From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
To: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: rostedt@goodmis.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v10 04/12] tracing: Add 'snapshot' event trigger command
Date: Tue, 15 Oct 2013 18:23:41 +0900 [thread overview]
Message-ID: <525D099D.1010005@hitachi.com> (raw)
In-Reply-To: <1381500268.19281.19.camel@empanada>
(2013/10/11 23:04), Tom Zanussi wrote:
> On Fri, 2013-10-11 at 22:47 +0900, Masami Hiramatsu wrote:
>> (2013/10/11 9:48), Tom Zanussi wrote:
>>> /**
>>> + * tracing_alloc_snapshot - allocate snapshot buffer.
>>> + *
>>> + * This only allocates the snapshot buffer if it isn't already
>>> + * allocated - it doesn't also take a snapshot.
>>> + *
>>> + * This is meant to be used in cases where the snapshot buffer needs
>>> + * to be set up for events that can't sleep but need to be able to
>>> + * trigger a snapshot.
>>> + */
>>> +int tracing_alloc_snapshot(void)
>>> +{
>>> + struct trace_array *tr = &global_trace;
>>> + int ret;
>>> +
>>> + ret = alloc_snapshot(tr);
>>> + WARN_ON(ret < 0);
>>> +
>>> + return ret;
>>> +}
>>> +EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
>>
>> Out of curiously, why this symbol is exported to modules?
>> The functions which are called directly from trace_event macros
>> should be exported because those macros can be used in module code,
>> but I couldn't find this in such code, at a glance.
>>
>
> tracing_alloc_snapshot() goes along with tracing_snapshot() and
> tracing_snapshot_alloc() which are already exported - you should be able
> to take a snapshot from a module, or do a combined snapshot/alloc or
> (now) just the alloc.
Hmm, it seems that Steven added these EXPORT_SYMBOL_GPL at commit 1b22e382.
Steven, would you have any idea to call these functions from outside of
the ftrace?
Thank you,
--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com
next prev parent reply other threads:[~2013-10-15 9:23 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-11 0:48 [PATCH v10 00/12] tracing: trace event triggers Tom Zanussi
2013-10-11 0:48 ` [PATCH v10 01/12] tracing: Add support for SOFT_DISABLE to syscall events Tom Zanussi
2013-10-11 0:48 ` [PATCH v10 02/12] tracing: Add basic event trigger framework Tom Zanussi
2013-10-11 0:48 ` [PATCH v10 03/12] tracing: Add 'traceon' and 'traceoff' event trigger commands Tom Zanussi
2013-10-11 0:48 ` [PATCH v10 04/12] tracing: Add 'snapshot' event trigger command Tom Zanussi
2013-10-11 13:47 ` Masami Hiramatsu
2013-10-11 14:04 ` Tom Zanussi
2013-10-15 9:23 ` Masami Hiramatsu [this message]
2013-10-11 0:48 ` [PATCH v10 05/12] tracing: Add 'stacktrace' " Tom Zanussi
2013-10-11 0:48 ` [PATCH v10 06/12] tracing: Add 'enable_event' and 'disable_event' event trigger commands Tom Zanussi
2013-10-11 0:48 ` [PATCH v10 07/12] tracing: Add and use generic set_trigger_filter() implementation Tom Zanussi
2013-10-11 0:48 ` [PATCH v10 08/12] tracing: Update event filters for multibuffer Tom Zanussi
2013-10-11 0:48 ` [PATCH v10 09/12] tracing: Add documentation for trace event triggers Tom Zanussi
2013-10-11 0:48 ` [PATCH v10 10/12] tracing: Make register/unregister_ftrace_command __init Tom Zanussi
2013-10-11 0:48 ` [PATCH v10 11/12] tracing: fix tracing_snapshot kerneldoc Tom Zanussi
2013-10-11 12:50 ` Masami Hiramatsu
2013-10-11 13:29 ` Tom Zanussi
2013-10-11 20:57 ` Steven Rostedt
2013-10-11 0:48 ` [PATCH v10 12/12] tracing: define trace_dump_stack() if !CONFIG_STACKTRACE Tom Zanussi
2013-10-11 13:00 ` Masami Hiramatsu
2013-10-11 13:32 ` Tom Zanussi
2013-10-11 20:04 ` Steven Rostedt
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