Commit-ID: 1b959e18c4d6b4b981f887260b0f8e7939efa411
Gitweb: http://git.kernel.org/tip/1b959e18c4d6b4b981f887260b0f8e7939efa411
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Thu, 3 Sep 2009 10:12:13 -0400
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Fri, 4 Sep 2009 11:25:27 -0400
ring-buffer: remove unnecessary cpu_relax
The loops in the ring buffer that use cpu_relax are not dependent on
other CPUs. They simply came across some padding in the ring buffer and
are skipping over them. It is a normal loop and does not require a
cpu_relax.
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/ring_buffer.c | 16 ++++------------
1 files changed, 4 insertions(+), 12 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2878bd4..a05541a 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3132,10 +3132,8 @@ ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
spin_unlock(&cpu_buffer->reader_lock);
local_irq_restore(flags);
- if (event && event->type_len == RINGBUF_TYPE_PADDING) {
- cpu_relax();
+ if (event && event->type_len == RINGBUF_TYPE_PADDING)
goto again;
- }
return event;
}
@@ -3160,10 +3158,8 @@ ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
event = rb_iter_peek(iter, ts);
spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
- if (event && event->type_len == RINGBUF_TYPE_PADDING) {
- cpu_relax();
+ if (event && event->type_len == RINGBUF_TYPE_PADDING)
goto again;
- }
return event;
}
@@ -3209,10 +3205,8 @@ ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts)
out:
preempt_enable();
- if (event && event->type_len == RINGBUF_TYPE_PADDING) {
- cpu_relax();
+ if (event && event->type_len == RINGBUF_TYPE_PADDING)
goto again;
- }
return event;
}
@@ -3302,10 +3296,8 @@ ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts)
out:
spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
- if (event && event->type_len == RINGBUF_TYPE_PADDING) {
- cpu_relax();
+ if (event && event->type_len == RINGBUF_TYPE_PADDING)
goto again;
- }
return event;
}
--
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