From: Yongseok Koh <yskoh@mellanox.com>
To: Thomas Monjalon <thomas@monjalon.net>
Cc: Olivier Matz <olivier.matz@6wind.com>,
Andrew Rybchenko <arybchenko@solarflare.com>,
wenzhuo.lu@intel.com, jingjing.wu@intel.com, dev@dpdk.org,
konstantin.ananyev@intel.com, adrien.mazarguil@6wind.com,
nelio.laranjeiro@6wind.com
Subject: Re: [dpdk-dev] [PATCH v4 1/2] mbuf: support attaching external buffer to mbuf
Date: Tue, 24 Apr 2018 14:53:41 -0700 [thread overview]
Message-ID: <20180424215340.GA88208@yongseok-MBP.local> (raw)
In-Reply-To: <1963503.R6hUdDjUTB@xps>
On Tue, Apr 24, 2018 at 10:22:45PM +0200, Thomas Monjalon wrote:
> 24/04/2018 21:15, Olivier Matz:
> > On Tue, Apr 24, 2018 at 09:21:00PM +0300, Andrew Rybchenko wrote:
> > > On 04/24/2018 07:02 PM, Olivier Matz wrote:
> > > > On Tue, Apr 24, 2018 at 03:28:33PM +0300, Andrew Rybchenko wrote:
> > > > > On 04/24/2018 04:38 AM, Yongseok Koh wrote:
> > > > > > + * Returns TRUE if given mbuf is cloned by mbuf indirection, or FALSE
> > > > > > + * otherwise.
> > > > > > + *
> > > > > > + * If a mbuf has its data in another mbuf and references it by mbuf
> > > > > > + * indirection, this mbuf can be defined as a cloned mbuf.
> > > > > > + */
> > > > > > +#define RTE_MBUF_CLONED(mb) ((mb)->ol_flags & IND_ATTACHED_MBUF)
> > > > > > +
> > > > > > +/**
> > > > > > * Returns TRUE if given mbuf is indirect, or FALSE otherwise.
> > > > > > */
> > > > > > -#define RTE_MBUF_INDIRECT(mb) ((mb)->ol_flags & IND_ATTACHED_MBUF)
> > > > > > +#define RTE_MBUF_INDIRECT(mb) RTE_MBUF_CLONED(mb)
> > > > > It is still confusing that INDIRECT != !DIRECT.
> > > > > May be we have no good options right now, but I'd suggest to at least
> > > > > deprecate
> > > > > RTE_MBUF_INDIRECT() and completely remove it in the next release.
> > > > Agree. I may have missed something, but is my previous suggestion
> > > > not doable?
> > > >
> > > > - direct = embeds its own data (and indirect = !direct)
> > > > - clone (or another name) = data is another mbuf
> > > > - extbuf = data is in an external buffer
> > >
> > > I guess the problem that it changes INDIRECT semantics since EXTBUF
> > > is added as well. I think strictly speaking it is an API change.
> > > Is it OK to make it without announcement?
> >
> > In any case, there will be an ABI change, because an application
> > compiled for 18.02 will not be able to handle these new kind of
> > mbuf.
> >
> > So unfortunatly yes, I think this kind of changes should first be
> > announced.
> >
> > Thomas, what do you think?
>
> What is the impact for the application developer?
> Is there something to change in the application after this patch?
Let me address two concerns discussed here.
1) API breakage of RTE_MBUF_DIRECT()
Previously, direct == !indirect but now direct == !indirect && !extbuf. But to
set the new flag (EXT_ATTACHED_MBUF), the new API, rte_pktmbuf_attach_extbuf()
should be used and it is experimental. If application isn't compiled without
allowing experimental API or application doesn't use the new API, it is always
true that direct == !indirect. It looks logically okay to me. And FYI, it passed
the mbuf_autotest.
2) ABI breakage of mlx5's new Multi-Packet RQ (a.k.a MPRQ) feature
It's right that it could breadk ABI if the PMD delivers packets with external
buffer attached. But, the MPRQ feature is disabled by default and it can be
enabled only by the newly introduced PMD parameter (mprq_en). So, there's no
possibility that 18.02-based application receives a mbuf having an external
buffer. And, like Olivier mentioned, there's another ABI breakage by removing
control mbuf anyway.
