From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com,
sbw@mit.edu, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 2/7] rcu: Avoid invoking RCU core on offline CPUs
Date: Mon, 18 Mar 2013 14:16:51 -0700 [thread overview]
Message-ID: <1363641416-18642-2-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <1363641416-18642-1-git-send-email-paulmck@linux.vnet.ibm.com>
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Offline CPUs transition through the scheduler to the idle loop one
last time before being shut down. This can result in RCU raising
softirq on this CPU, which is at best useless given that the CPU's
callbacks will be offloaded at CPU_DEAD time. This commit therefore
avoids raising softirq on offline CPUs.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcutree.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 157539a..b2fc234 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -2169,7 +2169,8 @@ static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp)
static void invoke_rcu_core(void)
{
- raise_softirq(RCU_SOFTIRQ);
+ if (cpu_online(smp_processor_id()))
+ raise_softirq(RCU_SOFTIRQ);
}
/*
--
1.8.1.5
next prev parent reply other threads:[~2013-03-18 21:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-18 21:16 [PATCH tip/core/rcu 0/7] Fixes for 3.9 Paul E. McKenney
2013-03-18 21:16 ` [PATCH tip/core/rcu 1/7] rcu: Fix spacing problem Paul E. McKenney
2013-03-18 21:16 ` Paul E. McKenney [this message]
2013-03-18 21:16 ` [PATCH tip/core/rcu 3/7] rcu: Remove comment referring to __stop_machine() Paul E. McKenney
2013-03-18 21:16 ` [PATCH tip/core/rcu 4/7] rcu: Delete unused rcu_node "wakemask" field Paul E. McKenney
2013-03-18 21:16 ` [PATCH tip/core/rcu 5/7] rcu: Fix hlist_bl_set_first_rcu() annotation Paul E. McKenney
2013-03-18 21:16 ` [PATCH tip/core/rcu 6/7] rcu: Add softirq-stall indications to stall-warning messages Paul E. McKenney
2013-03-18 21:16 ` [PATCH tip/core/rcu 7/7] rcu: Tone down debugging during boot-up and shutdown Paul E. McKenney
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