Re: [PATCH v6 1/2] mm/vmscan: Skip memcg with !usage in shrink_node_memcgs()

["Michal Koutný" <mkoutny@suse.com>]

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On Mon, Apr 14, 2025 at 09:15:57AM -0400, Waiman Long <llong@redhat.com> wrote:
> I did see some low event in the no usage case because of the ">=" comparison
> used in mem_cgroup_below_min().

Do you refer to A/B/E or A/B/F from the test?
It's OK to see some events if there was non-zero usage initially.

Nevertheless, which situation this patch changes that is not handled by
mem_cgroup_below_min() already?

> Yes, low event count for E is 0 in the !memory_recursiveprot case, but C/D
> still have low events and setting no_low_events_index to -1 will fail the
> test and it is not the same as not checking low event counts at all.

I added yet another ignore_low_events_index variable (in my original
proposal) not to fail the test. But feel free to come up with another
implementation, I wanted to point out the "not specified" expectation
for E with memory_recursiveprot.

Michal

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