From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux trace kernel <linux-trace-kernel@vger.kernel.org>,
bpf <bpf@vger.kernel.org>, Masami Hiramatsu <mhiramat@kernel.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v5] tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast
Date: Tue, 13 Jan 2026 15:23:40 +0100 [thread overview]
Message-ID: <20260113142340.xEFFVvni@linutronix.de> (raw)
In-Reply-To: <CAADnVQKvY026HSFGOsavJppm3-Ajm-VsLzY-OeFUe+BaKMRnDg@mail.gmail.com>
On 2026-01-12 09:19:58 [-0800], Alexei Starovoitov wrote:
> > Now if you are saying that BPF will handle migrate_disable() on its own
> > and not require the tracepoint infrastructure to do it for it, then
> > this is perfect. And I can then simplify this code, and just use
> > srcu_fast for both RT and !RT.
>
> Agree. Just add migrate_disable to __bpf_trace_run,
> or, better yet, use rcu_read_lock_dont_migrate() in there.
Wonderful, thank you.
Is this "must remain on the same CPU and can be re-entrant" because BPF
core code such memory allocator/ data structures use per-CPU data
structures and must use the same through the whole invocation?
I did audit network related BPF code and their per-CPU usage usually had
a local_bh_disable() in the relevant spots.
Sebastian
next prev parent reply other threads:[~2026-01-13 14:23 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-09 3:05 [PATCH v5] tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast Steven Rostedt
2026-01-09 14:40 ` Mathieu Desnoyers
2026-01-09 17:21 ` Steven Rostedt
2026-01-09 18:58 ` Mathieu Desnoyers
2026-01-13 13:56 ` Sebastian Andrzej Siewior
2026-01-09 19:10 ` Alexei Starovoitov
2026-01-09 19:19 ` Steven Rostedt
2026-01-09 20:21 ` Mathieu Desnoyers
2026-01-09 21:02 ` Steven Rostedt
2026-01-12 7:23 ` Menglong Dong
2026-01-12 15:31 ` Peter Zijlstra
2026-01-12 15:36 ` Steven Rostedt
2026-01-12 15:44 ` Peter Zijlstra
2026-01-09 21:54 ` Alexei Starovoitov
2026-01-09 22:00 ` Steven Rostedt
2026-01-09 22:18 ` Alexei Starovoitov
2026-01-09 22:31 ` Mathieu Desnoyers
2026-01-09 22:33 ` Steven Rostedt
2026-01-09 22:39 ` Steven Rostedt
2026-01-10 0:35 ` Alexei Starovoitov
2026-01-10 16:14 ` Steven Rostedt
2026-01-11 20:04 ` Alexei Starovoitov
2026-01-11 22:09 ` Steven Rostedt
2026-01-11 23:38 ` Alexei Starovoitov
2026-01-12 13:53 ` Steven Rostedt
2026-01-12 17:19 ` Alexei Starovoitov
2026-01-13 14:23 ` Sebastian Andrzej Siewior [this message]
2026-01-13 23:44 ` Alexei Starovoitov
2026-01-09 19:19 ` Yonghong Song
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