1 files changed, 100 insertions, 0 deletions
diff --git a/tools/testing/selftests/sched_ext/numa.bpf.c b/tools/testing/selftests/sched_ext/numa.bpf.c
new file mode 100644
index 000000000000..a79d86ed54a1
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/numa.bpf.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * A scheduler that validates the behavior of the NUMA-aware
+ * functionalities.
+ *
+ * The scheduler creates a separate DSQ for each NUMA node, ensuring tasks
+ * are exclusively processed by CPUs within their respective nodes. Idle
+ * CPUs are selected only within the same node, so task migration can only
+ * occurs between CPUs belonging to the same node.
+ *
+ * Copyright (c) 2025 Andrea Righi <arighi@nvidia.com>
+ */
+
+#include <scx/common.bpf.h>
+
+char _license[] SEC("license") = "GPL";
+
+UEI_DEFINE(uei);
+
+const volatile unsigned int __COMPAT_SCX_PICK_IDLE_IN_NODE;
+
+static bool is_cpu_idle(s32 cpu, int node)
+{
+	const struct cpumask *idle_cpumask;
+	bool idle;
+
+	idle_cpumask = __COMPAT_scx_bpf_get_idle_cpumask_node(node);
+	idle = bpf_cpumask_test_cpu(cpu, idle_cpumask);
+	scx_bpf_put_cpumask(idle_cpumask);
+
+	return idle;
+}
+
+s32 BPF_STRUCT_OPS(numa_select_cpu,
+		   struct task_struct *p, s32 prev_cpu, u64 wake_flags)
+{
+	int node = __COMPAT_scx_bpf_cpu_node(scx_bpf_task_cpu(p));
+	s32 cpu;
+
+	/*
+	 * We could just use __COMPAT_scx_bpf_pick_any_cpu_node() here,
+	 * since it already tries to pick an idle CPU within the node
+	 * first, but let's use both functions for better testing coverage.
+	 */
+	cpu = __COMPAT_scx_bpf_pick_idle_cpu_node(p->cpus_ptr, node,
+					__COMPAT_SCX_PICK_IDLE_IN_NODE);
+	if (cpu < 0)
+		cpu = __COMPAT_scx_bpf_pick_any_cpu_node(p->cpus_ptr, node,
+						__COMPAT_SCX_PICK_IDLE_IN_NODE);
+
+	if (is_cpu_idle(cpu, node))
+		scx_bpf_error("CPU %d should be marked as busy", cpu);
+
+	if (__COMPAT_scx_bpf_cpu_node(cpu) != node)
+		scx_bpf_error("CPU %d should be in node %d", cpu, node);
+
+	return cpu;
+}
+
+void BPF_STRUCT_OPS(numa_enqueue, struct task_struct *p, u64 enq_flags)
+{
+	int node = __COMPAT_scx_bpf_cpu_node(scx_bpf_task_cpu(p));
+
+	scx_bpf_dsq_insert(p, node, SCX_SLICE_DFL, enq_flags);
+}
+
+void BPF_STRUCT_OPS(numa_dispatch, s32 cpu, struct task_struct *prev)
+{
+	int node = __COMPAT_scx_bpf_cpu_node(cpu);
+
+	scx_bpf_dsq_move_to_local(node);
+}
+
+s32 BPF_STRUCT_OPS_SLEEPABLE(numa_init)
+{
+	int node, err;
+
+	bpf_for(node, 0, __COMPAT_scx_bpf_nr_node_ids()) {
+		err = scx_bpf_create_dsq(node, node);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+void BPF_STRUCT_OPS(numa_exit, struct scx_exit_info *ei)
+{
+	UEI_RECORD(uei, ei);
+}
+
+SEC(".struct_ops.link")
+struct sched_ext_ops numa_ops = {
+	.select_cpu		= (void *)numa_select_cpu,
+	.enqueue		= (void *)numa_enqueue,
+	.dispatch		= (void *)numa_dispatch,
+	.init			= (void *)numa_init,
+	.exit			= (void *)numa_exit,
+	.name			= "numa",
+};