Re: [PATCH tip/core/rcu 01/22] rcu: Control RCU_FANOUT_LEAF from boot-time parameter

Rusty Russell
2012-07-01T06:54:17Z

On Fri, 22 Jun 2012 08:17:00 -0700, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:
> From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
>
> 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.
...
> +static int rcu_fanout_leaf = CONFIG_RCU_FANOUT_LEAF;
> +module_param(rcu_fanout_leaf, int, 0);

Maybe it's overkill, but 0400 or 0444 might be a nice touch.

Cheers,
Rusty.