linux-kernel - Re: [PATCH bpf-next v2 0/3] xdp: recycle Page Pool backed skbs built from XDP frames

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Message-ID: <e5be0165-c398-c84b-4f16-18e5b302290d@intel.com>
Date:   Thu, 9 Mar 2023 17:25:40 +0100
From:   Alexander Lobakin <aleksander.lobakin@...el.com>
To:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <martin.lau@...ux.dev>
CC:     Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
        Larysa Zaremba <larysa.zaremba@...el.com>,
        Toke Høiland-Jørgensen <toke@...hat.com>,
        Song Liu <song@...nel.org>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        Menglong Dong <imagedong@...cent.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Eric Dumazet <edumazet@...gle.com>, <bpf@...r.kernel.org>,
        <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH bpf-next v2 0/3] xdp: recycle Page Pool backed skbs built
 from XDP frames

From: Alexander Lobakin <aleksander.lobakin@...el.com>
Date: Fri, 3 Mar 2023 14:32:29 +0100

> Yeah, I still remember that "Who needs cpumap nowadays" (c), but anyway.
> 
> __xdp_build_skb_from_frame() missed the moment when the networking stack
> became able to recycle skb pages backed by a page_pool. This was making
> e.g. cpumap redirect even less effective than simple %XDP_PASS. veth was
> also affected in some scenarios.
> A lot of drivers use skb_mark_for_recycle() already, it's been almost
> two years and seems like there are no issues in using it in the generic
> code too. {__,}xdp_release_frame() can be then removed as it losts its
> last user.
> Page Pool becomes then zero-alloc (or almost) in the abovementioned
> cases, too. Other memory type models (who needs them at this point)
> have no changes.

Ping?
The discussion in the v1 thread is unrelated to the patch subject :D

[...]

Thanks,
Olek