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From: Tariq Toukan <tariqt@nvidia.com>
To: Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>
Cc: Jiri Pirko <jiri@resnulli.us>, Jonathan Corbet <corbet@lwn.net>,
	"Leon Romanovsky" <leon@kernel.org>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Saeed Mahameed <saeedm@nvidia.com>,
	Tariq Toukan <tariqt@nvidia.com>, Mark Bloch <mbloch@nvidia.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Jesper Dangaard Brouer <hawk@kernel.org>,
	"John Fastabend" <john.fastabend@gmail.com>,
	<netdev@vger.kernel.org>, <linux-doc@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <linux-rdma@vger.kernel.org>,
	<bpf@vger.kernel.org>, Gal Pressman <gal@nvidia.com>,
	Cosmin Ratiu <cratiu@nvidia.com>,
	Dragos Tatulea <dtatulea@nvidia.com>,
	Jiri Pirko <jiri@nvidia.com>, Jason Gunthorpe <jgg@nvidia.com>
Subject: [PATCH net-next V2 05/10] net/mlx5e: Prepare for using multiple TX doorbells
Date: Tue, 16 Sep 2025 17:11:39 +0300	[thread overview]
Message-ID: <1758031904-634231-6-git-send-email-tariqt@nvidia.com> (raw)
In-Reply-To: <1758031904-634231-1-git-send-email-tariqt@nvidia.com>

From: Cosmin Ratiu <cratiu@nvidia.com>

The driver allocates a single doorbell per device and uses
it for all Send Queues (SQs). This can become a bottleneck due to the
high number of concurrent MMIO accesses when ringing the same doorbell
from many channels.

This patch makes the doorbells used by channel queues configurable.

mlx5e_channel_pick_doorbell() is added to select the doorbell to be used
for a given channel, picking the default for now.

When opening a channel, the selected doorbell is saved to the channel
struct and used whenever channel-related queues are created.

Finally, 'uar_page' is added to 'struct mlx5e_create_sq_param' to
control which doorbell to use when allocating an SQ, since that can
happen outside channel context (e.g. for PTP).

Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en.h   |  1 +
 .../ethernet/mellanox/mlx5/core/en/params.h    |  1 +
 .../net/ethernet/mellanox/mlx5/core/en/ptp.c   |  4 +++-
 .../net/ethernet/mellanox/mlx5/core/en/ptp.h   |  1 +
 .../net/ethernet/mellanox/mlx5/core/en_main.c  | 18 ++++++++++++++----
 5 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 0dd3bc0f4caa..9c73165653bf 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -788,6 +788,7 @@ struct mlx5e_channel {
 	int                        vec_ix;
 	int                        sd_ix;
 	int                        cpu;
+	struct mlx5_sq_bfreg      *bfreg;
 	/* Sync between icosq recovery and XSK enable/disable. */
 	struct mutex               icosq_recovery_lock;
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/params.h b/drivers/net/ethernet/mellanox/mlx5/core/en/params.h
index e3edf79dde5f..00617c65fe3c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/params.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/params.h
@@ -51,6 +51,7 @@ struct mlx5e_create_sq_param {
 	u32                         tisn;
 	u8                          tis_lst_sz;
 	u8                          min_inline_mode;
+	u32                         uar_page;
 };
 
 /* Striding RQ dynamic parameters */
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c
index 7c1d9a9ea464..a392578a063c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c
@@ -334,7 +334,7 @@ static int mlx5e_ptp_alloc_txqsq(struct mlx5e_ptp *c, int txq_ix,
 	sq->mdev      = mdev;
 	sq->ch_ix     = MLX5E_PTP_CHANNEL_IX;
 	sq->txq_ix    = txq_ix;
-	sq->uar_map   = mdev->priv.bfreg.map;
+	sq->uar_map   = c->bfreg->map;
 	sq->min_inline_mode = params->tx_min_inline_mode;
 	sq->hw_mtu    = MLX5E_SW2HW_MTU(params, params->sw_mtu);
 	sq->stats     = &c->priv->ptp_stats.sq[tc];
@@ -486,6 +486,7 @@ static int mlx5e_ptp_open_txqsq(struct mlx5e_ptp *c, u32 tisn,
 	csp.wq_ctrl         = &txqsq->wq_ctrl;
 	csp.min_inline_mode = txqsq->min_inline_mode;
 	csp.ts_cqe_to_dest_cqn = ptpsq->ts_cq.mcq.cqn;
+	csp.uar_page = c->bfreg->index;
 
