[RFC PATCH v5 4/4] scheduler: Add cluster scheduler level for x86

[Tim Chen]

On 3/18/21 9:16 PM, Barry Song wrote:
> From: Tim Chen <tim.c.chen at linux.intel.com>
> 
> There are x86 CPU architectures (e.g. Jacobsville) where L2 cahce
> is shared among a cluster of cores instead of being exclusive
> to one single core.
> 
> To prevent oversubscription of L2 cache, load should be
> balanced between such L2 clusters, especially for tasks with
> no shared data.
> 
> Also with cluster scheduling policy where tasks are woken up
> in the same L2 cluster, we will benefit from keeping tasks
> related to each other and likely sharing data in the same L2
> cluster.
> 
> Add CPU masks of CPUs sharing the L2 cache so we can build such
> L2 cluster scheduler domain.
> 
> Signed-off-by: Tim Chen <tim.c.chen at linux.intel.com>
> Signed-off-by: Barry Song <song.bao.hua at hisilicon.com>


Barry,

Can you also add this chunk to the patch.
Thanks.

Tim


diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index 2a11ccc14fb1..800fa48c9fcd 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -115,6 +115,7 @@ extern unsigned int __max_die_per_package;
 
 #ifdef CONFIG_SMP
 #define topology_die_cpumask(cpu)		(per_cpu(cpu_die_map, cpu))
+#define topology_cluster_cpumask(cpu)		(cpu_clustergroup_mask(cpu))
 #define topology_core_cpumask(cpu)		(per_cpu(cpu_core_map, cpu))
 #define topology_sibling_cpumask(cpu)		(per_cpu(cpu_sibling_map, cpu))