From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ferruh Yigit Subject: Re: [PATCH] ethdev: add function name to log message Date: Wed, 17 Oct 2018 18:08:07 +0100 Message-ID: References: <20181011175940.6800-1-stephen@networkplumber.org> <98717fc3-c3dd-cc4f-e5ff-b5310e47d6ee@intel.com> <696e6f90-3d0c-acd4-d72d-bbebe1ff6f54@intel.com> <20181012124357.GR18937@6wind.com> <20181012075424.79383f32@xeon-e3> <2ed85850-f6f3-1f99-375b-85910479a9a2@intel.com> <20181017092631.bklpipmyfeatvotv@bidouze.vm.6wind.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: Stephen Hemminger , Adrien Mazarguil , thomas@monjalon.net, dev@dpdk.org To: =?UTF-8?Q?Ga=c3=abtan_Rivet?= Return-path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id 1D2847D4E for ; Wed, 17 Oct 2018 19:08:09 +0200 (CEST) In-Reply-To: <20181017092631.bklpipmyfeatvotv@bidouze.vm.6wind.com> Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 10/17/2018 10:26 AM, Gaëtan Rivet wrote: > Hi Ferruh, > > On Tue, Oct 16, 2018 at 04:55:43PM +0100, Ferruh Yigit wrote: >> On 10/12/2018 3:54 PM, Stephen Hemminger wrote: >>> On Fri, 12 Oct 2018 14:43:57 +0200 >>> Adrien Mazarguil wrote: >>> >>>> On Fri, Oct 12, 2018 at 11:45:01AM +0100, Ferruh Yigit wrote: >>>>> On 10/12/2018 11:42 AM, Ferruh Yigit wrote: >>>>>> On 10/11/2018 6:59 PM, Stephen Hemminger wrote: >>>>>>> @@ -161,8 +161,9 @@ extern "C" { >>>>>>> >>>>>>> extern int rte_eth_dev_logtype; >>>>>>> >>>>>>> -#define RTE_ETHDEV_LOG(level, ...) \ >>>>>>> - rte_log(RTE_LOG_ ## level, rte_eth_dev_logtype, "" __VA_ARGS__) >>>>>>> +#define RTE_ETHDEV_LOG(level, fmt, ...) \ >>>>>>> + rte_log(RTE_LOG_ ## level, rte_eth_dev_logtype, \ >>>>>>> + "%s():" fmt, __func__, ## __VA_ARGS__) >>>>>> >>>>>> +1 to adding function name, but >>>>>> >>>>>> failsafe is giving build error [1] with clang because of ## usage [2], that is >>>>>> why I add this as ` "" __VA_ARGS__` at first place but you can't do this trick >>>>>> if __VA_ARGS__ used after fmt. >>>>>> >>>>>> I am not aware of a solution for this, __VA_OPT__(,) also didn't worked with clang. >>>>> >>>>> +cc Adrien & Gaetan, >>>>> >>>>> I saw Adrien put some "workaround" to this for mlx5 >>>> >>>> Yes, through RTE_FMT() (rte_common.h). Something like this: >>>> >>>> #define RTE_ETHDEV_LOG(level, fmt, ...) \ >>>> rte_log(RTE_LOG_ ## level, \ >>>> rte_eth_dev_logtype, \ >>>> "%s():" fmt, \ >>>> __func__, \ >>>> ## __VA_ARGS__) >>>> >>>> Can be rewritten like that: >>>> >>>> #define RTE_ETHDEV_LOG(level, ...) \ >>>> rte_log(RTE_LOG_ ## level, \ >>>> rte_eth_dev_logtype, \ >>>> RTE_FMT("%s():" RTE_FMT_HEAD(__VA_ARGS__,), \ >>>> __func__, \ >>>> RTE_FMT_TAIL(__VA_ARGS__,))) >>>> >>>> Although not too pretty and convenient, it does the job. In short: >>>> >>>> - Remove "fmt" argument from prototype. >>>> - Enclose format string and its arguments in RTE_FMT(). >>>> - Replace "fmt" with RTE_FMT_HEAD(__VA_ARGS__,). >>>> - Replace "## __VA_ARGS__" with RTE_FMT_TAIL(__VA_ARGS__,). >>>> - Yes, trailing commas are mandatory in RTE_FMT_(HEAD|TAIL)(). >>>> - Note it quietly appends a dummy "%.0s" argument to the format string. >>>> >>>>>> [1] >>>>>> .../build/include/rte_ethdev.h:166:26: error: token pasting of ',' and >>>>>> __VA_ARGS__ is a GNU extension [-Werror,-Wgnu-zero-variadic-macro-arguments] >>>>>> "%s():" fmt, __func__, ## __VA_ARGS__) >>>>>> ^ >>>>>> >>>>>> [2] >>>>>> This seems because of "-pedantic" argument driver uses, and other PMDs using >>>>>> "-pedantic", like mlx, will have same error although they are disable by >>>>>> default and error not observed in default build. >>>>>> >>>>> >>>> >>> >>> Since zero varadic macros is a GNU extension, maybe just adding GNU source? >> >> I think `-pedantic` is preventing using extension whether we have `_GNU_SOURCE` >> or not. >> >> Gaetan, >> >> Why we have `-pedantic` option enabled for failsafe? > > Because I wanted to enforce it in failsafe, and core DPDK headers were > compatible so it wasn't too much of a hassle. > > If rte_ethdev.h is meant to lose this compatibility, then pedantic will > be disabled upon including it. But I guess if it was kept compatible > until now, then it was a deliberate effort? I think it is deliberate effort, I remember Adrien put some patches in the past to make DPDK headers pedantic compatible by adding __extension__ keywords. I tried to use __extension__ for ## but not able to make it work, is there a way to do this? And I see the reasoning of making DPDK headers pedantic compatible, I think we should keep them compatible.