From 45975c7d21a1c0aba97e3d8007e2a7c123145748 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 2 Jul 2018 14:30:37 -0700 Subject: rcu: Define RCU-sched API in terms of RCU for Tree RCU PREEMPT builds Now that RCU-preempt knows about preemption disabling, its implementation of synchronize_rcu() works for synchronize_sched(), and likewise for the other RCU-sched update-side API members. This commit therefore confines the RCU-sched update-side code to CONFIG_PREEMPT=n builds, and defines RCU-sched's update-side API members in terms of those of RCU-preempt. This means that any given build of the Linux kernel has only one update-side flavor of RCU, namely RCU-preempt for CONFIG_PREEMPT=y builds and RCU-sched for CONFIG_PREEMPT=n builds. This in turn means that kernels built with CONFIG_RCU_NOCB_CPU=y have only one rcuo kthread per CPU. Signed-off-by: Paul E. McKenney Cc: Andi Kleen --- kernel/rcu/tree.h | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) (limited to 'kernel/rcu/tree.h') diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index e02c882861eb..38658ca87dcb 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -225,9 +225,6 @@ struct rcu_data { /* 5) _rcu_barrier(), OOM callbacks, and expediting. */ struct rcu_head barrier_head; -#ifdef CONFIG_RCU_FAST_NO_HZ - struct rcu_head oom_head; -#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ int exp_dynticks_snap; /* Double-check need for IPI. */ /* 6) Callback offloading. */ @@ -433,8 +430,7 @@ DECLARE_PER_CPU(char, rcu_cpu_has_work); /* Forward declarations for rcutree_plugin.h */ static void rcu_bootup_announce(void); -static void rcu_preempt_qs(void); -static void rcu_preempt_note_context_switch(bool preempt); +static void rcu_qs(void); static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp); #ifdef CONFIG_HOTPLUG_CPU static bool rcu_preempt_has_tasks(struct rcu_node *rnp); @@ -444,9 +440,8 @@ static int rcu_print_task_stall(struct rcu_node *rnp); static int rcu_print_task_exp_stall(struct rcu_node *rnp); static void rcu_preempt_check_blocked_tasks(struct rcu_state *rsp, struct rcu_node *rnp); -static void rcu_preempt_check_callbacks(void); +static void rcu_flavor_check_callbacks(int user); void call_rcu(struct rcu_head *head, rcu_callback_t func); -static void __init __rcu_init_preempt(void); static void dump_blkd_tasks(struct rcu_state *rsp, struct rcu_node *rnp, int ncheck); static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags); -- cgit v1.2.3