From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH] rcu: more careful check for the last non-dyntick-idle CPU
Date: Tue, 30 Mar 2010 18:40:36 +0800 [thread overview]
Message-ID: <4BB1D524.9050508@cn.fujitsu.com> (raw)
Warning: I just did build test.
Subject: [PATCH] rcu: more careful check for the last non-dyntick-idle CPU
If a CPU is not in nohz_cpu_mask, it does not means this
CPU is a non-dyntick-idle CPU, because this CPU may be offline or not exist.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 4befb64..6086a7d 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -1026,7 +1026,7 @@ int rcu_needs_cpu(int cpu)
/* Don't bother unless we are the last non-dyntick-idle CPU. */
for_each_cpu_not(thatcpu, nohz_cpu_mask)
- if (thatcpu != cpu) {
+ if (cpu_online(thatcpu) && thatcpu != cpu) {
per_cpu(rcu_dyntick_drain, cpu) = 0;
per_cpu(rcu_dyntick_holdoff, cpu) = jiffies - 1;
return rcu_needs_cpu_quick_check(cpu);
next reply other threads:[~2010-03-30 10:40 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-30 10:40 Lai Jiangshan [this message]
2010-03-30 15:50 ` [PATCH] rcu: more careful check for the last non-dyntick-idle CPU Paul E. McKenney
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