From: Josh Triplett <josh@joshtriplett.org>
To: Rusty Russell <rusty@ozlabs.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, mingo@elte.hu,
laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, Valdis.Kletnieks@vt.edu,
dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com,
fweisbec@gmail.com, sbw@mit.edu, patches@linaro.org
Subject: Re: [PATCH tip/core/rcu 01/22] rcu: Control RCU_FANOUT_LEAF from boot-time parameter
Date: Sun, 1 Jul 2012 00:17:58 -0700 [thread overview]
Message-ID: <20120701071757.GA8749@leaf> (raw)
In-Reply-To: <87y5n4xatd.fsf@rustcorp.com.au>
On Sun, Jul 01, 2012 at 03:49:42PM +0930, Rusty Russell wrote:
> 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.
I agree. 0 almost never makes sense; root should almost always have the
ability to read module parameters. And in this case, I see no reason
not to make it 0444.
- Josh Triplett
next prev parent reply other threads:[~2012-07-01 7:18 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-22 15:16 [PATCH tip/core/rcu 0/22] v2 Improvements to rcu_barrier() and RT response on big systems Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 01/22] rcu: Control RCU_FANOUT_LEAF from boot-time parameter Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 02/22] rcu: Four-level hierarchy is no longer experimental Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 03/22] rcu: Size rcu_node tree from nr_cpu_ids rather than NR_CPUS Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 04/22] rcu: Prevent excessive line length in RCU_STATE_INITIALIZER() Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 05/22] rcu: Place pointer to call_rcu() in rcu_data structure Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 06/22] rcu: Move _rcu_barrier()'s rcu_head structures to rcu_data structures Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 07/22] rcu: Move rcu_barrier_cpu_count to rcu_state structure Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 08/22] rcu: Move rcu_barrier_completion " Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 09/22] rcu: Move rcu_barrier_mutex " Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 10/22] rcu: Remove needless initialization Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 11/22] rcu: Increase rcu_barrier() concurrency Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 12/22] rcu: Add tracing for _rcu_barrier() Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 13/22] rcu: Add rcu_barrier() statistics to debugfs tracing Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 14/22] rcu: Remove unneeded __rcu_process_callbacks() argument Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 15/22] rcu: Introduce for_each_rcu_flavor() and use it Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 16/22] rcu: Use for_each_rcu_flavor() in TREE_RCU tracing Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 17/22] rcu: RCU_SAVE_DYNTICK code no longer ever dead Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 18/22] rcu: Move RCU grace-period initialization into a kthread Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 19/22] rcu: Allow RCU grace-period initialization to be preempted Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 20/22] rcu: Move RCU grace-period cleanup into kthread Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 21/22] rcu: Allow RCU grace-period cleanup to be preempted Paul E. McKenney
2012-06-22 15:17 ` [PATCH tip/core/rcu 22/22] rcu: Prevent offline CPUs from executing RCU core code Paul E. McKenney
2012-07-01 6:19 ` [PATCH tip/core/rcu 01/22] rcu: Control RCU_FANOUT_LEAF from boot-time parameter Rusty Russell
2012-07-01 7:17 ` Josh Triplett [this message]
2012-07-01 12:52 ` Paul E. McKenney
2012-07-01 17:45 ` Josh Triplett
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