From: Tom Zanussi <tom.zanussi@linux.intel.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: masami.hiramatsu.pt@hitachi.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 01/10] tracing: Add support for SOFT_DISABLE to syscall events
Date: Tue, 27 Aug 2013 18:29:06 -0500 [thread overview]
Message-ID: <1377646146.15688.52.camel@empanada> (raw)
In-Reply-To: <20130827160150.36f10869@gandalf.local.home>
On Tue, 2013-08-27 at 16:01 -0400, Steven Rostedt wrote:
> On Tue, 27 Aug 2013 14:40:13 -0500
> Tom Zanussi <tom.zanussi@linux.intel.com> wrote:
>
> return;
> > - if (!test_bit(syscall_nr, tr->enabled_enter_syscalls))
> > +
> > + /* Here we're inside the tp handler's rcu_read_lock (__DO_TRACE()) */
> > + ftrace_file = rcu_dereference_raw(tr->enter_syscall_files[syscall_nr]);
>
> What's the reason for using rcu_dereference_raw() and not normal
> rcu_dereference?
>
This is because we know the tracepoint handler has rcu_read_lock_held()
and so we don't need to do the rcu_dereference_check().
Tom
> -- Steve
>
> > + if (!ftrace_file)
> > + return;
> > +
> > + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
> > return;
> >
next prev parent reply other threads:[~2013-08-27 23:29 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-27 19:40 [PATCH v7 00/10] tracing: trace event triggers (repost) Tom Zanussi
2013-08-27 19:40 ` [PATCH v7 01/10] tracing: Add support for SOFT_DISABLE to syscall events Tom Zanussi
2013-08-27 20:01 ` Steven Rostedt
2013-08-27 23:29 ` Tom Zanussi [this message]
2013-08-27 23:41 ` Steven Rostedt
2013-08-27 20:08 ` Steven Rostedt
2013-08-27 23:32 ` Tom Zanussi
2013-08-27 19:40 ` [PATCH v7 02/10] tracing: add basic event trigger framework Tom Zanussi
2013-08-27 20:15 ` Steven Rostedt
2013-08-27 23:38 ` Tom Zanussi
2013-08-27 20:17 ` Steven Rostedt
2013-08-27 19:40 ` [PATCH v7 03/10] tracing: add 'traceon' and 'traceoff' event trigger commands Tom Zanussi
2013-08-27 19:40 ` [PATCH v7 04/10] tracing: add 'snapshot' event trigger command Tom Zanussi
2013-08-27 19:40 ` [PATCH v7 05/10] tracing: add 'stacktrace' " Tom Zanussi
2013-08-27 19:40 ` [PATCH v7 06/10] tracing: add 'enable_event' and 'disable_event' event trigger commands Tom Zanussi
2013-08-27 19:40 ` [PATCH v7 07/10] tracing: add and use generic set_trigger_filter() implementation Tom Zanussi
2013-08-28 16:38 ` Steven Rostedt
2013-08-29 2:52 ` Tom Zanussi
2013-08-27 19:40 ` [PATCH v7 08/10] tracing: update event filters for multibuffer Tom Zanussi
2013-08-28 18:00 ` Steven Rostedt
2013-08-27 19:40 ` [PATCH v7 09/10] tracing: add documentation for trace event triggers Tom Zanussi
2013-08-27 19:40 ` [PATCH v7 10/10] tracing: make register/unregister_ftrace_command __init Tom Zanussi
2013-08-28 1:28 ` [PATCH v7 00/10] tracing: trace event triggers (repost) Masami Hiramatsu
2013-08-28 19:51 ` Steven Rostedt
2013-08-29 2:54 ` Tom Zanussi
-- strict thread matches above, loose matches on Subject: below --
2013-08-27 3:55 [PATCH v7 00/10] tracing: trace event triggers Tom Zanussi
2013-08-27 3:55 ` [PATCH v7 01/10] tracing: Add support for SOFT_DISABLE to syscall events Tom Zanussi
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