From 5ac251c8a05ce074e5efac779debf82a15d870a3 Mon Sep 17 00:00:00 2001 From: Yicong Yang 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 Cc: Vincent Guittot Cc: Ionela Voinescu Cc: Greg KH Reviewed-by: Sudeep Holla Signed-off-by: Yicong Yang Link: https://lore.kernel.org/r/20220905122615.12946-1-yangyicong@huawei.com Signed-off-by: Greg Kroah-Hartman --- 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 eaa1b8d2d39d..46cbe4471e78 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; }