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Sender: Tejun Heo <htejun@gmail.com>
Date:   Fri, 20 May 2022 12:57:20 -1000
From:   Tejun Heo <tj@kernel.org>
To:     Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc:     Yosry Ahmed <yosryahmed@google.com>, Hao Luo <haoluo@google.com>,
        Yonghong Song <yhs@fb.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
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Subject: Re: [PATCH bpf-next v1 3/5] bpf: Introduce cgroup iter
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Hello,

On Fri, May 20, 2022 at 03:19:19PM -0700, Alexei Starovoitov wrote:
> We have bpf_map iterator that walks all bpf maps.
> When map iterator is parametrized with map_fd the iterator walks
> all elements of that map.
> cgroup iterator should have similar semantics.
> When non-parameterized it will walk all cgroups and their descendent
> depth first way. I believe that's what Yonghong is proposing.
> When parametrized it will start from that particular cgroup and
> walk all descendant of that cgroup only.
> The bpf prog can stop the iteration right away with ret 1.
> Maybe we can add two parameters. One -> cgroup_fd to use and another ->
> the order of iteration css_for_each_descendant_pre vs _post.
> wdyt?

Sounds perfectly reasonable to me.

Thanks.

-- 
tejun