diff options
author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-04-11 10:15:52 -0700 |
---|---|---|
committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-06-10 13:45:52 -0700 |
commit | 2439b696cb5303f1eeb6aeebcee19e0056c3dd6e (patch) | |
tree | d3f58ced257743911040a2cff5b03cd82aacc8a7 | |
parent | 7807acdb6b794b3af42dfa1912edd4fba8d0b622 (diff) |
rcu: Shrink TINY_RCU by moving exit_rcu()
Now that TINY_PREEMPT_RCU is no more, exit_rcu() is always an empty
function. But if TINY_RCU is going to have an empty function, it should
be in include/linux/rcutiny.h, where it does not bloat the kernel.
This commit therefore moves exit_rcu() out of kernel/rcupdate.c to
kernel/rcutree_plugin.h, and places a static inline empty function in
include/linux/rcutiny.h in order to shrink TINY_RCU a bit.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
-rw-r--r-- | include/linux/rcupdate.h | 2 | ||||
-rw-r--r-- | include/linux/rcutiny.h | 4 | ||||
-rw-r--r-- | include/linux/rcutree.h | 2 | ||||
-rw-r--r-- | kernel/rcupdate.c | 26 | ||||
-rw-r--r-- | kernel/rcutree_plugin.h | 26 |
5 files changed, 33 insertions, 27 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 257b50f9d2d..4b14bdc911d 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -240,8 +240,6 @@ static inline void rcu_user_hooks_switch(struct task_struct *prev, struct task_struct *next) { } #endif /* CONFIG_RCU_USER_QS */ -extern void exit_rcu(void); - /** * RCU_NONIDLE - Indicate idle-loop code that needs RCU readers * @a: Code that RCU needs to pay attention to. diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 51230b63be9..e31005ee339 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -119,6 +119,10 @@ static inline void rcu_cpu_stall_reset(void) { } +static inline void exit_rcu(void) +{ +} + #ifdef CONFIG_DEBUG_LOCK_ALLOC extern int rcu_scheduler_active __read_mostly; extern void rcu_scheduler_starting(void); diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 3f1aa8f9866..226169d1bd2 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -85,6 +85,8 @@ extern void rcu_force_quiescent_state(void); extern void rcu_bh_force_quiescent_state(void); extern void rcu_sched_force_quiescent_state(void); +extern void exit_rcu(void); + extern void rcu_scheduler_starting(void); extern int rcu_scheduler_active __read_mostly; diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 48ab70384a4..0be1fa2ea52 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -104,31 +104,7 @@ void __rcu_read_unlock(void) } EXPORT_SYMBOL_GPL(__rcu_read_unlock); -/* - * Check for a task exiting while in a preemptible-RCU read-side - * critical section, clean up if so. No need to issue warnings, - * as debug_check_no_locks_held() already does this if lockdep - * is enabled. - */ -void exit_rcu(void) -{ - struct task_struct *t = current; - - if (likely(list_empty(¤t->rcu_node_entry))) - return; - t->rcu_read_lock_nesting = 1; - barrier(); - t->rcu_read_unlock_special = RCU_READ_UNLOCK_BLOCKED; - __rcu_read_unlock(); -} - -#else /* #ifdef CONFIG_PREEMPT_RCU */ - -void exit_rcu(void) -{ -} - -#endif /* #else #ifdef CONFIG_PREEMPT_RCU */ +#endif /* #ifdef CONFIG_PREEMPT_RCU */ #ifdef CONFIG_DEBUG_LOCK_ALLOC static struct lock_class_key rcu_lock_key; diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 207844ea022..de701bbdb62 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -932,6 +932,24 @@ static void __init __rcu_init_preempt(void) rcu_init_one(&rcu_preempt_state, &rcu_preempt_data); } +/* + * Check for a task exiting while in a preemptible-RCU read-side + * critical section, clean up if so. No need to issue warnings, + * as debug_check_no_locks_held() already does this if lockdep + * is enabled. + */ +void exit_rcu(void) +{ + struct task_struct *t = current; + + if (likely(list_empty(¤t->rcu_node_entry))) + return; + t->rcu_read_lock_nesting = 1; + barrier(); + t->rcu_read_unlock_special = RCU_READ_UNLOCK_BLOCKED; + __rcu_read_unlock(); +} + #else /* #ifdef CONFIG_TREE_PREEMPT_RCU */ static struct rcu_state *rcu_state = &rcu_sched_state; @@ -1100,6 +1118,14 @@ static void __init __rcu_init_preempt(void) { } +/* + * Because preemptible RCU does not exist, tasks cannot possibly exit + * while in preemptible RCU read-side critical sections. + */ +void exit_rcu(void) +{ +} + #endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */ #ifdef CONFIG_RCU_BOOST |