From 25f3d7effab632eb10d145f1a5aebf6515a04b98 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 1 Feb 2018 22:05:38 -0800 Subject: rcu: Parallelize expedited grace-period initialization The latency of RCU expedited grace periods grows with increasing numbers of CPUs, eventually failing to be all that expedited. Much of the growth in latency is in the initialization phase, so this commit uses workqueues to carry out this initialization concurrently on a rcu_node-by-rcu_node basis. This change makes use of a new rcu_par_gp_wq because flushing a work item from another work item running from the same workqueue can result in deadlock. Signed-off-by: Paul E. McKenney Tested-by: Nicholas Piggin --- kernel/rcu/rcu.h | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/rcu/rcu.h') diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 7a693e31184a..976019d6fa06 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -486,6 +486,7 @@ void rcu_force_quiescent_state(void); void rcu_bh_force_quiescent_state(void); void rcu_sched_force_quiescent_state(void); extern struct workqueue_struct *rcu_gp_wq; +extern struct workqueue_struct *rcu_par_gp_wq; #endif /* #else #ifdef CONFIG_TINY_RCU */ #ifdef CONFIG_RCU_NOCB_CPU -- cgit v1.2.3