rcu: Move _rcu_barrier()'s rcu_head structures to rcu_data structures (06668efa) · Commits · 戴 / test

In order for multiple flavors of RCU to each concurrently run one rcu_barrier(), each flavor needs its own per-CPU set of rcu_head structures. This commit therefore moves _rcu_barrier()'s set of per-CPU rcu_head structures from per-CPU variables to the existing per-CPU and per-RCU-flavor rcu_data structures. Signed-off-by:

Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by:

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

Josh Triplett <josh@joshtriplett.org>

kernel/rcutree.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -157,7 +157,6 @@ unsigned long rcutorture_vernum;

		/* State information for rcu_barrier() and friends. */

		static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL};
		static atomic_t rcu_barrier_cpu_count;
		static DEFINE_MUTEX(rcu_barrier_mutex);
		static struct completion rcu_barrier_completion;
		@@ -2282,12 +2281,11 @@ static void rcu_barrier_callback(struct rcu_head *notused)
		*/
		static void rcu_barrier_func(void *type)
		{
		int cpu = smp_processor_id();
		struct rcu_head *head = &per_cpu(rcu_barrier_head, cpu);
		struct rcu_state *rsp = type;
		struct rcu_data *rdp = __this_cpu_ptr(rsp->rda);

		atomic_inc(&rcu_barrier_cpu_count);
		rsp->call(head, rcu_barrier_callback);
		rsp->call(&rdp->barrier_head, rcu_barrier_callback);
		}

		/*

kernel/rcutree.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -314,6 +314,9 @@ struct rcu_data {
		unsigned long n_rp_need_fqs;
		unsigned long n_rp_need_nothing;

		/* 6) _rcu_barrier() callback. */
		struct rcu_head barrier_head;

		int cpu;
		struct rcu_state *rsp;
		};

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