[systemd-devel] oomd wake-up frequency

[Christian Hergert]

Thanks for responding! Comments inline.

On 8/25/23 7:54 AM, Michal Koutný wrote:
> Do you have any "Swap Monitored CGroups:" in output of `oomctl dump`?

"Swap Monitored CGroups:" appears to be empty on the three physical 
machines I have at my disposal to test. (Fedora 38, Fedora 39, and GNOME 
OS).

> I think the loop's event source could be disabled when no cgroups
> require swap monitoring [1] (and enabled lazily when such are
> configured).

That sounds like a great idea!

> Not sure whether/how much SWAP_INTERVAL_USEC could be increased to
> retain responsiveness.

Given the empirical evidence here of all these machines not having swap 
monitoring to begin with, I think the interval is less of an issue 
compared to dynamic event sources.

As it were, things like thermald are waking up every 4 seconds when the 
underlying hardware doesn't support async notification. It would be 
fantastic if we had a poll() mechanism that would coalesce the sorts of 
wake-ups across processes.

-- Christian