From 5f52bbf2f6e0997394cf9c449d44e1c80ff4282c Mon Sep 17 00:00:00 2001
From: Andrea Righi <arighi@nvidia.com>
Date: Sat, 25 Jan 2025 18:14:12 +0100
Subject: [PATCH] tools/sched_ext: Add helper to check task migration state
Introduce a new helper for BPF schedulers to determine whether a task
can migrate or not (supporting both SMP and UP systems).
Fixes: e9fe182772dc ("sched_ext: selftests/dsp_local_on: Fix sporadic failures")
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
tools/sched_ext/include/scx/common.bpf.h | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/tools/sched_ext/include/scx/common.bpf.h b/tools/sched_ext/include/scx/common.bpf.h
index f3e15e9efa76..f254a39b86a5 100644
--- a/tools/sched_ext/include/scx/common.bpf.h
+++ b/tools/sched_ext/include/scx/common.bpf.h
@@ -404,6 +404,17 @@ static __always_inline const struct cpumask *cast_mask(struct bpf_cpumask *mask)
return (const struct cpumask *)mask;
}
+/*
+ * Return true if task @p cannot migrate to a different CPU, false
+ * otherwise.
+ */
+static inline bool is_migration_disabled(const struct task_struct *p)
+{
+ if (bpf_core_field_exists(p->migration_disabled))
+ return p->migration_disabled;
+ return false;
+}
+
/* rcu */
void bpf_rcu_read_lock(void) __ksym;
void bpf_rcu_read_unlock(void) __ksym;