Messages in this thread | | | Subject | Re: [PATCH v2] arch_topology: Make cluster topology span at least SMT CPUs | From | Yicong Yang <> | Date | Mon, 5 Sep 2022 11:41:38 +0800 |
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On 2022/9/3 14:00, Greg KH wrote: > On Thu, Aug 25, 2022 at 05:20:07PM +0800, Yicong Yang wrote: >> From: Yicong Yang <yangyicong@hisilicon.com> >> >> 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. >> >> Cc: Sudeep Holla <sudeep.holla@arm.com> >> Cc: Vincent Guittot <vincent.guittot@linaro.org> >> Cc: Ionela Voinescu <ionela.voinescu@arm.com> >> Fixes: bfcc4397435d ("arch_topology: Limit span of cpu_clustergroup_mask()") >> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> >> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> >> Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com> >> --- >> Change since v1: >> - mention the kernel config CONFIG_SCHED_CLUSTER=y, per Ionela >> Link:https://lore.kernel.org/lkml/20220823073044.58697-1-yangyicong@huawei.com/ >> >> 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 0424b59b695e..0056a1273275 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 cpu_smt_mask(cpu); > > As the kernel-test robot reported, this breaks the build on some > architectures, so I'll go and revert it from my tree now. >
Sorry for the regression.
The build error is because cpu_smt_mask() is defined only when CONFIG_SCHED_SMT=y so we'll fail when CONFIG_SCHED_SMT=n. Should use topology_sibling_cpumask() to get SMT mask here. Will respin this.
Thanks.
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