From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by dpdk.org (Postfix) with ESMTP id B66382C15 for ; Wed, 3 Oct 2018 01:58:30 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Oct 2018 16:58:29 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,333,1534834800"; d="scan'208";a="96901937" Received: from fmsmsx104.amr.corp.intel.com ([10.18.124.202]) by orsmga002.jf.intel.com with ESMTP; 02 Oct 2018 16:58:23 -0700 Received: from fmsmsx102.amr.corp.intel.com (10.18.124.200) by fmsmsx104.amr.corp.intel.com (10.18.124.202) with Microsoft SMTP Server (TLS) id 14.3.319.2; Tue, 2 Oct 2018 16:58:22 -0700 Received: from fmsmsx151.amr.corp.intel.com ([169.254.7.87]) by FMSMSX102.amr.corp.intel.com ([169.254.10.220]) with mapi id 14.03.0319.002; Tue, 2 Oct 2018 16:58:21 -0700 From: "Wang, Yipeng1" To: "Van Haaren, Harry" , Honnappa Nagarahalli , "Richardson, Bruce" CC: "De Lara Guarch, Pablo" , "dev@dpdk.org" , "Gavin Hu (Arm Technology China)" , "Steve Capper" , Ola Liljedahl , nd , "Gobriel, Sameh" Thread-Topic: [dpdk-dev] [PATCH 3/4] hash: fix rw concurrency while moving keys Thread-Index: AQHUVwkACltYuMWFq0OFAy/59/n9TqUJ4m0AgAKJQACAAD1o4A== Date: Tue, 2 Oct 2018 23:58:21 +0000 Message-ID: References: <1536253938-192391-1-git-send-email-honnappa.nagarahalli@arm.com> <1536253938-192391-4-git-send-email-honnappa.nagarahalli@arm.com> <20180928082610.GA7592@bricha3-MOBL.ger.corp.intel.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-version: 11.0.400.15 dlp-reaction: no-action x-ctpclassification: CTP_NT x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiOTZmNjVhMWQtMGI3Mi00MjhiLThjY2ItNTcxNWJmOTAwNjY5IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX05UIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE3LjEwLjE4MDQuNDkiLCJUcnVzdGVkTGFiZWxIYXNoIjoiWmE1R2xUQjhKZXhCSG9rTWdxYVpaejRQVFhnTlRBVkZ5NjlTVTdOeGpwSlwvVXh5RDNaT2FCMHZUaHlzQnYxeWoifQ== x-originating-ip: [10.1.200.107] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH 3/4] hash: fix rw concurrency while moving keys X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 02 Oct 2018 23:58:31 -0000 >-----Original Message----- >From: Van Haaren, Harry >> > > > > /** >> > > > > * Add a key to an existing hash table. >> > > > >@@ -222,7 +222,7 @@ rte_hash_add_key(const struct rte_hash *h, >> > > > >const void >> > > *key); >> > > > > * array of user data. This value is unique for this key. >> > > > > */ >> > > > > int32_t >> > > > >-rte_hash_add_key_with_hash(const struct rte_hash *h, const void >> > > > >*key, >> > > hash_sig_t sig); >> > > > >+rte_hash_add_key_with_hash(struct rte_hash *h, const void *key, >> > > hash_sig_t sig); >> > > > > >> > > > > / >> > > > >> > > > I think the above changes will break ABI by changing the parameter >> type? >> > > Other people may know better on this. >> > > >> > > Just removing a const should not change the ABI, I believe, since th= e >> > > const is just advisory hint to the compiler. Actual parameter size a= nd >> > > count remains unchanged so I don't believe there is an issue. >> > > [ABI experts, please correct me if I'm wrong on this] >> > >> > >> > [Certainly no ABI expert, but...] >> > >> > I think this is an API break, not ABI break. >> > >> > Given application code as follows, it will fail to compile - even thou= gh >> running >> > the new code as a .so wouldn't cause any issues (AFAIK). >> > >> > void do_hash_stuff(const struct rte_hash *h, ...) { >> > /* parameter passed in is const, but updated function prototype is >> non- >> > const */ >> > rte_hash_add_key_with_hash(h, ...); >> > } >> > >> > This means that we can't recompile apps against latest patch without >> > application code changes, if the app was passing a const rte_hash stru= ct >> as >> > the first parameter. >> > >> Agree. Do we need to do anything for this? > >I think we should try to avoid breaking API wherever possible. >If we must, then I suppose we could follow the ABI process of >a deprecation notice. > >>From my reading of the versioning docs, it doesn't document this case: >https://doc.dpdk.org/guides/contributing/versioning.html > >I don't recall a similar situation in DPDK previously - so I suggest >you ask Tech board for input here. > >Hope that helps! -Harry [Wang, Yipeng]=20 Honnappa, how about use a pointer to the counter in the rte_hash struct ins= tead of the counter? Will this avoid API change?