patches for DPDK stable branches
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From: "Dumitrescu, Cristian" <cristian.dumitrescu@intel.com>
To: "Yigit, Ferruh" <ferruh.yigit@intel.com>,
	Ray Kinsella <mdr@ashroe.eu>, Neil Horman <nhorman@tuxdriver.com>,
	Eelco Chaudron <echaudro@redhat.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	Thomas Monjalon <thomas@monjalon.net>,
	David Marchand <david.marchand@redhat.com>,
	"stable@dpdk.org" <stable@dpdk.org>,
	Luca Boccassi <bluca@debian.org>,
	"Richardson, Bruce" <bruce.richardson@intel.com>,
	"Stokes, Ian" <ian.stokes@intel.com>,
	"Andrzej Ostruszka" <amo@semihalf.com>
Subject: Re: [dpdk-stable] [PATCH v4] meter: provide experimental alias of API for old apps
Date: Sun, 17 May 2020 19:52:03 +0000
Message-ID: <BYAPR11MB2935E7073F458CB6E0F57170EBBB0@BYAPR11MB2935.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20200514161104.1546493-1-ferruh.yigit@intel.com>

Hi Ferruh,

> -----Original Message-----
> From: Yigit, Ferruh <ferruh.yigit@intel.com>
> Sent: Thursday, May 14, 2020 5:11 PM
> To: Ray Kinsella <mdr@ashroe.eu>; Neil Horman
> <nhorman@tuxdriver.com>; Dumitrescu, Cristian
> <cristian.dumitrescu@intel.com>; Eelco Chaudron <echaudro@redhat.com>
> Cc: dev@dpdk.org; Yigit, Ferruh <ferruh.yigit@intel.com>; Thomas Monjalon
> <thomas@monjalon.net>; David Marchand <david.marchand@redhat.com>;
> stable@dpdk.org; Luca Boccassi <bluca@debian.org>; Richardson, Bruce
> <bruce.richardson@intel.com>; Stokes, Ian <ian.stokes@intel.com>; Andrzej
> Ostruszka <amo@semihalf.com>
> Subject: [PATCH v4] meter: provide experimental alias of API for old apps
> 
> On v20.02 some meter APIs have been matured and symbols moved from
> EXPERIMENTAL to DPDK_20.0.1 block.
> 
> This can break the applications that were using these mentioned APIs on
> v19.11. Although there is no modification on the APIs and the action is
> positive and matures the APIs, the affect can be negative to
> applications.
> 
> Since experimental APIs can change or go away without notice as part of
> contract, to prevent this negative affect that may occur by maturing
> experimental API, a process update already suggested, which enables
> aliasing without forcing it:
> https://patches.dpdk.org/patch/65863/
> 

Personally, I am not convinced this is really needed.

Are there any users asking for this?

Is there any other library where this is also applied, or is librte_meter the only library?

