linux-kernel - [for-next][PATCH] ring_buffer: Allow to exit the ring buffer benchmark immediately

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Date:	Tue, 23 Jun 2015 12:07:40 -0400
From:	Steven Rostedt <rostedt@...dmis.org>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Petr Mladek <pmladek@...e.cz>
Subject: [for-next][PATCH] ring_buffer: Allow to exit the ring buffer
 benchmark immediately

Grumble, I had this tested and sitting locally in my repo for over a
week. I'll let this sit in next for a couple of days before doing my
pull request. Although, this is specific to a benchmark module, thus I
may not wait.

-- Steve


  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
for-next

Head SHA1: b44754d8262d3aab842998cf747f44fe6090be9f


Petr Mladek (1):
      ring_buffer: Allow to exit the ring buffer benchmark immediately

----
 kernel/trace/ring_buffer_benchmark.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)
---------------------------
commit b44754d8262d3aab842998cf747f44fe6090be9f
Author: Petr Mladek <pmladek@...e.cz>
Date:   Mon Jun 15 15:53:10 2015 +0200

    ring_buffer: Allow to exit the ring buffer benchmark immediately
    
    It takes a while until the ring_buffer_benchmark module is removed
    when the ring buffer hammer is running. It is because it takes
    few seconds and kthread_should_stop() is not being checked.
    
    This patch adds the check for kthread termination into the producer.
    It uses the existing @kill_test flag to finish the kthreads as
    cleanly as possible.
    
    It disables printing the "ERROR" message when the kthread is going.
    
    It makes sure that producer does not go into the 10sec sleep
    when it is being killed.
    
    Finally, it does not call wait_to_die() when kthread_should_stop()
    already returns true.
    
    Link: http://lkml.kernel.org/r/20150615155428.GD3135@pathway.suse.cz
    
    Signed-off-by: Petr Mladek <pmladek@...e.cz>
    Signed-off-by: Steven Rostedt <rostedt@...dmis.org>

diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index 2430563cf2bc..5ffbae3d3f86 100644
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -263,6 +263,8 @@ static void ring_buffer_producer(void)
 		if (cnt % wakeup_interval)
 			cond_resched();
 #endif
+		if (kthread_should_stop())
+			kill_test = 1;
 
 	} while (ktime_before(end_time, timeout) && !kill_test);
 	trace_printk("End ring buffer hammer\n");
@@ -285,7 +287,7 @@ static void ring_buffer_producer(void)
 	entries = ring_buffer_entries(buffer);
 	overruns = ring_buffer_overruns(buffer);
 
-	if (kill_test)
+	if (kill_test && !kthread_should_stop())
 		trace_printk("ERROR!\n");
 
 	if (!disable_reader) {
@@ -379,7 +381,7 @@ static int ring_buffer_consumer_thread(void *arg)
 	}
 	__set_current_state(TASK_RUNNING);
 
-	if (kill_test)
+	if (!kthread_should_stop())
 		wait_to_die();
 
 	return 0;
@@ -399,13 +401,16 @@ static int ring_buffer_producer_thread(void *arg)
 		}
 
 		ring_buffer_producer();
+		if (kill_test)
+			goto out_kill;
 
 		trace_printk("Sleeping for 10 secs\n");
 		set_current_state(TASK_INTERRUPTIBLE);
 		schedule_timeout(HZ * SLEEP_TIME);
 	}
 
-	if (kill_test)
+out_kill:
+	if (!kthread_should_stop())
 		wait_to_die();
 
 	return 0;
--
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