ftrace: show buffer size in kilobytes

		only be recorded if the latency is greater than

		the value in this file. (in microseconds)

  buffer_size_kb: This sets or displays the number of bytes each CPU

  buffer_size_kb: This sets or displays the number of kilobytes each CPU

		buffer can hold. The tracer buffers are the same size

		for each CPU. The displayed number is the size of the

		CPU buffer and not total size of all buffers. The

number of entries.

 # cat /debug/tracing/buffer_size_kb

65620

1408 (units kilobytes)

Note, to modify this, you must have tracing completely disabled. To do that,

echo "nop" into the current_tracer. If the current_tracer is not set

to "nop", an EINVAL error will be returned.

 # echo nop > /debug/tracing/current_tracer

 # echo 100000 > /debug/tracing/buffer_size_kb

 # echo 10000 > /debug/tracing/buffer_size_kb

 # cat /debug/tracing/buffer_size_kb

100045

Notice that we echoed in 100,000 but the size is 100,045. The entries

are held in individual pages. It allocates the number of pages it takes

to fulfill the request. If more entries may fit on the last page

then they will be added.

 # echo 1 > /debug/tracing/buffer_size_kb

 # cat /debug/tracing/buffer_size_kb

85

This shows us that 85 entries can fit in a single page.

10000 (units kilobytes)

The number of pages which will be allocated is limited to a percentage

of available memory. Allocating too much will produce an error.

	char buf[64];

	int r;

	r = sprintf(buf, "%lu\n", tr->entries);

	r = sprintf(buf, "%lu\n", tr->entries >> 10);

	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);

}

			atomic_inc(&max_tr.data[cpu]->disabled);

	}

	/* value is in KB */

	val <<= 10;

	if (val != global_trace.entries) {

		ret = ring_buffer_resize(global_trace.buffer, val);

		if (ret < 0) {