linux-kernel - Re: [PATCH] tracing: Have synthetic event test use raw_smp_processor

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Date:   Thu, 20 Feb 2020 16:14:40 -0600
From:   Tom Zanussi <zanussi@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     Masami Hiramatsu <mhiramat@...nel.org>
Subject: Re: [PATCH] tracing: Have synthetic event test use
 raw_smp_processor_id()

Hi Steve,

On Thu, 2020-02-20 at 16:29 -0500, Steven Rostedt wrote:
> From: "Steven Rostedt (VMware)" <rostedt@...dmis.org>
> 
> The test code that tests synthetic event creation pushes in as one of
> its
> test fields the current CPU using "smp_processor_id()". As this is
> just
> something to see if the value is correctly passed in, and the actual
> CPU
> used does not matter, use raw_smp_processor_id(), otherwise with
> debug
> preemption enabled, a warning happens as the smp_processor_id() is
> called
> without preemption enabled.
> 
> Signed-off-by: Steven Rostedt (VMware) <rostedt@...dmis.org>

Makes sense - I guess it's simpler than Masami's and fine for this
purpose.

Reviewed-by: Tom Zanussi <zanussi@...nel.org>

Thanks,

Tom

> ---
>  kernel/trace/synth_event_gen_test.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/kernel/trace/synth_event_gen_test.c
> b/kernel/trace/synth_event_gen_test.c
> index 6866280a9b10..7d56d621ffea 100644
> --- a/kernel/trace/synth_event_gen_test.c
> +++ b/kernel/trace/synth_event_gen_test.c
> @@ -114,7 +114,7 @@ static int __init test_gen_synth_cmd(void)
>  	vals[1] = (u64)(long)"hula hoops";	/* next_comm_field
> */
>  	vals[2] = 1000000;		/* ts_ns */
>  	vals[3] = 1000;			/* ts_ms */
> -	vals[4] = smp_processor_id();	/* cpu */
> +	vals[4] = raw_smp_processor_id(); /* cpu */
>  	vals[5] = (u64)(long)"thneed";	/* my_string_field */
>  	vals[6] = 598;			/* my_int_field */
>  
> @@ -221,7 +221,7 @@ static int __init test_empty_synth_event(void)
>  	vals[1] = (u64)(long)"tiddlywinks";	/*
> next_comm_field */
>  	vals[2] = 1000000;		/* ts_ns */
>  	vals[3] = 1000;			/* ts_ms */
> -	vals[4] = smp_processor_id();	/* cpu */
> +	vals[4] = raw_smp_processor_id(); /* cpu */
>  	vals[5] = (u64)(long)"thneed_2.0";	/* my_string_field
> */
>  	vals[6] = 399;			/* my_int_field */
>  
> @@ -293,7 +293,7 @@ static int __init test_create_synth_event(void)
>  	vals[1] = (u64)(long)"tiddlywinks";	/*
> next_comm_field */
>  	vals[2] = 1000000;		/* ts_ns */
>  	vals[3] = 1000;			/* ts_ms */
> -	vals[4] = smp_processor_id();	/* cpu */
> +	vals[4] = raw_smp_processor_id(); /* cpu */
>  	vals[5] = (u64)(long)"thneed";	/* my_string_field */
>  	vals[6] = 398;			/* my_int_field */
>  
> @@ -345,7 +345,7 @@ static int __init test_add_next_synth_val(void)
>  		goto out;
>  
>  	/* cpu */
> -	ret = synth_event_add_next_val(smp_processor_id(),
> &trace_state);
> +	ret = synth_event_add_next_val(raw_smp_processor_id(),
> &trace_state);
>  	if (ret)
>  		goto out;
>  
> @@ -388,7 +388,7 @@ static int __init test_add_synth_val(void)
>  	if (ret)
>  		goto out;
>  
> -	ret = synth_event_add_val("cpu", smp_processor_id(),
> &trace_state);
> +	ret = synth_event_add_val("cpu", raw_smp_processor_id(),
> &trace_state);
>  	if (ret)
>  		goto out;
>  
> @@ -427,7 +427,7 @@ static int __init test_trace_synth_event(void)
>  				(u64)(long)"clackers",	/*
> next_comm_field */
>  				(u64)1000000,		/*
> ts_ns */
>  				(u64)1000,		/* ts_ms
> */
> -				(u64)smp_processor_id(),/* cpu */
> +				(u64)raw_smp_processor_id(), /* cpu
> */
>  				(u64)(long)"Thneed",	/*
> my_string_field */
>  				(u64)999);		/*
> my_int_field */
>  	return ret;