From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Matteo Croce <mcroce@linux.microsoft.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Jonathan Lemon <jonathan.lemon@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Ilias Apalodimas <ilias.apalodimas@linaro.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Lorenzo Bianconi <lorenzo@kernel.org>,
Saeed Mahameed <saeedm@nvidia.com>,
David Ahern <dsahern@gmail.com>,
Saeed Mahameed <saeed@kernel.org>, Andrew Lunn <andrew@lunn.ch>
Subject: Re: [PATCH net-next 6/6] mvneta: recycle buffers
Date: Wed, 24 Mar 2021 10:28:35 +0100 [thread overview]
Message-ID: <YFsGQx6XMbYRtBOR@lore-desk> (raw)
In-Reply-To: <20210323160611.28ddc712@carbon>
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[...]
> > diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> > index a635cf84608a..8b3250394703 100644
> > --- a/drivers/net/ethernet/marvell/mvneta.c
> > +++ b/drivers/net/ethernet/marvell/mvneta.c
> > @@ -2332,7 +2332,7 @@ mvneta_swbm_build_skb(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
> > if (!skb)
> > return ERR_PTR(-ENOMEM);
> >
> > - page_pool_release_page(rxq->page_pool, virt_to_page(xdp->data));
> > + skb_mark_for_recycle(skb, virt_to_page(xdp->data), &xdp->rxq->mem);
> >
> > skb_reserve(skb, xdp->data - xdp->data_hard_start);
> > skb_put(skb, xdp->data_end - xdp->data);
> > @@ -2344,7 +2344,7 @@ mvneta_swbm_build_skb(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
> > skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
> > skb_frag_page(frag), skb_frag_off(frag),
> > skb_frag_size(frag), PAGE_SIZE);
> > - page_pool_release_page(rxq->page_pool, skb_frag_page(frag));
> > + skb_mark_for_recycle(skb, skb_frag_page(frag), &xdp->rxq->mem);
> > }
> >
> > return skb;
>
> This cause skb_mark_for_recycle() to set 'skb->pp_recycle=1' multiple
> times, for the same SKB. (copy-pasted function below signature to help
> reviewers).
>
> This makes me question if we need an API for setting this per page
> fragment?
> Or if the API skb_mark_for_recycle() need to walk the page fragments in
> the SKB and set the info stored in the page for each?
Considering just performances, I guess it is better open-code here since the
driver already performs a loop over fragments to build the skb, but I guess
this approach is quite risky and I would prefer to have a single utility
routine to take care of linear area + fragments. What do you think?
Regards,
Lorenzo
>
>
> --
> Best regards,
> Jesper Dangaard Brouer
> MSc.CS, Principal Kernel Engineer at Red Hat
> LinkedIn: http://www.linkedin.com/in/brouer
>
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next prev parent reply other threads:[~2021-03-24 9:29 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 17:02 [PATCH net-next 0/6] page_pool: recycle buffers Matteo Croce
2021-03-22 17:02 ` [PATCH net-next 1/6] xdp: reduce size of struct xdp_mem_info Matteo Croce
2021-03-22 17:02 ` [PATCH net-next 2/6] mm: add a signature in struct page Matteo Croce
2021-03-22 17:02 ` [PATCH net-next 3/6] page_pool: DMA handling and allow to recycles frames via SKB Matteo Croce
2021-03-22 19:38 ` Matteo Croce
2021-03-22 17:02 ` [PATCH net-next 4/6] net: change users of __skb_frag_unref() and add an extra argument Matteo Croce
2021-03-22 17:03 ` [PATCH net-next 5/6] mvpp2: recycle buffers Matteo Croce
2021-03-22 17:03 ` [PATCH net-next 6/6] mvneta: " Matteo Croce
2021-03-23 15:06 ` Jesper Dangaard Brouer
2021-03-24 9:28 ` Lorenzo Bianconi [this message]
2021-03-24 21:48 ` Ilias Apalodimas
2021-03-23 14:57 ` [PATCH net-next 0/6] page_pool: " David Ahern
2021-03-23 15:03 ` Ilias Apalodimas
2021-03-23 15:41 ` Alexander Lobakin
2021-03-23 15:47 ` Ilias Apalodimas
2021-03-23 16:04 ` Jesper Dangaard Brouer
2021-03-23 16:10 ` Ilias Apalodimas
2021-03-23 16:28 ` Matteo Croce
2021-03-23 16:55 ` Alexander Lobakin
2021-03-23 17:01 ` Ilias Apalodimas
2021-03-23 20:03 ` Alexander Lobakin
2021-03-24 7:50 ` Ilias Apalodimas
2021-03-24 11:42 ` Alexander Lobakin
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