Subject: Re: [PATCH net-next v2] net: mana: Implement get_ringparam/set_ringparam for mana

From: Zhu Yanjun <[email-masked]>
Date: Sun, 4 Aug 2024 02:09:21 +0800

在 2024/7/31 1:01, Shradha Gupta 写道:
> Currently the values of WQs for RX and TX queues for MANA devices
> are hardcoded to default sizes.
> Allow configuring these values for MANA devices as ringparam
> configuration(get/set) through ethtool_ops.
> 
> Signed-off-by: Shradha Gupta <[email-masked]>
> Reviewed-by: Haiyang Zhang <[email-masked]>
> Reviewed-by: Long Li <[email-masked]>
> ---
>   Changes in v2:
>   * Removed unnecessary validations in mana_set_ringparam()
>   * Fixed codespell error
>   * Improved error message to indicate issue with the parameter
> ---
>   drivers/net/ethernet/microsoft/mana/mana_en.c | 20 +++---
>   .../ethernet/microsoft/mana/mana_ethtool.c    | 66 +++++++++++++++++++
>   include/net/mana/mana.h                       | 21 +++++-
>   3 files changed, 96 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
> index d2f07e179e86..598ac62be47d 100644
> --- a/drivers/net/ethernet/microsoft/mana/mana_en.c
> +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
> @@ -618,7 +618,7 @@ static int mana_pre_alloc_rxbufs(struct mana_port_context *mpc, int new_mtu)
>   
>   	dev = mpc->ac->gdma_dev->gdma_context->dev;
>   
> -	num_rxb = mpc->num_queues * RX_BUFFERS_PER_QUEUE;
> +	num_rxb = mpc->num_queues * mpc->rx_queue_size;
>   
>   	WARN(mpc->rxbufs_pre, "mana rxbufs_pre exists\n");
>   	mpc->rxbufs_pre = kmalloc_array(num_rxb, sizeof(void *), GFP_KERNEL);
> @@ -1899,14 +1899,15 @@ static int mana_create_txq(struct mana_port_context *apc,
>   		return -ENOMEM;
>   
>   	/*  The minimum size of the WQE is 32 bytes, hence
> -	 *  MAX_SEND_BUFFERS_PER_QUEUE represents the maximum number of WQEs
> +	 *  apc->tx_queue_size represents the maximum number of WQEs
>   	 *  the SQ can store. This value is then used to size other queues
>   	 *  to prevent overflow.
> +	 *  Also note that the txq_size is always going to be MANA_PAGE_ALIGNED,
> +	 *  as tx_queue_size is always a power of 2.
>   	 */
> -	txq_size = MAX_SEND_BUFFERS_PER_QUEUE * 32;
> -	BUILD_BUG_ON(!MANA_PAGE_ALIGNED(txq_size));
> +	txq_size = apc->tx_queue_size * 32;

Not sure if the following is needed or not.
"
WARN_ON(!MANA_PAGE_ALIGNED(txq_size));
"

