Subject: Re: [PATCH RFC 1/5] powerpc:numa Add numa_cpu_lookup function to update lookup table

From: Raghavendra K T <[email-masked]>
Date: Mon, 28 Sep 2015 00:11:01 +0530

On 09/27/2015 11:59 PM, Raghavendra K T wrote:
> We access numa_cpu_lookup_table array directly in all the places
> to read/update numa cpu lookup information. Instead use a helper
> function to update.
>
> This is helpful in changing the way numa<-->cpu mapping in single
> place when needed.
>
> This is a cosmetic change, no change in functionality.
>
> Signed-off-by: Raghavendra K T <[email-masked]>
Signed-off-by: Raghavendra K T <[email-masked]>
> ---
Sorry:  changelog edit messed it.. :(

>   arch/powerpc/include/asm/mmzone.h |  2 +-
>   arch/powerpc/kernel/smp.c         | 10 +++++-----
>   arch/powerpc/mm/numa.c            | 28 +++++++++++++++++-----------
>   3 files changed, 23 insertions(+), 17 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/mmzone.h b/arch/powerpc/include/asm/mmzone.h
> index 7b58917..c24a5f4 100644
> --- a/arch/powerpc/include/asm/mmzone.h
> +++ b/arch/powerpc/include/asm/mmzone.h
> @@ -29,7 +29,7 @@ extern struct pglist_data *node_data[];
>    * Following are specific to this numa platform.
>    */
>
> -extern int numa_cpu_lookup_table[];
> +extern int numa_cpu_lookup(int cpu);
>   extern cpumask_var_t node_to_cpumask_map[];
>   #ifdef CONFIG_MEMORY_HOTPLUG
>   extern unsigned long max_pfn;
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index ec9ec20..56fbe9e 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -381,9 +381,9 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
>   		 * numa_node_id() works after this.
>   		 */
>   		if (cpu_present(cpu)) {
> -			set_cpu_numa_node(cpu, numa_cpu_lookup_table[cpu]);
> +			set_cpu_numa_node(cpu, numa_cpu_lookup(cpu));
>   			set_cpu_numa_mem(cpu,
> -				local_memory_node(numa_cpu_lookup_table[cpu]));
> +				local_memory_node(numa_cpu_lookup(cpu)));
>   		}
>   	}
>
> @@ -400,7 +400,7 @@ void smp_prepare_boot_cpu(void)
>   #ifdef CONFIG_PPC64
>   	paca[boot_cpuid].__current = current;
>   #endif
> -	set_numa_node(numa_cpu_lookup_table[boot_cpuid]);
> +	set_numa_node(numa_cpu_lookup(boot_cpuid));
>   	current_set[boot_cpuid] = task_thread_info(current);
>   }
>
> @@ -718,8 +718,8 @@ void start_secondary(void *unused)
>   	}
>   	traverse_core_siblings(cpu, true);
>
> -	set_numa_node(numa_cpu_lookup_table[cpu]);
> -	set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
> +	set_numa_node(numa_cpu_lookup(cpu));
> +	set_numa_mem(local_memory_node(numa_cpu_lookup(cpu)));
>
>   	smp_wmb();
>   	notify_cpu_starting(cpu);
> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
> index 8b9502a..d5e6eee 100644
> --- a/arch/powerpc/mm/numa.c
> +++ b/arch/powerpc/mm/numa.c
> @@ -52,7 +52,6 @@ int numa_cpu_lookup_table[NR_CPUS];
>   cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
>   struct pglist_data *node_data[MAX_NUMNODES];
>
> -EXPORT_SYMBOL(numa_cpu_lookup_table);
>   EXPORT_SYMBOL(node_to_cpumask_map);
>   EXPORT_SYMBOL(node_data);
>
> @@ -134,19 +133,25 @@ static int __init fake_numa_create_new_node(unsigned long end_pfn,
>   	return 0;
>   }
>
> -static void reset_numa_cpu_lookup_table(void)
> +int numa_cpu_lookup(int cpu)
>   {
> -	unsigned int cpu;
> -
> -	for_each_possible_cpu(cpu)
> -		numa_cpu_lookup_table[cpu] = -1;
> +	return numa_cpu_lookup_table[cpu];
>   }
> +EXPORT_SYMBOL(numa_cpu_lookup);
>
> -static void update_numa_cpu_lookup_table(unsigned int cpu, int node)
> +static inline void update_numa_cpu_lookup_table(unsigned int cpu, int node)
>   {
>   	numa_cpu_lookup_table[cpu] = node;
>   }
>
> +static void reset_numa_cpu_lookup_table(void)
> +{
> +	unsigned int cpu;
> +
> +	for_each_possible_cpu(cpu)
> +		update_numa_cpu_lookup_table(cpu, -1);
> +}
> +
>   static void map_cpu_to_node(int cpu, int node)
>   {
>   	update_numa_cpu_lookup_table(cpu, node);
> @@ -160,7 +165,7 @@ static void map_cpu_to_node(int cpu, int node)
>   #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_PPC_SPLPAR)
>   static void unmap_cpu_from_node(unsigned long cpu)
>   {
> -	int node = numa_cpu_lookup_table[cpu];
> +	int node = numa_cpu_lookup(cpu);
>
>   	dbg("removing cpu %lu from node %d\n", cpu, node);
>
> @@ -536,7 +541,8 @@ static int numa_setup_cpu(unsigned long lcpu)
>   	 * directly instead of querying the firmware, since it represents
>   	 * the most recent mapping notified to us by the platform (eg: VPHN).
>   	 */
> -	if ((nid = numa_cpu_lookup_table[lcpu]) >= 0) {
> +	nid = numa_cpu_lookup(lcpu);
> +	if (nid >= 0) {
>   		map_cpu_to_node(lcpu, nid);
>   		return nid;
>   	}
> @@ -1413,7 +1419,7 @@ int arch_update_cpu_topology(void)
>   		if (new_nid < 0 || !node_online(new_nid))
>   			new_nid = first_online_node;
>
> -		if (new_nid == numa_cpu_lookup_table[cpu]) {
> +		if (new_nid == numa_cpu_lookup(cpu)) {
>   			cpumask_andnot(&cpu_associativity_changes_mask,
>   					&cpu_associativity_changes_mask,
>   					cpu_sibling_mask(cpu));
> @@ -1425,7 +1431,7 @@ int arch_update_cpu_topology(void)
>   			ud = &updates[i++];
>   			ud->cpu = sibling;
>   			ud->new_nid = new_nid;
> -			ud->old_nid = numa_cpu_lookup_table[sibling];
> +			ud->old_nid = numa_cpu_lookup(sibling);
>   			cpumask_set_cpu(sibling, &updated_cpus);
>   			if (i < weight)
>   				ud->next = &updates[i];
>