ring-buffer: Add per_cpu ring buffer control files
authorVaibhav Nagarnaik <vnagarnaik@google.com>
Thu, 2 Feb 2012 20:00:41 +0000 (12:00 -0800)
committerSteven Rostedt <rostedt@goodmis.org>
Tue, 24 Apr 2012 01:17:51 +0000 (21:17 -0400)
commit438ced1720b584000a9e8a4349d1f6bb7ee3ad6d
tree2c769e58411c68b298ab816c577ecb2119c7067c
parent5a26c8f0cf1e95106858bb4e23ca6dd14c9b842f
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>
include/linux/ring_buffer.h
kernel/trace/ring_buffer.c
kernel/trace/trace.c
kernel/trace/trace.h