netdev - [PATCH iwl-next v2] ice: use netif_get_num_default_rss

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Message-ID: <20251028070634.2124215-1-michal.swiatkowski@linux.intel.com>
Date: Tue, 28 Oct 2025 08:06:34 +0100
From: Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>
To: intel-wired-lan@...ts.osuosl.org
Cc: netdev@...r.kernel.org,
	pmenzel@...gen.mpg.de,
	aleksander.lobakin@...el.com,
	przemyslaw.kitszel@...el.com,
	jacob.e.keller@...el.com,
	Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>
Subject: [PATCH iwl-next v2] ice: use netif_get_num_default_rss_queues()

On some high-core systems (like AMD EPYC Bergamo, Intel Clearwater
Forest) loading ice driver with default values can lead to queue/irq
exhaustion. It will result in no additional resources for SR-IOV.

In most cases there is no performance reason for more than half
num_cpus(). Limit the default value to it using generic
netif_get_num_default_rss_queues().

Still, using ethtool the number of queues can be changed up to
num_online_cpus(). It can be done by calling:
$ethtool -L ethX combined max_cpu

This change affects only the default queue amount.

Signed-off-by: Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>
---
v1 --> v2:
 * Follow Olek's comment and switch from custom limiting to the generic
   netif_...() function.
 * Add more info in commit message (Paul)
 * Dropping RB tags, as it is different patch now
---
 drivers/net/ethernet/intel/ice/ice_irq.c |  5 +++--
 drivers/net/ethernet/intel/ice/ice_lib.c | 12 ++++++++----
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_irq.c b/drivers/net/ethernet/intel/ice/ice_irq.c
index 30801fd375f0..1d9b2d646474 100644
--- a/drivers/net/ethernet/intel/ice/ice_irq.c
+++ b/drivers/net/ethernet/intel/ice/ice_irq.c
@@ -106,9 +106,10 @@ static struct ice_irq_entry *ice_get_irq_res(struct ice_pf *pf,
 #define ICE_RDMA_AEQ_MSIX 1
 static int ice_get_default_msix_amount(struct ice_pf *pf)
 {
-	return ICE_MIN_LAN_OICR_MSIX + num_online_cpus() +
+	return ICE_MIN_LAN_OICR_MSIX + netif_get_num_default_rss_queues() +
 	       (test_bit(ICE_FLAG_FD_ENA, pf->flags) ? ICE_FDIR_MSIX : 0) +
-	       (ice_is_rdma_ena(pf) ? num_online_cpus() + ICE_RDMA_AEQ_MSIX : 0);
+	       (ice_is_rdma_ena(pf) ? netif_get_num_default_rss_queues() +
+				      ICE_RDMA_AEQ_MSIX : 0);
 }
 
 /**
diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index bac481e8140d..e366d089bef9 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -159,12 +159,14 @@ static void ice_vsi_set_num_desc(struct ice_vsi *vsi)
 
 static u16 ice_get_rxq_count(struct ice_pf *pf)
 {
-	return min(ice_get_avail_rxq_count(pf), num_online_cpus());
+	return min(ice_get_avail_rxq_count(pf),
+		   netif_get_num_default_rss_queues());
 }
 
 static u16 ice_get_txq_count(struct ice_pf *pf)
 {
-	return min(ice_get_avail_txq_count(pf), num_online_cpus());
+	return min(ice_get_avail_txq_count(pf),
+		   netif_get_num_default_rss_queues());
 }
 
 /**
@@ -907,13 +909,15 @@ static void ice_vsi_set_rss_params(struct ice_vsi *vsi)
 		if (vsi->type == ICE_VSI_CHNL)
 			vsi->rss_size = min_t(u16, vsi->num_rxq, max_rss_size);
 		else
-			vsi->rss_size = min_t(u16, num_online_cpus(),
+			vsi->rss_size = min_t(u16,
+					      netif_get_num_default_rss_queues(),
 					      max_rss_size);
 		vsi->rss_lut_type = ICE_LUT_PF;
 		break;
 	case ICE_VSI_SF:
 		vsi->rss_table_size = ICE_LUT_VSI_SIZE;
-		vsi->rss_size = min_t(u16, num_online_cpus(), max_rss_size);
+		vsi->rss_size = min_t(u16, netif_get_num_default_rss_queues(),
+				      max_rss_size);
 		vsi->rss_lut_type = ICE_LUT_VSI;
 		break;
 	case ICE_VSI_VF:
-- 
2.49.0