rcu: Remove !PREEMPT code from rcu_note_voluntary_context_switch() (4d232dfe) · Commits · 戴 / test

Because RCU-tasks exists only in PREEMPT kernels and because RCU-sched no longer exists in PREEMPT kernels, it is no longer necessary for the rcu_note_voluntary_context_switch() macro to do anything for !PREEMPT kernels. This commit therefore removes !PREEMPT-related code from this macro, namely, the rcu_all_qs(). Signed-off-by:

Paul E. McKenney <paulmck@linux.vnet.ibm.com>

include/linux/rcupdate.h

+2 −6

Original line number	Diff line number	Diff line
		@@ -150,18 +150,14 @@ static inline void rcu_init_nohz(void) { }
		if (READ_ONCE((t)->rcu_tasks_holdout)) \
		WRITE_ONCE((t)->rcu_tasks_holdout, false); \
		} while (0)
		#define rcu_note_voluntary_context_switch(t) \
		do { \
		rcu_all_qs(); \
		rcu_tasks_qs(t); \
		} while (0)
		#define rcu_note_voluntary_context_switch(t) rcu_tasks_qs(t)
		void call_rcu_tasks(struct rcu_head *head, rcu_callback_t func);
		void synchronize_rcu_tasks(void);
		void exit_tasks_rcu_start(void);
		void exit_tasks_rcu_finish(void);
		#else /* #ifdef CONFIG_TASKS_RCU */
		#define rcu_tasks_qs(t) do { } while (0)
		#define rcu_note_voluntary_context_switch(t) rcu_all_qs()
		#define rcu_note_voluntary_context_switch(t) do { } while (0)
		#define call_rcu_tasks call_rcu
		#define synchronize_rcu_tasks synchronize_rcu
		static inline void exit_tasks_rcu_start(void) { }

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