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Commit 398953e6 authored by Lihao Liang's avatar Lihao Liang Committed by Paul E. McKenney
Browse files

rcu: Remove unnecessary spinlock in rcu_boot_init_percpu_data() 



Since rcu_boot_init_percpu_data() is only called at boot time,
there is no data race and spinlock is not needed.

Signed-off-by: default avatarLihao Liang <lianglihao@huawei.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 7928b2cb

kernel/rcu/tree.c

+0 −4
Original line number Diff line number Diff line
@@ -3636,12 +3636,9 @@ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf) 
static void __init

rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)

{

	unsigned long flags;

	struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);

	struct rcu_node *rnp = rcu_get_root(rsp);



	/* Set up local state, ensuring consistent view of global state. */

	raw_spin_lock_irqsave_rcu_node(rnp, flags);

	rdp->grpmask = leaf_node_cpu_bit(rdp->mynode, cpu);

	rdp->dynticks = &per_cpu(rcu_dynticks, cpu);

	WARN_ON_ONCE(rdp->dynticks->dynticks_nesting != 1);
@@ -3649,7 +3646,6 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp) 
	rdp->cpu = cpu;

	rdp->rsp = rsp;

	rcu_boot_init_nocb_percpu_data(rdp);

	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);

}



/*