Re: [PATCH v2 5/6] powerpc/smp: Add read_mostly attribute

Michael Ellerman
2023-10-19T04:49:59Z

Srikar Dronamraju <srikar@linux.vnet.ibm.com> writes:
> There are some variables that are only updated at boot time.
> So add read_mostly attribute to such variables

If they're only updated at boot time then __ro_after_init would be the
better annotation.

cheers

> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index 29da9262cb17..b1eb11a66902 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -77,10 +77,10 @@ static DEFINE_PER_CPU(int, cpu_state) = { 0 };
> #endif
>
> struct task_struct *secondary_current;
> -bool has_big_cores;
> -bool coregroup_enabled;
> -bool thread_group_shares_l2;
> -bool thread_group_shares_l3;
> +bool has_big_cores __read_mostly;
> +bool coregroup_enabled __read_mostly;
> +bool thread_group_shares_l2 __read_mostly;
> +bool thread_group_shares_l3 __read_mostly;
>
> DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
> DEFINE_PER_CPU(cpumask_var_t, cpu_smallcore_map);
> @@ -987,7 +987,7 @@ static int __init init_thread_group_cache_map(int cpu, int cache_property)
> return 0;
> }
>
> -static bool shared_caches;
> +static bool shared_caches __read_mostly;
> DEFINE_STATIC_KEY_FALSE(powerpc_asym_packing);
>
> #ifdef CONFIG_SCHED_SMT
> --
> 2.31.1