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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-04-23 15:52:53 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-07-02 12:33:20 -0700 |
| commit | f885b7f2b2de70be266d2cecc476f773a1e2ca5d (patch) | |
| tree | c4f4d03ca1469f22701b848274034a74c5ae2b04 /kernel/rcutree_plugin.h | |
| parent | cba6d0d64ee53772b285d0c0c288deefbeaf7775 (diff) | |
| download | lwn-f885b7f2b2de70be266d2cecc476f773a1e2ca5d.tar.gz lwn-f885b7f2b2de70be266d2cecc476f773a1e2ca5d.zip | |
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 <efault@gmx.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcutree_plugin.h')
| -rw-r--r-- | kernel/rcutree_plugin.h | 2 |
1 files changed, 2 insertions, 0 deletions
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 |