From: Steven Rostedt <rostedt@goodmis.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Beau Belgrave <beaub@linux.microsoft.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-trace-kernel@vger.kernel.org,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>, bpf <bpf@vger.kernel.org>,
David Vernet <void@manifault.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] tracing/user_events: Run BPF program if attached
Date: Tue, 9 May 2023 16:42:44 -0400 [thread overview]
Message-ID: <20230509164244.3163e421@rorschach.local.home> (raw)
In-Reply-To: <20230509163050.127d5123@rorschach.local.home>
On Tue, 9 May 2023 16:30:50 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> >From the user space side, which does:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/samples/user_events/example.c#n60
>
> /* Check if anyone is listening */
> if (enabled) {
Hmm, looking at this deeper, we should update it to prevent the
compiler from optimizing it, and keeping "enabled" in a register. Which
would not work. Should probably add:
if (*(const volatile int *)&enabled) {
-- Steve
> /* Yep, trace out our data */
> writev(data_fd, (const struct iovec *)io, 2);
>
> /* Increase the count */
> count++;
>
> printf("Something was attached, wrote data\n");
> }
next prev parent reply other threads:[~2023-05-09 20:42 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-08 16:37 [PATCH] tracing/user_events: Run BPF program if attached Beau Belgrave
2023-05-09 15:24 ` Alexei Starovoitov
2023-05-09 17:01 ` Steven Rostedt
2023-05-09 20:30 ` Steven Rostedt
2023-05-09 20:42 ` Steven Rostedt [this message]
2023-05-15 16:57 ` Alexei Starovoitov
2023-05-15 18:33 ` Steven Rostedt
2023-05-15 19:35 ` Beau Belgrave
2023-05-15 21:38 ` Steven Rostedt
2023-05-15 19:24 ` Beau Belgrave
2023-05-15 21:57 ` Steven Rostedt
2023-05-17 0:36 ` Alexei Starovoitov
2023-05-17 0:56 ` Linus Torvalds
2023-05-17 1:46 ` Linus Torvalds
2023-05-17 2:29 ` Steven Rostedt
2023-05-17 3:03 ` Linus Torvalds
2023-05-17 17:22 ` Beau Belgrave
2023-05-17 18:15 ` Linus Torvalds
2023-05-17 19:07 ` Beau Belgrave
2023-05-17 19:26 ` Linus Torvalds
2023-05-17 19:36 ` Beau Belgrave
2023-05-17 19:36 ` Linus Torvalds
2023-05-17 19:37 ` Linus Torvalds
2023-05-17 23:00 ` Beau Belgrave
2023-05-17 23:14 ` Linus Torvalds
2023-05-17 23:25 ` Steven Rostedt
2023-05-18 0:14 ` Beau Belgrave
2023-05-18 0:23 ` Linus Torvalds
2023-05-17 20:08 ` Linus Torvalds
2023-05-17 1:26 ` Steven Rostedt
2023-05-17 16:50 ` Beau Belgrave
2023-05-18 0:10 ` Alexei Starovoitov
2023-05-18 0:19 ` Beau Belgrave
2023-05-18 0:56 ` Alexei Starovoitov
2023-05-18 1:18 ` Beau Belgrave
2023-05-18 2:08 ` Steven Rostedt
2023-05-18 3:14 ` Alexei Starovoitov
2023-05-18 13:36 ` Steven Rostedt
2023-05-18 17:28 ` Beau Belgrave
2023-06-01 9:46 ` Christian Brauner
2023-06-01 15:24 ` Beau Belgrave
2023-06-01 15:57 ` Christian Brauner
2023-06-01 16:29 ` Beau Belgrave
2023-06-06 13:37 ` Masami Hiramatsu
2023-06-06 17:05 ` Beau Belgrave
2023-06-07 14:07 ` Masami Hiramatsu
2023-06-07 19:26 ` Beau Belgrave
2023-06-08 0:25 ` Masami Hiramatsu
2023-05-17 17:51 ` Beau Belgrave
2023-06-06 13:57 ` Masami Hiramatsu
2023-06-06 16:57 ` Andrii Nakryiko
2023-06-06 20:57 ` Beau Belgrave
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