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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-11-17 19:27:16 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-02-17 16:03:09 -0800
commitffa83fb565fbc397cbafb4b71fd1cce276d4c3b6 (patch)
treec849b1ea3517d6853b7b4cd386a682187e314f09 /kernel/rcu
parent2f33b512a5460578f6cf11d7b7867bed53157c7c (diff)
downloadblackbird-op-linux-ffa83fb565fbc397cbafb4b71fd1cce276d4c3b6.tar.gz
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rcu: Optimize rcu_needs_cpu() for RCU_NOCB_CPU_ALL
If CONFIG_RCU_NOCB_CPU_ALL=y, then rcu_needs_cpu() will always return false, however, the current version nevertheless checks for RCU callbacks. This commit therefore creates a static inline implementation of rcu_needs_cpu() that unconditionally returns false when CONFIG_RCU_NOCB_CPU_ALL=y. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree.c2
-rw-r--r--kernel/rcu/tree_plugin.h4
2 files changed, 5 insertions, 1 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index b3d116cd072d..c2c8234a0291 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2880,7 +2880,7 @@ static int rcu_pending(int cpu)
* non-NULL, store an indication of whether all callbacks are lazy.
* (If there are no callbacks, all of them are deemed to be lazy.)
*/
-static int rcu_cpu_has_callbacks(int cpu, bool *all_lazy)
+static int __maybe_unused rcu_cpu_has_callbacks(int cpu, bool *all_lazy)
{
bool al = true;
bool hc = false;
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 39a50b918bff..820b06aefbee 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1586,11 +1586,13 @@ static void rcu_prepare_kthreads(int cpu)
* Because we not have RCU_FAST_NO_HZ, just check whether this CPU needs
* any flavor of RCU.
*/
+#ifndef CONFIG_RCU_NOCB_CPU_ALL
int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
{
*delta_jiffies = ULONG_MAX;
return rcu_cpu_has_callbacks(cpu, NULL);
}
+#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
/*
* Because we do not have RCU_FAST_NO_HZ, don't bother cleaning up
@@ -1696,6 +1698,7 @@ static bool rcu_try_advance_all_cbs(void)
*
* The caller must have disabled interrupts.
*/
+#ifndef CONFIG_RCU_NOCB_CPU_ALL
int rcu_needs_cpu(int cpu, unsigned long *dj)
{
struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
@@ -1726,6 +1729,7 @@ int rcu_needs_cpu(int cpu, unsigned long *dj)
}
return 0;
}
+#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
/*
* Prepare a CPU for idle from an RCU perspective. The first major task
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