> This patch provides aliasing by duplicating the existing and versioned
> symbols as experimental.
> 
> Since symbols moved from DPDK_20.0.1 to DPDK_21 block in the v20.05, the
> aliasing done between EXPERIMENTAL and DPDK_21.
> 
> Also following changes done to enabling aliasing:
> 
> Created VERSION_SYMBOL_EXPERIMENTAL helper macro.
> 
> Updated the 'check-symbols.sh' buildtool, which was complaining that the
> symbol is in EXPERIMENTAL tag in .map file but it is not in the
> .experimental section (__rte_experimental tag is missing).
> Updated tool in a way it won't complain if the symbol in the
> EXPERIMENTAL tag duplicated in some other block in .map file (versioned)
> 
> Enabled function versioning for meson build for the library.
> 
> Fixes: 30512af820fe ("meter: remove experimental flag from RFC4115 trTCM
> API")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
> Cc: Neil Horman <nhorman@tuxdriver.com>
> Cc: Thomas Monjalon <thomas@monjalon.net>
> Cc: Luca Boccassi <bluca@debian.org>
> Cc: David Marchand <david.marchand@redhat.com>
> Cc: Bruce Richardson <bruce.richardson@intel.com>
> Cc: Ian Stokes <ian.stokes@intel.com>
> Cc: Eelco Chaudron <echaudro@redhat.com>
> Cc: Andrzej Ostruszka <amo@semihalf.com>
> Cc: Ray Kinsella <mdr@ashroe.eu>
> 
> v2:
> * Commit log updated
> 
> v3:
> * added suggested comment to VERSION_SYMBOL_EXPERIMENTAL macro
> 
> v4:
> * update script name in commit log, remove empty line
> ---
>  buildtools/check-symbols.sh                   |  3 +-
>  .../include/rte_function_versioning.h         |  9 +++
>  lib/librte_meter/meson.build                  |  1 +
>  lib/librte_meter/rte_meter.c                  | 59 ++++++++++++++++++-
>  lib/librte_meter/rte_meter_version.map        |  8 +++
>  5 files changed, 76 insertions(+), 4 deletions(-)
> 
> diff --git a/buildtools/check-symbols.sh b/buildtools/check-symbols.sh
> index 3df57c322c..e407553a34 100755
> --- a/buildtools/check-symbols.sh
> +++ b/buildtools/check-symbols.sh
> @@ -26,7 +26,8 @@ ret=0
>  for SYM in `$LIST_SYMBOL -S EXPERIMENTAL $MAPFILE |cut -d ' ' -f 3`
>  do
>  	if grep -q "\.text.*[[:space:]]$SYM$" $DUMPFILE &&
> -		! grep -q "\.text\.experimental.*[[:space:]]$SYM$"
> $DUMPFILE
> +		! grep -q "\.text\.experimental.*[[:space:]]$SYM$"
> $DUMPFILE &&
> +		$LIST_SYMBOL -s $SYM $MAPFILE | grep -q EXPERIMENTAL
>  	then
>  		cat >&2 <<- END_OF_MESSAGE
>  		$SYM is not flagged as experimental
> diff --git a/lib/librte_eal/include/rte_function_versioning.h
> b/lib/librte_eal/include/rte_function_versioning.h
> index b9f862d295..f588f2643b 100644
> --- a/lib/librte_eal/include/rte_function_versioning.h
> +++ b/lib/librte_eal/include/rte_function_versioning.h
> @@ -46,6 +46,14 @@
>   */
>  #define VERSION_SYMBOL(b, e, n) __asm__(".symver " RTE_STR(b)
> RTE_STR(e) ", " RTE_STR(b) "@DPDK_" RTE_STR(n))
> 
> +/*
> + * VERSION_SYMBOL_EXPERIMENTAL
> + * Creates a symbol version table entry binding the symbol
> <b>@EXPERIMENTAL to the internal
> + * function name <b><e>. The macro is used when a symbol matures to
> become part of the stable ABI,
> + * to provide an alias to experimental for some time.
> + */
> +#define VERSION_SYMBOL_EXPERIMENTAL(b, e) __asm__(".symver "
> RTE_STR(b) RTE_STR(e) ", " RTE_STR(b) "@EXPERIMENTAL")
> +
>  /*
>   * BIND_DEFAULT_SYMBOL
>   * Creates a symbol version entry instructing the linker to bind references to
> @@ -79,6 +87,7 @@
>   * No symbol versioning in use
>   */
>  #define VERSION_SYMBOL(b, e, n)
