sched-migrate-disable.patch

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 18 insertions, 3 deletions

diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index f237ebd..fbf934b 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -130,6 +130,14 @@ do { \
 
 #endif /* CONFIG_PREEMPT_COUNT */
 
+#ifdef CONFIG_SMP
+extern void migrate_disable(void);
+extern void migrate_enable(void);
+#else
+# define migrate_disable()		barrier()
+# define migrate_enable()		barrier()
+#endif
+
 #ifdef CONFIG_PREEMPT_RT_FULL
 # define preempt_disable_rt()		preempt_disable()
 # define preempt_enable_rt()		preempt_enable()
diff --git a/include/linux/sched.h b/include/linux/sched.h
index bf1cf6d..9861c9b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1063,6 +1063,7 @@ struct task_struct {
 #endif
 
 	unsigned int policy;
+	int migrate_disable;
 	int nr_cpus_allowed;
 	cpumask_t cpus_allowed;
 
@@ -1436,9 +1437,6 @@ struct task_struct {
 #endif
 };
 
-/* Future-safe accessor for struct task_struct's cpus_allowed. */
-#define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
-
 #ifdef CONFIG_NUMA_BALANCING
 extern void task_numa_fault(int node, int pages, bool migrated);
 extern void set_numabalancing_state(bool enabled);
@@ -2734,6 +2732,15 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
 
 #endif /* CONFIG_SMP */
 
+/* Future-safe accessor for struct task_struct's cpus_allowed. */
+static inline const struct cpumask *tsk_cpus_allowed(struct task_struct *p)
+{
+	if (p->migrate_disable)
+		return cpumask_of(task_cpu(p));
+
+	return &p->cpus_allowed;
+}
+
 extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
 extern long sched_getaffinity(pid_t pid, struct cpumask *mask);