rcu: Inline rcu_preempt_do_callback() into its sole caller (be01b4ca) · Commits · 戴 / test

The rcu_preempt_do_callbacks() function was introduced in commit (rcu: Use softirq to address performance regression), where it was necessary to handle kernel builds both containing and not containing RCU-preempt. Since then, various changes (most notably ("rcu: use softirq instead of kthreads except when RCU_BOOST=y")) have resulted in this function being invoked only from rcu_kthread_do_work(), which is present only in kernels containing RCU-preempt, which in turn means that the rcu_preempt_do_callbacks() function is no longer needed. This commit therefore inlines rcu_preempt_do_callbacks() into its sole remaining caller and also removes the rcu_state_p and rcu_data_p indirection for added clarity. Signed-off-by:

Byungchul Park <byungchul.park@lge.com> Reviewed-by:

Steven Rostedt (VMware) <rostedt@goodmis.org> [ paulmck: Remove the rcu_state_p and rcu_data_p indirection. ] Signed-off-by:

Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by:

Nicholas Piggin <npiggin@gmail.com>

kernel/rcu/tree.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -438,7 +438,6 @@ static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
		static void invoke_rcu_callbacks_kthread(void);
		static bool rcu_is_callbacks_kthread(void);
		#ifdef CONFIG_RCU_BOOST
		static void rcu_preempt_do_callbacks(void);
		static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
		struct rcu_node *rnp);
		#endif /* #ifdef CONFIG_RCU_BOOST */

kernel/rcu/tree_plugin.h

+1 −10

Original line number	Diff line number	Diff line
		@@ -685,15 +685,6 @@ static void rcu_preempt_check_callbacks(void)
		t->rcu_read_unlock_special.b.need_qs = true;
		}

		#ifdef CONFIG_RCU_BOOST

		static void rcu_preempt_do_callbacks(void)
		{
		rcu_do_batch(rcu_state_p, this_cpu_ptr(rcu_data_p));
		}

		#endif /* #ifdef CONFIG_RCU_BOOST */

		/**
		* call_rcu() - Queue an RCU callback for invocation after a grace period.
		* @head: structure to be used for queueing the RCU updates.
		@@ -1140,7 +1131,7 @@ static void rcu_kthread_do_work(void)
		{
		rcu_do_batch(&rcu_sched_state, this_cpu_ptr(&rcu_sched_data));
		rcu_do_batch(&rcu_bh_state, this_cpu_ptr(&rcu_bh_data));
		rcu_preempt_do_callbacks();
		rcu_do_batch(&rcu_preempt_state, this_cpu_ptr(&rcu_preempt_data));
		}

		static void rcu_cpu_kthread_setup(unsigned int cpu)

Admin message