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-rw-r--r--include/linux/sched.h12
1 files changed, 12 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index dc37cbe2b13c..37261afbf16a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -3510,6 +3510,18 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
#endif /* CONFIG_SMP */
+/*
+ * In order to reduce various lock holder preemption latencies provide an
+ * interface to see if a vCPU is currently running or not.
+ *
+ * This allows us to terminate optimistic spin loops and block, analogous to
+ * the native optimistic spin heuristic of testing if the lock owner task is
+ * running or not.
+ */
+#ifndef vcpu_is_preempted
+# define vcpu_is_preempted(cpu) false
+#endif
+
extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
extern long sched_getaffinity(pid_t pid, struct cpumask *mask);