[PATCH 1/2] sched/topology: introduce node_has_cpus() macro

[PATCH 1/2] sched/topology: introduce node_has_cpus() macro

[Yury Norov]

Currently, to check if NUMA node has CPUs, one has to use the
nr_cpus_node() macro, which ends up with cpumask_weight. We can do it
better with cpumask_empty(), because the latter can potentially return
earlier - as soon as 1st set bit found.

This patch adds a node_has_cpus() macro to implement that.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
 include/linux/topology.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/linux/topology.h b/include/linux/topology.h
index fea32377f7c7..7e0d8f8f5a39 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -39,9 +39,11 @@
 #define nr_cpus_node(node) cpumask_weight(cpumask_of_node(node))
 #endif
 
+#define node_has_cpus(node) (!cpumask_empty(cpumask_of_node(node)))
+
 #define for_each_node_with_cpus(node)			\
 	for_each_online_node(node)			\
-		if (nr_cpus_node(node))
+		if (node_has_cpus(node))
 
 int arch_update_cpu_topology(void);
 
-- 
2.34.1

[PATCH 2/2] powerpc: use node_has_cpus() instead of nr_cpus_node()

[Yury Norov]

Use node_has_cpus() as more efficient alternative to nr_cpus_node()
where possible.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
 arch/powerpc/platforms/cell/spu_priv1_mmio.c | 2 +-
 arch/powerpc/platforms/cell/spufs/sched.c    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/cell/spu_priv1_mmio.c b/arch/powerpc/platforms/cell/spu_priv1_mmio.c
index d150e3987304..55b5024b256b 100644
--- a/arch/powerpc/platforms/cell/spu_priv1_mmio.c
+++ b/arch/powerpc/platforms/cell/spu_priv1_mmio.c
@@ -64,7 +64,7 @@ static void cpu_affinity_set(struct spu *spu, int cpu)
 	u64 target;
 	u64 route;
 
-	if (nr_cpus_node(spu->node)) {
+	if (node_has_cpus(spu->node)) {
 		const struct cpumask *spumask = cpumask_of_node(spu->node),
 			*cpumask = cpumask_of_node(cpu_to_node(cpu));
 
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 99bd027a7f7c..9d29cc2c6bcb 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -154,7 +154,7 @@ void spu_update_sched_info(struct spu_context *ctx)
 
 static int __node_allowed(struct spu_context *ctx, int node)
 {
-	if (nr_cpus_node(node)) {
+	if (node_has_cpus(node)) {
 		const struct cpumask *mask = cpumask_of_node(node);
 
 		if (cpumask_intersects(mask, &ctx->cpus_allowed))
-- 
2.34.1

Re: [PATCH 1/2] sched/topology: introduce node_has_cpus() macro

[Valentin Schneider]

On 21/02/23 18:50, Yury Norov wrote:
> Currently, to check if NUMA node has CPUs, one has to use the
> nr_cpus_node() macro, which ends up with cpumask_weight. We can do it
> better with cpumask_empty(), because the latter can potentially return
> earlier - as soon as 1st set bit found.
>
> This patch adds a node_has_cpus() macro to implement that.
>
> Signed-off-by: Yury Norov <yury.norov@gmail.com>

Reviewed-by: Valentin Schneider <vschneid@redhat.com>

Re: [PATCH 2/2] powerpc: use node_has_cpus() instead of nr_cpus_node()

[Valentin Schneider]

On 21/02/23 18:50, Yury Norov wrote:
> Use node_has_cpus() as more efficient alternative to nr_cpus_node()
> where possible.
>
> Signed-off-by: Yury Norov <yury.norov@gmail.com>

Reviewed-by: Valentin Schneider <vschneid@redhat.com>