Re: [PATCH v2 3/5] trace: Add per_cpu ring buffer control files

[Steven Rostedt]

On Tue, 2011-08-16 at 14:46 -0700, Vaibhav Nagarnaik wrote:
> 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.
> 
> Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@xxxxxxxxxx>

This patch wasn't tested against any of the latency tracers being
enabled or hot plug:


/home/rostedt/work/autotest/nobackup/linux-test.git/kernel/trace/ring_buffer.c: In function 'ring_buffer_swap_cpu':
/home/rostedt/work/autotest/nobackup/linux-test.git/kernel/trace/ring_buffer.c:3761:14: error: 'struct ring_buffer' has no member named 'pages'
/home/rostedt/work/autotest/nobackup/linux-test.git/kernel/trace/ring_buffer.c:3761:33: error: 'struct ring_buffer' has no member named 'pages'
  CC      kernel/trace/trace_syscalls.o
/home/rostedt/work/autotest/nobackup/linux-test.git/kernel/trace/ring_buffer.c: In function 'rb_cpu_notify':
/home/rostedt/work/autotest/nobackup/linux-test.git/kernel/trace/ring_buffer.c:4136:4: error: too few arguments to function 'rb_allocate_cpu_buffer'
/home/rostedt/work/autotest/nobackup/linux-test.git/kernel/trace/ring_buffer.c:1066:1: note: declared here


-- Steve


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