From: Johannes Weiner <hannes@cmpxchg.org>
To: Roman Gushchin <guro@fb.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, Shakeel Butt <shakeelb@google.com>,
Michal Hocko <mhocko@kernel.org>,
linux-kernel@vger.kernel.org,
David Rientjes <rientjes@google.com>,
kernel-team@fb.com, Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH v1 1/3] mm: memcg: deprecate the non-hierarchical mode
Date: Thu, 12 Nov 2020 11:31:19 -0500 [thread overview]
Message-ID: <20201112163119.GC873621@cmpxchg.org> (raw)
In-Reply-To: <20201110220800.929549-2-guro@fb.com>
On Tue, Nov 10, 2020 at 02:07:58PM -0800, Roman Gushchin wrote:
> The non-hierarchical cgroup v1 mode is a legacy of early days
> of the memory controller and doesn't bring any value today.
> However, it complicates the code and creates many edge cases
> all over the memory controller code.
>
> It's a good time to deprecate it completely.
>
> Functionally this patch enabled is by default for all cgroups
> and forbids switching it off. Nothing changes if cgroup v2 is used:
> hierarchical mode was enforced from scratch.
>
> To protect the ABI memory.use_hierarchy interface is preserved
> with a limited functionality: reading always returns "1", writing
> of "1" passes silently, writing of any other value fails with
> -EINVAL and a warning to dmesg (on the first occasion).
>
> Signed-off-by: Roman Gushchin <guro@fb.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Reviewed-by: Shakeel Butt <shakeelb@google.com>
> Acked-by: David Rientjes <rientjes@google.com>
...and don't let the door hit you on the way out ;-)
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
next prev parent reply other threads:[~2020-11-12 16:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-10 22:07 [PATCH v1 0/3] mm: memcg: deprecate cgroup v1 " Roman Gushchin
2020-11-10 22:07 ` [PATCH v1 1/3] mm: memcg: deprecate the " Roman Gushchin
2020-11-12 16:31 ` Johannes Weiner [this message]
2020-11-10 22:07 ` [PATCH v1 2/3] docs: cgroup-v1: reflect the deprecation of " Roman Gushchin
2020-11-12 16:32 ` Johannes Weiner
2020-11-10 22:08 ` [PATCH v1 3/3] cgroup: remove obsoleted broken_hierarchy and warned_broken_hierarchy Roman Gushchin
2020-11-12 16:32 ` Johannes Weiner
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