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From:   Eric Dumazet <edumazet@google.com>
Date:   Mon, 3 Jul 2023 19:15:48 +0200
Message-ID: <CANn89iJLAnnvFfkmJbQ=ZFMwaqiYDOTD3-P+NpkEMzP9aKV-ig@mail.gmail.com>
Subject: Re: Memory providers multiplexing (Was: [PATCH net-next v4 4/5]
 page_pool: remove PP_FLAG_PAGE_FRAG flag)
To:     David Ahern <dsahern@kernel.org>
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        Jakub Kicinski <kuba@kernel.org>,
        Jesper Dangaard Brouer <jbrouer@redhat.com>,
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On Mon, Jul 3, 2023 at 4:45=E2=80=AFPM David Ahern <dsahern@kernel.org> wro=
te:

> That is my expectation. The tcpdump is just an easy example of accessing
> the skb page frags. skb_copy_and_csum_bits used by icmp is another
> example that can walk frags wanting access to device memory. You did not
> cause a panic or trip a WARN_ON for example with the tcpdump?
>

ICMP packets do not land on the queues having devmem buffers, for
obvious reasons.

Only chosen TCP flows are steered to these queues.