ring-buffer: Add per_cpu ring buffer control files
Add a debugfs entry under per_cpu/ folder for each cpu called
buffer_size_kb to control the ring buffer size for each CPU
independently.
If the global file buffer_size_kb is used to set size, the individual
ring buffers will be adjusted to the given size. The buffer_size_kb will
report the common size to maintain backward compatibility.
If the buffer_size_kb file under the per_cpu/ directory is used to
change buffer size for a specific CPU, only the size of the respective
ring buffer is updated. When tracing/buffer_size_kb is read, it reports
'X' to indicate that sizes of per_cpu ring buffers are not equivalent.
Link: http://lkml.kernel.org/r/1328212844-11889-1-git-send-email-vnagarnaik@google.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Justin Teravest <teravest@google.com>
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f9d8550..1c8b7c6 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -131,6 +131,7 @@
atomic_t disabled;
void *buffer_page; /* ring buffer spare */
+ unsigned long entries;
unsigned long saved_latency;
unsigned long critical_start;
unsigned long critical_end;
@@ -152,7 +153,6 @@
*/
struct trace_array {
struct ring_buffer *buffer;
- unsigned long entries;
int cpu;
int buffer_disabled;
cycle_t time_start;
