ring-buffer: Micro-optimize with some strategic inlining

By using inline and noinline, we are able to make the fast path of
recording an event 4% faster.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index d9f3e7a..f5007d0 100644 (file)
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2078,7 +2078,7 @@ static void rb_start_commit(struct ring_buffer_per_cpu *cpu_buffer)
        local_inc(&cpu_buffer->commits);
 }
 
-static void rb_end_commit(struct ring_buffer_per_cpu *cpu_buffer)
+static inline void rb_end_commit(struct ring_buffer_per_cpu *cpu_buffer)
 {
        unsigned long commits;
 
@@ -2193,13 +2193,9 @@ rb_reserve_next_event(struct ring_buffer *buffer,
 
 #define TRACE_RECURSIVE_DEPTH 16
 
-static int trace_recursive_lock(void)
+/* Keep this code out of the fast path cache */
+static noinline void trace_recursive_fail(void)
 {
-       current->trace_recursion++;
-
-       if (likely(current->trace_recursion < TRACE_RECURSIVE_DEPTH))
-               return 0;
-
        /* Disable all tracing before we do anything else */
        tracing_off_permanent();
 
@@ -2211,10 +2207,21 @@ static int trace_recursive_lock(void)
                    in_nmi());
 
        WARN_ON_ONCE(1);
+}
+
+static inline int trace_recursive_lock(void)
+{
+       current->trace_recursion++;
+
+       if (likely(current->trace_recursion < TRACE_RECURSIVE_DEPTH))
+               return 0;
+
+       trace_recursive_fail();
+
        return -1;
 }
 
-static void trace_recursive_unlock(void)
+static inline void trace_recursive_unlock(void)
 {
        WARN_ON_ONCE(!current->trace_recursion);