Commit 417e8d26 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Eliminate redundant rcu_sysidle_state variable 



Now that we have rcu_state_p, which references rcu_preempt_state for
TREE_PREEMPT_RCU and rcu_sched_state for TREE_RCU, we don't need a
separate rcu_sysidle_state variable.  This commit therefore eliminates
rcu_preempt_state in favor of rcu_state_p.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarPranith Kumar <bobby.prani@gmail.com>
Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Tested-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
parent 22c2f669

kernel/rcu/tree_plugin.h

+6 −17
Original line number Diff line number Diff line
@@ -2690,16 +2690,6 @@ static void __maybe_unused rcu_kick_nohz_cpu(int cpu) 


#ifdef CONFIG_NO_HZ_FULL_SYSIDLE



/*

 * Define RCU flavor that holds sysidle state.  This needs to be the

 * most active flavor of RCU.

 */

#ifdef CONFIG_PREEMPT_RCU

static struct rcu_state *rcu_sysidle_state = &rcu_preempt_state;

#else /* #ifdef CONFIG_PREEMPT_RCU */

static struct rcu_state *rcu_sysidle_state = &rcu_sched_state;

#endif /* #else #ifdef CONFIG_PREEMPT_RCU */



static int full_sysidle_state;		/* Current system-idle state. */

#define RCU_SYSIDLE_NOT		0	/* Some CPU is not idle. */

#define RCU_SYSIDLE_SHORT	1	/* All CPUs idle for brief period. */
@@ -2841,7 +2831,7 @@ static void rcu_sysidle_check_cpu(struct rcu_data *rdp, bool *isidle, 
	 * not the flavor of RCU that tracks sysidle state, or if this

	 * is an offline or the timekeeping CPU, nothing to do.

	 */

	if (!*isidle || rdp->rsp != rcu_sysidle_state ||

	if (!*isidle || rdp->rsp != rcu_state_p ||

	    cpu_is_offline(rdp->cpu) || rdp->cpu == tick_do_timer_cpu)

		return;

	if (rcu_gp_in_progress(rdp->rsp))
@@ -2867,7 +2857,7 @@ static void rcu_sysidle_check_cpu(struct rcu_data *rdp, bool *isidle, 
 */

static bool is_sysidle_rcu_state(struct rcu_state *rsp)

{

	return rsp == rcu_sysidle_state;

	return rsp == rcu_state_p;

}



/*
@@ -2945,7 +2935,7 @@ static void rcu_sysidle_cancel(void) 
static void rcu_sysidle_report(struct rcu_state *rsp, int isidle,

			       unsigned long maxj, bool gpkt)

{

	if (rsp != rcu_sysidle_state)

	if (rsp != rcu_state_p)

		return;  /* Wrong flavor, ignore. */

	if (gpkt && nr_cpu_ids <= CONFIG_NO_HZ_FULL_SYSIDLE_SMALL)

		return;  /* Running state machine from timekeeping CPU. */
@@ -3014,13 +3004,12 @@ bool rcu_sys_is_idle(void) 


			/* Scan all the CPUs looking for nonidle CPUs. */

			for_each_possible_cpu(cpu) {

				rdp = per_cpu_ptr(rcu_sysidle_state->rda, cpu);

				rdp = per_cpu_ptr(rcu_state_p->rda, cpu);

				rcu_sysidle_check_cpu(rdp, &isidle, &maxj);

				if (!isidle)

					break;

			}

			rcu_sysidle_report(rcu_sysidle_state,

					   isidle, maxj, false);

			rcu_sysidle_report(rcu_state_p, isidle, maxj, false);

			oldrss = rss;

			rss = ACCESS_ONCE(full_sysidle_state);

		}
@@ -3047,7 +3036,7 @@ bool rcu_sys_is_idle(void) 
	 * provided by the memory allocator.

	 */

	if (nr_cpu_ids > CONFIG_NO_HZ_FULL_SYSIDLE_SMALL &&

	    !rcu_gp_in_progress(rcu_sysidle_state) &&

	    !rcu_gp_in_progress(rcu_state_p) &&

	    !rsh.inuse && xchg(&rsh.inuse, 1) == 0)

		call_rcu(&rsh.rh, rcu_sysidle_cb);

	return false;

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