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From: Jesper Dangaard Brouer <brouer@redhat•com>
To: Eric Dumazet <edumazet@google•com>
Cc: Alexander Duyck <alexander.duyck@gmail•com>,
	Tariq Toukan <ttoukan.linux@gmail•com>,
	"David S . Miller" <davem@davemloft•net>,
	netdev <netdev@vger•kernel.org>,
	Tariq Toukan <tariqt@mellanox•com>,
	Martin KaFai Lau <kafai@fb•com>,
	Saeed Mahameed <saeedm@mellanox•com>,
	Willem de Bruijn <willemb@google•com>,
	Brenden Blanco <bblanco@plumgrid•com>,
	Alexei Starovoitov <ast@kernel•org>,
	Eric Dumazet <eric.dumazet@gmail•com>,
	linux-mm <linux-mm@kvack•org>,
	brouer@redhat•com
Subject: Re: [PATCH v3 net-next 08/14] mlx4: use order-0 pages for RX
Date: Tue, 14 Feb 2017 21:02:19 +0100	[thread overview]
Message-ID: <20170214210219.1ea87229@redhat.com> (raw)
In-Reply-To: <CANn89iK4fnsjsK+GHYdT7_F0f++sa+t2LqrZWftjEryhF=hX+w@mail.gmail.com>

On Tue, 14 Feb 2017 11:02:01 -0800
Eric Dumazet <edumazet@google•com> wrote:

> On Tue, Feb 14, 2017 at 10:46 AM, Jesper Dangaard Brouer
> <brouer@redhat•com> wrote:
> >  
> 
> >
> > With this Intel driver page count based recycle approach, the recycle
> > size is tied to the size of the RX ring.  As Eric and Tariq discovered.
> > And for other performance reasons (memory footprint of walking RX ring
> > data-structures), don't want to increase the RX ring sizes.  Thus, it
> > create two opposite performance needs.  That is why I think a more
> > explicit approach with a pool is more attractive.
> >
> > How is this approach doing to work for XDP?
> > (XDP doesn't "share" the page, and in-general we don't want the extra
> > atomic.)
> >
> > We absolutely need recycling with XDP, when transmitting out another
> > device, and the other devices DMA-TX completion need some way of
> > returning this page.
> > What is basically needed is a standardized callback to allow the remote
> > driver to return the page to the originating driver.  As we don't have
> > a NDP for XDP-forward/transmit yet, we could pass this callback as a
> > parameter along with the packet-page to send?
> >
> >  
> 
> 
> mlx4 already has a cache for XDP.
> I believe I did not change this part, it still should work.
> 
> commit d576acf0a22890cf3f8f7a9b035f1558077f6770
> Author: Brenden Blanco <bblanco@plumgrid•com>
> Date:   Tue Jul 19 12:16:52 2016 -0700
> 
>     net/mlx4_en: add page recycle to prepare rx ring for tx support

This obviously does not work for the case I'm talking about
(transmitting out another device with XDP).

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

  reply	other threads:[~2017-02-14 20:02 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-13 19:58 [PATCH v3 net-next 00/14] mlx4: order-0 allocations and page recycling Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 01/14] mlx4: use __skb_fill_page_desc() Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 02/14] mlx4: dma_dir is a mlx4_en_priv attribute Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 03/14] mlx4: remove order field from mlx4_en_frag_info Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 04/14] mlx4: get rid of frag_prefix_size Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 05/14] mlx4: rx_headroom is a per port attribute Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 06/14] mlx4: reduce rx ring page_cache size Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 07/14] mlx4: removal of frag_sizes[] Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 08/14] mlx4: use order-0 pages for RX Eric Dumazet
2017-02-13 20:51   ` Alexander Duyck
2017-02-13 21:09     ` Eric Dumazet
2017-02-13 23:16       ` Alexander Duyck
2017-02-13 23:22         ` Eric Dumazet
2017-02-13 23:26           ` Alexander Duyck
2017-02-13 23:29             ` Eric Dumazet
2017-02-13 23:47               ` Alexander Duyck
2017-02-14  0:22                 ` Eric Dumazet
2017-02-14  0:34                   ` Alexander Duyck
2017-02-14  0:46                     ` Eric Dumazet
2017-02-14  0:47                       ` Eric Dumazet
2017-02-14  0:57                       ` Eric Dumazet
2017-02-14  1:32                         ` Alexander Duyck
2017-02-14 12:12         ` Jesper Dangaard Brouer
2017-02-14 13:45           ` Eric Dumazet
2017-02-14 14:12             ` Eric Dumazet
2017-02-14 14:56             ` Tariq Toukan
2017-02-14 15:51               ` Eric Dumazet
2017-02-14 16:03                 ` Eric Dumazet
2017-02-14 17:29                 ` Tom Herbert
2017-02-15 16:42                   ` Tariq Toukan
2017-02-15 16:57                     ` Eric Dumazet
2017-02-16 13:08                       ` Tariq Toukan
2017-02-16 15:47                         ` Eric Dumazet
2017-02-16 17:05                         ` Tom Herbert
2017-02-16 17:11                           ` Eric Dumazet
2017-02-16 20:49                             ` Saeed Mahameed
2017-02-16 19:03                           ` David Miller
2017-02-16 21:06                             ` Saeed Mahameed
2017-02-14 17:04               ` David Miller
2017-02-14 17:17                 ` David Laight
2017-02-14 17:22                   ` David Miller
2017-02-14 19:38                 ` Jesper Dangaard Brouer
2017-02-14 19:59                   ` David Miller
2017-02-14 17:29               ` Alexander Duyck
2017-02-14 18:46                 ` Jesper Dangaard Brouer
2017-02-14 19:02                   ` Eric Dumazet
2017-02-14 20:02                     ` Jesper Dangaard Brouer [this message]
2017-02-14 21:56                       ` Eric Dumazet
2017-02-14 19:06                   ` Alexander Duyck
2017-02-14 19:50                     ` Jesper Dangaard Brouer
2017-02-22 16:22   ` Eric Dumazet
2017-02-22 17:23     ` Alexander Duyck
2017-02-22 17:58       ` David Laight
2017-02-22 18:21       ` Eric Dumazet
2017-02-23  1:08         ` Alexander Duyck
2017-02-23  2:06           ` Eric Dumazet
2017-02-23  2:18             ` Alexander Duyck
2017-02-23 14:02               ` Tariq Toukan
2017-02-24  9:42             ` Jesper Dangaard Brouer
2017-03-12 14:57             ` Eric Dumazet
2017-03-12 15:29               ` Eric Dumazet
2017-03-12 15:49                 ` Saeed Mahameed
2017-03-12 16:49                   ` Eric Dumazet
2017-03-13  9:20                     ` Saeed Mahameed
2017-02-13 19:58 ` [PATCH v3 net-next 09/14] mlx4: add page recycling in receive path Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 10/14] mlx4: add rx_alloc_pages counter in ethtool -S Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 11/14] mlx4: do not access rx_desc from mlx4_en_process_rx_cq() Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 12/14] mlx4: factorize page_address() calls Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 13/14] mlx4: make validate_loopback() more generic Eric Dumazet
2017-02-13 19:58 ` [PATCH v3 net-next 14/14] mlx4: remove duplicate code in mlx4_en_process_rx_cq() Eric Dumazet
2017-02-17 16:00 ` [PATCH v3 net-next 00/14] mlx4: order-0 allocations and page recycling David Miller

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