Zhu Yanjun

>   
> -	cq_size = MAX_SEND_BUFFERS_PER_QUEUE * COMP_ENTRY_SIZE;
> +	cq_size = apc->tx_queue_size * COMP_ENTRY_SIZE;
>   	cq_size = MANA_PAGE_ALIGN(cq_size);
>   
>   	gc = gd->gdma_context;
> @@ -2145,10 +2146,11 @@ static int mana_push_wqe(struct mana_rxq *rxq)
>   
>   static int mana_create_page_pool(struct mana_rxq *rxq, struct gdma_context *gc)
>   {
> +	struct mana_port_context *mpc = netdev_priv(rxq->ndev);
>   	struct page_pool_params pprm = {};
>   	int ret;
>   
> -	pprm.pool_size = RX_BUFFERS_PER_QUEUE;
> +	pprm.pool_size = mpc->rx_queue_size;
>   	pprm.nid = gc->numa_node;
>   	pprm.napi = &rxq->rx_cq.napi;
>   	pprm.netdev = rxq->ndev;
> @@ -2180,13 +2182,13 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,
>   
>   	gc = gd->gdma_context;
>   
> -	rxq = kzalloc(struct_size(rxq, rx_oobs, RX_BUFFERS_PER_QUEUE),
> +	rxq = kzalloc(struct_size(rxq, rx_oobs, apc->rx_queue_size),
>   		      GFP_KERNEL);
>   	if (!rxq)
>   		return NULL;
>   
>   	rxq->ndev = ndev;
> -	rxq->num_rx_buf = RX_BUFFERS_PER_QUEUE;
> +	rxq->num_rx_buf = apc->rx_queue_size;
>   	rxq->rxq_idx = rxq_idx;
>   	rxq->rxobj = INVALID_MANA_HANDLE;
>   
> @@ -2734,6 +2736,8 @@ static int mana_probe_port(struct mana_context *ac, int port_idx,
>   	apc->ndev = ndev;
>   	apc->max_queues = gc->max_num_queues;
>   	apc->num_queues = gc->max_num_queues;
> +	apc->tx_queue_size = DEF_TX_BUFFERS_PER_QUEUE;
> +	apc->rx_queue_size = DEF_RX_BUFFERS_PER_QUEUE;
>   	apc->port_handle = INVALID_MANA_HANDLE;
>   	apc->pf_filter_handle = INVALID_MANA_HANDLE;
>   	apc->port_idx = port_idx;
> diff --git a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
> index 146d5db1792f..34707da6ff68 100644
> --- a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
> +++ b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
> @@ -369,6 +369,70 @@ static int mana_set_channels(struct net_device *ndev,
>   	return err;
>   }
>   
> +static void mana_get_ringparam(struct net_device *ndev,
> +			       struct ethtool_ringparam *ring,
> +			       struct kernel_ethtool_ringparam *kernel_ring,
> +			       struct netlink_ext_ack *extack)
> +{
> +	struct mana_port_context *apc = netdev_priv(ndev);
> +
> +	ring->rx_pending = apc->rx_queue_size;
> +	ring->tx_pending = apc->tx_queue_size;
> +	ring->rx_max_pending = MAX_RX_BUFFERS_PER_QUEUE;
> +	ring->tx_max_pending = MAX_TX_BUFFERS_PER_QUEUE;
> +}
> +
> +static int mana_set_ringparam(struct net_device *ndev,
> +			      struct ethtool_ringparam *ring,
> +			      struct kernel_ethtool_ringparam *kernel_ring,
> +			      struct netlink_ext_ack *extack)
> +{
> +	struct mana_port_context *apc = netdev_priv(ndev);
> +	u32 new_tx, new_rx;
> +	u32 old_tx, old_rx;
> +	int err1, err2;
> +
> +	old_tx = apc->tx_queue_size;
> +	old_rx = apc->rx_queue_size;
> +	new_tx = clamp_t(u32, ring->tx_pending, MIN_TX_BUFFERS_PER_QUEUE, MAX_TX_BUFFERS_PER_QUEUE);
> +	new_rx = clamp_t(u32, ring->rx_pending, MIN_RX_BUFFERS_PER_QUEUE, MAX_RX_BUFFERS_PER_QUEUE);
> +
> +	if (!is_power_of_2(new_tx)) {
> +		netdev_err(ndev, "%s:Tx:%d not supported. Needs to be a power of 2\n",
> +			   __func__, new_tx);
> +		return -EINVAL;
> +	}
> +
> +	if (!is_power_of_2(new_rx)) {
> +		netdev_err(ndev, "%s:Rx:%d not supported. Needs to be a power of 2\n",
> +			   __func__, new_rx);
> +		return -EINVAL;
> +	}
> +
> +	err1 = mana_detach(ndev, false);
> +	if (err1) {
> +		netdev_err(ndev, "mana_detach failed: %d\n", err1);
> +		return err1;
> +	}
> +
> +	apc->tx_queue_size = new_tx;
> +	apc->rx_queue_size = new_rx;
> +	err1 = mana_attach(ndev);
> +	if (!err1)
> +		return 0;
> +
> +	netdev_err(ndev, "mana_attach failed: %d\n", err1);
> +
> +	/* Try rolling back to the older values */
> +	apc->tx_queue_size = old_tx;
> +	apc->rx_queue_size = old_rx;
> +	err2 = mana_attach(ndev);
> +	if (err2)
> +		netdev_err(ndev, "mana_reattach failed: %d\n", err2);
> +
> +	return err1;
> +}
> +
>   const struct ethtool_ops mana_ethtool_ops = {
>   	.get_ethtool_stats	= mana_get_ethtool_stats,
>   	.get_sset_count		= mana_get_sset_count,
> @@ -380,4 +444,6 @@ const struct ethtool_ops mana_ethtool_ops = {
>   	.set_rxfh		= mana_set_rxfh,
>   	.get_channels		= mana_get_channels,
>   	.set_channels		= mana_set_channels,
> +	.get_ringparam          = mana_get_ringparam,
> +	.set_ringparam          = mana_set_ringparam,
>   };
> diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h
> index 6439fd8b437b..8f922b389883 100644
> --- a/include/net/mana/mana.h
> +++ b/include/net/mana/mana.h
> @@ -38,9 +38,21 @@ enum TRI_STATE {
>   
>   #define COMP_ENTRY_SIZE 64
>   
> -#define RX_BUFFERS_PER_QUEUE 512
> +/* This Max value for RX buffers is derived from __alloc_page()'s max page
> + * allocation calculation. It allows maximum 2^(MAX_ORDER -1) pages. RX buffer
> + * size beyond this value gets rejected by __alloc_page() call.
> + */
> +#define MAX_RX_BUFFERS_PER_QUEUE 8192
> +#define DEF_RX_BUFFERS_PER_QUEUE 512
> +#define MIN_RX_BUFFERS_PER_QUEUE 128
>   
> -#define MAX_SEND_BUFFERS_PER_QUEUE 256
> +/* This max value for TX buffers is derived as the maximum allocatable
> + * pages supported on host per guest through testing. TX buffer size beyond
> + * this value is rejected by the hardware.
> + */
> +#define MAX_TX_BUFFERS_PER_QUEUE 16384
> +#define DEF_TX_BUFFERS_PER_QUEUE 256
> +#define MIN_TX_BUFFERS_PER_QUEUE 128
>   
>   #define EQ_SIZE (8 * MANA_PAGE_SIZE)
>   
> @@ -285,7 +297,7 @@ struct mana_recv_buf_oob {
>   	void *buf_va;
>   	bool from_pool; /* allocated from a page pool */
>   
> -	/* SGL of the buffer going to be sent has part of the work request. */
> +	/* SGL of the buffer going to be sent as part of the work request. */
>   	u32 num_sge;
>   	struct gdma_sge sgl[MAX_RX_WQE_SGL_ENTRIES];
>   
> @@ -437,6 +449,9 @@ struct mana_port_context {
>   	unsigned int max_queues;
>   	unsigned int num_queues;
>   
> +	unsigned int rx_queue_size;
> +	unsigned int tx_queue_size;
> +
>   	mana_handle_t port_handle;
>   	mana_handle_t pf_filter_handle;
>