From 9dd8fb16c36178df2066387d2abd44d8b4dca8c8 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 13 Apr 2012 12:54:22 -0700 Subject: rcu: Make exit_rcu() more precise and consolidate When running preemptible RCU, if a task exits in an RCU read-side critical section having blocked within that same RCU read-side critical section, the task must be removed from the list of tasks blocking a grace period (perhaps the current grace period, perhaps the next grace period, depending on timing). The exit() path invokes exit_rcu() to do this cleanup. However, the current implementation of exit_rcu() needlessly does the cleanup even if the task did not block within the current RCU read-side critical section, which wastes time and needlessly increases the size of the state space. Fix this by only doing the cleanup if the current task is actually on the list of tasks blocking some grace period. While we are at it, consolidate the two identical exit_rcu() functions into a single function. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Tested-by: Linus Torvalds Conflicts: kernel/rcupdate.c --- include/linux/rcutree.h | 12 ------------ 1 file changed, 12 deletions(-) (limited to 'include/linux/rcutree.h') diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index e8ee5dd0854c..782a8ab51bc1 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -45,18 +45,6 @@ static inline void rcu_virt_note_context_switch(int cpu) rcu_note_context_switch(cpu); } -#ifdef CONFIG_TREE_PREEMPT_RCU - -extern void exit_rcu(void); - -#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */ - -static inline void exit_rcu(void) -{ -} - -#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */ - extern void synchronize_rcu_bh(void); extern void synchronize_sched_expedited(void); extern void synchronize_rcu_expedited(void); -- cgit v1.2.3