Commit-ID: f6195aa09e618d712f52bf4fa33b5293820eb93d
Gitweb: http://git.kernel.org/tip/f6195aa09e618d712f52bf4fa33b5293820eb93d
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Wed, 1 Sep 2010 12:23:12 -0400
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Wed, 1 Sep 2010 12:23:12 -0400
ring-buffer: Place duplicate expression into a single function
While discussing the strictness of the 80 character limit on the
Kernel Summit Discussion mailing list, I showed examples that I
broke that limit slightly with some algorithms. In discussing with
John Linville, what looked better, I realized that two of the
80 char breaking culprits were an identical expression.
As a clean up, this patch moves the identical expression into its
own helper function and that is used instead. As a side effect,
the offending code is now under the 80 character limit. :-)
This clean up code also changes the expression from
(A - B) - C to A - (B + C)
This makes the code look a little nicer too.
Cc: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/ring_buffer.c | 21 +++++++++++++++------
1 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 19cccc3..ef27017 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2606,6 +2606,19 @@ void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu)
}
EXPORT_SYMBOL_GPL(ring_buffer_record_enable_cpu);
+/*
+ * The total entries in the ring buffer is the running counter
+ * of entries entered into the ring buffer, minus the sum of
+ * the entries read from the ring buffer and the number of
+ * entries that were overwritten.
+ */
+static inline unsigned long
+rb_num_of_entries(struct ring_buffer_per_cpu *cpu_buffer)
+{
+ return local_read(&cpu_buffer->entries) -
+ (local_read(&cpu_buffer->overrun) + cpu_buffer->read);
+}
+
/**
* ring_buffer_entries_cpu - get the number of entries in a cpu buffer
* @buffer: The ring buffer
@@ -2614,16 +2627,13 @@ EXPORT_SYMBOL_GPL(ring_buffer_record_enable_cpu);
unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu)
{
struct ring_buffer_per_cpu *cpu_buffer;
- unsigned long ret;
if (!cpumask_test_cpu(cpu, buffer->cpumask))
return 0;
cpu_buffer = buffer->buffers[cpu];
- ret = (local_read(&cpu_buffer->entries) - local_read(&cpu_buffer->overrun))
- - cpu_buffer->read;
- return ret;
+ return rb_num_of_entries(cpu_buffer);
}
EXPORT_SYMBOL_GPL(ring_buffer_entries_cpu);
@@ -2684,8 +2694,7 @@ unsigned long ring_buffer_entries(struct ring_buffer *buffer)
/* if you care about this being correct, lock the buffer */
for_each_buffer_cpu(buffer, cpu) {
cpu_buffer = buffer->buffers[cpu];
- entries += (local_read(&cpu_buffer->entries) -
- local_read(&cpu_buffer->overrun)) - cpu_buffer->read;
+ entries += rb_num_of_entries(cpu_buffer);
}
return entries;
--
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