Messages in this thread | | | Date | Thu, 21 Apr 2022 09:04:55 +0200 | Subject | Re: [PATCH v3] RISC-V: Increase range and default value of NR_CPUS | From | Heinrich Schuchardt <> |
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On 4/20/22 13:24, Anup Patel wrote: > Currently, the range and default value of NR_CPUS is too restrictive > for high-end RISC-V systems with large number of HARTs. The latest > QEMU virt machine supports upto 512 CPUs so the current NR_CPUS is > restrictive for QEMU as well. Other major architectures (such as > ARM64, x86_64, MIPS, etc) have a much higher range and default > value of NR_CPUS. > > This patch increases NR_CPUS range to 2-512 and default value to > XLEN (i.e. 32 for RV32 and 64 for RV64). > > Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> --- > Changes since v2: > - Rebased on Linux-5.18-rc3 > - Use a different range when SBI v0.1 is enabled > Changes since v1: > - Updated NR_CPUS range to 2-512 which reflects maximum number of > CPUs supported by QEMU virt machine. > --- > arch/riscv/Kconfig | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index 00fd9c548f26..1823f281069f 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -275,10 +275,13 @@ config SMP > If you don't know what to do here, say N. > > config NR_CPUS > - int "Maximum number of CPUs (2-32)" > - range 2 32 > + int "Maximum number of CPUs (2-512)" > depends on SMP > - default "8" > + range 2 512 if !SBI_V01 > + range 2 32 if SBI_V01 && 32BIT > + range 2 64 if SBI_V01 && 64BIT > + default "32" if 32BIT > + default "64" if 64BIT > > config HOTPLUG_CPU > bool "Support for hot-pluggable CPUs"
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