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From: Song Liu <songliubraving@fb.com>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: "open list:BPF (Safe dynamic programs and tools)" 
	<netdev@vger.kernel.org>,
	"open list:BPF (Safe dynamic programs and tools)" 
	<bpf@vger.kernel.org>,
	"duanxiongchun@bytedance.com" <duanxiongchun@bytedance.com>,
	"wangdongdong.6@bytedance.com" <wangdongdong.6@bytedance.com>,
	Muchun Song <songmuchun@bytedance.com>,
	"Cong Wang" <cong.wang@bytedance.com>,
	Alexei Starovoitov <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>, "Martin Lau" <kafai@fb.com>,
	Yonghong Song <yhs@fb.com>
Subject: Re: [RFC Patch bpf-next] bpf: introduce bpf timer
Date: Tue, 6 Apr 2021 01:07:57 +0000	[thread overview]
Message-ID: <DCAF6E05-7690-4B1D-B2AD-633B58E8985F@fb.com> (raw)
In-Reply-To: <CAM_iQpXrnXU85J=fa5+QjRqgo_evGfkfLU9_-aVdoyM_DJU2nA@mail.gmail.com>



> On Apr 5, 2021, at 4:49 PM, Cong Wang <xiyou.wangcong@gmail.com> wrote:
> 
> On Fri, Apr 2, 2021 at 4:31 PM Song Liu <songliubraving@fb.com> wrote:
>> 
>> 
>> 
>>> On Apr 2, 2021, at 1:57 PM, Cong Wang <xiyou.wangcong@gmail.com> wrote:
>>> 
>>> Ideally I even prefer to create timers in kernel-space too, but as I already
>>> explained, this seems impossible to me.
>> 
>> Would hrtimer (include/linux/hrtimer.h) work?
> 
> By impossible, I meant it is impossible (to me) to take a refcnt to the callback
> prog if we create the timer in kernel-space. So, hrtimer is the same in this
> perspective.
> 
> Thanks.

I guess I am not following 100%. Here is what I would propose:

We only introduce a new program type BPF_PROG_TYPE_TIMER. No new map type. 
The new program will trigger based on a timer, and the program can somehow 
control the period of the timer (for example, via return value).

With this approach, the user simply can create multiple timer programs and 
hold the fd for them. And these programs trigger up to timer expiration. 

Does this make sense?

Thanks,
Song

  reply	other threads:[~2021-04-06  1:08 UTC|newest]

Thread overview: 77+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-01  4:26 [RFC Patch bpf-next] bpf: introduce bpf timer Cong Wang
2021-04-01  6:38 ` Song Liu
2021-04-01 17:28   ` Cong Wang
2021-04-01 20:17     ` Song Liu
2021-04-02 17:34       ` Cong Wang
2021-04-02 17:57         ` Song Liu
2021-04-02 19:08           ` Cong Wang
2021-04-02 19:43             ` Song Liu
2021-04-02 20:57               ` Cong Wang
2021-04-02 23:31                 ` Song Liu
2021-04-05 23:49                   ` Cong Wang
2021-04-06  1:07                     ` Song Liu [this message]
2021-04-06  1:24                       ` Cong Wang
2021-04-06  6:17                         ` Song Liu
2021-04-06 16:48                           ` Cong Wang
2021-04-06 23:36                             ` Song Liu
2021-04-08 22:45                               ` Cong Wang
2021-04-02 19:28 ` Alexei Starovoitov
2021-04-02 21:24   ` Cong Wang
2021-04-02 23:45     ` Alexei Starovoitov
2021-04-06  0:36       ` Cong Wang
2021-04-12 23:01         ` Alexei Starovoitov
2021-04-15  4:02           ` Cong Wang
2021-04-15  4:25             ` Alexei Starovoitov
2021-04-15 15:51               ` Cong Wang
2021-04-26 23:00               ` Cong Wang
2021-04-26 23:05                 ` Alexei Starovoitov
2021-04-26 23:37                   ` Cong Wang
2021-04-27  2:01                     ` Alexei Starovoitov
2021-04-27 11:52                       ` Jamal Hadi Salim
2021-04-27 16:36                       ` Cong Wang
2021-04-27 18:33                         ` Alexei Starovoitov
2021-05-09  5:37                           ` Cong Wang
2021-05-10 20:55                             ` Jamal Hadi Salim
2021-05-11 21:29                               ` Cong Wang
2021-05-12 22:56                                 ` Jamal Hadi Salim
2021-05-11  5:05                             ` Joe Stringer
2021-05-11 21:08                               ` Cong Wang
2021-05-12 22:43                               ` Jamal Hadi Salim
2021-05-13 18:45                                 ` Jamal Hadi Salim
2021-05-14  2:53                                   ` Cong Wang
2021-08-11 21:03                                     ` Joe Stringer
2021-05-20 18:55 [RFC PATCH bpf-next] bpf: Introduce bpf_timer Alexei Starovoitov
2021-05-21 14:38 ` Alexei Starovoitov
2021-05-21 21:37 ` Cong Wang
2021-05-23 16:01   ` Alexei Starovoitov
2021-05-24  8:45     ` Lorenz Bauer
2021-05-25  3:16     ` Cong Wang
2021-05-25  4:59       ` Cong Wang
2021-05-25 18:21         ` Alexei Starovoitov
2021-05-25 19:35           ` Jamal Hadi Salim
2021-05-25 19:57             ` Alexei Starovoitov
2021-05-25 21:09               ` Jamal Hadi Salim
2021-05-25 22:08                 ` Alexei Starovoitov
2021-05-26 15:34                   ` Jamal Hadi Salim
2021-05-26 16:58                     ` Alexei Starovoitov
2021-05-26 18:25                       ` Jamal Hadi Salim
2021-05-30  6:36           ` Cong Wang
2021-06-02  2:00             ` Alexei Starovoitov
2021-06-02  8:48               ` Toke Høiland-Jørgensen
2021-06-02 17:54                 ` Martin KaFai Lau
2021-06-02 18:13                   ` Kumar Kartikeya Dwivedi
2021-06-02 18:26                     ` Alexei Starovoitov
2021-06-02 18:30                       ` Kumar Kartikeya Dwivedi
2021-06-02 18:46                     ` John Fastabend
2021-05-23 11:48 ` Toke Høiland-Jørgensen
2021-05-23 15:58   ` Alexei Starovoitov
2021-05-24  8:42     ` Lorenz Bauer
2021-05-24 14:48       ` Alexei Starovoitov
2021-05-24 17:33     ` Alexei Starovoitov
2021-05-24 18:39       ` Toke Høiland-Jørgensen
2021-05-24 18:38     ` Toke Høiland-Jørgensen
2021-05-24 11:49 ` Lorenz Bauer
2021-05-24 14:56   ` Alexei Starovoitov
2021-05-24 19:13     ` Andrii Nakryiko
2021-05-25  5:22       ` Cong Wang
2021-05-25 19:47         ` Andrii Nakryiko

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