From 5ac251c8a05ce074e5efac779debf82a15d870a3 Mon Sep 17 00:00:00 2001
From: Yicong Yang <yangyicong@hisilicon.com>
Date: Mon, 5 Sep 2022 20:26:15 +0800
Subject: [PATCH] arch_topology: Make cluster topology span at least SMT CPUs
Currently cpu_clustergroup_mask() will return CPU mask if cluster span more
or the same CPUs as cpu_coregroup_mask(). This will result topology borken
on non-Cluster SMT machines when building with CONFIG_SCHED_CLUSTER=y.
Test with:
qemu-system-aarch64 -enable-kvm -machine virt \
-net none \
-cpu host \
-bios ./QEMU_EFI.fd \
-m 2G \
-smp 48,sockets=2,cores=12,threads=2 \
-kernel $Image \
-initrd $Rootfs \
-nographic
-append "rdinit=init console=ttyAMA0 sched_verbose loglevel=8"
We'll get below error:
[ 3.084568] BUG: arch topology borken
[ 3.084570] the SMT domain not a subset of the CLS domain
Since cluster is a level higher than SMT, fix this by making cluster
spans at least SMT CPUs.
Fixes: bfcc4397435d ("arch_topology: Limit span of cpu_clustergroup_mask()")
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Ionela Voinescu <ionela.voinescu@arm.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/20220905122615.12946-1-yangyicong@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/base/arch_topology.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index eaa1b8d2d39d3..46cbe4471e785 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -724,7 +724,7 @@ const struct cpumask *cpu_clustergroup_mask(int cpu)
*/
if (cpumask_subset(cpu_coregroup_mask(cpu),
&cpu_topology[cpu].cluster_sibling))
- return get_cpu_mask(cpu);
+ return topology_sibling_cpumask(cpu);
return &cpu_topology[cpu].cluster_sibling;
}
--
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