diff options
| -rw-r--r-- | include/linux/rcupdate.h | 8 | ||||
| -rw-r--r-- | include/linux/rcutiny.h | 9 | ||||
| -rw-r--r-- | include/linux/rcutree.h | 2 | ||||
| -rw-r--r-- | kernel/rcutiny.c | 4 | ||||
| -rw-r--r-- | kernel/rcutree.c | 13 |
5 files changed, 30 insertions, 6 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index f1f1bc39346b..a53a21a2808c 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -261,6 +261,10 @@ static inline void rcu_user_hooks_switch(struct task_struct *prev, rcu_irq_exit(); \ } while (0) +#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP) +extern int rcu_is_cpu_idle(void); +#endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP) */ + /* * Infrastructure to implement the synchronize_() primitives in * TREE_RCU and rcu_barrier_() primitives in TINY_RCU. @@ -297,10 +301,6 @@ static inline void destroy_rcu_head_on_stack(struct rcu_head *head) } #endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */ -#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SMP) -extern int rcu_is_cpu_idle(void); -#endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SMP) */ - #if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU) bool rcu_lockdep_current_cpu_online(void); #else /* #if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU) */ diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index e31005ee339e..bee665964878 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -132,4 +132,13 @@ static inline void rcu_scheduler_starting(void) } #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ +#ifdef CONFIG_RCU_TRACE + +static inline bool __rcu_is_watching(void) +{ + return !rcu_is_cpu_idle(); +} + +#endif /* #ifdef CONFIG_RCU_TRACE */ + #endif /* __LINUX_RCUTINY_H */ diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 226169d1bd2b..293613dfd2a5 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -90,4 +90,6 @@ extern void exit_rcu(void); extern void rcu_scheduler_starting(void); extern int rcu_scheduler_active __read_mostly; +extern bool __rcu_is_watching(void); + #endif /* __LINUX_RCUTREE_H */ diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c index 9ed6075dc562..b4bc61874d77 100644 --- a/kernel/rcutiny.c +++ b/kernel/rcutiny.c @@ -174,7 +174,7 @@ void rcu_irq_enter(void) } EXPORT_SYMBOL_GPL(rcu_irq_enter); -#ifdef CONFIG_DEBUG_LOCK_ALLOC +#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) /* * Test whether RCU thinks that the current CPU is idle. @@ -185,7 +185,7 @@ int rcu_is_cpu_idle(void) } EXPORT_SYMBOL(rcu_is_cpu_idle); -#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ +#endif /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */ /* * Test whether the current CPU was interrupted from idle. Nested diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 32618b3fe4e6..910d868808dc 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -671,6 +671,19 @@ int rcu_is_cpu_idle(void) } EXPORT_SYMBOL(rcu_is_cpu_idle); +/** + * __rcu_is_watching - are RCU read-side critical sections safe? + * + * Return true if RCU is watching the running CPU, which means that + * this CPU can safely enter RCU read-side critical sections. Unlike + * rcu_is_cpu_idle(), the caller of __rcu_is_watching() must have at + * least disabled preemption. + */ +bool __rcu_is_watching(void) +{ + return !!(atomic_read(this_cpu_ptr(&rcu_dynticks.dynticks)) & 0x1); +} + #if defined(CONFIG_PROVE_RCU) && defined(CONFIG_HOTPLUG_CPU) /* |