Messages in this thread | | | Date | Thu, 7 Jul 2022 10:47:56 +0100 | From | Sudeep Holla <> | Subject | Re: [PATCH] riscv: arch-topology: fix default topology reporting |
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On Wed, Jul 06, 2022 at 02:38:01PM -0700, Atish Patra wrote: > On Wed, Jul 6, 2022 at 11:46 AM Conor Dooley <mail@conchuod.ie> wrote: > > > > From: Conor Dooley <conor.dooley@microchip.com> > > > > RISC-V has no sane defaults to fall back on where there is no cpu-map > > in the devicetree. > > Without sane defaults, the package, core and thread IDs are all set to > > -1. This causes user-visible inaccuracies for tools like hwloc/lstopo > > which rely on the sysfs cpu topology files to detect a system's > > topology. > > > > Add sane defaults in ~the exact same way as ARM64. > > > > CC: stable@vger.kernel.org > > Fixes: 03f11f03dbfe ("RISC-V: Parse cpu topology during boot.") > > Reported-by: Brice Goglin <Brice.Goglin@inria.fr> > > Link: https://github.com/open-mpi/hwloc/issues/536 > > Signed-off-by: Conor Dooley <conor.dooley@microchip.com> > > --- > > > > Sudeep suggested that this be backported rather than the changes to > > the devicetrees adding cpu-map since that property is optional. > > That patchset is still valid in it's own right. > > > > arch/riscv/include/asm/topology.h | 13 +++++++++++++ > > arch/riscv/kernel/Makefile | 1 + > > arch/riscv/kernel/smpboot.c | 4 ++++ > > arch/riscv/kernel/topology.c | 32 +++++++++++++++++++++++++++++++ > > 4 files changed, 50 insertions(+) > > create mode 100644 arch/riscv/include/asm/topology.h > > create mode 100644 arch/riscv/kernel/topology.c > > > > diff --git a/arch/riscv/include/asm/topology.h b/arch/riscv/include/asm/topology.h > > new file mode 100644 > > index 000000000000..36bc6ecda898 > > --- /dev/null > > +++ b/arch/riscv/include/asm/topology.h > > @@ -0,0 +1,13 @@ > > +/* SPDX-License-Identifier: GPL-2.0-only */ > > +/* > > + * Copyright (c) 2022 Microchip Technology Inc. and its subsidiaries > > + */ > > + > > +#ifndef _ASM_RISCV_TOPOLOGY_H > > +#define _ASM_RISCV_TOPOLOGY_H > > + > > +#include <asm-generic/topology.h> > > + > > +void store_cpu_topology(unsigned int cpuid); > > + > > +#endif /* _ASM_RISCV_TOPOLOGY_H */ > > diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile > > index c71d6591d539..9518882ba6f9 100644 > > --- a/arch/riscv/kernel/Makefile > > +++ b/arch/riscv/kernel/Makefile > > @@ -50,6 +50,7 @@ obj-y += riscv_ksyms.o > > obj-y += stacktrace.o > > obj-y += cacheinfo.o > > obj-y += patch.o > > +obj-y += topology.o > > obj-y += probes/ > > obj-$(CONFIG_MMU) += vdso.o vdso/ > > > > diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c > > index f1e4948a4b52..d551c7f452d4 100644 > > --- a/arch/riscv/kernel/smpboot.c > > +++ b/arch/riscv/kernel/smpboot.c > > @@ -32,6 +32,7 @@ > > #include <asm/sections.h> > > #include <asm/sbi.h> > > #include <asm/smp.h> > > +#include <asm/topology.h> > > > > #include "head.h" > > > > @@ -40,6 +41,8 @@ static DECLARE_COMPLETION(cpu_running); > > void __init smp_prepare_boot_cpu(void) > > { > > init_cpu_topology(); > > + > > + store_cpu_topology(smp_processor_id()); > > } > > > > void __init smp_prepare_cpus(unsigned int max_cpus) > > @@ -161,6 +164,7 @@ asmlinkage __visible void smp_callin(void) > > mmgrab(mm); > > current->active_mm = mm; > > > > + store_cpu_topology(curr_cpuid); > > notify_cpu_starting(curr_cpuid); > > numa_add_cpu(curr_cpuid); > > update_siblings_masks(curr_cpuid); > > diff --git a/arch/riscv/kernel/topology.c b/arch/riscv/kernel/topology.c > > new file mode 100644 > > index 000000000000..db72862bd5b5 > > --- /dev/null > > +++ b/arch/riscv/kernel/topology.c > > @@ -0,0 +1,32 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +/* > > + * Copyright (c) 2022 Microchip Technology Inc. and its subsidiaries > > + * > > + * Based on the arm64 version, which was in turn based on arm32, which was > > + * ultimately based on sh's. > > + * The arm64 version was listed as: > > + * Copyright (C) 2011,2013,2014 Linaro Limited. > > + */ > > + > > +#include <linux/arch_topology.h> > > +#include <linux/topology.h> > > +#include <asm/topology.h> > > + > > +void store_cpu_topology(unsigned int cpuid) > > +{ > > + struct cpu_topology *cpuid_topo = &cpu_topology[cpuid]; > > + > > + if (cpuid_topo->package_id != -1) > > + goto topology_populated; > > + > > + cpuid_topo->thread_id = -1; > > + cpuid_topo->core_id = cpuid; > > + cpuid_topo->package_id = cpu_to_node(cpuid); > > + > > + pr_debug("CPU%u: package %d core %d thread %d\n", > > + cpuid, cpuid_topo->package_id, cpuid_topo->core_id, > > + cpuid_topo->thread_id); > > + > > +topology_populated: > > + update_siblings_masks(cpuid); > > +} > > > > This function is pretty much the same as the arm64 one except the > UP/mpidr check. > Can we move this to the common code as well ? >
While I completely agree with the idea, not sure if that makes backports (if required) any difficult. If so, I would rather keep this way for a release and then move both to the common place in arch_topology.
> > base-commit: b6f1f2fa2bddd69ff46a190b8120bd440fd50563 > > -- > > 2.37.0 > > > > > -- > Regards, > Atish
-- Regards, Sudeep
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