Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1262383

[for-next][PATCH 10/13] ring_buffer: Remove unneeded smp_wmb() before wakeup of reader benchmark

From Steven Rostedt <rostedt@goodmis.org>
Newsgroups linux.kernel
Subject [for-next][PATCH 10/13] ring_buffer: Remove unneeded smp_wmb() before wakeup of reader benchmark
Date 2015-11-04 16:40 +0100
Message-ID <qr8kk-2go-75@gated-at.bofh.it> (permalink)
References <qr8kh-2go-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

wake_up_process() has a memory barrier before doing anything, thus adding a
memory barrier before calling it is redundant.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer_benchmark.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index 9e00fd178226..6df9a83e20d7 100644
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -288,8 +288,6 @@ static void ring_buffer_producer(void)
 		/* the completions must be visible before the finish var */
 		smp_wmb();
 		reader_finish = 1;
-		/* finish var visible before waking up the consumer */
-		smp_wmb();
 		wake_up_process(consumer);
 		wait_for_completion(&read_done);
 	}
-- 
2.6.1


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread


Thread

[for-next][PATCH 00/13] tracing: Some more last minute cleanups and fixes for 4.4 Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100
  [for-next][PATCH 13/13] tracing: Put back comma for empty fields in boot string parsing Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100
  [for-next][PATCH 05/13] tracing: Rename max_stack_lock to stack_trace_max_lock Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100
  [for-next][PATCH 12/13] tracing: Apply tracer specific options from kernel command line. Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100
  [for-next][PATCH 09/13] tracing: Allow dumping traces without tracking trace started cpus Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100
  [for-next][PATCH 02/13] recordmcount: Fix endianness handling bug for nop_mcount Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100
  [for-next][PATCH 07/13] ring_buffer: Do no not complete benchmark reader too early Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100
  [for-next][PATCH 06/13] tracing: Remove redundant TP_ARGS redefining Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100
  [for-next][PATCH 08/13] ring_buffer: Fix more races when terminating the producer in the  benchmark Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100
  [for-next][PATCH 10/13] ring_buffer: Remove unneeded smp_wmb() before wakeup of reader  benchmark Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100
  [for-next][PATCH 04/13] tracing: Allow arch-specific stack tracer Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100
  [for-next][PATCH 03/13] recordmcount: arm64: Replace the ignored mcount call into nop Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100
  [for-next][PATCH 01/13] tracepoints: Fix documentation of RCU lockdep checks Steven Rostedt <rostedt@goodmis.org> - 2015-11-04 16:40 +0100

csiph-web