From: Steven Rostedt <rostedt@goodmis.org>
To: Beau Belgrave <beaub@linux.microsoft.com>
Cc: mhiramat@kernel.org, linux-trace-devel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 09/10] user_events: Optimize writing events by only copying data once
Date: Mon, 8 Nov 2021 18:04:52 -0500 [thread overview]
Message-ID: <20211108180452.3ec1f4ec@gandalf.local.home> (raw)
In-Reply-To: <20211108230034.GB1452@kbox>
On Mon, 8 Nov 2021 15:00:34 -0800
Beau Belgrave <beaub@linux.microsoft.com> wrote:
> > > - memcpy(entry + 1, data, datalen);
> > > + if (unlikely(!copy_nofault(entry + 1, i->count, i)))
> >
> > Need:
> > __trace_event_discard_commit(event_buffer.buffer, event_buffer.event);
> >
> > Because the trace_event_buffer_reserve() will not only allocate space on
> > the ring buffer, but may also disable preemption.
> >
> > -- Steve
> >
>
> Ah, thank you!
Which reminds me that trace_event_buffer_reserve() expects to be called
with preemption disabled. And I'm guessing that may not be the case for you.
I'll change this so that it always disables preemption even if it uses the
filter buffer, and *always* disables preemption on return.
-- Steve
next prev parent reply other threads:[~2021-11-08 23:04 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-04 17:04 [PATCH v4 00/10] user_events: Enable user processes to create and write to trace events Beau Belgrave
2021-11-04 17:04 ` [PATCH v4 01/10] user_events: Add UABI header for user access to user_events Beau Belgrave
2021-11-04 17:04 ` [PATCH v4 02/10] user_events: Add minimal support for trace_event into ftrace Beau Belgrave
2021-11-04 21:34 ` kernel test robot
2021-11-08 2:32 ` Masami Hiramatsu
2021-11-08 16:59 ` Beau Belgrave
2021-11-07 14:31 ` Masami Hiramatsu
2021-11-08 17:13 ` Beau Belgrave
2021-11-08 18:16 ` Steven Rostedt
2021-11-08 20:25 ` Beau Belgrave
2021-11-08 21:00 ` Steven Rostedt
2021-11-08 22:09 ` Beau Belgrave
2021-11-08 22:30 ` Steven Rostedt
2021-11-08 22:59 ` Beau Belgrave
2021-11-09 4:58 ` Masami Hiramatsu
2021-11-09 2:56 ` Masami Hiramatsu
2021-11-09 19:08 ` Beau Belgrave
2021-11-09 19:25 ` Steven Rostedt
2021-11-09 20:14 ` Beau Belgrave
2021-11-09 20:45 ` Steven Rostedt
2021-11-09 21:27 ` Beau Belgrave
2021-11-09 21:39 ` Steven Rostedt
2021-11-10 13:56 ` Masami Hiramatsu
2021-11-11 17:33 ` Beau Belgrave
2021-11-12 13:40 ` Masami Hiramatsu
2021-11-07 18:18 ` Steven Rostedt
2021-11-08 19:56 ` Beau Belgrave
2021-11-08 20:53 ` Steven Rostedt
2021-11-08 21:15 ` Beau Belgrave
2021-11-04 17:04 ` [PATCH v4 03/10] user_events: Add print_fmt generation support for basic types Beau Belgrave
2021-11-08 22:03 ` Steven Rostedt
2021-11-04 17:04 ` [PATCH v4 04/10] user_events: Handle matching arguments from dyn_events Beau Belgrave
2021-11-08 22:05 ` Steven Rostedt
2021-11-04 17:04 ` [PATCH v4 05/10] user_events: Add basic perf and eBPF support Beau Belgrave
2021-11-04 17:04 ` [PATCH v4 06/10] user_events: Add self-test for ftrace integration Beau Belgrave
2021-11-04 17:04 ` [PATCH v4 07/10] user_events: Add self-test for dynamic_events integration Beau Belgrave
2021-11-04 17:04 ` [PATCH v4 08/10] user_events: Add self-test for perf_event integration Beau Belgrave
2021-11-04 17:04 ` [PATCH v4 09/10] user_events: Optimize writing events by only copying data once Beau Belgrave
2021-11-08 22:45 ` Steven Rostedt
2021-11-08 23:00 ` Beau Belgrave
2021-11-08 23:04 ` Steven Rostedt [this message]
2021-11-08 23:17 ` Beau Belgrave
2021-11-08 23:20 ` Steven Rostedt
2021-11-04 17:04 ` [PATCH v4 10/10] user_events: Add documentation file Beau Belgrave
2021-11-04 19:05 ` Jonathan Corbet
2021-11-04 21:08 ` Beau Belgrave
2021-11-04 21:18 ` Jonathan Corbet
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