Re: [tip:sched/fifo 44/45] ERROR: modpost: "sched_setscheduler" undefined!

[Peter Zijlstra <peterz@infradead.org>]

On Thu, Jul 09, 2020 at 11:58:18AM -0400, Steven Rostedt wrote:
> On Thu, 9 Jul 2020 14:45:05 +0200
> Peter Zijlstra <peterz@infradead.org> wrote:
> 
> > On Fri, Jun 19, 2020 at 10:15:51PM +0800, kernel test robot wrote:
> > > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched/fifo
> > > head:   8b700983de82f79e05b2c1136d6513ea4c9b22c4
> > > commit: 616d91b68cd56bcb1954b6a5af7d542401fde772 [44/45] sched: Remove sched_setscheduler*() EXPORTs
> > > config: x86_64-rhel (attached as .config)
> > > compiler: gcc-9 (Debian 9.3.0-13) 9.3.0
> > > reproduce (this is a W=1 build):
> > >         git checkout 616d91b68cd56bcb1954b6a5af7d542401fde772
> > >         # save the attached .config to linux build tree
> > >         make W=1 ARCH=x86_64 
> > > 
> > > If you fix the issue, kindly add following tag as appropriate
> > > Reported-by: kernel test robot <lkp@intel.com>
> > > 
> > > All errors (new ones prefixed by >>, old ones prefixed by <<):
> > >   
> > > >> ERROR: modpost: "sched_setscheduler" [kernel/trace/ring_buffer_benchmark.ko] undefined!  
> > 
> > Steve, do you have any preference on how to go about fixing this one?
> 
> Well, I use to manually set the priority of the test, but I guess we
> can switch the parameters to accepting a "high, medium, and low" that
> will correspond to your setting of the other sched_setscheduler() calls
> that were replaced.

Steve, would this work for you, or would you prefer renaming the
parameters as well?

---
 kernel/trace/ring_buffer_benchmark.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index 8df0aa810950..0ee3d41ceee4 100644
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -455,21 +455,19 @@ static int __init ring_buffer_benchmark_init(void)
 	 * Run them as low-prio background tasks by default:
 	 */
 	if (!disable_reader) {
-		if (consumer_fifo >= 0) {
-			struct sched_param param = {
-				.sched_priority = consumer_fifo
-			};
-			sched_setscheduler(consumer, SCHED_FIFO, &param);
-		} else
+		if (consumer_fifo > 1)
+			sched_set_fifo(consumer);
+		else if (consumer_fifo >= 0)
+			sched_set_fifo_low(consumer);
+		else
 			set_user_nice(consumer, consumer_nice);
 	}
 
-	if (producer_fifo >= 0) {
-		struct sched_param param = {
-			.sched_priority = producer_fifo
-		};
-		sched_setscheduler(producer, SCHED_FIFO, &param);
-	} else
+	if (producer_fifo > 1)
+		sched_set_fifo(producer);
+	else if (producer_fifo >= 0)
+		sched_set_fifo_low(producer);
+	else
 		set_user_nice(producer, producer_nice);
 
 	return 0;