[dpdk-dev] [PATCH 0/2] Removal of RTE_MBUF_REFCNT
Stephen Hemminger
stephen at networkplumber.org
Mon Feb 16 21:47:10 CET 2015
On Mon, 16 Feb 2015 16:08:31 +0000
Sergio Gonzalez Monroy <sergio.gonzalez.monroy at intel.com> wrote:
> This patch tries to remove the RTE_MBUF_REFCNT config options and dependencies
> by introducing a new mbuf flag IND_ATTACHED_MBUF that would indicate when the mbuf
> is an indirect attached mbuf, to differentiate between indirect mbufs and mbufs
> with external memory buffers (ie. vhost zero copy).
>
> Previous discussion:
> http://dpdk.org/ml/archives/dev/2014-October/007127.html
>
> Currently for mbufs with refcnt, we cannot free mbufs with external memory
> buffers (ie. vhost zero copy), as they are recognized as indirect
> attached mbufs and therefore we free the direct mbuf it points to,
> resulting in an error in the case of external memory buffers.
>
> We solve the issue by introducing the IND_ATTACHED_MBUF flag, which indicates
> that the mbuf is an indirect attached mbuf pointing to another mbuf.
> When we free an mbuf, we only free the direct mbuf if the flag is set.
> Freeing an mbuf with external buffer is the same as freeing a non attached mbuf.
> The flag is set during attach and clear on detach.
>
> So in the case of vhost zero copy where we have mbufs with external
> buffers, by default we just free the mbuf and it is up to the user to deal with
> the external buffer.
>
> Sergio Gonzalez Monroy (2):
> mbuf: Introduce IND_ATTACHED_MBUF flag
> Remove RTE_MBUF_REFCNT references
>
> app/test/test_link_bonding.c | 15 -----------
> app/test/test_mbuf.c | 17 +++----------
> config/common_bsdapp | 1 -
> config/common_linuxapp | 1 -
> examples/Makefile | 4 +--
> examples/ip_fragmentation/Makefile | 4 ---
> examples/ip_pipeline/Makefile | 3 ---
> examples/ip_pipeline/main.c | 5 ----
> examples/ipv4_multicast/Makefile | 4 ---
> examples/vhost/main.c | 19 +++-----------
> lib/librte_ip_frag/Makefile | 4 ---
> lib/librte_ip_frag/rte_ip_frag.h | 4 ---
> lib/librte_mbuf/rte_mbuf.c | 2 --
> lib/librte_mbuf/rte_mbuf.h | 45 +++++++--------------------------
> lib/librte_pmd_bond/Makefile | 4 ---
> lib/librte_pmd_bond/rte_eth_bond.h | 2 --
> lib/librte_pmd_bond/rte_eth_bond_args.c | 2 --
> lib/librte_pmd_bond/rte_eth_bond_pmd.c | 10 --------
> lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 8 ------
> lib/librte_port/Makefile | 4 ---
> 20 files changed, 19 insertions(+), 139 deletions(-)
>
What about supporting a clone operation instead of and in addition
to attach? The refcnt is also useful when there are two paths for
a packet (going into mulitple rings).
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