Commit c4c9cebe authored by Waiman Long's avatar Waiman Long Committed by Tejun Heo
Browse files

cgroup/cpuset: Further optimize code if CONFIG_CPUSETS_V1 not set 



Currently the cpuset code uses group_subsys_on_dfl() to check if we
are running with cgroup v2. If CONFIG_CPUSETS_V1 isn't set, there is
really no need to do this check and we can optimize out some of the
unneeded v1 specific code paths. Introduce a new cpuset_v2() and use it
to replace the cgroup_subsys_on_dfl() check to further optimize the
code.

Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent a040c351

kernel/cgroup/cpuset.c

+19 −20
Original line number Diff line number Diff line
@@ -293,6 +293,12 @@ static inline void dec_attach_in_progress(struct cpuset *cs) 
	mutex_unlock(&cpuset_mutex);

}



static inline bool cpuset_v2(void)

{

	return !IS_ENABLED(CONFIG_CPUSETS_V1) ||

		cgroup_subsys_on_dfl(cpuset_cgrp_subsys);

}



/*

 * Cgroup v2 behavior is used on the "cpus" and "mems" control files when

 * on default hierarchy or when the cpuset_v2_mode flag is set by mounting
@@ -303,7 +309,7 @@ static inline void dec_attach_in_progress(struct cpuset *cs) 
 */

static inline bool is_in_v2_mode(void)

{

	return cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||

	return cpuset_v2() ||

	      (cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE);

}
@@ -738,7 +744,7 @@ static int generate_sched_domains(cpumask_var_t **domains, 
	int nslot;		/* next empty doms[] struct cpumask slot */

	struct cgroup_subsys_state *pos_css;

	bool root_load_balance = is_sched_load_balance(&top_cpuset);

	bool cgrpv2 = cgroup_subsys_on_dfl(cpuset_cgrp_subsys);

	bool cgrpv2 = cpuset_v2();

	int nslot_update;



	doms = NULL;
@@ -1198,7 +1204,7 @@ static void reset_partition_data(struct cpuset *cs) 
{

	struct cpuset *parent = parent_cs(cs);



	if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys))

	if (!cpuset_v2())

		return;



	lockdep_assert_held(&callback_lock);
@@ -2017,7 +2023,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, 
		 */

		if (!cp->partition_root_state && !force &&

		    cpumask_equal(tmp->new_cpus, cp->effective_cpus) &&

		    (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||

		    (!cpuset_v2() ||

		    (is_sched_load_balance(parent) == is_sched_load_balance(cp)))) {

			pos_css = css_rightmost_descendant(pos_css);

			continue;
@@ -2091,8 +2097,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, 
		 * from parent if current cpuset isn't a valid partition root

		 * and their load balance states differ.

		 */

		if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&

		    !is_partition_valid(cp) &&

		if (cpuset_v2() && !is_partition_valid(cp) &&

		    (is_sched_load_balance(parent) != is_sched_load_balance(cp))) {

			if (is_sched_load_balance(parent))

				set_bit(CS_SCHED_LOAD_BALANCE, &cp->flags);
@@ -2108,8 +2113,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, 
		 */

		if (!cpumask_empty(cp->cpus_allowed) &&

		    is_sched_load_balance(cp) &&

		   (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||

		    is_partition_valid(cp)))

		   (!cpuset_v2() || is_partition_valid(cp)))

			need_rebuild_sched_domains = true;



		rcu_read_lock();
@@ -2246,7 +2250,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, 


	retval = validate_change(cs, trialcs);



	if ((retval == -EINVAL) && cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) {

	if ((retval == -EINVAL) && cpuset_v2()) {

		struct cgroup_subsys_state *css;

		struct cpuset *cp;
@@ -2738,8 +2742,7 @@ int cpuset_update_flag(cpuset_flagbits_t bit, struct cpuset *cs, 
	spin_unlock_irq(&callback_lock);



	if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed) {

		if (!IS_ENABLED(CONFIG_CPUSETS_V1) ||

		    cgroup_subsys_on_dfl(cpuset_cgrp_subsys))

		if (cpuset_v2())

			cpuset_force_rebuild();

		else

			rebuild_sched_domains_locked();
@@ -2925,8 +2928,7 @@ static int cpuset_can_attach(struct cgroup_taskset *tset) 
		 * migration permission derives from hierarchy ownership in

		 * cgroup_procs_write_permission()).

		 */

		if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||

		    (cpus_updated || mems_updated)) {

		if (!cpuset_v2() || (cpus_updated || mems_updated)) {

			ret = security_task_setscheduler(task);

			if (ret)

				goto out_unlock;
@@ -3040,8 +3042,7 @@ static void cpuset_attach(struct cgroup_taskset *tset) 
	 * in effective cpus and mems. In that case, we can optimize out

	 * by skipping the task iteration and update.

	 */

	if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&

	    !cpus_updated && !mems_updated) {

	if (cpuset_v2() && !cpus_updated && !mems_updated) {

		cpuset_attach_nodemask_to = cs->effective_mems;

		goto out;

	}
@@ -3391,7 +3392,7 @@ cpuset_css_alloc(struct cgroup_subsys_state *parent_css) 
	INIT_LIST_HEAD(&cs->remote_sibling);



	/* Set CS_MEMORY_MIGRATE for default hierarchy */

	if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys))

	if (cpuset_v2())

		__set_bit(CS_MEMORY_MIGRATE, &cs->flags);



	return &cs->css;
@@ -3418,8 +3419,7 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) 
	/*

	 * For v2, clear CS_SCHED_LOAD_BALANCE if parent is isolated

	 */

	if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&

	    !is_sched_load_balance(parent))

	if (cpuset_v2() && !is_sched_load_balance(parent))

		clear_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);



	cpuset_inc();
@@ -3489,8 +3489,7 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css) 
	if (is_partition_valid(cs))

		update_prstate(cs, 0);



	if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&

	    is_sched_load_balance(cs))

	if (!cpuset_v2() && is_sched_load_balance(cs))

		cpuset_update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);



	cpuset_dec();