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Subject: Re: [PATCH memcg v4] net: set proper memcg for net_init hooks allocations
From:   Roman Gushchin <roman.gushchin@linux.dev>
In-Reply-To: <78b556f9-e57b-325d-89ce-7a482ef4ea21@openvz.org>
Date:   Sun, 1 May 2022 14:09:49 -0700
Cc:     Shakeel Butt <shakeelb@google.com>,
        =?utf-8?Q?Michal_Koutn=C3=BD?= <mkoutny@suse.com>,
        Vlastimil Babka <vbabka@suse.cz>, kernel@openvz.org,
        Florian Westphal <fw@strlen.de>,
        LKML <linux-kernel@vger.kernel.org>,
        Michal Hocko <mhocko@suse.com>,
        Cgroups <cgroups@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Message-Id: <092476D2-C2C4-496C-A92C-EC0B331990ED@linux.dev>
References: <78b556f9-e57b-325d-89ce-7a482ef4ea21@openvz.org>
To:     Vasily Averin <vvs@openvz.org>
Precedence: bulk


> On May 1, 2022, at 6:44 AM, Vasily Averin <vvs@openvz.org> wrote:
>=20
> =EF=BB=BFOn 4/28/22 01:47, Shakeel Butt wrote:
>>> On Wed, Apr 27, 2022 at 3:43 PM Vasily Averin <vvs@openvz.org> wrote:
>>>=20
>>> On 4/27/22 18:06, Shakeel Butt wrote:
>>>> On Wed, Apr 27, 2022 at 5:22 AM Michal Koutn=C3=BD <mkoutny@suse.com> w=
rote:
>>>>>=20
>>>>> On Tue, Apr 26, 2022 at 10:23:32PM -0700, Shakeel Butt <shakeelb@googl=
e.com> wrote:
>>>>>> [...]
>>>>>>>=20
>>>>>>> +static inline struct mem_cgroup *get_mem_cgroup_from_obj(void *p)
>>>>>>> +{
>>>>>>> +       struct mem_cgroup *memcg;
>>>>>>> +
>>>>>>=20
>>>>>> Do we need memcg_kmem_enabled() check here or maybe
>>>>>> mem_cgroup_from_obj() should be doing memcg_kmem_enabled() instead of=

>>>>>> mem_cgroup_disabled() as we can have "cgroup.memory=3Dnokmem" boot
>>>>>> param.
>>>=20
>>> Shakeel, unfortunately I'm not ready to answer this question right now.
>>> I even did not noticed that memcg_kmem_enabled() and mem_cgroup_disabled=
()
>>> have a different nature.
>>> If you have no objections I'm going to keep this place as is and investi=
gate
>>> this question later.
>>>=20
>>=20
>> Patch is good as is. Just add the documentation to the functions in
>> the next version and you can keep the ACKs.
>=20
> I noticed that the kernel already has a function get_mem_cgroup_from_objcg=
(),
> the name of which is very similar to my new function get_mem_cgroup_from_o=
bj().
> Maybe it's better to rename my function to get_mem_cgroup_from_ptr()?

I don=E2=80=99t think it=E2=80=99s a problem: objcg is a widely used abbrevi=
ation and in my opinion is different enough from obj. I=E2=80=99d keep it fo=
r the consistency with the mem_cgroup_from_obj().

Thanks!=