Messages in this thread Patch in this message | | | Date | Tue, 30 Mar 2010 18:40:36 +0800 | From | Lai Jiangshan <> | Subject | [PATCH] rcu: more careful check for the last non-dyntick-idle CPU |
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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);
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