Re: Memory providers multiplexing (Was: [PATCH net-next v4 4/5] page_pool: remove PP_FLAG_PAGE_FRAG flag)

From: David Ahern
Date: Mon Jul 03 2023 - 13:26:06 EST


On 7/3/23 11:15 AM, Eric Dumazet wrote:
> On Mon, Jul 3, 2023 at 4:45 PM David Ahern <dsahern@xxxxxxxxxx> wrote:
>
>> 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.

I was not referring to ICMP packets coming in to the nic, but rather an
icmp getting triggered during stack processing.

>
> Only chosen TCP flows are steered to these queues.

of course.