Re: [PATCH net-next v1 0/5] net: deprecate skb->pp_recycle and skb_mark_for_recycle()

[Jesper Dangaard Brouer <hawk@kernel.org>]

On 11/3/26 22:14, Mina Almasry wrote:
> Remove the per-SKB skb->pp_recycle bitfield and skb_mark_for_recycle()
> helper, and reference-count netmems directly by their underlying type
> via netmem_is_pp() inside netmem_inc_ref() and netmem_dec_ref().
> 
> This series simplifies SKB and netmem reference counting:
> - Reclaims 1 bit from struct sk_buff (skb->pp_recycle).
> - Unifies reference counting of SKB fragment netmems and regular netmems
>    under netmem_inc_ref() and netmem_dec_ref(), eliminating the separate
>    skb_netmem_ref(), skb_netmem_unref(), and skb_mark_for_recycle() APIs.

Part of the performance gain from page_pool was to completely avoid the
atomic refcnt operation, when we can see that page refcnt==1.
Are you removing this?


> - Removes 110 net lines of non-test/doc code across 63 files (196
>    insertions, 306 deletions).
> 
> 1/5: net: skbuff: skip managed zerocopy frags in skb_frag_ref()
> 2/5: net: skbuff: refcount spliced page_pool frags via skb_pipe_buf_ops
> 3/5: net: datagram: refcount page_pool frags in zerocopy_fill_skb_from_iter()
> 4/5: net: remove skb->pp_recycle and consolidate netmem refcounting
> 5/5: net: remove skb_mark_for_recycle()
> 
> Mina Almasry (5):
>    net: skbuff: skip managed zerocopy frags in skb_frag_ref()
>    net: skbuff: refcount spliced page_pool frags via skb_pipe_buf_ops
>    net: datagram: refcount page_pool frags in
>      zerocopy_fill_skb_from_iter()
>    net: remove skb->pp_recycle and consolidate netmem refcounting
>    net: remove skb_mark_for_recycle()
> 
>   Documentation/networking/page_pool.rst        |   1 -
>   drivers/net/ethernet/airoha/airoha_eth.c      |   1 -
>   drivers/net/ethernet/alibaba/eea/eea_rx.c     |   3 -
>   .../net/ethernet/broadcom/asp2/bcmasp_intf.c  |   1 -
>   .../net/ethernet/broadcom/bnge/bnge_txrx.c    |   5 -
>   drivers/net/ethernet/broadcom/bnxt/bnxt.c     |   8 -
>   .../net/ethernet/broadcom/genet/bcmgenet.c    |   2 -
>   drivers/net/ethernet/cisco/enic/enic_rq.c     |   1 -
>   drivers/net/ethernet/engleder/tsnep_main.c    |   2 -
>   drivers/net/ethernet/freescale/fec_main.c     |   1 -
>   drivers/net/ethernet/google/gve/gve_rx_dqo.c  |   9 -
>   .../net/ethernet/hisilicon/hibmcge/hbg_txrx.c |   1 -
>   .../net/ethernet/hisilicon/hns3/hns3_enet.c   |   6 -
>   .../net/ethernet/huawei/hinic3/hinic3_rx.c    |   1 -
>   drivers/net/ethernet/intel/iavf/iavf_txrx.c   |   2 -
>   drivers/net/ethernet/marvell/mvneta.c         |   2 -
>   .../net/ethernet/marvell/mvpp2/mvpp2_main.c   |   2 -
>   .../marvell/octeontx2/nic/otx2_txrx.c         |   1 -
>   drivers/net/ethernet/mediatek/mtk_eth_soc.c   |   1 -
>   drivers/net/ethernet/mellanox/mlx4/en_rx.c    |   1 -
>   .../net/ethernet/mellanox/mlx5/core/en_rx.c   |   8 -
>   drivers/net/ethernet/mellanox/mlxsw/pci.c     |   2 -
>   .../ethernet/microchip/lan966x/lan966x_fdma.c |   2 -
>   .../microchip/sparx5/lan969x/lan969x_fdma.c   |   1 -
>   drivers/net/ethernet/microsoft/mana/mana_en.c |   3 -
>   .../net/ethernet/mucse/rnpgbe/rnpgbe_lib.c    |   1 -
>   .../net/ethernet/pensando/ionic/ionic_txrx.c  |   2 -
>   .../net/ethernet/realtek/rtase/rtase_main.c   |   1 -
>   drivers/net/ethernet/renesas/ravb_main.c      |   2 -
>   drivers/net/ethernet/socionext/netsec.c       |   1 -
>   .../net/ethernet/stmicro/stmmac/stmmac_main.c |   1 -
>   drivers/net/ethernet/tehuti/tn40.c            |   1 -
>   drivers/net/ethernet/ti/am65-cpsw-nuss.c      |   1 -
>   drivers/net/ethernet/ti/cpsw.c                |   2 -
>   drivers/net/ethernet/ti/cpsw_new.c            |   2 -
>   drivers/net/ethernet/ti/icssg/icssg_common.c  |   1 -
>   drivers/net/ethernet/wangxun/libwx/wx_lib.c   |   2 -
>   drivers/net/veth.c                            |   3 +-
>   drivers/net/virtio_net.c                      |  16 +-
>   drivers/net/vmxnet3/vmxnet3_xdp.c             |   1 -
>   drivers/net/wireless/mediatek/mt76/dma.c      |   1 -
>   .../net/wireless/mediatek/mt76/mt7996/mac.c   |   1 -
>   drivers/net/wireless/mediatek/mt76/npu.c      |   1 -
>   drivers/net/wireless/mediatek/mt76/usb.c      |   1 -
>   drivers/net/xen-netfront.c                    |   1 -
>   include/linux/mm.h                            |   2 +-
>   include/linux/skbuff.h                        |  12 +-
>   include/linux/skbuff_ref.h                    |  60 +--
>   include/net/netmem.h                          |  39 +-
>   include/net/page_pool/helpers.h               |  46 ++-
>   net/core/datagram.c                           |   5 +
>   net/core/gro.c                                |   9 -
>   net/core/net_test.c                           | 369 +++++++++++-------
>   net/core/netmem_priv.h                        |  23 +-
>   net/core/page_pool.c                          |   8 +-
>   net/core/skbuff.c                             |  78 ++--
>   net/core/xdp.c                                |  13 +-
>   net/ipv4/esp4.c                               |  11 +-
>   net/ipv6/esp6.c                               |  11 +-
>   net/tls/tls_device.c                          |  14 +-
>   net/tls/tls_device_fallback.c                 |   6 +-
>   net/tls/tls_main.c                            |   4 +-
>   net/wireless/util.c                           |  31 +-
>   net/xfrm/trace_iptfs.h                        |   6 +-
>   net/xfrm/xfrm_iptfs.c                         |  16 +-
>   65 files changed, 418 insertions(+), 454 deletions(-)
> 
> 
> base-commit: 7b6ab4dbc156e2f96419715130b3d5738a306c93