Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH tip/core/rcu 08/14] rcu: Don't spawn rcub kthreads on root rcu_node structure | Date | Wed, 7 Jan 2015 09:32:27 -0800 |
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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Now that offlining CPUs no longer moves leaf rcu_node structures' ->blkd_tasks lists to the root, there is no way for the root rcu_node structure's ->blkd_task list to be nonempty, unless the root node is also the sole leaf node. This commit therefore refrains from creating an rcub kthread for the root rcu_node structure unless it is also the sole leaf.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- kernel/rcu/tree_plugin.h | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index bcc6d9134d47..3e64bb197b1a 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -1352,12 +1352,8 @@ static void __init rcu_spawn_boost_kthreads(void) for_each_possible_cpu(cpu) per_cpu(rcu_cpu_has_work, cpu) = 0; BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec)); - rnp = rcu_get_root(rcu_state_p); - (void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp); - if (NUM_RCU_NODES > 1) { - rcu_for_each_leaf_node(rcu_state_p, rnp) - (void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp); - } + rcu_for_each_leaf_node(rcu_state_p, rnp) + (void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp); } static void rcu_prepare_kthreads(int cpu) -- 1.8.1.5
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