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From 6b0fb5b2a7a157c04d8ab6ad71b092034d0048bf Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Wed, 11 Feb 2015 16:19:26 -0600
Subject: [PATCH 102/114] cpuidle: skip synchronize_rcu() on single CPU systems
synchronize_rcu() is pretty expensive, and on single CPU systems we don't need
it in this specific case, so skip it.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
---
drivers/cpuidle/cpuidle.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 62810ff3b00f..f1d110411098 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -324,8 +324,11 @@ void cpuidle_uninstall_idle_handler(void)
/*
* Make sure external observers (such as the scheduler)
* are done looking at pointed idle states.
+ * This is only relevant if there is more than one cpu,
+ * if there is only one CPU, that is us... and we're
+ * coherent to ourselves.
*/
- synchronize_rcu();
+
}
/**
--
2.11.1
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