2021-09-22 02:53:27

by Jackie Liu

Subject: [PATCH v2] tracing: fix missing osnoise tracer on max_latency

From: Jackie Liu <[email protected]>

The compiler warns when the data are actually unused:

kernel/trace/trace.c:1712:13: error: ‘trace_create_maxlat_file’ defined but not used [-Werror=unused-function]
1712 | static void trace_create_maxlat_file(struct trace_array *tr,
| ^~~~~~~~~~~~~~~~~~~~~~~~

[Why]
CONFIG_HWLAT_TRACER=n, CONFIG_TRACER_MAX_TRACE=n, CONFIG_OSNOISE_TRACER=y
gcc report warns.

[How]
Now trace_create_maxlat_file will only take effect when
CONFIG_HWLAT_TRACER=y or CONFIG_TRACER_MAX_TRACE=y. In fact, after
adding osnoise trace, it also needs to take effect.

Fixes: bce29ac9ce0b ("trace: Add osnoise tracer")
Cc: Daniel Bristot de Oliveira <[email protected]>
Suggested-by: Steven Rostedt <[email protected]>
Signed-off-by: Jackie Liu <[email protected]>
---
kernel/trace/trace.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7896d30d90f7..bc677cd64224 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1744,16 +1744,15 @@ void latency_fsnotify(struct trace_array *tr)
irq_work_queue(&tr->fsnotify_irqwork);
}

-/*
- * (defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)) && \
- * defined(CONFIG_FSNOTIFY)
- */
-#else
+#elif defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER) \
+ || defined(CONFIG_OSNOISE_TRACER)

#define trace_create_maxlat_file(tr, d_tracer) \
trace_create_file("tracing_max_latency", 0644, d_tracer, \
&tr->max_latency, &tracing_max_lat_fops)

+#else
+#define trace_create_maxlat_file(tr, d_tracer) do { } while (0)
#endif

#ifdef CONFIG_TRACER_MAX_TRACE
@@ -9473,9 +9472,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)

create_trace_options_dir(tr);

-#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
trace_create_maxlat_file(tr, d_tracer);
-#endif

if (ftrace_create_function_files(tr, d_tracer))
MEM_FAIL(1, "Could not allocate function filter files");
--
2.25.1

2021-09-22 10:07:21

by Daniel Bristot de Oliveira

Subject: Re: [PATCH v2] tracing: fix missing osnoise tracer on max_latency

On 9/22/21 4:51 AM, Jackie Liu wrote:
> From: Jackie Liu <[email protected]>
>
> The compiler warns when the data are actually unused:
>
> kernel/trace/trace.c:1712:13: error: ‘trace_create_maxlat_file’ defined but not used [-Werror=unused-function]
> 1712 | static void trace_create_maxlat_file(struct trace_array *tr,
> | ^~~~~~~~~~~~~~~~~~~~~~~~
>
> [Why]
> CONFIG_HWLAT_TRACER=n, CONFIG_TRACER_MAX_TRACE=n, CONFIG_OSNOISE_TRACER=y
> gcc report warns.
>
> [How]
> Now trace_create_maxlat_file will only take effect when
> CONFIG_HWLAT_TRACER=y or CONFIG_TRACER_MAX_TRACE=y. In fact, after
> adding osnoise trace, it also needs to take effect.
>
> Fixes: bce29ac9ce0b ("trace: Add osnoise tracer")
> Cc: Daniel Bristot de Oliveira <[email protected]>

Reviewed-by: Daniel Bristot de Oliveira <[email protected]>

Thanks!
-- Daniel
> Suggested-by: Steven Rostedt <[email protected]>
> Signed-off-by: Jackie Liu <[email protected]>
> ---
> kernel/trace/trace.c | 11 ++++-------
> 1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 7896d30d90f7..bc677cd64224 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -1744,16 +1744,15 @@ void latency_fsnotify(struct trace_array *tr)
> irq_work_queue(&tr->fsnotify_irqwork);
> }
>
> -/*
> - * (defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)) && \
> - * defined(CONFIG_FSNOTIFY)
> - */
> -#else
> +#elif defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER) \
> + || defined(CONFIG_OSNOISE_TRACER)
>
> #define trace_create_maxlat_file(tr, d_tracer) \
> trace_create_file("tracing_max_latency", 0644, d_tracer, \
> &tr->max_latency, &tracing_max_lat_fops)
>
> +#else
> +#define trace_create_maxlat_file(tr, d_tracer) do { } while (0)
> #endif
>
> #ifdef CONFIG_TRACER_MAX_TRACE
> @@ -9473,9 +9472,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
>
> create_trace_options_dir(tr);
>
> -#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
> trace_create_maxlat_file(tr, d_tracer);
> -#endif
>
> if (ftrace_create_function_files(tr, d_tracer))
> MEM_FAIL(1, "Could not allocate function filter files");
>