migrate_disable() is called to disable migration in the kernel, and it is
used togather with rcu_read_lock() oftenly.
However, with PREEMPT_RCU disabled, it's unnecessary, as rcu_read_lock()
will disable preemption, which will also disable migration.
Introduce rcu_migrate_enable() and rcu_migrate_disable(), which will do
the migration enable and disable only when the rcu_read_lock() can't do
it.
Signed-off-by: Menglong Dong <dongml2@xxxxxxxxxxxxxxx>
---
include/linux/rcupdate.h | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 120536f4c6eb..0d9dbd90d025 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -72,6 +72,16 @@ static inline bool same_state_synchronize_rcu(unsigned long oldstate1, unsigned
void __rcu_read_lock(void);
void __rcu_read_unlock(void);
+static inline void rcu_migrate_enable(void)
+{
+ migrate_enable();
+}
+
+static inline void rcu_migrate_disable(void)
+{
+ migrate_disable();
+}
+
/*
* Defined as a macro as it is a very low level header included from
* areas that don't even know about current. This gives the rcu_read_lock()
@@ -105,6 +115,14 @@ static inline int rcu_preempt_depth(void)
return 0;
}
+static inline void rcu_migrate_enable(void)
+{
+}
+
+static inline void rcu_migrate_disable(void)
+{
+}
+
#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
#ifdef CONFIG_RCU_LAZY
--
2.50.1
