex hierarchy, since in the basic 
case ancestor_usage is "similar enough" to the test leaf cgroup's usage.