Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 24 Jan 2019 18:01:17 +0100
From:   Michal Hocko <mhocko@kernel.org>
To:     Johannes Weiner <hannes@cmpxchg.org>
Cc:     Chris Down <chris@chrisdown.name>,
        Andrew Morton <akpm@linux-foundation.org>,
        Tejun Heo <tj@kernel.org>, Roman Gushchin <guro@fb.com>,
        Dennis Zhou <dennis@kernel.org>, linux-kernel@vger.kernel.org,
        cgroups@vger.kernel.org, linux-mm@kvack.org, kernel-team@fb.com
Subject: Re: [PATCH 2/2] mm: Consider subtrees in memory.events
Message-ID: <20190124170117.GS4087@dhcp22.suse.cz>
References: <20190123223144.GA10798@chrisdown.name>
 <20190124082252.GD4087@dhcp22.suse.cz>
 <20190124160009.GA12436@cmpxchg.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20190124160009.GA12436@cmpxchg.org>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu 24-01-19 11:00:10, Johannes Weiner wrote:
[...]
> We cannot fully eliminate a risk for regression, but it strikes me as
> highly unlikely, given the extremely young age of cgroup2-based system
> management and surrounding tooling.

I am not really sure what you consider young but this interface is 4.0+
IIRC and the cgroup v2 is considered stable since 4.5 unless I
missrememeber and that is not a short time period in my book. Changing
interfaces now represents a non-trivial risk and so far I haven't heard
any actual usecase where the current semantic is actually wrong.
Inconsistency on its own is not a sufficient justification IMO.
-- 
Michal Hocko
SUSE Labs