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Commit f5393693 authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Linus Torvalds
Browse files

cpuset: speed up sched domain partition 



All child cpusets contain a subset of the parent's cpus, so we can skip
them when partitioning sched domains. This decreases 'csa' greately for
cpusets with multi-level hierarchy.

Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: default avatarPaul Jackson <pj@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8d1e6266

kernel/cpuset.c

+37 −4
Original line number Diff line number Diff line
@@ -486,13 +486,38 @@ static int cpusets_overlap(struct cpuset *a, struct cpuset *b) 
static void

update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)

{

	if (!dattr)

		return;

	if (dattr->relax_domain_level < c->relax_domain_level)

		dattr->relax_domain_level = c->relax_domain_level;

	return;

}



static void

update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c)

{

	LIST_HEAD(q);



	list_add(&c->stack_list, &q);

	while (!list_empty(&q)) {

		struct cpuset *cp;

		struct cgroup *cont;

		struct cpuset *child;



		cp = list_first_entry(&q, struct cpuset, stack_list);

		list_del(q.next);



		if (cpus_empty(cp->cpus_allowed))

			continue;



		if (is_sched_load_balance(cp))

			update_domain_attr(dattr, cp);



		list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {

			child = cgroup_cs(cont);

			list_add_tail(&child->stack_list, &q);

		}

	}

}



/*

 * rebuild_sched_domains()

 *
@@ -614,8 +639,16 @@ void rebuild_sched_domains(void) 
		if (cpus_empty(cp->cpus_allowed))

			continue;



		if (is_sched_load_balance(cp))

		/*

		 * All child cpusets contain a subset of the 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 (is_sched_load_balance(cp)) {

			csa[csn++] = cp;

			continue;

		}



		list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {

			child = cgroup_cs(cont);
@@ -686,7 +719,7 @@ void rebuild_sched_domains(void) 
					cpus_or(*dp, *dp, b->cpus_allowed);

					b->pn = -1;

					if (dattr)

						update_domain_attr(dattr

						update_domain_attr_tree(dattr

								   + nslot, b);

				}

			}