v4.19.13 snapshot.
diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
new file mode 100644
index 0000000..4a6582c
--- /dev/null
+++ b/include/linux/sched/isolation.h
@@ -0,0 +1,52 @@
+#ifndef _LINUX_SCHED_ISOLATION_H
+#define _LINUX_SCHED_ISOLATION_H
+
+#include <linux/cpumask.h>
+#include <linux/init.h>
+#include <linux/tick.h>
+
+enum hk_flags {
+ HK_FLAG_TIMER = 1,
+ HK_FLAG_RCU = (1 << 1),
+ HK_FLAG_MISC = (1 << 2),
+ HK_FLAG_SCHED = (1 << 3),
+ HK_FLAG_TICK = (1 << 4),
+ HK_FLAG_DOMAIN = (1 << 5),
+ HK_FLAG_WQ = (1 << 6),
+};
+
+#ifdef CONFIG_CPU_ISOLATION
+DECLARE_STATIC_KEY_FALSE(housekeeping_overriden);
+extern int housekeeping_any_cpu(enum hk_flags flags);
+extern const struct cpumask *housekeeping_cpumask(enum hk_flags flags);
+extern void housekeeping_affine(struct task_struct *t, enum hk_flags flags);
+extern bool housekeeping_test_cpu(int cpu, enum hk_flags flags);
+extern void __init housekeeping_init(void);
+
+#else
+
+static inline int housekeeping_any_cpu(enum hk_flags flags)
+{
+ return smp_processor_id();
+}
+
+static inline const struct cpumask *housekeeping_cpumask(enum hk_flags flags)
+{
+ return cpu_possible_mask;
+}
+
+static inline void housekeeping_affine(struct task_struct *t,
+ enum hk_flags flags) { }
+static inline void housekeeping_init(void) { }
+#endif /* CONFIG_CPU_ISOLATION */
+
+static inline bool housekeeping_cpu(int cpu, enum hk_flags flags)
+{
+#ifdef CONFIG_CPU_ISOLATION
+ if (static_branch_unlikely(&housekeeping_overriden))
+ return housekeeping_test_cpu(cpu, flags);
+#endif
+ return true;
+}
+
+#endif /* _LINUX_SCHED_ISOLATION_H */