Re: [net-next PATCH v3 01/14] net: dsa: qca8k: cache match data to speed up access

Vladimir Oltean
2022-07-24T22:30:44Z

On Sat, Jul 23, 2022 at 04:18:32PM +0200, Christian Marangi wrote:
> Using of_device_get_match_data is expensive. Cache match data to speed

'is expensive' sounds like it's terribly expensive. It's just more than
it needs to be.

> up access and rework user of match data to use the new cached value.
>
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> ---
> drivers/net/dsa/qca/qca8k.c | 28 ++++++++++------------------
> drivers/net/dsa/qca/qca8k.h | 1 +
> 2 files changed, 11 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/net/dsa/qca/qca8k.c b/drivers/net/dsa/qca/qca8k.c
> index 1cbb05b0323f..212b284f9f73 100644
> --- a/drivers/net/dsa/qca/qca8k.c
> +++ b/drivers/net/dsa/qca/qca8k.c
> @@ -3168,6 +3155,11 @@ qca8k_sw_probe(struct mdio_device *mdiodev)
> if (ret)
> return ret;
>
> + /* Cache match data in priv struct.
> + * Match data is already checked in read_switch_id.
> + */
> + priv->info = of_device_get_match_data(priv->dev);
> +

So why don't you set priv->info right before calling qca8k_read_switch_id(),
then?

> priv->ds = devm_kzalloc(&mdiodev->dev, sizeof(*priv->ds), GFP_KERNEL);
> if (!priv->ds)
> return -ENOMEM;
> diff --git a/drivers/net/dsa/qca/qca8k.h b/drivers/net/dsa/qca/qca8k.h
> index ec58d0e80a70..0b990b46890a 100644
> --- a/drivers/net/dsa/qca/qca8k.h
> +++ b/drivers/net/dsa/qca/qca8k.h
> @@ -401,6 +401,7 @@ struct qca8k_priv {
> struct qca8k_mdio_cache mdio_cache;
> struct qca8k_pcs pcs_port_0;
> struct qca8k_pcs pcs_port_6;
> + const struct qca8k_match_data *info;
> };
>
> struct qca8k_mib_desc {
> --
> 2.36.1
>