Commit 9424b867 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Eliminate rcu_implicit_dynticks_qs() local variable ruqp 



The rcu_implicit_dynticks_qs() function's local variable ruqp references
the ->rcu_urgent_qs field in the rcu_data structure referenced by the
function parameter rdp, with a rather odd method for computing the
pointer to this field.  This commit therefore simplifies things and
saves a couple of lines of code by replacing each instance of ruqp with
&rdp->need_heavy_qs.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 88ee23ef

kernel/rcu/tree.c

+3 −5
Original line number Diff line number Diff line
@@ -1219,7 +1219,6 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp) 
static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)

{

	unsigned long jtsq;

	bool *ruqp;

	struct rcu_node *rnp = rdp->mynode;



	/*
@@ -1284,16 +1283,15 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) 
	 * is set way high.

	 */

	jtsq = READ_ONCE(jiffies_to_sched_qs);

	ruqp = per_cpu_ptr(&rcu_data.rcu_urgent_qs, rdp->cpu);

	if (!READ_ONCE(rdp->rcu_need_heavy_qs) &&

	    (time_after(jiffies, rcu_state.gp_start + jtsq * 2) ||

	     time_after(jiffies, rcu_state.jiffies_resched) ||

	     rcu_state.cbovld)) {

		WRITE_ONCE(rdp->rcu_need_heavy_qs, true);

		/* Store rcu_need_heavy_qs before rcu_urgent_qs. */

		smp_store_release(ruqp, true);

		smp_store_release(&rdp->rcu_urgent_qs, true);

	} else if (time_after(jiffies, rcu_state.gp_start + jtsq)) {

		WRITE_ONCE(*ruqp, true);

		WRITE_ONCE(rdp->rcu_urgent_qs, true);

	}



	/*
@@ -1307,7 +1305,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) 
	if (tick_nohz_full_cpu(rdp->cpu) &&

	    (time_after(jiffies, READ_ONCE(rdp->last_fqs_resched) + jtsq * 3) ||

	     rcu_state.cbovld)) {

		WRITE_ONCE(*ruqp, true);

		WRITE_ONCE(rdp->rcu_urgent_qs, true);

		resched_cpu(rdp->cpu);

		WRITE_ONCE(rdp->last_fqs_resched, jiffies);

	}