Re: [v1 PATCH 4/4] RISC-V: Support nr_cpus command line option.

[Damien Le Moal <Damien.LeMoal@wdc.com>]

On 2019/03/20 7:20, Atish Patra wrote:
> If nr_cpus command line option is set, maximum possible cpu should be
> set to that value.
> 
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> ---
>  arch/riscv/kernel/smpboot.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> index 609475c5..a8fe590c 100644
> --- a/arch/riscv/kernel/smpboot.c
> +++ b/arch/riscv/kernel/smpboot.c
> @@ -86,11 +86,19 @@ void __init setup_smp(void)
>  		}
>  
>  		cpuid_to_hartid_map(cpuid) = hart;
> -		set_cpu_possible(cpuid, true);

This looks weird: the code being changed does not match what patch 3/4 did.

>  		cpuid++;
>  	}
>  
>  	BUG_ON(!found_boot_cpu);
> +
> +	if (cpuid > nr_cpu_ids)
> +		pr_warn("Total number of cpus [%d] are greater than configured via nr_cpus [%d]\n",

"The total number of cpus [%d] is greater than nr_cpus option value [%d]\n"

> +			cpuid, nr_cpu_ids);
> +
> +	for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) {
> +		if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID)
> +			set_cpu_possible(cpuid, true);
> +	}
>  }
>  
>  int __cpu_up(unsigned int cpu, struct task_struct *tidle)
> 


-- 
Damien Le Moal
Western Digital Research