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From:   Jinshan Xiong <jinshan.xiong@uber.com>
Date:   Wed, 18 Sep 2019 19:41:29 -0700
Message-ID: <CA+-8EHRHTUPNJEwT_wb+O-CStvCoT2=U4h=0JqB6mXfzBArbvQ@mail.gmail.com>
Subject: Re: [PATCH] staging: tracing/kprobe: filter kprobe based perf event
To:     Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc:     Yonghong Song <yhs@fb.com>,
        "jinshan.xiong@gmail.com" <jinshan.xiong@gmail.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "rostedt@goodmis.org" <rostedt@goodmis.org>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "bpf@vger.kernel.org" <bpf@vger.kernel.org>
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That's bloody true. Thanks for your insights.

I will make an example program and commit into bcc repository.

Jinshan


On Wed, Sep 18, 2019 at 1:22 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Wed, Sep 18, 2019 at 8:13 AM Jinshan Xiong <jinshan.xiong@uber.com> wr=
ote:
> >
> > The problem with the current approach is that it would be difficult to =
filter cgroup, especially the cgroup in question has descendents, and also =
it would spawn new descendents after BPF program is installed. it's hard to=
 filter it inside a BPF program.
>
> Why is that?
> bpf_current_task_under_cgroup() fits exactly that purpose.