 	err = mlx5e_create_sq_rdy(c->mdev, sqp, &csp, 0, &txqsq->sqn);
 	if (err)
@@ -900,6 +901,7 @@ int mlx5e_ptp_open(struct mlx5e_priv *priv, struct mlx5e_params *params,
 	c->num_tc   = mlx5e_get_dcb_num_tc(params);
 	c->stats    = &priv->ptp_stats.ch;
 	c->lag_port = lag_port;
+	c->bfreg    = &mdev->priv.bfreg;
 
 	err = mlx5e_ptp_set_state(c, params);
 	if (err)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.h b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.h
index 883c044852f1..1b3c9648220b 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.h
@@ -66,6 +66,7 @@ struct mlx5e_ptp {
 	struct mlx5_core_dev      *mdev;
 	struct hwtstamp_config    *tstamp;
 	DECLARE_BITMAP(state, MLX5E_PTP_STATE_NUM_STATES);
+	struct mlx5_sq_bfreg      *bfreg;
 };
 
 static inline bool mlx5e_use_ptpsq(struct sk_buff *skb)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 02a538ec2ecb..0425f0e3d3a0 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -1532,7 +1532,7 @@ static int mlx5e_alloc_xdpsq(struct mlx5e_channel *c,
 	sq->pdev      = c->pdev;
 	sq->mkey_be   = c->mkey_be;
 	sq->channel   = c;
-	sq->uar_map   = mdev->priv.bfreg.map;
+	sq->uar_map   = c->bfreg->map;
 	sq->min_inline_mode = params->tx_min_inline_mode;
 	sq->hw_mtu    = MLX5E_SW2HW_MTU(params, params->sw_mtu) - ETH_FCS_LEN;
 	sq->xsk_pool  = xsk_pool;
@@ -1617,7 +1617,7 @@ static int mlx5e_alloc_icosq(struct mlx5e_channel *c,
 	int err;
 
 	sq->channel   = c;
-	sq->uar_map   = mdev->priv.bfreg.map;
+	sq->uar_map   = c->bfreg->map;
 	sq->reserved_room = param->stop_room;
 
 	param->wq.db_numa_node = cpu_to_node(c->cpu);
@@ -1702,7 +1702,7 @@ static int mlx5e_alloc_txqsq(struct mlx5e_channel *c,
 	sq->priv      = c->priv;
 	sq->ch_ix     = c->ix;
 	sq->txq_ix    = txq_ix;
-	sq->uar_map   = mdev->priv.bfreg.map;
+	sq->uar_map   = c->bfreg->map;
 	sq->min_inline_mode = params->tx_min_inline_mode;
 	sq->hw_mtu    = MLX5E_SW2HW_MTU(params, params->sw_mtu);
 	sq->max_sq_mpw_wqebbs = mlx5e_get_max_sq_aligned_wqebbs(mdev);
@@ -1778,7 +1778,7 @@ static int mlx5e_create_sq(struct mlx5_core_dev *mdev,
 	MLX5_SET(sqc,  sqc, flush_in_error_en, 1);
 
 	MLX5_SET(wq,   wq, wq_type,       MLX5_WQ_TYPE_CYCLIC);
-	MLX5_SET(wq,   wq, uar_page,      mdev->priv.bfreg.index);
+	MLX5_SET(wq,   wq, uar_page,      csp->uar_page);
 	MLX5_SET(wq,   wq, log_wq_pg_sz,  csp->wq_ctrl->buf.page_shift -
 					  MLX5_ADAPTER_PAGE_SHIFT);
 	MLX5_SET64(wq, wq, dbr_addr,      csp->wq_ctrl->db.dma);
@@ -1882,6 +1882,7 @@ int mlx5e_open_txqsq(struct mlx5e_channel *c, u32 tisn, int txq_ix,
 	csp.cqn             = sq->cq.mcq.cqn;
 	csp.wq_ctrl         = &sq->wq_ctrl;
 	csp.min_inline_mode = sq->min_inline_mode;
+	csp.uar_page        = c->bfreg->index;
 	err = mlx5e_create_sq_rdy(c->mdev, param, &csp, qos_queue_group_id, &sq->sqn);
 	if (err)
 		goto err_free_txqsq;
@@ -2052,6 +2053,7 @@ static int mlx5e_open_icosq(struct mlx5e_channel *c, struct mlx5e_params *params
 	csp.cqn             = sq->cq.mcq.cqn;
 	csp.wq_ctrl         = &sq->wq_ctrl;
 	csp.min_inline_mode = params->tx_min_inline_mode;
+	csp.uar_page        = c->bfreg->index;
 	err = mlx5e_create_sq_rdy(c->mdev, param, &csp, 0, &sq->sqn);
 	if (err)
 		goto err_free_icosq;
@@ -2112,6 +2114,7 @@ int mlx5e_open_xdpsq(struct mlx5e_channel *c, struct mlx5e_params *params,
 	csp.cqn             = sq->cq.mcq.cqn;
 	csp.wq_ctrl         = &sq->wq_ctrl;
 	csp.min_inline_mode = sq->min_inline_mode;
+	csp.uar_page        = c->bfreg->index;
 	set_bit(MLX5E_SQ_STATE_ENABLED, &sq->state);
 
