[PATCH 11/15] ring-buffer: add tracing_is_on to test if ring buffer is enabled

Steven Rostedt
2009-02-17T05:16:49Z

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From: Steven Rostedt <srostedt@redhat.com>

This patch adds the tracing_is_on() interface to tell if the ring
buffer is turned on or not.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
---
include/linux/ring_buffer.h | 2 ++
kernel/trace/ring_buffer.c | 9 +++++++++
2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 8e6646a..f5e793d 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -128,10 +128,12 @@ void ring_buffer_normalize_time_stamp(int cpu, u64 *ts);
void tracing_on(void);
void tracing_off(void);
void tracing_off_permanent(void);
+int tracing_is_on(void);
#else
static inline void tracing_on(void) { }
static inline void tracing_off(void) { }
static inline void tracing_off_permanent(void) { }
+static inline int tracing_is_on(void) { return 0; }
#endif

void *ring_buffer_alloc_read_page(struct ring_buffer *buffer);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2b4626c..8f19f1a 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -98,6 +98,15 @@ void tracing_off_permanent(void)
set_bit(RB_BUFFERS_DISABLED_BIT, &ring_buffer_flags);
}

+/**
+ * tracing_is_on - show state of ring buffers enabled
+ */
+int tracing_is_on(void)
+{
+ return ring_buffer_flags == RB_BUFFERS_ON;
+}
+EXPORT_SYMBOL_GPL(tracing_is_on);
+
#include "trace.h"

/* Up this if you want to test the TIME_EXTENTS and normalization */
--
1.5.6.5

--