So, I don't think there's need for developers to change their application after
this patch unless they want to use the new feature.
Thanks,
Yongseok
next prev parent reply other threads:[~2018-04-24 21:53 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-10 1:25 [dpdk-dev] [PATCH v1 0/6] net/mlx5: add Multi-Packet Rx support Yongseok Koh
2018-03-10 1:25 ` [dpdk-dev] [PATCH v1 1/6] mbuf: add buffer offset field for flexible indirection Yongseok Koh
2018-03-10 1:25 ` [dpdk-dev] [PATCH v1 2/6] net/mlx5: separate filling Rx flags Yongseok Koh
2018-03-10 1:25 ` [dpdk-dev] [PATCH v1 3/6] net/mlx5: add a function to rdma-core glue Yongseok Koh
2018-03-12 9:13 ` Nélio Laranjeiro
2018-03-10 1:25 ` [dpdk-dev] [PATCH v1 4/6] net/mlx5: add Multi-Packet Rx support Yongseok Koh
2018-03-12 9:20 ` Nélio Laranjeiro
2018-03-10 1:25 ` [dpdk-dev] [PATCH v1 5/6] net/mlx5: release Tx queue resource earlier than Rx Yongseok Koh
2018-03-10 1:25 ` [dpdk-dev] [PATCH v1 6/6] app/testpmd: conserve mbuf indirection flag Yongseok Koh
2018-04-02 18:50 ` [dpdk-dev] [PATCH v2 0/6] net/mlx5: add Multi-Packet Rx support Yongseok Koh
2018-04-02 18:50 ` [dpdk-dev] [PATCH v2 1/6] mbuf: add buffer offset field for flexible indirection Yongseok Koh
2018-04-03 8:26 ` Olivier Matz
2018-04-04 0:12 ` Yongseok Koh
2018-04-09 16:04 ` Olivier Matz
2018-04-10 1:59 ` Yongseok Koh
2018-04-11 0:25 ` Ananyev, Konstantin
2018-04-11 5:33 ` Yongseok Koh
2018-04-11 11:39 ` Ananyev, Konstantin
2018-04-11 14:02 ` Andrew Rybchenko
2018-04-11 17:18 ` Yongseok Koh
2018-04-11 17:08 ` Yongseok Koh
2018-04-12 16:34 ` Ananyev, Konstantin
2018-04-12 18:58 ` Yongseok Koh
2018-04-02 18:50 ` [dpdk-dev] [PATCH v2 2/6] net/mlx5: separate filling Rx flags Yongseok Koh
2018-04-02 18:50 ` [dpdk-dev] [PATCH v2 3/6] net/mlx5: add a function to rdma-core glue Yongseok Koh
2018-04-02 18:50 ` [dpdk-dev] [PATCH v2 4/6] net/mlx5: add Multi-Packet Rx support Yongseok Koh
2018-04-02 18:50 ` [dpdk-dev] [PATCH v2 5/6] net/mlx5: release Tx queue resource earlier than Rx Yongseok Koh
2018-04-02 18:50 ` [dpdk-dev] [PATCH v2 6/6] app/testpmd: conserve mbuf indirection flag Yongseok Koh
2018-04-19 1:11 ` [dpdk-dev] [PATCH v3 1/2] mbuf: support attaching external buffer to mbuf Yongseok Koh
2018-04-19 1:11 ` [dpdk-dev] [PATCH v3 2/2] app/testpmd: conserve offload flags of mbuf Yongseok Koh
2018-04-23 11:53 ` [dpdk-dev] [PATCH v3 1/2] mbuf: support attaching external buffer to mbuf Ananyev, Konstantin
2018-04-24 2:04 ` Yongseok Koh
2018-04-25 13:16 ` Ananyev, Konstantin
2018-04-25 16:44 ` Yongseok Koh
2018-04-25 18:05 ` Ananyev, Konstantin
