cpuset: replace cpuset->stack_list with cpuset_for_each_descendant_pre()
Implement cpuset_for_each_descendant_pre() and replace the cpuset-specific tree walking using cpuset->stack_list with it. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizefan@huawei.com>
This commit is contained in:
Tejun Heo
Родитель
5d21cc2db0
Коммит
fc560a26ac
123
kernel/cpuset.c
123
kernel/cpuset.c
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@ -103,9 +103,6 @@ struct cpuset {
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/* for custom sched domain */
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int relax_domain_level;
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/* used for walking a cpuset hierarchy */
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struct list_head stack_list;
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struct work_struct hotplug_work;
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};
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@ -207,6 +204,20 @@ static struct cpuset top_cpuset = {
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cgroup_for_each_child((pos_cgrp), (parent_cs)->css.cgroup) \
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if (is_cpuset_online(((child_cs) = cgroup_cs((pos_cgrp)))))
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/**
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* cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants
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* @des_cs: loop cursor pointing to the current descendant
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* @pos_cgrp: used for iteration
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* @root_cs: target cpuset to walk ancestor of
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*
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* Walk @des_cs through the online descendants of @root_cs. Must be used
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* with RCU read locked. The caller may modify @pos_cgrp by calling
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* cgroup_rightmost_descendant() to skip subtree.
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*/
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#define cpuset_for_each_descendant_pre(des_cs, pos_cgrp, root_cs) \
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cgroup_for_each_descendant_pre((pos_cgrp), (root_cs)->css.cgroup) \
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if (is_cpuset_online(((des_cs) = cgroup_cs((pos_cgrp)))))
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/*
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* There are two global mutexes guarding cpuset structures - cpuset_mutex
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* and callback_mutex. The latter may nest inside the former. We also
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@ -507,31 +518,24 @@ update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)
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return;
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}
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static void
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update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c)
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static void update_domain_attr_tree(struct sched_domain_attr *dattr,
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struct cpuset *root_cs)
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{
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LIST_HEAD(q);
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struct cpuset *cp;
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struct cgroup *pos_cgrp;
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list_add(&c->stack_list, &q);
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while (!list_empty(&q)) {
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struct cpuset *cp;
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struct cgroup *cont;
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struct cpuset *child;
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cp = list_first_entry(&q, struct cpuset, stack_list);
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list_del(q.next);
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if (cpumask_empty(cp->cpus_allowed))
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rcu_read_lock();
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cpuset_for_each_descendant_pre(cp, pos_cgrp, root_cs) {
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/* skip the whole subtree if @cp doesn't have any CPU */
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if (cpumask_empty(cp->cpus_allowed)) {
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pos_cgrp = cgroup_rightmost_descendant(pos_cgrp);
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continue;
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}
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if (is_sched_load_balance(cp))
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update_domain_attr(dattr, cp);
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rcu_read_lock();
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cpuset_for_each_child(child, cont, cp)
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list_add_tail(&child->stack_list, &q);
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rcu_read_unlock();
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}
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rcu_read_unlock();
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}
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/*
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@ -591,7 +595,6 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c)
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static int generate_sched_domains(cpumask_var_t **domains,
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struct sched_domain_attr **attributes)
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{
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LIST_HEAD(q); /* queue of cpusets to be scanned */
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struct cpuset *cp; /* scans q */
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struct cpuset **csa; /* array of all cpuset ptrs */
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int csn; /* how many cpuset ptrs in csa so far */
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@ -600,6 +603,7 @@ static int generate_sched_domains(cpumask_var_t **domains,
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struct sched_domain_attr *dattr; /* attributes for custom domains */
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int ndoms = 0; /* number of sched domains in result */
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int nslot; /* next empty doms[] struct cpumask slot */
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struct cgroup *pos_cgrp;
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doms = NULL;
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dattr = NULL;
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@ -627,33 +631,27 @@ static int generate_sched_domains(cpumask_var_t **domains,
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goto done;
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csn = 0;
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list_add(&top_cpuset.stack_list, &q);
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while (!list_empty(&q)) {
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struct cgroup *cont;
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struct cpuset *child; /* scans child cpusets of cp */
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cp = list_first_entry(&q, struct cpuset, stack_list);
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list_del(q.next);
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if (cpumask_empty(cp->cpus_allowed))
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continue;
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rcu_read_lock();
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cpuset_for_each_descendant_pre(cp, pos_cgrp, &top_cpuset) {
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/*
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* All child cpusets contain a subset of the parent's cpus, so
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* just skip them, and then we call update_domain_attr_tree()
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* to calc relax_domain_level of the corresponding sched
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* domain.
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* Continue traversing beyond @cp iff @cp has some CPUs and
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* isn't load balancing. The former is obvious. The
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* latter: All child cpusets contain a subset of the
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* parent's cpus, so just skip them, and then we call
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* update_domain_attr_tree() to calc relax_domain_level of
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* the corresponding sched domain.
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*/
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if (is_sched_load_balance(cp)) {
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csa[csn++] = cp;
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if (!cpumask_empty(cp->cpus_allowed) &&
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!is_sched_load_balance(cp))
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continue;
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}
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rcu_read_lock();
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cpuset_for_each_child(child, cont, cp)
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list_add_tail(&child->stack_list, &q);
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rcu_read_unlock();
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}
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if (is_sched_load_balance(cp))
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csa[csn++] = cp;
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/* skip @cp's subtree */
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pos_cgrp = cgroup_rightmost_descendant(pos_cgrp);
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}
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rcu_read_unlock();
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for (i = 0; i < csn; i++)
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csa[i]->pn = i;
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@ -2068,31 +2066,6 @@ static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
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move_member_tasks_to_cpuset(cs, parent);
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}
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/*
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* Helper function to traverse cpusets.
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* It can be used to walk the cpuset tree from top to bottom, completing
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* one layer before dropping down to the next (thus always processing a
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* node before any of its children).
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*/
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static struct cpuset *cpuset_next(struct list_head *queue)
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{
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struct cpuset *cp;
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struct cpuset *child; /* scans child cpusets of cp */
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struct cgroup *cont;
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if (list_empty(queue))
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return NULL;
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cp = list_first_entry(queue, struct cpuset, stack_list);
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list_del(queue->next);
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rcu_read_lock();
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cpuset_for_each_child(child, cont, cp)
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list_add_tail(&child->stack_list, queue);
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rcu_read_unlock();
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return cp;
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}
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/**
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* cpuset_propagate_hotplug_workfn - propagate CPU/memory hotplug to a cpuset
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* @cs: cpuset in interest
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@ -2229,12 +2202,12 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
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/* if cpus or mems went down, we need to propagate to descendants */
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if (cpus_offlined || mems_offlined) {
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struct cpuset *cs;
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LIST_HEAD(queue);
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struct cgroup *pos_cgrp;
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list_add_tail(&top_cpuset.stack_list, &queue);
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while ((cs = cpuset_next(&queue)))
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if (cs != &top_cpuset)
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schedule_cpuset_propagate_hotplug(cs);
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rcu_read_lock();
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cpuset_for_each_descendant_pre(cs, pos_cgrp, &top_cpuset)
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schedule_cpuset_propagate_hotplug(cs);
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rcu_read_unlock();
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}
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mutex_unlock(&cpuset_mutex);
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