From mboxrd@z Thu Jan  1 00:00:00 1970
From: Roman Gushchin <guro@fb.com>
Date: Tue, 3 Nov 2020 13:30:10 -0800
Subject: [LTP] [RFC PATCH] mm: memcg/slab: Stop reparented obj_cgroups
 from charging root
In-Reply-To: <20201103132221.GI21990@dhcp22.suse.cz>
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 <20201020162714.GC46039@blackbook>
 <20201020170717.GA153102@carbon.DHCP.thefacebook.com>
 <20201020181822.GA397401@cmpxchg.org>
 <20201021193322.GA300658@carbon.dhcp.thefacebook.com>
 <20201103132221.GI21990@dhcp22.suse.cz>
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On Tue, Nov 03, 2020 at 02:22:21PM +0100, Michal Hocko wrote:
> Hi,
> I am sorry but I was quite busy at the time this has been discussed.
> Now that I got to this thread finally I am wondering whether this
> resp. other root cgroup exceptions have any follow up.

I'll address a feedback I've got from Johannes and will post and updated
version soon.

> 
> I have seen the issue is fixed in Linus tree by 8de15e920dc8 ("mm:
> memcg: link page counters to root if use_hierarchy is false"). Thanks
> for taking care of that! I do agree that this approach is the most
> reasonable immediate fix.

Thanks!

> 
> Btw. we have been carrying a warning about non hierarchical hierarchies
> for years in our distribution kernels and haven't heard of any actual
> bug reports (except for LTP driven ones). So we might be really close to
> simply drop this functionality completely. This would simplify the code
> and prevent from future surprises.

Just sent an rfc patchset. Your feedback will be greatly appreciated!

Thanks!