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From:   Yosry Ahmed <yosryahmed@google.com>
Date:   Thu, 20 Jul 2023 14:34:16 -0700
Message-ID: <CAJD7tkYhu3g9u7HkUTFBtT3Q4edVZ2g1TWV1FDcyM9srrYCBLg@mail.gmail.com>
Subject: Re: [RFC PATCH 0/8] memory recharging for offline memcgs
To:     Tejun Heo <tj@kernel.org>
Cc:     Johannes Weiner <hannes@cmpxchg.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@kernel.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Shakeel Butt <shakeelb@google.com>,
        Muchun Song <muchun.song@linux.dev>,
        "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        Zefan Li <lizefan.x@bytedance.com>,
        Yu Zhao <yuzhao@google.com>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Iurii Zaikin <yzaikin@google.com>,
        "T.J. Mercier" <tjmercier@google.com>,
        Greg Thelen <gthelen@google.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, cgroups@vger.kernel.org
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On Thu, Jul 20, 2023 at 12:57=E2=80=AFPM Tejun Heo <tj@kernel.org> wrote:
>
> On Thu, Jul 20, 2023 at 11:35:15AM -0400, Johannes Weiner wrote:
> > It could also be argued that if you don't want to lose control over a
> > set of resources, then maybe don't delete their control domain while
> > they are still alive and in use. For example, when restarting a
> > workload, and the new instance is expected to have largely the same
> > workingset, consider reusing the cgroup instead of making a new one.
>
> Or just create a nesting layer so that there's a cgroup which represents =
the
> persistent resources and a nested cgroup instance inside representing the
> current instance.

In practice it is not easy to know exactly which resources are shared
and used by which cgroups, especially in a large dynamic environment.

>
> Thanks.
>
> --
> tejun