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authorSteven Rostedt <srostedt@redhat.com>2010-09-01 12:23:12 -0400
committerSteven Rostedt <rostedt@goodmis.org>2010-09-01 12:23:12 -0400
commitf6195aa09e618d712f52bf4fa33b5293820eb93d (patch)
treea41ef0dce7ebb3e670b6e1a7214a4f558110178e /kernel/trace/ring_buffer.c
parentc9cf4a019cff198ee5638323e3b0ee18886467e8 (diff)
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@tuxdriver.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/ring_buffer.c')
-rw-r--r--kernel/trace/ring_buffer.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 19cccc3c3028..ef27017caa56 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)
2606} 2606}
2607EXPORT_SYMBOL_GPL(ring_buffer_record_enable_cpu); 2607EXPORT_SYMBOL_GPL(ring_buffer_record_enable_cpu);
2608 2608
2609/*
2610 * The total entries in the ring buffer is the running counter
2611 * of entries entered into the ring buffer, minus the sum of
2612 * the entries read from the ring buffer and the number of
2613 * entries that were overwritten.
2614 */
2615static inline unsigned long
2616rb_num_of_entries(struct ring_buffer_per_cpu *cpu_buffer)
2617{
2618 return local_read(&cpu_buffer->entries) -
2619 (local_read(&cpu_buffer->overrun) + cpu_buffer->read);
2620}
2621
2609/** 2622/**
2610 * ring_buffer_entries_cpu - get the number of entries in a cpu buffer 2623 * ring_buffer_entries_cpu - get the number of entries in a cpu buffer
2611 * @buffer: The ring buffer 2624 * @buffer: The ring buffer
@@ -2614,16 +2627,13 @@ EXPORT_SYMBOL_GPL(ring_buffer_record_enable_cpu);
2614unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu) 2627unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu)
2615{ 2628{
2616 struct ring_buffer_per_cpu *cpu_buffer; 2629 struct ring_buffer_per_cpu *cpu_buffer;
2617 unsigned long ret;
2618 2630
2619 if (!cpumask_test_cpu(cpu, buffer->cpumask)) 2631 if (!cpumask_test_cpu(cpu, buffer->cpumask))
2620 return 0; 2632 return 0;
2621 2633
2622 cpu_buffer = buffer->buffers[cpu]; 2634 cpu_buffer = buffer->buffers[cpu];
2623 ret = (local_read(&cpu_buffer->entries) - local_read(&cpu_buffer->overrun))
2624 - cpu_buffer->read;
2625 2635
2626 return ret; 2636 return rb_num_of_entries(cpu_buffer);
2627} 2637}
2628EXPORT_SYMBOL_GPL(ring_buffer_entries_cpu); 2638EXPORT_SYMBOL_GPL(ring_buffer_entries_cpu);
2629 2639
@@ -2684,8 +2694,7 @@ unsigned long ring_buffer_entries(struct ring_buffer *buffer)
2684 /* if you care about this being correct, lock the buffer */ 2694 /* if you care about this being correct, lock the buffer */
2685 for_each_buffer_cpu(buffer, cpu) { 2695 for_each_buffer_cpu(buffer, cpu) {
2686 cpu_buffer = buffer->buffers[cpu]; 2696 cpu_buffer = buffer->buffers[cpu];
2687 entries += (local_read(&cpu_buffer->entries) - 2697 entries += rb_num_of_entries(cpu_buffer);
2688 local_read(&cpu_buffer->overrun)) - cpu_buffer->read;
2689 } 2698 }
2690 2699
2691 return entries; 2700 return entries;