Now that nodes_and() returns true if the result nodemask is not empty, drop useless nodes_intersects() in guarantee_online_mems() and nodes_empty() in update_nodemasks_hier(), which both are O(N). Signed-off-by: Yury Norov --- kernel/cgroup/cpuset.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 3e8cc34d8d50..e962efbb300d 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -456,9 +456,8 @@ static void guarantee_active_cpus(struct task_struct *tsk, */ static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask) { - while (!nodes_intersects(cs->effective_mems, node_states[N_MEMORY])) + while (!nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY])) cs = parent_cs(cs); - nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]); } /** @@ -2862,13 +2861,13 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems) cpuset_for_each_descendant_pre(cp, pos_css, cs) { struct cpuset *parent = parent_cs(cp); - nodes_and(*new_mems, cp->mems_allowed, parent->effective_mems); + bool has_mems = nodes_and(*new_mems, cp->mems_allowed, parent->effective_mems); /* * If it becomes empty, inherit the effective mask of the * parent, which is guaranteed to have some MEMs. */ - if (is_in_v2_mode() && nodes_empty(*new_mems)) + if (is_in_v2_mode() && !has_mems) *new_mems = parent->effective_mems; /* Skip the whole subtree if the nodemask remains the same. */ -- 2.43.0