Commit 5ac251c8 authored by Yicong Yang's avatar Yicong Yang Committed by Greg Kroah-Hartman

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: bfcc4397 ("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: default avatarSudeep Holla <sudeep.holla@arm.com>
Signed-off-by: default avatarYicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/20220905122615.12946-1-yangyicong@huawei.comSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c2e40659
......@@ -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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