From 127781d1ba1ee5bbe1780afa35dd0e71583b143d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 27 Mar 2013 08:44:00 -0700 Subject: rcu: Remove TINY_PREEMPT_RCU TINY_PREEMPT_RCU adds significant code and complexity, but does not offer commensurate benefits. People currently using TINY_PREEMPT_RCU can get much better memory footprint with TINY_RCU, or, if they really need preemptible RCU, they can use TREE_PREEMPT_RCU with a relatively minor degradation in memory footprint. Please note that this move has been widely publicized on LKML (https://lkml.org/lkml/2012/11/12/545) and on LWN (http://lwn.net/Articles/541037/). This commit therefore removes TINY_PREEMPT_RCU. Signed-off-by: Paul E. McKenney [ paulmck: Updated to eliminate #else in rcutiny.h as suggested by Josh ] Reviewed-by: Josh Triplett --- include/linux/rcupdate.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/rcupdate.h') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index ddcc7826d907..70b1522badd3 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -277,7 +277,7 @@ void wait_rcu_gp(call_rcu_func_t crf); #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU) #include -#elif defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU) +#elif defined(CONFIG_TINY_RCU) #include #else #error "Unknown RCU implementation specified to kernel configuration" -- cgit v1.2.3 From 9dc5ad32488a75504349372330cc228d4dd678db Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 27 Mar 2013 10:11:15 -0700 Subject: rcu: Simplify RCU_TINY RCU callback invocation TINY_PREEMPT_RCU could use a kthread to handle RCU callback invocation, which required an API to abstract kthread vs. softirq invocation. Now that TINY_PREEMPT_RCU is no longer with us, this commit retires this API in favor of direct use of the relevant softirq primitives. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- include/linux/rcupdate.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/rcupdate.h') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 70b1522badd3..257b50f9d2dc 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -216,6 +216,7 @@ static inline int rcu_preempt_depth(void) #endif /* #else #ifdef CONFIG_PREEMPT_RCU */ /* Internal to kernel */ +extern void rcu_init(void); extern void rcu_sched_qs(int cpu); extern void rcu_bh_qs(int cpu); extern void rcu_check_callbacks(int cpu, int user); -- cgit v1.2.3 From 2439b696cb5303f1eeb6aeebcee19e0056c3dd6e Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 11 Apr 2013 10:15:52 -0700 Subject: 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 Reviewed-by: Josh Triplett --- include/linux/rcupdate.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux/rcupdate.h') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 257b50f9d2dc..4b14bdc911d7 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. -- cgit v1.2.3