 	err = mlx5e_create_sq_rdy(c->mdev, param, &csp, 0, &sq->sqn);
@@ -2740,6 +2743,11 @@ void mlx5e_trigger_napi_sched(struct napi_struct *napi)
 	local_bh_enable();
 }
 
+static void mlx5e_channel_pick_doorbell(struct mlx5e_channel *c)
+{
+	c->bfreg = &c->mdev->priv.bfreg;
+}
+
 static int mlx5e_open_channel(struct mlx5e_priv *priv, int ix,
 			      struct mlx5e_params *params,
 			      struct xsk_buff_pool *xsk_pool,
@@ -2794,6 +2802,8 @@ static int mlx5e_open_channel(struct mlx5e_priv *priv, int ix,
 	c->aff_mask = irq_get_effective_affinity_mask(irq);
 	c->lag_port = mlx5e_enumerate_lag_port(mdev, ix);
 
+	mlx5e_channel_pick_doorbell(c);
+
 	netif_napi_add_config_locked(netdev, &c->napi, mlx5e_napi_poll, ix);
 	netif_napi_set_irq_locked(&c->napi, irq);
 
-- 
2.31.1


  parent reply	other threads:[~2025-09-16 14:13 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-16 14:11 [PATCH net-next V2 00/10] net/mlx5e: Use multiple doorbells Tariq Toukan
2025-09-16 14:11 ` [PATCH net-next V2 01/10] net/mlx5: Fix typo of MLX5_EQ_DOORBEL_OFFSET Tariq Toukan
2025-09-17 12:53   ` Simon Horman
2025-09-16 14:11 ` [PATCH net-next V2 02/10] net/mlx5: Remove unused 'offset' field from mlx5_sq_bfreg Tariq Toukan
2025-09-17 12:53   ` Simon Horman
2025-09-16 14:11 ` [PATCH net-next V2 03/10] net/mlx5e: Remove unused 'xsk' param of mlx5e_build_xdpsq_param Tariq Toukan
2025-09-17 12:53   ` Simon Horman
2025-09-16 14:11 ` [PATCH net-next V2 04/10] net/mlx5: Store the global doorbell in mlx5_priv Tariq Toukan
2025-09-17 12:54   ` Simon Horman
2025-09-16 14:11 ` Tariq Toukan [this message]
2025-09-17 12:54   ` [PATCH net-next V2 05/10] net/mlx5e: Prepare for using multiple TX doorbells Simon Horman
2025-09-16 14:11 ` [PATCH net-next V2 06/10] net/mlx5e: Prepare for using different CQ doorbells Tariq Toukan
2025-09-17 12:54   ` Simon Horman
2025-09-16 14:11 ` [PATCH net-next V2 07/10] net/mlx5e: Use multiple TX doorbells Tariq Toukan
2025-09-17 12:55   ` Simon Horman
2025-09-16 14:11 ` [PATCH net-next V2 08/10] net/mlx5e: Use multiple CQ doorbells Tariq Toukan
2025-09-17 12:55   ` Simon Horman
2025-09-16 14:11 ` [PATCH net-next V2 09/10] devlink: Add a 'num_doorbells' driverinit param Tariq Toukan
2025-09-17 12:56   ` Simon Horman
2025-09-16 14:11 ` [PATCH net-next V2 10/10] net/mlx5e: Use the 'num_doorbells' devlink param Tariq Toukan
2025-09-17 12:56   ` Simon Horman
2025-09-18  1:40 ` [PATCH net-next V2 00/10] net/mlx5e: Use multiple doorbells patchwork-bot+netdevbpf

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