> +#define VERSION_SYMBOL_EXPERIMENTAL(b, e)
>  #define __vsym
>  #define BIND_DEFAULT_SYMBOL(b, e, n)
>  #define MAP_STATIC_SYMBOL(f, p) f __attribute__((alias(RTE_STR(p))))
> diff --git a/lib/librte_meter/meson.build b/lib/librte_meter/meson.build
> index 646fd4d43f..fce0368437 100644
> --- a/lib/librte_meter/meson.build
> +++ b/lib/librte_meter/meson.build
> @@ -3,3 +3,4 @@
> 
>  sources = files('rte_meter.c')
>  headers = files('rte_meter.h')
> +use_function_versioning = true
> diff --git a/lib/librte_meter/rte_meter.c b/lib/librte_meter/rte_meter.c
> index da01429a8b..c600b05064 100644
> --- a/lib/librte_meter/rte_meter.c
> +++ b/lib/librte_meter/rte_meter.c
> @@ -9,6 +9,7 @@
>  #include <rte_common.h>
>  #include <rte_log.h>
>  #include <rte_cycles.h>
> +#include <rte_function_versioning.h>
> 
>  #include "rte_meter.h"
> 
> @@ -119,8 +120,8 @@ rte_meter_trtcm_config(struct rte_meter_trtcm *m,
>  	return 0;
>  }
> 
> -int
> -rte_meter_trtcm_rfc4115_profile_config(
> +static int
> +rte_meter_trtcm_rfc4115_profile_config_(
>  	struct rte_meter_trtcm_rfc4115_profile *p,
>  	struct rte_meter_trtcm_rfc4115_params *params)
>  {
> @@ -145,7 +146,35 @@ rte_meter_trtcm_rfc4115_profile_config(
>  }
> 
>  int
> -rte_meter_trtcm_rfc4115_config(
> +rte_meter_trtcm_rfc4115_profile_config_s(
> +	struct rte_meter_trtcm_rfc4115_profile *p,
> +	struct rte_meter_trtcm_rfc4115_params *params);
> +int
> +rte_meter_trtcm_rfc4115_profile_config_s(
> +	struct rte_meter_trtcm_rfc4115_profile *p,
> +	struct rte_meter_trtcm_rfc4115_params *params)
> +{
> +	return rte_meter_trtcm_rfc4115_profile_config_(p, params);
> +}
> +BIND_DEFAULT_SYMBOL(rte_meter_trtcm_rfc4115_profile_config, _s, 21);
> +MAP_STATIC_SYMBOL(int rte_meter_trtcm_rfc4115_profile_config(struct
> rte_meter_trtcm_rfc4115_profile *p,
> +		struct rte_meter_trtcm_rfc4115_params *params),
> rte_meter_trtcm_rfc4115_profile_config_s);
> +
> +int
> +rte_meter_trtcm_rfc4115_profile_config_e(
> +	struct rte_meter_trtcm_rfc4115_profile *p,
> +	struct rte_meter_trtcm_rfc4115_params *params);
> +int
> +rte_meter_trtcm_rfc4115_profile_config_e(
> +	struct rte_meter_trtcm_rfc4115_profile *p,
> +	struct rte_meter_trtcm_rfc4115_params *params)
> +{
> +	return rte_meter_trtcm_rfc4115_profile_config_(p, params);
> +}
> +VERSION_SYMBOL_EXPERIMENTAL(rte_meter_trtcm_rfc4115_profile_conf
> ig, _e);
> +
> +static int
> +rte_meter_trtcm_rfc4115_config_(
>  	struct rte_meter_trtcm_rfc4115 *m,
>  	struct rte_meter_trtcm_rfc4115_profile *p)
>  {
> @@ -160,3 +189,27 @@ rte_meter_trtcm_rfc4115_config(
> 
>  	return 0;
>  }
> +
> +int
> +rte_meter_trtcm_rfc4115_config_s(struct rte_meter_trtcm_rfc4115 *m,
> +	struct rte_meter_trtcm_rfc4115_profile *p);
> +int
> +rte_meter_trtcm_rfc4115_config_s(struct rte_meter_trtcm_rfc4115 *m,
> +	struct rte_meter_trtcm_rfc4115_profile *p)
> +{
> +	return rte_meter_trtcm_rfc4115_config_(m, p);
> +}
> +BIND_DEFAULT_SYMBOL(rte_meter_trtcm_rfc4115_config, _s, 21);
> +MAP_STATIC_SYMBOL(int rte_meter_trtcm_rfc4115_config(struct
> rte_meter_trtcm_rfc4115 *m,
> +		 struct rte_meter_trtcm_rfc4115_profile *p),
> rte_meter_trtcm_rfc4115_config_s);
> +
> +int
> +rte_meter_trtcm_rfc4115_config_e(struct rte_meter_trtcm_rfc4115 *m,
> +	struct rte_meter_trtcm_rfc4115_profile *p);
> +int
> +rte_meter_trtcm_rfc4115_config_e(struct rte_meter_trtcm_rfc4115 *m,
> +	struct rte_meter_trtcm_rfc4115_profile *p)
> +{
> +	return rte_meter_trtcm_rfc4115_config_(m, p);
> +}
> +VERSION_SYMBOL_EXPERIMENTAL(rte_meter_trtcm_rfc4115_config, _e);

