[v6,0/5] mbuf: detach mbuf with pinned external buffer

  Today's pktmbuf pool contains only mbufs with no external buffers.
This means data buffer for the mbuf should be placed right after the
mbuf structure (+ the private data when enabled).

On some cases, the application would want to have the buffers allocated
from a different device in the platform. This is in order to do zero
copy for the packet directly to the device memory. Examples for such
devices can be GPU or storage device. For such cases the native pktmbuf
pool does not fit since each mbuf would need to point to external
buffer.

To support above, the pktmbuf pool will be populated with mbuf pointing
to the device buffers using the mbuf external buffer feature.
The PMD will populate its receive queues with those buffer, so that
every packet received will be scattered directly to the device memory.
on the other direction, embedding the buffer pointer to the transmit
queues of the NIC, will make the DMA to fetch device memory
using peer to peer communication.

Such mbuf with external buffer should be handled with care when mbuf is
freed. Mainly The external buffer should not be detached, so that it can
be reused for the next packet receive.

This patch introduce a new flag on the rte_pktmbuf_pool_private
structure to specify this mempool is for mbuf with pinned external
buffer. Upon detach this flag is validated and buffer is not detached.
A new mempool create wrapper is also introduced to help application to
create and populate such mempool.

The unit test (as part of test_mbuf application) will be provided
as dedicated patch.

Signed-off-by: Shahaf Shuler <shahafs@mellanox.com>
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>

RFC: http://patches.dpdk.org/patch/63077
v1: http://patches.dpdk.org/cover/64424
v2: - fix rte_experimantal issue on comment addressing
    - rte_mbuf_has_pinned_extbuf return type is uint32_t
    - fix Power9 compilation issue
v3: - fix "#include <stdbool.h> leftover
v4: - https://patches.dpdk.org/cover/64809/
    - introduce rte_pktmbuf_priv_flags
    - support cloning pinned mbufs as for regular mbufs
      with external buffers
    - address the minor comments
v5: - http://patches.dpdk.org/cover/64979/
    - update rte_pktmbuf_prefree_seg
    - rename __rte_pktmbuf_extbuf_detach
    - __rte_pktmbuf_init_extmem is static
    - const qualifier is specified for external memory
      description parameter of rte_pktmbuf_pool_create_extbuf
    - addressing minor comments
    - fix typos
v6: - new lines inserted
    - struct rte_pktmbuf_extmem_init_ctx is local to rte_mbuf.c

Viacheslav Ovsiienko (5):
  mbuf: introduce routine to get private mbuf pool flags
  mbuf: detach mbuf with pinned external buffer
  mbuf: create packet pool with external memory buffers
  app/testpmd: add mempool with external data buffers
  net/mlx5: allow use allocated mbuf with external buffer

 app/test-pmd/config.c                    |   2 +
 app/test-pmd/flowgen.c                   |   3 +-
 app/test-pmd/parameters.c                |   2 +
 app/test-pmd/testpmd.c                   |  81 ++++++++++++
 app/test-pmd/testpmd.h                   |   4 +-
 app/test-pmd/txonly.c                    |   3 +-
 drivers/net/mlx5/mlx5_rxq.c              |   7 +-
 drivers/net/mlx5/mlx5_rxtx.c             |   2 +-
 drivers/net/mlx5/mlx5_rxtx.h             |   2 +-
 drivers/net/mlx5/mlx5_rxtx_vec.h         |  14 +--
 drivers/net/mlx5/mlx5_rxtx_vec_altivec.h |   5 +-
 drivers/net/mlx5/mlx5_rxtx_vec_neon.h    |  29 ++---
 drivers/net/mlx5/mlx5_rxtx_vec_sse.h     |   2 +-
 lib/librte_mbuf/rte_mbuf.c               | 204 ++++++++++++++++++++++++++++++-
 lib/librte_mbuf/rte_mbuf.h               | 180 +++++++++++++++++++++++++--
 lib/librte_mbuf/rte_mbuf_version.map     |   1 +
 16 files changed, 495 insertions(+), 46 deletions(-)
  

20/01/2020 20:16, Viacheslav Ovsiienko:
> Today's pktmbuf pool contains only mbufs with no external buffers.
> This means data buffer for the mbuf should be placed right after the
> mbuf structure (+ the private data when enabled).
> 
> On some cases, the application would want to have the buffers allocated
> from a different device in the platform. This is in order to do zero
> copy for the packet directly to the device memory. Examples for such
> devices can be GPU or storage device. For such cases the native pktmbuf
> pool does not fit since each mbuf would need to point to external
> buffer.
> 
> To support above, the pktmbuf pool will be populated with mbuf pointing
> to the device buffers using the mbuf external buffer feature.
> The PMD will populate its receive queues with those buffer, so that
> every packet received will be scattered directly to the device memory.
> on the other direction, embedding the buffer pointer to the transmit
> queues of the NIC, will make the DMA to fetch device memory
> using peer to peer communication.
> 
> Such mbuf with external buffer should be handled with care when mbuf is
> freed. Mainly The external buffer should not be detached, so that it can
> be reused for the next packet receive.
> 
> This patch introduce a new flag on the rte_pktmbuf_pool_private
> structure to specify this mempool is for mbuf with pinned external
> buffer. Upon detach this flag is validated and buffer is not detached.
> A new mempool create wrapper is also introduced to help application to
> create and populate such mempool.
> 
> The unit test (as part of test_mbuf application) will be provided
> as dedicated patch.
> 
> Signed-off-by: Shahaf Shuler <shahafs@mellanox.com>
> Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> 
> RFC: http://patches.dpdk.org/patch/63077
> v1: http://patches.dpdk.org/cover/64424
> v2: - fix rte_experimantal issue on comment addressing
>     - rte_mbuf_has_pinned_extbuf return type is uint32_t
>     - fix Power9 compilation issue
> v3: - fix "#include <stdbool.h> leftover
> v4: - https://patches.dpdk.org/cover/64809/
>     - introduce rte_pktmbuf_priv_flags
>     - support cloning pinned mbufs as for regular mbufs
>       with external buffers
>     - address the minor comments
> v5: - http://patches.dpdk.org/cover/64979/
>     - update rte_pktmbuf_prefree_seg
>     - rename __rte_pktmbuf_extbuf_detach
>     - __rte_pktmbuf_init_extmem is static
>     - const qualifier is specified for external memory
>       description parameter of rte_pktmbuf_pool_create_extbuf
>     - addressing minor comments
>     - fix typos
> v6: - new lines inserted
>     - struct rte_pktmbuf_extmem_init_ctx is local to rte_mbuf.c
> 
> Viacheslav Ovsiienko (5):
>   mbuf: introduce routine to get private mbuf pool flags
>   mbuf: detach mbuf with pinned external buffer
>   mbuf: create packet pool with external memory buffers
>   app/testpmd: add mempool with external data buffers
>   net/mlx5: allow use allocated mbuf with external buffer

Applied, thanks