From f885b7f2b2de70be266d2cecc476f773a1e2ca5d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 23 Apr 2012 15:52:53 -0700 Subject: rcu: Control RCU_FANOUT_LEAF from boot-time parameter Although making RCU_FANOUT_LEAF a kernel configuration parameter rather than a fixed constant makes it easier for people to decrease cache-miss overhead for large systems, it is of little help for people who must run a single pre-built kernel binary. This commit therefore allows the value of RCU_FANOUT_LEAF to be increased (but not decreased!) via a boot-time parameter named rcutree.rcu_fanout_leaf. Reported-by: Mike Galbraith Signed-off-by: Paul E. McKenney --- kernel/rcutree_plugin.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/rcutree_plugin.h') diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 3e4899459f3d..fb92b6dd9980 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -70,6 +70,8 @@ static void __init rcu_bootup_announce_oddness(void) #if NUM_RCU_LVL_4 != 0 printk(KERN_INFO "\tExperimental four-level hierarchy is enabled.\n"); #endif + if (rcu_fanout_leaf != CONFIG_RCU_FANOUT_LEAF) + printk(KERN_INFO "\tExperimental boot-time adjustment of leaf fanout to %d.\n", rcu_fanout_leaf); } #ifdef CONFIG_TREE_PREEMPT_RCU -- cgit v1.2.3