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authorSteven Rostedt <srostedt@redhat.com>2009-09-04 22:24:40 +0400
committerSteven Rostedt <rostedt@goodmis.org>2009-09-05 03:42:22 +0400
commit85bac32c4a52c592b857f2c360cc5ec93a097d70 (patch)
tree510e516dd5fa388cb9582a2f6b055f3725fbf2c1 /include/linux/ring_buffer.h
parent62f0b3eb5cb58931a02ee4e599e19c80a171e351 (diff)
downloadlinux-85bac32c4a52c592b857f2c360cc5ec93a097d70.tar.xz
ring-buffer: only enable ring_buffer_swap_cpu when needed
Since the ability to swap the cpu buffers adds a small overhead to the recording of a trace, we only want to add it when needed. Only the irqsoff and preemptoff tracers use this feature, and both are not recommended for production kernels. This patch disables its use when neither irqsoff nor preemptoff is configured. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/ring_buffer.h')
-rw-r--r--include/linux/ring_buffer.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index e061b4ecdc3a..5fcc31ed5771 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -140,8 +140,17 @@ unsigned long ring_buffer_size(struct ring_buffer *buffer);
void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
void ring_buffer_reset(struct ring_buffer *buffer);
+#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
struct ring_buffer *buffer_b, int cpu);
+#else
+static inline int
+ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
+ struct ring_buffer *buffer_b, int cpu)
+{
+ return -ENODEV;
+}
+#endif
int ring_buffer_empty(struct ring_buffer *buffer);
int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);