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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
	akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
	josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
	rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
	dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com,
	bobby.prani@gmail.com,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 07/14] rcu: Make use of rcu_preempt_has_tasks()
Date: Wed,  7 Jan 2015 09:32:26 -0800	[thread overview]
Message-ID: <1420651953-2651-7-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <1420651953-2651-1-git-send-email-paulmck@linux.vnet.ibm.com>

From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

Given that there is now arcu_preempt_has_tasks() function that checks
to see if the ->blkd_tasks list is non-empty, this commit makes use of it.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 kernel/rcu/tree_plugin.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index d594da48f4b4..bcc6d9134d47 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -540,7 +540,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp)
 static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp)
 {
 	WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp));
-	if (!list_empty(&rnp->blkd_tasks))
+	if (rcu_preempt_has_tasks(rnp))
 		rnp->gp_tasks = rnp->blkd_tasks.next;
 	WARN_ON_ONCE(rnp->qsmask);
 }
@@ -706,7 +706,7 @@ sync_rcu_preempt_exp_init(struct rcu_state *rsp, struct rcu_node *rnp)
 
 	raw_spin_lock_irqsave(&rnp->lock, flags);
 	smp_mb__after_unlock_lock();
-	if (list_empty(&rnp->blkd_tasks)) {
+	if (!rcu_preempt_has_tasks(rnp)) {
 		raw_spin_unlock_irqrestore(&rnp->lock, flags);
 	} else {
 		rnp->exp_tasks = rnp->blkd_tasks.next;
@@ -985,7 +985,7 @@ void exit_rcu(void)
 
 static void rcu_initiate_boost_trace(struct rcu_node *rnp)
 {
-	if (list_empty(&rnp->blkd_tasks))
+	if (!rcu_preempt_has_tasks(rnp))
 		rnp->n_balk_blkd_tasks++;
 	else if (rnp->exp_tasks == NULL && rnp->gp_tasks == NULL)
 		rnp->n_balk_exp_gp_tasks++;
-- 
1.8.1.5


  parent reply	other threads:[~2015-01-07 17:32 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-07 17:32 [PATCH tip/core/rcu 0/14] Preemptible-RCU updates for 3.20 Paul E. McKenney
2015-01-07 17:32 ` [PATCH tip/core/rcu 01/14] rcu: Protect rcu_boost() lockless accesses with ACCESS_ONCE() Paul E. McKenney
2015-01-07 17:32   ` [PATCH tip/core/rcu 02/14] rcu: Rename "empty" to "empty_norm" in preparation for boost rework Paul E. McKenney
2015-01-07 17:32   ` [PATCH tip/core/rcu 03/14] rcu: Abstract rcu_cleanup_dead_rnp() from rcu_cleanup_dead_cpu() Paul E. McKenney
2015-01-07 17:32   ` [PATCH tip/core/rcu 04/14] rcu: Make rcu_read_unlock_special() propagate ->qsmaskinit bit clearing Paul E. McKenney
2015-01-07 17:32   ` [PATCH tip/core/rcu 05/14] rcu: Don't migrate blocked tasks even if all corresponding CPUs offline Paul E. McKenney
2015-01-07 17:32   ` [PATCH tip/core/rcu 06/14] rcu: Shorten irq-disable region in rcu_cleanup_dead_cpu() Paul E. McKenney
2015-01-07 17:32   ` Paul E. McKenney [this message]
2015-01-07 17:32   ` [PATCH tip/core/rcu 08/14] rcu: Don't spawn rcub kthreads on root rcu_node structure Paul E. McKenney
2015-01-07 17:32   ` [PATCH tip/core/rcu 09/14] rcu: Don't initiate RCU priority boosting on root rcu_node Paul E. McKenney
2015-01-07 17:32   ` [PATCH tip/core/rcu 10/14] rcu: Don't bother affinitying rcub kthreads away from offline CPUs Paul E. McKenney
2015-01-07 17:32   ` [PATCH tip/core/rcu 11/14] rcu: Note quiescent state when CPU goes offline Paul E. McKenney
2015-01-07 17:32   ` [PATCH tip/core/rcu 12/14] rcu: Revert "Allow post-unlock reference for rt_mutex" to avoid priority-inversion Paul E. McKenney
2015-01-07 17:32   ` [PATCH tip/core/rcu 13/14] rcu: Don't scan root rcu_node structure for stalled tasks Paul E. McKenney
2015-01-07 17:32   ` [PATCH tip/core/rcu 14/14] rcu: Remove redundant callback-list initialization Paul E. McKenney
2015-01-08  9:41   ` [PATCH tip/core/rcu 01/14] rcu: Protect rcu_boost() lockless accesses with ACCESS_ONCE() Peter Zijlstra
2015-01-08 15:22     ` Paul E. McKenney
2015-01-09  6:41       ` Davidlohr Bueso
2015-01-09 13:49         ` Paul E. McKenney
2015-01-09 13:56           ` Peter Zijlstra
2015-01-09 14:07             ` Paul E. McKenney
2015-01-09 16:53               ` Mathieu Desnoyers
2015-01-09 21:58             ` Christian Borntraeger
2015-01-10  0:27               ` Davidlohr Bueso
2015-01-12  8:59               ` Peter Zijlstra
2015-01-12 22:12                 ` Paul E. McKenney
2015-01-13  8:18                   ` Christian Borntraeger
2015-01-13  9:29                     ` Peter Zijlstra
2015-01-13 17:47                     ` Paul E. McKenney
2015-01-13 19:12                     ` Davidlohr Bueso

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