To me, this is a significant amount of dead code that does not add any functionality and does not bring any added value to the library for any user. I am not a build system expert, but I would definitely prefer avoiding adding any C code to the library for this purpose, and just modify the map file, would this approach be possible?

Also, very important, is this C code to be added permanently or is it added just on a temporary basis? If temporary, when is it going to be removed?

> diff --git a/lib/librte_meter/rte_meter_version.map
> b/lib/librte_meter/rte_meter_version.map
> index 2c7dadbcac..b493bcebe9 100644
> --- a/lib/librte_meter/rte_meter_version.map
> +++ b/lib/librte_meter/rte_meter_version.map
> @@ -20,4 +20,12 @@ DPDK_21 {
>  	rte_meter_trtcm_rfc4115_color_blind_check;
>  	rte_meter_trtcm_rfc4115_config;
>  	rte_meter_trtcm_rfc4115_profile_config;
> +
>  } DPDK_20.0;
> +
> +EXPERIMENTAL {
> +       global:
> +
> +	rte_meter_trtcm_rfc4115_config;
> +	rte_meter_trtcm_rfc4115_profile_config;
> +};
> --
> 2.25.4

Regards,
Cristian

  parent reply	other threads:[~2020-05-17 19:52 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200513121149.2283385-1-ferruh.yigit@intel.com>
2020-05-13 18:05 ` [dpdk-stable] [PATCH v2] " Ferruh Yigit
2020-05-14  8:44   ` Ray Kinsella
2020-05-14 11:53     ` Ferruh Yigit
2020-05-14 11:52 ` [dpdk-stable] [PATCH v3] " Ferruh Yigit
2020-05-14 15:10   ` Ray Kinsella
2020-05-14 15:32   ` David Marchand
2020-05-14 15:56     ` Ray Kinsella
2020-05-14 16:07     ` Ferruh Yigit
2020-05-14 16:30       ` David Marchand
2020-05-14 16:11 ` [dpdk-stable] [PATCH v4] " Ferruh Yigit
2020-05-15 13:31   ` Thomas Monjalon
2020-05-15 14:41     ` Ray Kinsella
2020-05-15 15:03     ` Ray Kinsella
2020-05-15 14:36   ` [dpdk-stable] [dpdk-dev] " Ray Kinsella
2020-05-15 15:01   ` Ray Kinsella
2020-05-17 19:52   ` Dumitrescu, Cristian [this message]
2020-05-18  6:29     ` [dpdk-stable] " Ray Kinsella
2020-05-18  9:22       ` Thomas Monjalon
2020-05-18  9:30         ` Ray Kinsella
2020-05-18 10:46           ` Thomas Monjalon
2020-05-18 11:18             ` Dumitrescu, Cristian
2020-05-18 11:49               ` Ray Kinsella
2020-05-18 11:48             ` Ray Kinsella
2020-05-18 12:13               ` Thomas Monjalon
2020-05-18 13:06                 ` Ray Kinsella
2020-05-18 18:30 ` [dpdk-stable] [PATCH v5] " Ferruh Yigit
2020-05-19 12:16 ` [dpdk-stable] [PATCH v6] " Ferruh Yigit
2020-05-19 13:26   ` Dumitrescu, Cristian
2020-05-19 14:24     ` [dpdk-stable] [dpdk-dev] " Thomas Monjalon
2020-05-19 14:22   ` [dpdk-stable] " Ray Kinsella

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