2018-04-23 16:18 ` Olivier Matz
2018-04-24 1:29 ` Yongseok Koh
2018-04-24 15:36 ` Olivier Matz
2018-04-24 1:38 ` [dpdk-dev] [PATCH v4 " Yongseok Koh
2018-04-24 1:38 ` [dpdk-dev] [PATCH v4 2/2] app/testpmd: conserve offload flags of mbuf Yongseok Koh
2018-04-24 5:01 ` [dpdk-dev] [PATCH v4 1/2] mbuf: support attaching external buffer to mbuf Stephen Hemminger
2018-04-24 11:47 ` Yongseok Koh
2018-04-24 12:28 ` Andrew Rybchenko
2018-04-24 16:02 ` Olivier Matz
2018-04-24 18:21 ` [dpdk-dev] ***Spam*** " Andrew Rybchenko
2018-04-24 19:15 ` [dpdk-dev] " Olivier Matz
2018-04-24 20:22 ` Thomas Monjalon
2018-04-24 21:53 ` Yongseok Koh [this message]
2018-04-24 22:15 ` Thomas Monjalon
2018-04-25 8:21 ` Olivier Matz
2018-04-25 15:06 ` Stephen Hemminger
2018-04-24 23:34 ` Yongseok Koh
2018-04-25 14:45 ` Andrew Rybchenko
2018-04-25 17:40 ` Yongseok Koh
2018-04-25 8:28 ` Olivier Matz
2018-04-25 9:08 ` Yongseok Koh
2018-04-25 9:19 ` Yongseok Koh
2018-04-25 20:00 ` Olivier Matz
2018-04-25 22:54 ` Yongseok Koh
2018-04-24 22:30 ` Yongseok Koh
2018-04-25 2:53 ` [dpdk-dev] [PATCH v5 " Yongseok Koh
2018-04-25 2:53 ` [dpdk-dev] [PATCH v5 2/2] app/testpmd: conserve offload flags of mbuf Yongseok Koh
2018-04-25 13:31 ` [dpdk-dev] [PATCH v5 1/2] mbuf: support attaching external buffer to mbuf Ananyev, Konstantin
2018-04-25 17:06 ` Yongseok Koh
2018-04-25 17:23 ` Ananyev, Konstantin
2018-04-25 18:02 ` Yongseok Koh
2018-04-25 18:22 ` Yongseok Koh
2018-04-25 18:30 ` Yongseok Koh
2018-04-26 1:10 ` [dpdk-dev] [PATCH v6 " Yongseok Koh
2018-04-26 1:10 ` [dpdk-dev] [PATCH v6 2/2] app/testpmd: conserve offload flags of mbuf Yongseok Koh
2018-04-26 11:39 ` [dpdk-dev] [PATCH v6 1/2] mbuf: support attaching external buffer to mbuf Ananyev, Konstantin
2018-04-26 16:05 ` Andrew Rybchenko
2018-04-26 16:10 ` Thomas Monjalon
2018-04-26 19:42 ` Olivier Matz
2018-04-26 19:58 ` Thomas Monjalon
2018-04-26 20:07 ` Olivier Matz
2018-04-26 20:24 ` Thomas Monjalon
2018-04-26 17:18 ` Yongseok Koh
2018-04-26 19:45 ` Olivier Matz
2018-04-27 0:01 ` [dpdk-dev] [PATCH v7 " Yongseok Koh
2018-04-27 0:01 ` [dpdk-dev] [PATCH v7 2/2] app/testpmd: conserve offload flags of mbuf Yongseok Koh
2018-04-27 8:00 ` Andrew Rybchenko
2018-04-27 7:22 ` [dpdk-dev] [PATCH v7 1/2] mbuf: support attaching external buffer to mbuf Andrew Rybchenko
2018-04-27 17:22 ` [dpdk-dev] [PATCH v8 " Yongseok Koh
2018-04-27 17:22 ` [dpdk-dev] [PATCH v8 2/2] app/testpmd: conserve offload flags of mbuf Yongseok Koh
2018-04-27 18:09 ` [dpdk-dev] [PATCH v8 1/2] mbuf: support attaching external buffer to mbuf Thomas Monjalon
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