The generate_sched_domains() function and the hotplug code are modified to make them use the newly introduced isolated_cpus mask for schedule domains generation. Signed-off-by: Waiman Long <longman@xxxxxxxxxx> --- kernel/cgroup/cpuset.c | 33 +++++++++++++++++++++++++++++---- 1 file changed, 29 insertions(+), 4 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 368e1b7..0e75f83 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -672,13 +672,14 @@ static int generate_sched_domains(cpumask_var_t **domains, int ndoms = 0; /* number of sched domains in result */ int nslot; /* next empty doms[] struct cpumask slot */ struct cgroup_subsys_state *pos_css; + bool root_load_balance = is_sched_load_balance(&top_cpuset); doms = NULL; dattr = NULL; csa = NULL; /* Special case for the 99% of systems with one, full, sched domain */ - if (is_sched_load_balance(&top_cpuset)) { + if (root_load_balance && !top_cpuset.isolation_count) { ndoms = 1; doms = alloc_sched_domains(ndoms); if (!doms) @@ -701,6 +702,8 @@ static int generate_sched_domains(cpumask_var_t **domains, csn = 0; rcu_read_lock(); + if (root_load_balance) + csa[csn++] = &top_cpuset; cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) { if (cp == &top_cpuset) continue; @@ -711,6 +714,9 @@ static int generate_sched_domains(cpumask_var_t **domains, * parent's cpus, so just skip them, and then we call * update_domain_attr_tree() to calc relax_domain_level of * the corresponding sched domain. + * + * If root is load-balancing, we can skip @cp if it + * is a subset of the root's effective_cpus. */ if (!cpumask_empty(cp->cpus_allowed) && !(is_sched_load_balance(cp) && @@ -718,11 +724,16 @@ static int generate_sched_domains(cpumask_var_t **domains, housekeeping_cpumask(HK_FLAG_DOMAIN)))) continue; + if (root_load_balance && + cpumask_subset(cp->cpus_allowed, top_cpuset.effective_cpus)) + continue; + if (is_sched_load_balance(cp)) csa[csn++] = cp; - /* skip @cp's subtree */ - pos_css = css_rightmost_descendant(pos_css); + /* skip @cp's subtree if not a scheduling domain */ + if (!is_sched_domain(cp)) + pos_css = css_rightmost_descendant(pos_css); } rcu_read_unlock(); @@ -849,7 +860,12 @@ static void rebuild_sched_domains_locked(void) * passing doms with offlined cpu to partition_sched_domains(). * Anyways, hotplug work item will rebuild sched domains. */ - if (!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask)) + if (!top_cpuset.isolation_count && + !cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask)) + goto out; + + if (top_cpuset.isolation_count && + !cpumask_subset(top_cpuset.effective_cpus, cpu_active_mask)) goto out; /* Generate domain masks and attrs */ @@ -2624,6 +2640,11 @@ static void cpuset_hotplug_workfn(struct work_struct *work) cpumask_copy(&new_cpus, cpu_active_mask); new_mems = node_states[N_MEMORY]; + /* + * If isolated_cpus is populated, it is likely that the check below + * will produce a false positive on cpus_updated when the cpu list + * isn't changed. It is extra work, but it is better to be safe. + */ cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus); mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems); @@ -2632,6 +2653,10 @@ static void cpuset_hotplug_workfn(struct work_struct *work) spin_lock_irq(&callback_lock); if (!on_dfl) cpumask_copy(top_cpuset.cpus_allowed, &new_cpus); + + if (top_cpuset.isolation_count) + cpumask_andnot(&new_cpus, &new_cpus, + top_cpuset.isolated_cpus); cpumask_copy(top_cpuset.effective_cpus, &new_cpus); spin_unlock_irq(&callback_lock); /* we don't mess with cpumasks of tasks in top_cpuset */ -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html