Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230615034830.1361853-1-hezhongkun.hzk@bytedance.com> <CAOUHufZBUEm1P7gm0nFkPSFkNg2fPbs3v3qhL-R9m5yFNoW2YA@mail.gmail.com>
In-Reply-To: <CAOUHufZBUEm1P7gm0nFkPSFkNg2fPbs3v3qhL-R9m5yFNoW2YA@mail.gmail.com>
From:   =?UTF-8?B?6LS65Lit5Z2k?= <hezhongkun.hzk@bytedance.com>
Date:   Thu, 15 Jun 2023 17:41:51 +0800
Message-ID: <CACSyD1OFOz8F+2+mUxqLAMXx1p_Zv88iqrrDMd4kb9nYWE_FJA@mail.gmail.com>
Subject: Re: [External] Re: [RFC PATCH 1/3] zram: charge the compressed RAM to
 the page's memcgroup
To:     Yu Zhao <yuzhao@google.com>
Cc:     minchan@kernel.org, senozhatsky@chromium.org, mhocko@suse.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Fabian Deutsch <fdeutsch@redhat.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Thu, Jun 15, 2023 at 1:00=E2=80=AFPM Yu Zhao <yuzhao@google.com> wrote:
>
> On Wed, Jun 14, 2023 at 9:48=E2=80=AFPM Zhongkun He
> <hezhongkun.hzk@bytedance.com> wrote:
> >
> > The compressed RAM is currently charged to kernel, not to
> > any memory cgroup, which is not satisfy our usage scenario.
> > if the memory of a task is limited by memcgroup, it will
> > swap out the memory to zram swap device when the memory
> > is insufficient. In that case, the memory limit will have
> > no effect.
> >
> > So, it should makes sense to charge the compressed RAM to
> > the page's memory cgroup.
>
> We used to do this a long time ago, but we had per-memcg swapfiles [1[
> to prevent compressed pages from different memcgs from sharing the
> same zspage.
>
> Does this patchset alone suffer from the same problem, i.e., memcgs
> sharing zspages?
>
> [1] https://lwn.net/Articles/592923/

Thanks for your reply. Yes, different memcgs may share the same zspages.