Subject: Re: [PATCH 1/3, net-next] net: netsec: Use page_pool API

From: Jesper Dangaard Brouer <[email-masked]>
Date: Fri, 28 Jun 2019 15:04:34 +0200

On Fri, 28 Jun 2019 13:39:13 +0300
Ilias Apalodimas <[email-masked]> wrote:

> Use page_pool and it's DMA mapping capabilities for Rx buffers instead
> of netdev/napi_alloc_frag()
> 
> Although this will result in a slight performance penalty on small sized
> packets (~10%) the use of the API will allow to easily add XDP support.
> The penalty won't be visible in network testing i.e ipef/netperf etc, it
> only happens during raw packet drops.
> Furthermore we intend to add recycling capabilities on the API
> in the future. Once the recycling is added the performance penalty will
> go away.
> The only 'real' penalty is the slightly increased memory usage, since we
> now allocate a page per packet instead of the amount of bytes we need +
> skb metadata (difference is roughly 2kb per packet).
> With a minimum of 4BG of RAM on the only SoC that has this NIC the
> extra memory usage is negligible (a bit more on 64K pages)
> 
> Signed-off-by: Ilias Apalodimas <[email-masked]>
> ---
>  drivers/net/ethernet/socionext/Kconfig  |   1 +
>  drivers/net/ethernet/socionext/netsec.c | 121 +++++++++++++++---------
>  2 files changed, 75 insertions(+), 47 deletions(-)

Acked-by: Jesper Dangaard Brouer <[email-masked]>

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer