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From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	yrl.pp-manager.tt@hitachi.com
Subject: Re: [RFC][PATCH 02/13 v2] ftrace: Consolidate arch dependent functions with list function
Date: Fri, 15 Jun 2012 12:02:45 +0900	[thread overview]
Message-ID: <4FDAA5D5.7080606@hitachi.com> (raw)
In-Reply-To: <20120612225424.495625483@goodmis.org>

(2012/06/13 7:43), Steven Rostedt wrote:
> From: Steven Rostedt <srostedt@redhat.com>
> 
> As the function tracer starts to get more features, the support for
> theses features will spread out throughout the different architectures
> over time. These features boil down to what each arch does in the
> mcount trampoline (the ftrace_caller).
> 
> Currently there's two features that are not the same throughout the
> archs.
> 
>  1) Support to stop function tracing before the callback
>  2) passing of the ftrace ops
> 
> Both of these require placing an indirect function to support the
> features if the mcount trampoline does not.
> 
> On a side note, for all architectures, when more than one callback
> is registered to the function tracer, an intermediate 'list' function
> is called by the mcount trampoline to iterate through the callbacks
> that are registered.
> 
> Instead of making a separate function for each of these features,
> and requiring several indirect calls, just use the single 'list' function
> as the intermediate, to handle all cases. If an arch does not support
> the 'stop function tracing' or the passing of ftrace ops, just force
> it to use the list function that will handle the features required.

Ah, I see. so even if the arch doesn't support passing ftrace_ops in
mcount trampoline, this ensures that the correct ftrace_ops should
be passed to the handlers.

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thank you,


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com

  reply	other threads:[~2012-06-15  3:02 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-12 22:43 [RFC][PATCH 00/13 v2] kprobes/ftrace: Making ftrace usable for kprobes Steven Rostedt
2012-06-12 22:43 ` [RFC][PATCH 01/13 v2] ftrace: Pass ftrace_ops as third parameter to function trace callback Steven Rostedt
2012-06-15  3:02   ` Masami Hiramatsu
2012-08-21 14:58   ` [tip:perf/core] " tip-bot for Steven Rostedt
2012-06-12 22:43 ` [RFC][PATCH 02/13 v2] ftrace: Consolidate arch dependent functions with list function Steven Rostedt
2012-06-15  3:02   ` Masami Hiramatsu [this message]
2012-08-21 14:59   ` [tip:perf/core] ftrace: Consolidate arch dependent functions with 'list' function tip-bot for Steven Rostedt
2012-06-12 22:43 ` [RFC][PATCH 03/13 v2] ftrace: Return pt_regs to function trace callback Steven Rostedt
2012-06-15  3:02   ` Masami Hiramatsu
2012-06-15  3:17     ` Steven Rostedt
2012-06-12 22:43 ` [RFC][PATCH 04/13 v2] ftrace/x86_32: Push ftrace_ops in as 3rd parameter to function tracer Steven Rostedt
2012-06-15  3:03   ` Masami Hiramatsu
2012-08-21 15:01   ` [tip:perf/core] " tip-bot for Steven Rostedt
2012-06-12 22:43 ` [RFC][PATCH 05/13 v2] ftrace/x86: Add separate function to save regs Steven Rostedt
2012-06-15  8:15   ` Masami Hiramatsu
2012-06-15 11:33     ` Steven Rostedt
2012-06-18  9:14       ` Masami Hiramatsu
2012-06-12 22:43 ` [RFC][PATCH 06/13 v2] ftrace/x86: Add save_regs for i386 function calls Steven Rostedt
2012-06-15  6:03   ` Masami Hiramatsu
2012-06-15 11:29     ` Steven Rostedt
2012-06-12 22:43 ` [RFC][PATCH 07/13 v2] ftrace: add ftrace_set_filter_ip() for address based filter Steven Rostedt
2012-06-12 22:43 ` [RFC][PATCH 08/13 v2] kprobes: Inverse taking of module_mutex with kprobe_mutex Steven Rostedt
2012-06-12 22:43 ` [RFC][PATCH 09/13 v2] kprobes: cleanup to separate probe-able check Steven Rostedt
2012-06-12 22:43 ` [RFC][PATCH 10/13 v2] kprobes: Move locks into appropriate functions Steven Rostedt
2012-06-12 22:43 ` [RFC][PATCH 11/13 v2] ftrace: Make ftrace_location() a nop on !DYNAMIC_FTRACE Steven Rostedt
2012-08-21 15:12   ` [tip:perf/core] " tip-bot for Steven Rostedt
2012-06-12 22:43 ` [RFC][PATCH 12/13 v2] kprobes: introduce ftrace based optimization Steven Rostedt
2012-06-12 22:43 ` [RFC][PATCH 13/13 v2] kprobes/x86: ftrace based optimization for x86 Steven Rostedt
2012-06-13  8:25 ` [RFC][PATCH 00/13 v2] kprobes/ftrace: Making ftrace usable for kprobes Masami Hiramatsu
2012-06-13 11:12   ` Steven Rostedt

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