Re: [tip:tracing/urgent] ring-buffer: Make it generally available

[Steven Rostedt]

On Thu, 25 Jun 2009, tip-bot for Paul Mundt wrote:

> Commit-ID:  1155de47cd66d0c496d5a6fb2223e980ef1285b2
> Gitweb:     http://git.kernel.org/tip/1155de47cd66d0c496d5a6fb2223e980ef1285b2
> Author:     Paul Mundt <lethal@xxxxxxxxxxxx>
> AuthorDate: Thu, 25 Jun 2009 14:30:12 +0900
> Committer:  Ingo Molnar <mingo@xxxxxxx>
> CommitDate: Thu, 25 Jun 2009 10:31:30 +0200
> 
> ring-buffer: Make it generally available
> 
> In hunting down the cause for the hwlat_detector ring buffer spew in
> my failed -next builds it became obvious that folks are now treating
> ring_buffer as something that is generic independent of tracing and thus,
> suitable for public driver consumption.
> 
> Given that there are only a few minor areas in ring_buffer that have any
> reliance on CONFIG_TRACING or CONFIG_FUNCTION_TRACER, provide stubs for
> those and make it generally available.
> 
> Signed-off-by: Paul Mundt <lethal@xxxxxxxxxxxx>
> Cc: Jon Masters <jcm@xxxxxxxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>

Thanks!

Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>

-- Steve

> LKML-Reference: <20090625053012.GB19944@xxxxxxxxxxxx>
> Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> 
> 
> ---
>  kernel/Makefile            |    1 +
>  kernel/trace/ring_buffer.c |   11 +++++++++++
>  kernel/trace/trace.h       |    7 +++++++
>  3 files changed, 19 insertions(+), 0 deletions(-)
> 
> diff --git a/kernel/Makefile b/kernel/Makefile
> index 0a32cb2..0630e29 100644
> --- a/kernel/Makefile
> +++ b/kernel/Makefile
> @@ -96,6 +96,7 @@ obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
>  obj-$(CONFIG_FUNCTION_TRACER) += trace/
>  obj-$(CONFIG_TRACING) += trace/
>  obj-$(CONFIG_X86_DS) += trace/
> +obj-$(CONFIG_RING_BUFFER) += trace/
>  obj-$(CONFIG_SMP) += sched_cpupri.o
>  obj-$(CONFIG_SLOW_WORK) += slow-work.o
>  obj-$(CONFIG_PERF_COUNTERS) += perf_counter.o
> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
> index 04dac26..bf27bb7 100644
> --- a/kernel/trace/ring_buffer.c
> +++ b/kernel/trace/ring_buffer.c
> @@ -1563,6 +1563,8 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
>  	return NULL;
>  }
>  
> +#ifdef CONFIG_TRACING
> +
>  #define TRACE_RECURSIVE_DEPTH 16
>  
>  static int trace_recursive_lock(void)
> @@ -1593,6 +1595,13 @@ static void trace_recursive_unlock(void)
>  	current->trace_recursion--;
>  }
>  
> +#else
> +
> +#define trace_recursive_lock()		(0)
> +#define trace_recursive_unlock()	do { } while (0)
> +
> +#endif
> +
>  static DEFINE_PER_CPU(int, rb_need_resched);
>  
>  /**
> @@ -3104,6 +3113,7 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
>  }
>  EXPORT_SYMBOL_GPL(ring_buffer_read_page);
>  
> +#ifdef CONFIG_TRACING
>  static ssize_t
>  rb_simple_read(struct file *filp, char __user *ubuf,
>  	       size_t cnt, loff_t *ppos)
> @@ -3171,6 +3181,7 @@ static __init int rb_init_debugfs(void)
>  }
>  
>  fs_initcall(rb_init_debugfs);
> +#endif
>  
>  #ifdef CONFIG_HOTPLUG_CPU
>  static int rb_cpu_notify(struct notifier_block *self,
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index 6e735d4..3548ae5 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -597,6 +597,7 @@ print_graph_function(struct trace_iterator *iter)
>  
>  extern struct pid *ftrace_pid_trace;
>  
> +#ifdef CONFIG_FUNCTION_TRACER
>  static inline int ftrace_trace_task(struct task_struct *task)
>  {
>  	if (!ftrace_pid_trace)
> @@ -604,6 +605,12 @@ static inline int ftrace_trace_task(struct task_struct *task)
>  
>  	return test_tsk_trace_trace(task);
>  }
> +#else
> +static inline int ftrace_trace_task(struct task_struct *task)
> +{
> +	return 1;
> +}
> +#endif
>  
>  /*
>   * trace_iterator_flags is an enumeration that defines bit
> 
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