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Message-ID: <51DF7250.9020209@asianux.com>
Date: Fri, 12 Jul 2013 11:04:48 +0800
From: Chen Gang <gang.chen@...anux.com>
To: Steven Rostedt <rostedt@...dmis.org>
CC: Frederic Weisbecker <fweisbec@...il.com>,
"mingo@...hat.com" <mingo@...hat.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kernel: trace: remove __init from race_selftest_startup_function()
and trace_selftest_startup_function_graph()
On 07/12/2013 10:38 AM, Steven Rostedt wrote:
> On Fri, 2013-07-12 at 09:58 +0800, Chen Gang wrote:
>> On 07/12/2013 09:41 AM, Steven Rostedt wrote:
>>> On Fri, 2013-07-12 at 07:51 +0800, Chen Gang wrote:
>>>
>>>>> Hmm, can all trace_selftest_startup_* (*selftest* in trace_selftest.c)
>>>>> use '__init', so not waste memory keeping them around ?
>>> Yeah, they should all be set to __init, but that's pretty low on the
>>> totem poll, as distros don't enable selftests in their main kernels.
>>
>> Excuse me, my English is not quite well, I guess your meaning is:
>>
>> they should all be set to '__init', although it is minor in real world.
>>
>> Is it correct ?
>
> Correct.
>
>>
>>
>> For me, I recommend to let all *selftest* as the same: "all add '
>> __init' or none add '__init'" (if choose add, all report warnings).
>>
>> Is it suitable to still send new related patch for it ? If so, could
>> you provide your suggesting choice (all add, or none add) ?
>
> Does this patch fix your warning?
>
> -- Steve
>
I guess it can (although I do not give a compiling test), it seems a
better fixing.
And is it suitable to let all *selftest* as the same ? (all add, or none
add '__init').
Thanks.
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index a4ed382..5e794d1 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -680,6 +680,15 @@ extern int trace_selftest_startup_sched_switch(struct tracer *trace,
> struct trace_array *tr);
> extern int trace_selftest_startup_branch(struct tracer *trace,
> struct trace_array *tr);
> +/*
> + * Tracer data references selftest functions that only occur
> + * on boot up. These can be __init functions. Thus, when selftests
> + * are enabled, then the tracers need to reference __init functions.
> + */
> +#define __tracer_data __refdata
> +#else
> +/* Tracers are seldom changed. Optimize when selftests are disabled. */
> +#define __tracer_data __read_mostly
> #endif /* CONFIG_FTRACE_STARTUP_TEST */
>
> extern void *head_page(struct trace_array_cpu *data);
> diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
> index b863f93..38fe148 100644
> --- a/kernel/trace/trace_functions.c
> +++ b/kernel/trace/trace_functions.c
> @@ -199,7 +199,7 @@ static int func_set_flag(u32 old_flags, u32 bit, int set)
> return 0;
> }
>
> -static struct tracer function_trace __read_mostly =
> +static struct tracer function_trace __tracer_data =
> {
> .name = "function",
> .init = function_trace_init,
>
>
>
>
--
Chen Gang
--
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