From 3705b88db0d7cc4a097c32d9e554054103d3f807 Mon Sep 17 00:00:00 2001 From: Antti P Miettinen Date: Fri, 5 Oct 2012 09:59:15 +0300 Subject: rcu: Add a module parameter to force use of expedited RCU primitives There have been some embedded applications that would benefit from use of expedited grace-period primitives. In some ways, this is similar to synchronize_net() doing either a normal or an expedited grace period depending on lock state, but with control outside of the kernel. This commit therefore adds rcu_expedited boot and sysfs parameters that cause the kernel to substitute expedited primitives for the normal grace-period primitives. [ paulmck: Add trace/event/rcu.h to kernel/srcu.c to avoid build error. Get rid of infinite loop through contention path.] Signed-off-by: Antti P Miettinen Signed-off-by: Paul E. McKenney --- kernel/rcutree_plugin.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'kernel/rcutree_plugin.h') diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index f92115488187..c177ba0cce9a 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -679,7 +679,10 @@ void synchronize_rcu(void) "Illegal synchronize_rcu() in RCU read-side critical section"); if (!rcu_scheduler_active) return; - wait_rcu_gp(call_rcu); + if (rcu_expedited) + synchronize_rcu_expedited(); + else + wait_rcu_gp(call_rcu); } EXPORT_SYMBOL_GPL(synchronize_rcu); @@ -831,7 +834,7 @@ void synchronize_rcu_expedited(void) udelay(trycount * num_online_cpus()); } else { put_online_cpus(); - synchronize_rcu(); + wait_rcu_gp(call_rcu); return; } } -- cgit v1.2.3