Re: [PATCH net-next 1/3] net: sched: update default qdisc visibility after Tx queue cnt changes

On Fri, Sep 17, 2021 at 6:09 AM Jakub Kicinski [off-list ref] wrote:

On Thu, 16 Sep 2021 22:46:42 -0700 Cong Wang wrote:

quoted

On Wed, Sep 15, 2021 at 12:36 PM Jakub Kicinski [off-list ref] wrote:

quoted

On Wed, 15 Sep 2021 09:31:08 -0700 Cong Wang wrote:

quoted

Don't we need to flip the device with dev_deactivate()+dev_activate()?
It looks like the only thing this function resets is qdisc itself, and only
partially.

We're only making the qdiscs visible, there should be
no datapath-visible change.

Isn't every qdisc under mq visible to datapath?

Packets can be pending in qdisc's, and qdisc's can be scheduled
in TX softirq, so essentially we need to flip the device like other

By visible I mean tc qdisc dump shows them. I'm adding/removing
the qdiscs to netdev->qdisc_hash. That's only used by control
paths to dump or find qdiscs by handle.

Oh, I see, I missed this difference. If datapath can't see this change
immediately, we don't need to flip it.

Thanks.