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;
MIME-Version: 1.0
References: <1550278564-81540-1-git-send-email-yang.shi@linux.alibaba.com> <20190218210504.GT50184@devbig004.ftw2.facebook.com>
In-Reply-To: <20190218210504.GT50184@devbig004.ftw2.facebook.com>
From:   =?UTF-8?B?56a56Iif6ZSu?= <ufo19890607@gmail.com>
Date:   Tue, 19 Feb 2019 18:45:52 +0800
Message-ID: <CAHCio2g-S6snHsh84r0Wp1RQW1CR3t_eyUUjcdDaxnUHWTcdFw@mail.gmail.com>
Subject: Re: [PATCH] doc: cgroup: correct the wrong information about measure
 of memory pressure
To:     Tejun Heo <tj@kernel.org>
Cc:     Yang Shi <yang.shi@linux.alibaba.com>, hannes@cmpxchg.org,
        corbet@lwn.net, cgroups@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi TeJun
I've built the 5.0.0-rc6 kernel with psi option, but I cannot find any
cgroup.controllers when I mounted cgroup2.

[root@bogon /]# uname -r
[root@bogon /]# 5.0.0-rc6+
[root@bogon /]# mount -t cgroup2 none cgroup2/
[root@bogon /]# cat cgroup2/cgroup.controllers
[root@bogon /]
[root@bogon /]# cat cgroup2/cgroup.subtree_control
[root@bogon /]#

What's wrong with this kernel? Or maybe I lost some mount option?

Thanks
Yuzhoujian

Tejun Heo <tj@kernel.org> =E4=BA=8E2019=E5=B9=B42=E6=9C=8819=E6=97=A5=E5=91=
=A8=E4=BA=8C =E4=B8=8A=E5=8D=8810:32=E5=86=99=E9=81=93=EF=BC=9A
>
> On Sat, Feb 16, 2019 at 08:56:04AM +0800, Yang Shi wrote:
> > Since PSI has implemented some kind of measure of memory pressure, the
> > statement about lack of such measure is not true anymore.
> >
> > Cc: Tejun Heo <tj@kernel.org>
> > Cc: Johannes Weiner <hannes@cmpxchg.org>
> > Cc: Jonathan Corbet <corbet@lwn.net>
> > Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
> > ---
> >  Documentation/admin-guide/cgroup-v2.rst | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/ad=
min-guide/cgroup-v2.rst
> > index 7bf3f12..9a92013 100644
> > --- a/Documentation/admin-guide/cgroup-v2.rst
> > +++ b/Documentation/admin-guide/cgroup-v2.rst
> > @@ -1310,8 +1310,7 @@ network to a file can use all available memory bu=
t can also operate as
> >  performant with a small amount of memory.  A measure of memory
> >  pressure - how much the workload is being impacted due to lack of
> >  memory - is necessary to determine whether a workload needs more
> > -memory; unfortunately, memory pressure monitoring mechanism isn't
> > -implemented yet.
> > +memory.
>
> Maybe refer to PSI?
>
> Thanks.
>
> --
> tejun