Messages in this thread Patch in this message | | | From | Conor Dooley <> | Subject | [PATCH v4 2/2] riscv: topology: fix default topology reporting | Date | Fri, 15 Jul 2022 18:51:56 +0100 |
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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.
On a PolarFire SoC, which should have 4 harts with a thread each, lstopo currently reports:
Machine (793MB total) Package L#0 NUMANode L#0 (P#0 793MB) Core L#0 L1d L#0 (32KB) + L1i L#0 (32KB) + PU L#0 (P#0) L1d L#1 (32KB) + L1i L#1 (32KB) + PU L#1 (P#1) L1d L#2 (32KB) + L1i L#2 (32KB) + PU L#2 (P#2) L1d L#3 (32KB) + L1i L#3 (32KB) + PU L#3 (P#3)
Adding calls to store_cpu_topology() in {boot,smp} hart bringup code results in the correct topolgy being reported:
Machine (793MB total) Package L#0 NUMANode L#0 (P#0 793MB) L1d L#0 (32KB) + L1i L#0 (32KB) + Core L#0 + PU L#0 (P#0) L1d L#1 (32KB) + L1i L#1 (32KB) + Core L#1 + PU L#1 (P#1) L1d L#2 (32KB) + L1i L#2 (32KB) + Core L#2 + PU L#2 (P#2) L1d L#3 (32KB) + L1i L#3 (32KB) + Core L#3 + PU L#3 (P#3)
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> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> --- arch/riscv/Kconfig | 2 +- arch/riscv/kernel/smpboot.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 205c1e2f539c..7ffac8818060 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -52,7 +52,7 @@ config RISCV select COMMON_CLK select CPU_PM if CPU_IDLE select EDAC_SUPPORT - select GENERIC_ARCH_TOPOLOGY if SMP + select GENERIC_ARCH_TOPOLOGY select GENERIC_ATOMIC64 if !64BIT select GENERIC_CLOCKEVENTS_BROADCAST if SMP select GENERIC_EARLY_IOREMAP diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c index f1e4948a4b52..b4d5524b1077 100644 --- a/arch/riscv/kernel/smpboot.c +++ b/arch/riscv/kernel/smpboot.c @@ -49,6 +49,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus) unsigned int curr_cpuid; curr_cpuid = smp_processor_id(); + store_cpu_topology(curr_cpuid); numa_store_cpu_info(curr_cpuid); numa_add_cpu(curr_cpuid); @@ -161,9 +162,9 @@ 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); set_cpu_online(curr_cpuid, 1); /* -- 2.37.1
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