ring-buffer: Pass timestamp by value and not by reference
The original code for the ring buffer had locations that modified
the timestamp and that change was used by the callers. Now,
the timestamp is not reused by the callers and there is no reason
to pass it by reference.
By changing the call to pass by value, lets gcc optimize the code
a bit more where it can store the timestamp in a register and not
worry about updating the reference.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 0b88df8..c8ce6bd 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1829,7 +1829,7 @@
static noinline struct ring_buffer_event *
rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
unsigned long length, unsigned long tail,
- struct buffer_page *tail_page, u64 *ts)
+ struct buffer_page *tail_page, u64 ts)
{
struct buffer_page *commit_page = cpu_buffer->commit_page;
struct ring_buffer *buffer = cpu_buffer->buffer;
@@ -1912,8 +1912,8 @@
* Nested commits always have zero deltas, so
* just reread the time stamp
*/
- *ts = rb_time_stamp(buffer);
- next_page->page->time_stamp = *ts;
+ ts = rb_time_stamp(buffer);
+ next_page->page->time_stamp = ts;
}
out_again:
@@ -1932,7 +1932,7 @@
static struct ring_buffer_event *
__rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
- unsigned type, unsigned long length, u64 *ts)
+ unsigned type, unsigned long length, u64 ts)
{
struct buffer_page *tail_page;
struct ring_buffer_event *event;
@@ -1965,7 +1965,7 @@
* its timestamp.
*/
if (!tail)
- tail_page->page->time_stamp = *ts;
+ tail_page->page->time_stamp = ts;
return event;
}
@@ -2008,7 +2008,7 @@
static int
rb_add_time_stamp(struct ring_buffer_per_cpu *cpu_buffer,
- u64 *ts, u64 *delta)
+ u64 ts, u64 *delta)
{
struct ring_buffer_event *event;
int ret;
@@ -2016,7 +2016,7 @@
WARN_ONCE(*delta > (1ULL << 59),
KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n",
(unsigned long long)*delta,
- (unsigned long long)*ts,
+ (unsigned long long)ts,
(unsigned long long)cpu_buffer->write_stamp);
/*
@@ -2051,7 +2051,7 @@
event->array[0] = 0;
}
}
- cpu_buffer->write_stamp = *ts;
+ cpu_buffer->write_stamp = ts;
/* let the caller know this was the commit */
ret = 1;
} else {
@@ -2175,7 +2175,7 @@
delta = diff;
if (unlikely(test_time_stamp(delta))) {
- commit = rb_add_time_stamp(cpu_buffer, &ts, &delta);
+ commit = rb_add_time_stamp(cpu_buffer, ts, &delta);
if (commit == -EBUSY)
goto out_fail;
@@ -2187,7 +2187,7 @@
}
get_event:
- event = __rb_reserve_next(cpu_buffer, 0, length, &ts);
+ event = __rb_reserve_next(cpu_buffer, 0, length, ts);
if (unlikely(PTR_ERR(event) == -EAGAIN))
goto again;