From: William Tu witu@nvidia.com
[ Upstream commit b9cc8f9d700867aaa77aedddfea85e53d5e5d584 ]
By experiments, a single queue representor netdev consumes kernel memory around 2.8MB, and 1.8MB out of the 2.8MB is due to page pool for the RXQ. Scaling to a thousand representors consumes 2.8GB, which becomes a memory pressure issue for embedded devices such as BlueField-2 16GB / BlueField-3 32GB memory.
Since representor netdevs mostly handles miss traffic, and ideally, most of the traffic will be offloaded, reduce the default non-uplink rep netdev's RXQ default depth from 1024 to 256 if mdev is ecpf eswitch manager. This saves around 1MB of memory per regular RQ, (1024 - 256) * 2KB, allocated from page pool.
With rxq depth of 256, the netlink page pool tool reports $./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ --dump page-pool-get {'id': 277, 'ifindex': 9, 'inflight': 128, 'inflight-mem': 786432, 'napi-id': 775}]
This is due to mtu 1500 + headroom consumes half pages, so 256 rxq entries consumes around 128 pages (thus create a page pool with size 128), shown above at inflight.
Note that each netdev has multiple types of RQs, including Regular RQ, XSK, PTP, Drop, Trap RQ. Since non-uplink representor only supports regular rq, this patch only changes the regular RQ's default depth.
Signed-off-by: William Tu witu@nvidia.com Reviewed-by: Bodong Wang bodong@nvidia.com Reviewed-by: Saeed Mahameed saeedm@nvidia.com Signed-off-by: Tariq Toukan tariqt@nvidia.com Reviewed-by: Michal Swiatkowski michal.swiatkowski@linux.intel.com Link: https://patch.msgid.link/20250209101716.112774-8-tariqt@nvidia.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mellanox/mlx5/core/en_rep.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c index 6667ec26e079b..07f38f472a279 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c @@ -65,6 +65,7 @@ #define MLX5E_REP_PARAMS_DEF_LOG_SQ_SIZE \ max(0x7, MLX5E_PARAMS_MINIMUM_LOG_SQ_SIZE) #define MLX5E_REP_PARAMS_DEF_NUM_CHANNELS 1 +#define MLX5E_REP_PARAMS_DEF_LOG_RQ_SIZE 0x8
static const char mlx5e_rep_driver_name[] = "mlx5e_rep";
@@ -855,6 +856,8 @@ static void mlx5e_build_rep_params(struct net_device *netdev)
/* RQ */ mlx5e_build_rq_params(mdev, params); + if (!mlx5e_is_uplink_rep(priv) && mlx5_core_is_ecpf(mdev)) + params->log_rq_mtu_frames = MLX5E_REP_PARAMS_DEF_LOG_RQ_SIZE;
/* If netdev is already registered (e.g. move from nic profile to uplink, * RTNL lock must be held before triggering netdev notifiers.