Re: [PATCH] mm/memcontrol: Don't increase effective low/min if no protection needed

[Michal Koutný]

On Tue, Oct 11, 2022 at 07:04:32AM -1000, Tejun Heo <tj@xxxxxxxxxx> wrote:
> Wouldn't it make sense to fix the test? With recursive_prot on, the cgroup
> actually is under low protection and it seems like the correct behavior is
> to report the low events accordingly.

It depends whether the there is a residual protection that the
memory.low=0 sibling can use (with memory_recursiveprot).

In the discussed LTP test, there should be no residual protection that
would justify the apparently misreported memory.low events. I.e. the
test is correct, the failure points to a subtle issue with distributing
residual protection among siblings.

Been there, (haven't) done that:
1) https://bugzilla.suse.com/show_bug.cgi?id=1196298
2) https://lore.kernel.org/r/20220325103118.GC2828@xxxxxxxxxxxxxxxxx/

HTH,
Michal