From: Eric Dumazet <eric.dumazet@gmail•com>
To: Florian Westphal <fw@strlen•de>,
Jesper Dangaard Brouer <brouer@redhat•com>
Cc: netdev@vger•kernel.org, "David S. Miller" <davem@davemloft•net>,
"Toke Høiland-Jørgensen" <toke@toke•dk>,
ard.biesheuvel@linaro•org, "Jason Wang" <jasowang@redhat•com>,
ilias.apalodimas@linaro•org, BjörnTöpel <bjorn.topel@intel•com>,
w@1wt•eu, "Saeed Mahameed" <saeedm@mellanox•com>,
mykyta.iziumtsev@gmail•com,
"Daniel Borkmann" <borkmann@iogearbox•net>,
"Alexei Starovoitov" <alexei.starovoitov@gmail•com>,
"Tariq Toukan" <tariqt@mellanox•com>
Subject: Re: [net-next, RFC, 4/8] net: core: add recycle capabilities on skbs via page_pool API
Date: Sat, 8 Dec 2018 04:29:17 -0800 [thread overview]
Message-ID: <72f33f12-9222-cbe7-6ff2-e4b4f86fb17c@gmail.com> (raw)
In-Reply-To: <20181208095758.GA32028@strlen.de>
On 12/08/2018 01:57 AM, Florian Westphal wrote:
> Jesper Dangaard Brouer <brouer@redhat•com> wrote:
>> From: Ilias Apalodimas <ilias.apalodimas@linaro•org>
>>
>> This patch is changing struct sk_buff, and is thus per-definition
>> controversial.
>>
>> Place a new member 'mem_info' of type struct xdp_mem_info, just after
>> members (flags) head_frag and pfmemalloc, And not in between
>> headers_start/end to ensure skb_copy() and pskb_copy() work as-is.
>> Copying mem_info during skb_clone() is required. This makes sure that
>> pages are correctly freed or recycled during the altered
>> skb_free_head() invocation.
>
> I read this to mean that this 'info' isn't accessed/needed until skb
> is freed. Any reason its not added at the end?
>
> This would avoid moving other fields that are probably accessed
> more frequently during processing.
>
But I do not get why the patch is needed.
Adding extra cost for each skb destruction is costly.
I though XDP was all about _not_ having skbs.
Please let's do not slow down the non XDP stack only to make XDP more appealing.
next prev parent reply other threads:[~2018-12-08 12:29 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-06 23:25 [net-next PATCH RFC 0/8] page_pool DMA handling and allow to recycles frames via SKB Jesper Dangaard Brouer
2018-12-06 23:25 ` [net-next PATCH RFC 1/8] page_pool: add helper functions for DMA Jesper Dangaard Brouer
2018-12-08 7:06 ` David Miller
2018-12-08 7:55 ` Ilias Apalodimas
2018-12-06 23:25 ` [net-next PATCH RFC 2/8] net: mvneta: use page pool API for sw buffer manager Jesper Dangaard Brouer
2018-12-06 23:25 ` [net-next PATCH RFC 3/8] xdp: reduce size of struct xdp_mem_info Jesper Dangaard Brouer
2018-12-06 23:25 ` [net-next PATCH RFC 4/8] net: core: add recycle capabilities on skbs via page_pool API Jesper Dangaard Brouer
2018-12-08 7:15 ` David Miller
2018-12-08 7:54 ` Ilias Apalodimas
2018-12-08 9:57 ` [net-next, RFC, " Florian Westphal
2018-12-08 11:36 ` Jesper Dangaard Brouer
2018-12-08 20:10 ` David Miller
2018-12-08 12:29 ` Eric Dumazet [this message]
2018-12-08 12:34 ` Eric Dumazet
2018-12-08 13:45 ` Jesper Dangaard Brouer
2018-12-08 14:57 ` Ilias Apalodimas
2018-12-08 17:07 ` Andrew Lunn
2018-12-08 19:26 ` Eric Dumazet
2018-12-08 20:11 ` Jesper Dangaard Brouer
2018-12-08 20:14 ` Ilias Apalodimas
2018-12-08 21:06 ` Willy Tarreau
2018-12-10 7:54 ` Ilias Apalodimas
2018-12-08 22:36 ` Eric Dumazet
2018-12-08 20:21 ` David Miller
2018-12-08 20:29 ` Ilias Apalodimas
2018-12-10 9:51 ` Saeed Mahameed
2018-12-06 23:25 ` [net-next PATCH RFC 5/8] net: mvneta: remove copybreak, prefetch and use build_skb Jesper Dangaard Brouer
2018-12-06 23:25 ` [net-next PATCH RFC 6/8] mvneta: activate page recycling via skb using page_pool Jesper Dangaard Brouer
2018-12-06 23:26 ` [net-next PATCH RFC 7/8] xdp: bpf: cpumap redirect must update skb->mem_info Jesper Dangaard Brouer
2018-12-06 23:26 ` [net-next PATCH RFC 8/8] veth: xdp_frames redirected into veth need to transfer xdp_mem_info Jesper Dangaard Brouer
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