Date:   Fri, 3 Feb 2023 09:42:11 -0800
From:   Roman Gushchin <roman.gushchin@linux.dev>
To:     Michal Hocko <mhocko@suse.com>
Cc:     "zhaoyang.huang" <zhaoyang.huang@unisoc.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Shakeel Butt <shakeelb@google.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
        Zhaoyang Huang <huangzhaoyang@gmail.com>, ke.wang@unisoc.com
Subject: Re: [PATCH] mm: introduce entrance for root_mem_cgroup's current
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On Thu, Feb 02, 2023 at 09:27:39AM +0100, Michal Hocko wrote:
> On Thu 02-02-23 12:32:57, zhaoyang.huang wrote:
> > From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
> > 
> > Introducing memory.root_current for the memory charges on root_mem_cgroup.
> 
> Charges are not currently accounted for the root memcg universally. See
> try_charge which is used for all user space and skmem charges. I am not
> 100% sure about objcg based accounting because there is no explicit
> check for the root memcg but this might be hidden somewhere as well.

root_mem_cgroup has no corresponding obj_cgroup: see memcg_online_kmem().

Thanks