Subject: Re: [PATCH net-next 7/9] mlx5: psp: implement deferred tx key deletion

From: Jakub Kicinski <[email-masked]>
Date: Fri, 6 Feb 2026 20:30:26 -0800

On Wed, 04 Feb 2026 07:20:11 -0800 Daniel Zahka wrote:
> Implement the deferred tx key deletion api. In the case of mlx5,
> mlx5e_psp_tx_grace_begin() records the number of wqes retired on each
> tx queue, and then mlx5e_psp_tx_grace_end() returns 0 only if
> all tx queues have advanced a full ring cycle past the point where
> they were snapshotted.

Either Friday night enlightenment or I'm very tired -- but I wonder if
we can do with BQL, without touching the driver at all?

struct dql {
	/* Fields accessed in enqueue path (dql_queued) */
	unsigned int	num_queued;		/* Total ever queued */

...

	/* Fields accessed only by completion path (dql_completed) */
	unsigned int	num_completed;		/* Total ever completed */
...
};

These are free running counters of how many bytes were queued to 
the driver and how many driver finished xmit'ing.