list_lru operation for new child memcg?

[Christian König]

Hi guys,

On 5/27/25 01:49, Dave Chinner wrote: 
> I disagree - specifically ordered memcg traversal is not something
> that the list_lru implementation is currently doing, nor should it
> be doing.

I realized over night that I didn't fully explored a way of getting both advantages. And we actually don't need list_lru for that.

So here is a side question:

Is it possible to just have a per cgroup counter on how many pages a cgroup released back to a particular pool? E.g. something which is added up to the same counter on the parent when a cgroup is released.

Background is that the pages are not distinguishable from each other, e.g. they are not cache hot or cold or anything like this. So it doesn't matter which pages a cgroup has released but only how many.

If it would be possible to get such a counter then it would be like just a few lines of code to add the isolation and still get the advantage of sharing released pages between different cgroups.

Regards,
Christian.

> 
> -Dave.