linux-kernel - [PATCH 1/3] sched/fair: Introduce a new debugfs directory for EEVDF tests

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Message-ID: <20250422-b4-eevdf-tests-v1-post-v1-1-35d158254c72@gianis.ca>
Date: Wed, 23 Apr 2025 00:20:14 +0000
From: "Dhaval Giani (AMD)" <dhaval@...nis.ca>
To: Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>, Juri Lelli <juri.lelli@...hat.com>, Vincent Guittot <vincent.guittot@...aro.org>, Dietmar Eggemann <dietmar.eggemann@....com>, Steven Rostedt <rostedt@...dmis.org>, Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>, Valentin Schneider <vschneid@...hat.com>
Cc: linux-kernel@...r.kernel.org, Dhaval Giani <dhaval.giani@....com>, Gautham Shenoy <gautham.shenoy@....com>, K Prateek Nayak <kprateek.nayak@....com>, "Dhaval Giani (AMD)" <dhaval@...nis.ca>
Subject: [PATCH 1/3] sched/fair: Introduce a new debugfs directory for EEVDF tests

To: Ingo Molnar <mingo@...hat.com>
To: Peter Zijlstra <peterz@...radead.org>
To: Juri Lelli <juri.lelli@...hat.com>
To: Vincent Guittot <vincent.guittot@...aro.org>
To: Dietmar Eggemann <dietmar.eggemann@....com>
To: Steven Rostedt <rostedt@...dmis.org>
To: Ben Segall <bsegall@...gle.com>
To: Mel Gorman <mgorman@...e.de>
To: Valentin Schneider <vschneid@...hat.com>
Cc: linux-kernel@...r.kernel.org
Cc: Dhaval Giani <dhaval.giani@....com>
Cc: Gautham Shenoy <gautham.shenoy@....com>
Cc: K Prateek Nayak <kprateek.nayak@....com>
Signed-off-by: Dhaval Giani (AMD) <dhaval@...nis.ca>
---
 kernel/Kconfig.preempt     |  9 +++++++++
 kernel/sched/Makefile      |  1 +
 kernel/sched/debug.c       |  2 ++
 kernel/sched/eevdf-tests.c | 27 +++++++++++++++++++++++++++
 kernel/sched/sched.h       |  7 +++++++
 5 files changed, 46 insertions(+)

diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
index 54ea59ff8fbeb653b7084a78bd0d933076deaad5..96f47cf498aa10d7cbb375093e5533753ed7a414 100644
--- a/kernel/Kconfig.preempt
+++ b/kernel/Kconfig.preempt
@@ -176,3 +176,12 @@ config SCHED_CLASS_EXT
 	  For more information:
 	    Documentation/scheduler/sched-ext.rst
 	    https://github.com/sched-ext/scx
+
+config SCHED_EEVDF_TESTING
+	bool "EEVDF testing"
+	help
+	  This option is a debug option to test that your changes to the
+	  fair scheduling code do not break EEVDF invariants. There are
+	  controls exposted in debugfs to allow tests to be run. This has a
+	  performance impact, so do not enable unless you are a scheduler
+	  developer and know what you are doing.
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
index 8ae86371ddcddf836172ee93ca34f2e91b4057a7..1a8416b8009ebf7cf38ac7b326f4b6472e62909a 100644
--- a/kernel/sched/Makefile
+++ b/kernel/sched/Makefile
@@ -37,3 +37,4 @@ obj-y += core.o
 obj-y += fair.o
 obj-y += build_policy.o
 obj-y += build_utility.o
+obj-y += eevdf-tests.o
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 557246880a7e0839277df662703b7bfabeb3a497..e61acd5463145e4a54dcc816c1da774922ed0127 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -536,6 +536,8 @@ static __init int sched_init_debug(void)
 
 	debugfs_fair_server_init();
 
+	debugfs_eevdf_testing_init(debugfs_sched);
+
 	return 0;
 }
 late_initcall(sched_init_debug);
diff --git a/kernel/sched/eevdf-tests.c b/kernel/sched/eevdf-tests.c
new file mode 100644
index 0000000000000000000000000000000000000000..3bc016d3025733e53f586e30fcd31f650156d47e
--- /dev/null
+++ b/kernel/sched/eevdf-tests.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (C) 2025 Advanced Micro Devices, Inc
+ *
+ * Author: Dhaval Giani (AMD) <dhaval@...nis.ca>
+ *
+ * Basic functional tests for EEVDF - Invariants
+ *
+ * Use the debugfs triggers to run them
+ *
+ */
+
+#include <linux/debugfs.h>
+#include <linux/sched.h>
+
+#include "sched.h"
+
+#ifdef CONFIG_SCHED_EEVDF_TESTING
+
+static struct dentry *debugfs_eevdf_testing;
+void debugfs_eevdf_testing_init(struct dentry *debugfs_sched)
+{
+	debugfs_eevdf_testing = debugfs_create_dir("eevdf-testing", debugfs_sched);
+
+}
+#endif /* CONFIG_SCHED_EEVDF_TESTING */
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index c5a6a503eb6de3867ea25f13dca3660da2805ff8..09cefe2aa871bbd533a413c76026895e969a58e7 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -44,6 +44,7 @@
 #include <linux/lockdep.h>
 #include <linux/minmax.h>
 #include <linux/mm.h>
+#include <linux/mmu_context.h>
 #include <linux/module.h>
 #include <linux/mutex_api.h>
 #include <linux/plist.h>
@@ -3987,4 +3988,10 @@ void sched_enq_and_set_task(struct sched_enq_and_set_ctx *ctx);
 
 #include "ext.h"
 
+#ifdef CONFIG_SCHED_EEVDF_TESTING
+void debugfs_eevdf_testing_init(struct dentry *debugfs_sched);
+#else /* CONFIG_SCHED_EEVDF_TESTING */
+static inline void init_eevdf_testing_debugfs(struct dentry *debugfs_sched) {}
+#endif /* CONFIG_SCHED_EEVDF_TESTING */
+
 #endif /* _KERNEL_SCHED_SCHED_H */

-- 
2.49.0