[PATCH 1/4] net: mellanox: drop mlx5_cpumask_default_spread()

From: Yury Norov
Date: Sun Sep 24 2023 - 22:05:44 EST


The function duplicates existing cpumask_local_spread(), and it's O(N),
while cpumask_local_spread() implementation is based on bsearch, and
thus is O(log n), so drop mlx5_cpumask_default_spread() and use generic
cpumask_local_spread().

Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx>
Signed-off-by: Yury Norov <ynorov@xxxxxxxxxx>
---
drivers/net/ethernet/mellanox/mlx5/core/eq.c | 28 ++------------------
1 file changed, 2 insertions(+), 26 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eq.c b/drivers/net/ethernet/mellanox/mlx5/core/eq.c
index ea0405e0a43f..bd9f857cc52d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/eq.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eq.c
@@ -828,30 +828,6 @@ static void comp_irq_release_pci(struct mlx5_core_dev *dev, u16 vecidx)
mlx5_irq_release_vector(irq);
}

-static int mlx5_cpumask_default_spread(int numa_node, int index)
-{
- const struct cpumask *prev = cpu_none_mask;
- const struct cpumask *mask;
- int found_cpu = 0;
- int i = 0;
- int cpu;
-
- rcu_read_lock();
- for_each_numa_hop_mask(mask, numa_node) {
- for_each_cpu_andnot(cpu, mask, prev) {
- if (i++ == index) {
- found_cpu = cpu;
- goto spread_done;
- }
- }
- prev = mask;
- }
-
-spread_done:
- rcu_read_unlock();
- return found_cpu;
-}
-
static struct cpu_rmap *mlx5_eq_table_get_pci_rmap(struct mlx5_core_dev *dev)
{
#ifdef CONFIG_RFS_ACCEL
@@ -873,7 +849,7 @@ static int comp_irq_request_pci(struct mlx5_core_dev *dev, u16 vecidx)
int cpu;

rmap = mlx5_eq_table_get_pci_rmap(dev);
- cpu = mlx5_cpumask_default_spread(dev->priv.numa_node, vecidx);
+ cpu = cpumask_local_spread(vecidx, dev->priv.numa_node);
irq = mlx5_irq_request_vector(dev, cpu, vecidx, &rmap);
if (IS_ERR(irq))
return PTR_ERR(irq);
@@ -1125,7 +1101,7 @@ int mlx5_comp_vector_get_cpu(struct mlx5_core_dev *dev, int vector)
if (mask)
cpu = cpumask_first(mask);
else
- cpu = mlx5_cpumask_default_spread(dev->priv.numa_node, vector);
+ cpu = cpumask_local_spread(vector, dev->priv.numa_node);

return cpu;
}
--
2.39.2