Re: [PATCH v2 2/2] powerpc/topology: Check if a core is online

From: Shrikanth Hegde
Date: Wed Jul 31 2024 - 02:27:49 EST




On 7/31/24 8:31 AM, Nysal Jan K.A. wrote:
> From: "Nysal Jan K.A" <nysal@xxxxxxxxxxxxx>
>
> topology_is_core_online() checks if the core a CPU belongs to
> is online. The core is online if at least one of the sibling
> CPUs is online. The first CPU of an online core is also online
> in the common case, so this should be fairly quick.
>
> Signed-off-by: Nysal Jan K.A <nysal@xxxxxxxxxxxxx>
> ---
> arch/powerpc/include/asm/topology.h | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
> index f4e6f2dd04b7..16bacfe8c7a2 100644
> --- a/arch/powerpc/include/asm/topology.h
> +++ b/arch/powerpc/include/asm/topology.h
> @@ -145,6 +145,7 @@ static inline int cpu_to_coregroup_id(int cpu)
>
> #ifdef CONFIG_HOTPLUG_SMT
> #include <linux/cpu_smt.h>
> +#include <linux/cpumask.h>
> #include <asm/cputhreads.h>
>
> static inline bool topology_is_primary_thread(unsigned int cpu)
> @@ -156,6 +157,18 @@ static inline bool topology_smt_thread_allowed(unsigned int cpu)
> {
> return cpu_thread_in_core(cpu) < cpu_smt_num_threads;
> }
> +
> +#define topology_is_core_online topology_is_core_online
> +static inline bool topology_is_core_online(unsigned int cpu)
> +{
> + int i, first_cpu = cpu_first_thread_sibling(cpu);
> +
> + for (i = first_cpu; i < first_cpu + threads_per_core; ++i) {
> + if (cpu_online(i))
> + return true;
> + }
> + return false;
> +}
> #endif
>
> #endif /* __KERNEL__ */

Reviewed-by: Shrikanth Hegde <sshegde@xxxxxxxxxxxxx>