Messages in this thread | | | From | Pranith Kumar <> | Date | Wed, 23 Jul 2014 09:14:51 -0400 | Subject | Re: [PATCH 15/16] rcu: Check for a nocb cpu before trying to spawn nocb threads |
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On Wed, Jul 23, 2014 at 8:28 AM, Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote: > On Wed, Jul 23, 2014 at 01:09:52AM -0400, Pranith Kumar wrote: >> This commit tries to spawn nocb kthreads only when the CPU is marked as a nocb >> cpu. This is a minor optimization. >> >> Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> > > This only happens once at boot time, so I am happier with the single check > at the bottom. So sorry, but no. >
Actually this happens whenever a CPU is coming online, but yes, it is a minor optimization for hotplug.
> Thanx, Paul > >> --- >> kernel/rcu/tree_plugin.h | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h >> index 541c776..8abff0a 100644 >> --- a/kernel/rcu/tree_plugin.h >> +++ b/kernel/rcu/tree_plugin.h >> @@ -1490,7 +1490,8 @@ static void rcu_prepare_kthreads(int cpu) >> return; >> >> rcu_spawn_one_boost_kthread(rcu_state_p, rnp); >> - rcu_spawn_all_nocb_kthreads(cpu); >> + if (rcu_is_nocb_cpu(cpu)) >> + rcu_spawn_all_nocb_kthreads(cpu); >> } >> >> #else /* #ifdef CONFIG_RCU_BOOST */ >> -- >> 2.0.0.rc2 >> >
-- Pranith
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