From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH 0/2] Removal of RTE_MBUF_REFCNT Date: Mon, 16 Feb 2015 15:47:10 -0500 Message-ID: <20150216154710.42bd6fe9@uryu.home.lan> References: <1424102913-18944-1-git-send-email-sergio.gonzalez.monroy@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: dev-VfR2kkLFssw@public.gmane.org To: Sergio Gonzalez Monroy Return-path: In-Reply-To: <1424102913-18944-1-git-send-email-sergio.gonzalez.monroy-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" On Mon, 16 Feb 2015 16:08:31 +0000 Sergio Gonzalez Monroy 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).