[PATCH tip/core/rcu 1/2] rcu: fix holdoff for accelerated GPs for last non-dynticked CPU
From: Paul E. McKenney
Date: Sat Feb 27 2010 - 17:53:25 EST
Make the holdoff only happen when the full number of attempts have been
made.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcutree_plugin.h | 8 +++++---
1 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 464ad2c..79b53bd 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -1010,6 +1010,10 @@ int rcu_needs_cpu(int cpu)
int c = 0;
int thatcpu;
+ /* Check for being in the holdoff period. */
+ if (per_cpu(rcu_dyntick_holdoff, cpu) == jiffies)
+ return rcu_needs_cpu_quick_check(cpu);
+
/* Don't bother unless we are the last non-dyntick-idle CPU. */
for_each_cpu_not(thatcpu, nohz_cpu_mask)
if (thatcpu != cpu) {
@@ -1041,10 +1045,8 @@ int rcu_needs_cpu(int cpu)
}
/* If RCU callbacks are still pending, RCU still needs this CPU. */
- if (c) {
+ if (c)
raise_softirq(RCU_SOFTIRQ);
- per_cpu(rcu_dyntick_holdoff, cpu) = jiffies;
- }
return c;
}
--
1.6.6
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