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 <amiettinen@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
index 3d01902..f85016a 100644
--- a/kernel/rcutiny_plugin.h
+++ b/kernel/rcutiny_plugin.h
@@ -706,7 +706,10 @@
return;
/* Once we get past the fastpath checks, same code as rcu_barrier(). */
- rcu_barrier();
+ if (rcu_expedited)
+ synchronize_rcu_expedited();
+ else
+ rcu_barrier();
}
EXPORT_SYMBOL_GPL(synchronize_rcu);