Commit 3c2acae8 authored by Chen Ridong's avatar Chen Ridong Committed by Tejun Heo
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cgroup/cpuset: remove use_parent_ecpus of cpuset 



use_parent_ecpus is used to track whether the children are using the
parent's effective_cpus. When a parent's effective_cpus is changed
due to changes in a child partition's effective_xcpus, any child
using parent'effective_cpus must call update_cpumasks_hier. However,
if a child is not a valid partition, it is sufficient to determine
whether to call update_cpumasks_hier based on whether the child's
effective_cpus is going to change. To make the code more succinct,
it is suggested to remove use_parent_ecpus.

Signed-off-by: default avatarChen Ridong <chenridong@huawei.com>
Reviewed-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 9414f68d

kernel/cgroup/cpuset.c

+4 −26
Original line number Diff line number Diff line
@@ -185,12 +185,6 @@ struct cpuset { 
	/* partition root state */

	int partition_root_state;



	/*

	 * Default hierarchy only:

	 * use_parent_ecpus - set if using parent's effective_cpus

	 */

	int use_parent_ecpus;



	/*

	 * number of SCHED_DEADLINE tasks attached to this cpuset, so that we

	 * know when to rebuild associated root domain bandwidth information.
@@ -1505,12 +1499,9 @@ static void reset_partition_data(struct cpuset *cs) 
		if (is_cpu_exclusive(cs))

			clear_bit(CS_CPU_EXCLUSIVE, &cs->flags);

	}

	if (!cpumask_and(cs->effective_cpus,

			 parent->effective_cpus, cs->cpus_allowed)) {

		cs->use_parent_ecpus = true;

	if (!cpumask_and(cs->effective_cpus, parent->effective_cpus, cs->cpus_allowed))

		cpumask_copy(cs->effective_cpus, parent->effective_cpus);

}

}



/*

 * partition_xcpus_newstate - Exclusive CPUs state change
@@ -1683,8 +1674,6 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs, 
	spin_lock_irq(&callback_lock);

	isolcpus_updated = partition_xcpus_add(new_prs, NULL, tmp->new_cpus);

	list_add(&cs->remote_sibling, &remote_children);

	if (cs->use_parent_ecpus)

		cs->use_parent_ecpus = false;

	spin_unlock_irq(&callback_lock);

	update_unbound_workqueue_cpumask(isolcpus_updated);
@@ -2309,13 +2298,8 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, 
		 * it is a partition root that has explicitly distributed

		 * out all its CPUs.

		 */

		if (is_in_v2_mode() && !remote && cpumask_empty(tmp->new_cpus)) {

		if (is_in_v2_mode() && !remote && cpumask_empty(tmp->new_cpus))

			cpumask_copy(tmp->new_cpus, parent->effective_cpus);

			if (!cp->use_parent_ecpus)

				cp->use_parent_ecpus = true;

		} else if (cp->use_parent_ecpus) {

			cp->use_parent_ecpus = false;

		}



		if (remote)

			goto get_css;
@@ -2452,8 +2436,7 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs, 
	 * Check all its siblings and call update_cpumasks_hier()

	 * if their effective_cpus will need to be changed.

	 *

	 * With the addition of effective_xcpus which is a subset of

	 * cpus_allowed. It is possible a change in parent's effective_cpus

	 * It is possible a change in parent's effective_cpus

	 * due to a change in a child partition's effective_xcpus will impact

	 * its siblings even if they do not inherit parent's effective_cpus

	 * directly.
@@ -2467,8 +2450,7 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs, 
	cpuset_for_each_child(sibling, pos_css, parent) {

		if (sibling == cs)

			continue;

		if (!sibling->use_parent_ecpus &&

		    !is_partition_valid(sibling)) {

		if (!is_partition_valid(sibling)) {

			compute_effective_cpumask(tmp->new_cpus, sibling,

						  parent);

			if (cpumask_equal(tmp->new_cpus, sibling->effective_cpus))
@@ -4128,7 +4110,6 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) 
	if (is_in_v2_mode()) {

		cpumask_copy(cs->effective_cpus, parent->effective_cpus);

		cs->effective_mems = parent->effective_mems;

		cs->use_parent_ecpus = true;

	}

	spin_unlock_irq(&callback_lock);
@@ -4194,9 +4175,6 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css) 
	    is_sched_load_balance(cs))

		update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);



	if (cs->use_parent_ecpus)

		cs->use_parent_ecpus = false;



	cpuset_dec();

	clear_bit(CS_ONLINE, &cs->flags);