Unverified Commit e60ac071 authored Oct 18, 2023 by openeuler-ci-bot Committed by Gitee Oct 18, 2023

!2449 [OLK-5.10] arch_topology: Limit span of cpu_clustergroup_mask()

Merge Pull Request from: @liujie-248683921 
 
Currently the cluster identifier is not set on DT based platforms.
The reset or default value is -1 for all the CPUs. Once we assign the
cluster identifier values correctly, the cluster_sibling mask will be
populated and returned by cpu_clustergroup_mask() to contribute in the
creation of the CLS scheduling domain level, if SCHED_CLUSTER is
enabled.

To avoid topologies that will result in questionable or incorrect
scheduling domains, impose restrictions regarding the span of clusters,
as presented to scheduling domains building code: cluster_sibling should
not span more or the same CPUs as cpu_coregroup_mask().

This is needed in order to obtain a strict separation between the MC and
CLS levels, and maintain the same domains for existing platforms in
the presence of CONFIG_SCHED_CLUSTER, where the new cluster information
is redundant and irrelevant for the scheduler.

While previously the scheduling domain builder code would have removed MC
as redundant and kept CLS if SCHED_CLUSTER was enabled and the
cpu_coregroup_mask() and cpu_clustergroup_mask() spanned the same CPUs,
now CLS will be removed and MC kept.
 
 
Link:https://gitee.com/openeuler/kernel/pulls/2449

 

Reviewed-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>

parents 88b0d725 5e8c27f6

drivers/base/arch_topology.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -552,6 +552,14 @@ const struct cpumask *cpu_coregroup_mask(int cpu)

		const struct cpumask *cpu_clustergroup_mask(int cpu)
		{
		/*
		* Forbid cpu_clustergroup_mask() to span more or the same CPUs as
		* cpu_coregroup_mask().
		*/
		if (cpumask_subset(cpu_coregroup_mask(cpu),
		&cpu_topology[cpu].cluster_sibling))
		return topology_sibling_cpumask(cpu);

		return &cpu_topology[cpu].cluster_sibling;
		}