From: Frank Rowand <frowand.list@gmail.com>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
devicetree@vger.kernel.org,
Tyrel Datwyler <tyreld@linux.vnet.ibm.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
linux-renesas-soc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
Rob Herring <robh+dt@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v2 0/1] of: easier debugging for node life cycle issues
Date: Thu, 25 Jan 2018 13:49:01 -0800 [thread overview]
Message-ID: <a30d4cd3-0068-8cca-cc2f-ca207d0d278b@gmail.com> (raw)
In-Reply-To: <20180125060330.781667e9@vmware.local.home>
Hi Wolfram,
On 01/25/18 03:03, Steven Rostedt wrote:
> On Wed, 24 Jan 2018 22:55:13 -0800
> Frank Rowand <frowand.list@gmail.com> wrote:
>
>> Hi Steve,
>
>>
>> Off the top of your head, can you tell me know early in the boot
>> process a trace_event can be called and successfully provide the
>> data to someone trying to debug early boot issues?
>
> The trace events are enabled by early_initcall().
< snip >
This means that ftrace can not be used for the of_node_get(),
of_node_put(), and of_node_release() debug info, because
these functions are called before early_initcall(). Please
use pr_debug() for these functions.
As far as I know, the of_reconfig_notify() could remain an
ftrace instrumented function. But now that the only thing
that would be ftrace instrumented is of_reconfig_notify(),
I don't see a strong justification for changing the existing
pr_debug() calls to an ftrace alternative. Though I suspect
the original author of the patch still might desire to have
the "#ifdef DEBUG" surrounding the pr_debug() calls removed
since one of his issues was having to recompile his kernel
to do his debugging.
-Frank
next prev parent reply other threads:[~2018-01-25 21:49 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-21 14:31 [RFC PATCH v2 0/1] of: easier debugging for node life cycle issues Wolfram Sang
2018-01-21 14:31 ` [RFC PATCH v2 1/1] of: introduce event tracepoints for dynamic device_node lifecyle Wolfram Sang
2018-01-21 22:01 ` Steven Rostedt
2018-01-25 6:48 ` Frank Rowand
2018-01-25 6:58 ` Frank Rowand
[not found] ` <4cc627c4-1aaf-b8d5-5a26-eea7e596743f-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2018-01-25 8:01 ` Geert Uytterhoeven
2018-01-25 22:40 ` Tyrel Datwyler
[not found] ` <25f83d0d-bc67-f1b5-cadb-838987fd846d-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2018-01-25 23:31 ` Frank Rowand
2018-01-25 8:32 ` Frank Rowand
2018-01-22 8:43 ` [RFC PATCH v2 0/1] of: easier debugging for node life cycle issues Frank Rowand
2018-01-22 11:49 ` Wolfram Sang
2018-01-23 12:11 ` Michael Ellerman
2018-01-23 19:53 ` Frank Rowand
2018-01-25 6:47 ` Frank Rowand
[not found] ` <11cf8fac-d2fe-ecdb-546f-de3c3b42a637-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2018-01-25 23:12 ` Wolfram Sang
2018-01-26 0:42 ` Frank Rowand
2018-01-25 6:48 ` Frank Rowand
[not found] ` <20180121143117.19805-1-wsa+renesas-jBu1N2QxHDJrcw3mvpCnnVaTQe2KTcn/@public.gmane.org>
2018-01-25 6:55 ` Frank Rowand
2018-01-25 11:03 ` Steven Rostedt
2018-01-25 21:49 ` Frank Rowand [this message]
[not found] ` <a30d4cd3-0068-8cca-cc2f-ca207d0d278b-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2018-01-25 23:14 ` Wolfram Sang
2018-01-26 0:46 ` Frank Rowand
2018-02-01 17:10 ` Steven Rostedt
2018-01-25 23:53 ` Tyrel Datwyler
2018-01-26 1:08 ` Frank Rowand
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