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From:   Wei Fang <wei.fang@nxp.com>
To:     Jakub Kicinski <kuba@kernel.org>
CC:     Alexander Duyck <alexander.duyck@gmail.com>,
        dl-linux-imx <linux-imx@nxp.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "davem@davemloft.net" <davem@davemloft.net>,
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        Shenwei Wang <shenwei.wang@nxp.com>,
        Clark Wang <xiaoning.wang@nxp.com>,
        "pabeni@redhat.com" <pabeni@redhat.com>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: RE: [PATCH net] net: fec: tx processing does not call XDP APIs if
 budget is 0
Thread-Topic: [PATCH net] net: fec: tx processing does not call XDP APIs if
 budget is 0
Thread-Index: AQHZvsxwawoZvXvGy0ONq5DghKmkjq/KsvwAgACtTTCAANTXgIAAoH7ggAAujgCAABV/0A==
Date:   Thu, 27 Jul 2023 05:32:51 +0000
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> On Thu, 27 Jul 2023 02:08:32 +0000 Wei Fang wrote:
> > > Actually after talking with Jakub a bit more there is an issue here,
> > > but not freeing the frames isn't the solution. We likely need to
> > > just fix the page pool code so that it doesn't attempt to recycle
> > > the frames if operating in IRQ context.
> > >
> > > The way this is dealt with for skbs is that we queue skbs if we are
> > > in IRQ context so that it can be deferred to be freed by the
> > > net_tx_action. We likely need to look at doing something similar for
> > > page_pool pages or XDP frames.
> > >
> > After reading your discussion with Jakub, I understand this issue a bit=
 more.
> > But we are not sure when this issue will be fixed in page pool,
> > currently we can only tolerate a delay in sending of a netpoll
> > message. So I think this patch is necessary, and I will refine it in
> > the future when the page pool has fixed the issue. In addition, as you
> > mentioned before, napi_consume_skb should be used to instead of
> dev_kfree_skb_any, so I will improve this patch in version 2.
>=20
> I think so too, since the patch can only help, you already wrote it and i=
t won't
> be extra backporting work since the code is only present in
> 6.5 - I think it's worth applying. And we can refine things as page pool
> limitations get listed (the napi_consume_skb() is net-next material, anyw=
ay).
Okay, thank you. :)