From: Roman Gushchin <roman.gushchin@linux.dev>
To: Tejun Heo <tj@kernel.org>
Cc: Yafang Shao <laoar.shao@gmail.com>,
ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
kafai@fb.com, songliubraving@fb.com, yhs@fb.com,
john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org, hannes@cmpxchg.org,
mhocko@kernel.org, shakeelb@google.com, songmuchun@bytedance.com,
akpm@linux-foundation.org, lizefan.x@bytedance.com,
cgroups@vger.kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH bpf-next v3 00/13] bpf: Introduce selectable memcg for bpf map
Date: Wed, 7 Sep 2022 15:28:53 -0700 [thread overview]
Message-ID: <YxkVq4S1Eoa4edjZ@P9FQF9L96D.corp.robot.car> (raw)
In-Reply-To: <Yxi8I4fXXSCi6z9T@slm.duckdns.org>
On Wed, Sep 07, 2022 at 05:43:31AM -1000, Tejun Heo wrote:
> Hello,
>
> On Fri, Sep 02, 2022 at 02:29:50AM +0000, Yafang Shao wrote:
> ...
> > This patchset tries to resolve the above two issues by introducing a
> > selectable memcg to limit the bpf memory. Currently we only allow to
> > select its ancestor to avoid breaking the memcg hierarchy further.
> > Possible use cases of the selectable memcg as follows,
>
> As discussed in the following thread, there are clear downsides to an
> interface which requires the users to specify the cgroups directly.
>
> https://lkml.kernel.org/r/YwNold0GMOappUxc@slm.duckdns.org
>
> So, I don't really think this is an interface we wanna go for. I was hoping
> to hear more from memcg folks in the above thread. Maybe ping them in that
> thread and continue there?
As I said previously, I don't like it, because it's an attempt to solve a non
bpf-specific problem in a bpf-specific way.
Yes, memory cgroups are not great for accounting of shared resources, it's well
known. This patchset looks like an attempt to "fix" it specifically for bpf maps
in a particular cgroup setup. Honestly, I don't think it's worth the added
complexity. Especially because a similar behaviour can be achieved simple
by placing the task which creates the map into the desired cgroup.
Beatiful? Not. Neither is the proposed solution.
Thanks!
next prev parent reply other threads:[~2022-09-07 22:29 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-02 2:29 Yafang Shao
2022-09-02 2:29 ` [PATCH bpf-next v3 01/13] cgroup: Update the comment on cgroup_get_from_fd Yafang Shao
2022-09-02 2:29 ` [PATCH bpf-next v3 02/13] bpf: Introduce new helper bpf_map_put_memcg() Yafang Shao
2022-09-02 2:29 ` [PATCH bpf-next v3 03/13] bpf: Define bpf_map_{get,put}_memcg for !CONFIG_MEMCG_KMEM Yafang Shao
2022-09-02 2:29 ` [PATCH bpf-next v3 04/13] bpf: Call bpf_map_init_from_attr() immediately after map creation Yafang Shao
2022-09-02 2:29 ` [PATCH bpf-next v3 05/13] bpf: Save memcg in bpf_map_init_from_attr() Yafang Shao
2022-09-02 2:29 ` [PATCH bpf-next v3 06/13] bpf: Use scoped-based charge in bpf_map_area_alloc Yafang Shao
2022-09-02 2:29 ` [PATCH bpf-next v3 07/13] bpf: Introduce new helpers bpf_ringbuf_pages_{alloc,free} Yafang Shao
2022-09-02 2:29 ` [PATCH bpf-next v3 08/13] bpf: Use bpf_map_kzalloc in arraymap Yafang Shao
2022-09-02 2:29 ` [PATCH bpf-next v3 09/13] bpf: Use bpf_map_kvcalloc in bpf_local_storage Yafang Shao
2022-09-02 2:30 ` [PATCH bpf-next v3 10/13] mm, memcg: Add new helper get_obj_cgroup_from_cgroup Yafang Shao
2022-09-02 2:30 ` [PATCH bpf-next v3 11/13] mm, memcg: Add new helper task_under_memcg_hierarchy Yafang Shao
2022-09-02 2:30 ` [PATCH bpf-next v3 12/13] bpf: Add return value for bpf_map_init_from_attr Yafang Shao
2022-09-02 2:30 ` [PATCH bpf-next v3 13/13] bpf: Introduce selectable memcg for bpf map Yafang Shao
2022-09-07 15:43 ` [PATCH bpf-next v3 00/13] " Tejun Heo
2022-09-07 15:45 ` Tejun Heo
2022-09-07 16:13 ` Alexei Starovoitov
2022-09-07 16:18 ` Tejun Heo
2022-09-07 16:27 ` Alexei Starovoitov
2022-09-07 17:01 ` Tejun Heo
2022-09-08 2:44 ` Yafang Shao
2022-09-07 22:28 ` Roman Gushchin [this message]
2022-09-08 2:37 ` Yafang Shao
2022-09-08 2:43 ` Alexei Starovoitov
2022-09-08 2:48 ` Yafang Shao
2022-09-08 16:13 ` Roman Gushchin
2022-09-13 6:15 ` Yafang Shao
2022-09-16 16:53 ` Roman Gushchin
2022-09-18 3:44 ` Yafang Shao
2022-09-20 2:40 ` Roman Gushchin
2022-09-20 12:42 ` Yafang Shao
2022-09-20 23:15 ` Roman Gushchin
2022-09-21 9:36 ` Yafang Shao
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