Re: [PATCH v6 1/4] mac80211: Shrink the size of ack_frame_id to make room for tx_time_est

Johannes Berg
2019-11-08T10:03:26Z

On Wed, 2019-10-23 at 11:59 +0200, Toke Høiland-Jørgensen wrote:
> From: Toke Høiland-Jørgensen <toke@redhat.com>
>
> To implement airtime queue limiting, we need to keep a running account of
> the estimated airtime of all skbs queued into the device. Do to this
> correctly, we need to store the airtime estimate into the skb so we can
> decrease the outstanding balance when the skb is freed. This means that the
> time estimate must be stored somewhere that will survive for the lifetime
> of the skb.
>
> To get this, decrease the size of the ack_frame_id field to 6 bits, and
> lower the size of the ID space accordingly. This leaves 10 bits for use for
> tx_time_est, which is enough to store a maximum of 4096 us, if we shift the
> values so they become units of 4us.
>

I've applied this as preparation.

johannes