Commit f759081e authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu/nocb: Code-style nits in callback-offloading toggling 



This commit addresses a few code-style nits in callback-offloading
toggling, including one that predates this toggling.

Cc: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 3d0cef50

kernel/rcu/rcu_segcblist.h

+6 −13
Original line number Diff line number Diff line
@@ -80,17 +80,12 @@ static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp) 
	return rcu_segcblist_test_flags(rsclp, SEGCBLIST_ENABLED);

}



/* Is the specified rcu_segcblist offloaded?  */

/* Is the specified rcu_segcblist offloaded, or is SEGCBLIST_SOFTIRQ_ONLY set? */

static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)

{

	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU)) {

		/*

		 * Complete de-offloading happens only when SEGCBLIST_SOFTIRQ_ONLY

		 * is set.

		 */

		if (!rcu_segcblist_test_flags(rsclp, SEGCBLIST_SOFTIRQ_ONLY))

	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&

	    !rcu_segcblist_test_flags(rsclp, SEGCBLIST_SOFTIRQ_ONLY))

		return true;

	}



	return false;

}
@@ -99,10 +94,8 @@ static inline bool rcu_segcblist_completely_offloaded(struct rcu_segcblist *rscl 
{

	int flags = SEGCBLIST_KTHREAD_CB | SEGCBLIST_KTHREAD_GP | SEGCBLIST_OFFLOADED;



	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU)) {

		if ((rsclp->flags & flags) == flags)

	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) && (rsclp->flags & flags) == flags)

		return true;

	}



	return false;

}

kernel/rcu/rcutorture.c

+1 −1
Original line number Diff line number Diff line
@@ -1606,7 +1606,7 @@ rcu_torture_stats_print(void) 
		data_race(n_barrier_successes),

		data_race(n_barrier_attempts),

		data_race(n_rcu_torture_barrier_error));

	pr_cont("read-exits: %ld ", data_race(n_read_exits));

	pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic.

	pr_cont("nocb-toggles: %ld:%ld\n",

		atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload));

kernel/rcu/tree_plugin.h

+22 −23
Original line number Diff line number Diff line
@@ -1962,7 +1962,8 @@ static inline bool nocb_gp_update_state(struct rcu_data *rdp, bool *needwake_sta 
				*needwake_state = true;

		}

		return true;

	} else {

	}



	/*

	 * De-offloading. Clear our flag and notify the de-offload worker.

	 * We will ignore this rdp until it ever gets re-offloaded.
@@ -1973,7 +1974,6 @@ static inline bool nocb_gp_update_state(struct rcu_data *rdp, bool *needwake_sta 
		*needwake_state = true;

	return false;

}

}





/*
@@ -2005,6 +2005,7 @@ static void nocb_gp_wait(struct rcu_data *my_rdp) 
	WARN_ON_ONCE(my_rdp->nocb_gp_rdp != my_rdp);

	for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_cb_rdp) {

		bool needwake_state = false;



		if (!nocb_gp_enabled_cb(rdp))

			continue;

		trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("Check"));
@@ -2160,11 +2161,11 @@ static inline bool nocb_cb_wait_cond(struct rcu_data *rdp) 
static void nocb_cb_wait(struct rcu_data *rdp)

{

	struct rcu_segcblist *cblist = &rdp->cblist;

	struct rcu_node *rnp = rdp->mynode;

	bool needwake_state = false;

	bool needwake_gp = false;

	unsigned long cur_gp_seq;

	unsigned long flags;

	bool needwake_state = false;

	bool needwake_gp = false;

	struct rcu_node *rnp = rdp->mynode;



	local_irq_save(flags);

	rcu_momentary_dyntick_idle();
@@ -2217,8 +2218,8 @@ static void nocb_cb_wait(struct rcu_data *rdp) 
		swait_event_interruptible_exclusive(rdp->nocb_cb_wq,

						    nocb_cb_wait_cond(rdp));



		/* ^^^ Ensure CB invocation follows _sleep test. */

		if (smp_load_acquire(&rdp->nocb_cb_sleep)) {

		// VVV Ensure CB invocation follows _sleep test.

		if (smp_load_acquire(&rdp->nocb_cb_sleep)) { // ^^^

			WARN_ON(signal_pending(current));

			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WokeEmpty"));

		}
@@ -2323,7 +2324,7 @@ static int __rcu_nocb_rdp_deoffload(struct rcu_data *rdp) 
	unsigned long flags;

	int ret;



	printk("De-offloading %d\n", rdp->cpu);

	pr_info("De-offloading %d\n", rdp->cpu);



	rcu_nocb_lock_irqsave(rdp, flags);

	/*
@@ -2384,11 +2385,10 @@ int rcu_nocb_cpu_deoffload(int cpu) 
	mutex_lock(&rcu_state.barrier_mutex);

	cpus_read_lock();

	if (rcu_segcblist_is_offloaded(&rdp->cblist)) {

		if (cpu_online(cpu)) {

		if (cpu_online(cpu))

			ret = work_on_cpu(cpu, rcu_nocb_rdp_deoffload, rdp);

		} else {

		else

			ret = __rcu_nocb_rdp_deoffload(rdp);

		}

		if (!ret)

			cpumask_clear_cpu(cpu, rcu_nocb_mask);

	}
@@ -2412,7 +2412,7 @@ static int __rcu_nocb_rdp_offload(struct rcu_data *rdp) 
	if (!rdp->nocb_gp_rdp)

		return -EINVAL;



	printk("Offloading %d\n", rdp->cpu);

	pr_info("Offloading %d\n", rdp->cpu);

	/*

	 * Can't use rcu_nocb_lock_irqsave() while we are in

	 * SEGCBLIST_SOFTIRQ_ONLY mode.
@@ -2460,11 +2460,10 @@ int rcu_nocb_cpu_offload(int cpu) 
	mutex_lock(&rcu_state.barrier_mutex);

	cpus_read_lock();

	if (!rcu_segcblist_is_offloaded(&rdp->cblist)) {

		if (cpu_online(cpu)) {

		if (cpu_online(cpu))

			ret = work_on_cpu(cpu, rcu_nocb_rdp_offload, rdp);

		} else {

		else

			ret = __rcu_nocb_rdp_offload(rdp);

		}

		if (!ret)

			cpumask_set_cpu(cpu, rcu_nocb_mask);

	}

kernel/time/timer.c

+1 −0
Original line number Diff line number Diff line
@@ -1243,6 +1243,7 @@ bool timer_curr_running(struct timer_list *timer) 


	for (i = 0; i < NR_BASES; i++) {

		struct timer_base *base = this_cpu_ptr(&timer_bases[i]);



		if (base->running_timer == timer)

			return true;

	}