From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <dev-bounces@dpdk.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124])
	by smtp.lore.kernel.org (Postfix) with ESMTP id 324A3C48BC4
	for <dpdk-dev@archiver.kernel.org>; Sun, 18 Feb 2024 16:20:37 +0000 (UTC)
Received: from mails.dpdk.org (localhost [127.0.0.1])
	by mails.dpdk.org (Postfix) with ESMTP id 58E7D40262;
	Sun, 18 Feb 2024 17:20:36 +0100 (CET)
Received: from dkmailrelay1.smartsharesystems.com
 (smartserver.smartsharesystems.com [77.243.40.215])
 by mails.dpdk.org (Postfix) with ESMTP id 9AEDA4021D
 for <dev@dpdk.org>; Sun, 18 Feb 2024 17:20:34 +0100 (CET)
Received: from smartserver.smartsharesystems.com
 (smartserver.smartsharesys.local [192.168.4.10])
 by dkmailrelay1.smartsharesystems.com (Postfix) with ESMTP id 55DFE2011D;
 Sun, 18 Feb 2024 17:20:34 +0100 (CET)
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Subject: RE: [PATCH v4 01/18] mbuf: deprecate GCC marker in rte mbuf struct
X-MimeOLE: Produced By Microsoft Exchange V6.5
Date: Sun, 18 Feb 2024 17:20:32 +0100
Message-ID: <98CBD80474FA8B44BF855DF32C47DC35E9F22C@smartserver.smartshare.dk>
In-Reply-To: <5265622.RUnXabflUD@thomas>
X-MS-Has-Attach: 
X-MS-TNEF-Correlator: 
Thread-Topic: [PATCH v4 01/18] mbuf: deprecate GCC marker in rte mbuf struct
Thread-Index: Adpifki8g6lnk58CSxiBxrrLMix3oAAByvIw
References: <1706657173-26166-1-git-send-email-roretzla@linux.microsoft.com>
 <7561963.alqRGMn8q6@thomas>
 <98CBD80474FA8B44BF855DF32C47DC35E9F22B@smartserver.smartshare.dk>
 <5265622.RUnXabflUD@thomas>
From: =?iso-8859-1?Q?Morten_Br=F8rup?= <mb@smartsharesystems.com>
To: "Thomas Monjalon" <thomas@monjalon.net>, <dev@dpdk.org>,
 "Tyler Retzlaff" <roretzla@linux.microsoft.com>
Cc: "Ajit Khaparde" <ajit.khaparde@broadcom.com>,
 "Andrew Boyer" <andrew.boyer@amd.com>,
 "Andrew Rybchenko" <andrew.rybchenko@oktetlabs.ru>,
 "Bruce Richardson" <bruce.richardson@intel.com>,
 "Chenbo Xia" <chenbox@nvidia.com>,
 "Chengwen Feng" <fengchengwen@huawei.com>,
 "Dariusz Sosnowski" <dsosnowski@nvidia.com>,
 "David Christensen" <drc@linux.vnet.ibm.com>,
 "Hyong Youb Kim" <hyonkim@cisco.com>, "Jerin Jacob" <jerinj@marvell.com>,
 "Jie Hai" <haijie1@huawei.com>, "Jingjing Wu" <jingjing.wu@intel.com>,
 "John Daley" <johndale@cisco.com>, "Kevin Laatz" <kevin.laatz@intel.com>,
 "Kiran Kumar K" <kirankumark@marvell.com>,
 "Konstantin Ananyev" <konstantin.v.ananyev@yandex.ru>,
 "Maciej Czekaj" <mczekaj@marvell.com>, "Matan Azrad" <matan@nvidia.com>,
 "Maxime Coquelin" <maxime.coquelin@redhat.com>,
 "Nithin Dabilpuram" <ndabilpuram@marvell.com>,
 "Ori Kam" <orika@nvidia.com>, "Ruifeng Wang" <ruifeng.wang@arm.com>,
 "Satha Rao" <skoteshwar@marvell.com>,
 "Somnath Kotur" <somnath.kotur@broadcom.com>,
 "Suanming Mou" <suanmingm@nvidia.com>,
 "Sunil Kumar Kori" <skori@marvell.com>,
 "Viacheslav Ovsiienko" <viacheslavo@nvidia.com>,
 "Yisen Zhuang" <yisen.zhuang@huawei.com>,
 "Yuying Zhang" <Yuying.Zhang@intel.com>
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://mails.dpdk.org/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://mails.dpdk.org/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <https://mails.dpdk.org/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org

> From: Thomas Monjalon [mailto:thomas@monjalon.net]
> Sent: Sunday, 18 February 2024 16.22
>=20
> 18/02/2024 14:07, Morten Br=F8rup:
> > From: Thomas Monjalon [mailto:thomas@monjalon.net]
> > > 15/02/2024 07:21, Tyler Retzlaff:
> > > > --- a/lib/eal/include/rte_common.h
> > > > +++ b/lib/eal/include/rte_common.h
> > > > @@ -582,6 +582,12 @@ static void
> > > __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
> > > >  /** Marker for 8B alignment in a structure. */
> > > >  __extension__ typedef uint64_t RTE_MARKER64[0];
> > > >
> > > > +#define __rte_marker(type, name) type name /* __rte_deprecated
> */
> > > > +
> > > > +#else
> > > > +
> > > > +#define __rte_marker(type, name)
> > > > +
> > > >  #endif
> > > >
> > > >  /*********** Macros for calculating min and max **********/
> > > > diff --git a/lib/mbuf/rte_mbuf_core.h b/lib/mbuf/rte_mbuf_core.h
> > > > index 5688683..9e9590b 100644
> > > > --- a/lib/mbuf/rte_mbuf_core.h
> > > > +++ b/lib/mbuf/rte_mbuf_core.h
> > > > @@ -16,7 +16,10 @@
> > > >   * New fields and flags should fit in the "dynamic space".
> > > >   */
> > > >
> > > > +#include <assert.h>
> > > > +#include <stdalign.h>
> > > >  #include <stdint.h>
> > > > +#include <stddef.h>
> > > >
> > > >  #include <rte_byteorder.h>
> > > >  #include <rte_stdatomic.h>
> > > > @@ -464,204 +467,240 @@ enum {
> > > >   * The generic rte_mbuf, containing a packet mbuf.
> > > >   */
> > > >  struct rte_mbuf {
> > > > -	RTE_MARKER cacheline0;
> > > > -
> > > > -	void *buf_addr;           /**< Virtual address of segment
> buffer.
> > > */
> > > > +	__rte_marker(RTE_MARKER, cacheline0);
> > >
> > > You don't need to keep the first argument.
> > > This would be simpler:
> > > 	__rte_marker(cacheline0);
> > > You just need to create 2 functions: __rte_marker and
> __rte_marker64.
> > >
> > > You should replace all occurrences of RTE_MARKER in DPDK in one
> patch,
> > > and mark RTE_MARKER as deprecated (use #pragma GCC poison)
> >
> > I like this suggestion.
> > However, some applications might use RTE_MARKER in their own
> structures.
> > Wouldn't it be considered API breakage to mark RTE_MARKER as
> deprecated?
>=20
> Yes it is an API breakage.
> Do we prefer waiting 24.11 for poisoning this macro?

Personally, I generally don't mind API breakages, assuming that they are =
visible and thus don't silently introduce bugs.
The distro people might have a different opinion.