netdev - Re: [PATCH net-next v3 3/3] net: wangxun: support to use adaptive RX coalescing

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Message-ID: <20250725173428.1857c412@kernel.org>
Date: Fri, 25 Jul 2025 17:34:28 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Jiawen Wu <jiawenwu@...stnetic.com>
Cc: netdev@...r.kernel.org, Andrew Lunn <andrew+netdev@...n.ch>, "David S.
 Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Paolo
 Abeni <pabeni@...hat.com>, Simon Horman <horms@...nel.org>, Jacob Keller
 <jacob.e.keller@...el.com>, Mengyuan Lou <mengyuanlou@...-swift.com>
Subject: Re: [PATCH net-next v3 3/3] net: wangxun: support to use adaptive
 RX coalescing

On Thu, 24 Jul 2025 16:05:48 +0800 Jiawen Wu wrote:
> Support to turn on/off adaptive RX coalesce. When adaptive RX coalesce
> is on, use DIM algorithm for a dynamic interrupt moderation.

you say Rx, and you add Rx as the flag

> +				     ETHTOOL_COALESCE_USE_ADAPTIVE_RX,

so far so good, but then you also have dim instances for Tx ?!

> +		q_vector->tx.dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_CQE;

> +static void wx_tx_dim_work(struct work_struct *work)

I don't get it.

> @@ -363,10 +366,15 @@ int wx_set_coalesce(struct net_device *netdev,
>  	    (ec->tx_coalesce_usecs > (max_eitr >> 2)))
>  		return -EINVAL;
>  
> +	if (ec->use_adaptive_rx_coalesce) {
> +		wx->rx_itr_setting = 1;
> +		return 0;
> +	}
> +
>  	if (ec->rx_coalesce_usecs > 1)
>  		wx->rx_itr_setting = ec->rx_coalesce_usecs << 2;
>  	else
> -		wx->rx_itr_setting = ec->rx_coalesce_usecs;
> +		wx->rx_itr_setting = rx_itr_param;

looks racy, you should probably cancel the DIM works?
Otherwise if the work is in flight as the user sets the values
the work will overwrite user settings.
-- 
pw-bot: cr