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Message-ID: <93c3fc30-ad38-96fa-cf8e-20e55b267a3b@fb.com>
Date:   Wed, 2 Mar 2022 17:08:57 -0800
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Subject: Re: [PATCH bpf-next v1 4/9] bpf: Introduce sleepable tracepoints
Content-Language: en-US
To:     Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc:     Hao Luo <haoluo@google.com>, Alexei Starovoitov <ast@kernel.org>,
        Andrii Nakryiko <andrii@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>,
        KP Singh <kpsingh@kernel.org>,
        Shakeel Butt <shakeelb@google.com>,
        Joe Burton <jevburton.kernel@gmail.com>,
        Tejun Heo <tj@kernel.org>, joshdon@google.com,
        Stanislav Fomichev <sdf@google.com>, bpf <bpf@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
References: <20220225234339.2386398-1-haoluo@google.com>
 <20220225234339.2386398-5-haoluo@google.com>
 <c323bce9-a04e-b1c3-580a-783fde259d60@fb.com>
 <CAADnVQ+q0vF03cH8w0c50XMZU1yf_0UjZ+ZarQ_RqMQrVpOFPA@mail.gmail.com>
From:   Yonghong Song <yhs@fb.com>
In-Reply-To: <CAADnVQ+q0vF03cH8w0c50XMZU1yf_0UjZ+ZarQ_RqMQrVpOFPA@mail.gmail.com>
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On 3/2/22 1:30 PM, Alexei Starovoitov wrote:
> On Wed, Mar 2, 2022 at 1:23 PM Yonghong Song <yhs@fb.com> wrote:
>>
>>
>>
>> On 2/25/22 3:43 PM, Hao Luo wrote:
>>> Add a new type of bpf tracepoints: sleepable tracepoints, which allows
>>> the handler to make calls that may sleep. With sleepable tracepoints, a
>>> set of syscall helpers (which may sleep) may also be called from
>>> sleepable tracepoints.
>>
>> There are some old discussions on sleepable tracepoints, maybe
>> worthwhile to take a look.
>>
>> https://lore.kernel.org/bpf/20210218222125.46565-5-mjeanson@efficios.com/T/
> 
> Right. It's very much related, but obsolete too.
> We don't need any of that for sleeptable _raw_ tps.
> I prefer to stay with "sleepable" name as well to
> match the rest of the bpf sleepable code.
> In all cases it's faultable.

sounds good to me. Agree that for the bpf user case, Hao's 
implementation should be enough.