From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by dpdk.org (Postfix) with ESMTP id BD5516A9C for ; Tue, 30 Sep 2014 14:00:33 +0200 (CEST) Received: from azsmga001.ch.intel.com ([10.2.17.19]) by orsmga101.jf.intel.com with ESMTP; 30 Sep 2014 05:07:11 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,626,1406617200"; d="scan'208";a="480980937" Received: from irsmsx101.ger.corp.intel.com ([163.33.3.153]) by azsmga001.ch.intel.com with ESMTP; 30 Sep 2014 05:07:09 -0700 Received: from irsmsx108.ger.corp.intel.com (163.33.3.3) by IRSMSX101.ger.corp.intel.com (163.33.3.153) with Microsoft SMTP Server (TLS) id 14.3.195.1; Tue, 30 Sep 2014 13:05:24 +0100 Received: from irsmsx102.ger.corp.intel.com ([169.254.2.200]) by IRSMSX108.ger.corp.intel.com ([169.254.11.21]) with mapi id 14.03.0195.001; Tue, 30 Sep 2014 13:05:24 +0100 From: "Wodkowski, PawelX" To: "Wodkowski, PawelX" , "Richardson, Bruce" Thread-Topic: [dpdk-dev] [PATCH v2] Change alarm cancel function to thread-safe: Thread-Index: AQHP2MAapayPUkT5UUGj9XqXyFJ3T5wR4sKAgAAPjwCAABZmAIAAZLsAgADPUACAAB2vsIAAAhgAgAAUZmCAAAJtAIAACzAAgAALEACAAB2GAIAAGaqAgALq0gCAAE0RAIAAsPTwgAApkQCAABD+IP//+xeAgAGiIxCAABjfkA== Date: Tue, 30 Sep 2014 12:05:24 +0000 Message-ID: References: <20140926150156.GB5619@hmsreliant.think-freely.org> <2601191342CEEE43887BDE71AB9772582137D88E@IRSMSX104.ger.corp.intel.com> <20140926162134.GE5619@hmsreliant.think-freely.org> <2601191342CEEE43887BDE71AB9772582137D95F@IRSMSX104.ger.corp.intel.com> <20140926193905.GH5619@hmsreliant.think-freely.org> <2601191342CEEE43887BDE71AB9772582138410B@IRSMSX104.ger.corp.intel.com> <20140928204754.GC4012@localhost.localdomain> <2601191342CEEE43887BDE71AB977258213874C5@IRSMSX104.ger.corp.intel.com> <20140929103315.GB12072@BRICHA3-MOBL> In-Reply-To: Accept-Language: pl-PL, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [163.33.239.181] Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [PATCH v2] Change alarm cancel function to thread-safe: X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Sep 2014 12:00:34 -0000 > -----Original Message----- > Pawe=B3 >=20 > > On Mon, Sep 29, 2014 at 10:11:38AM +0000, Wodkowski, PawelX wrote: > > > > > > > > > > Image how you will be damned by someone that not even notice you > > change > > > > > and he Is managing some kind of resource based on returned number= of > > > > > set/canceled timers. If you suddenly start returning negative val= ues how > > those > > > > > application will behave? Silently changing returned value domain = is evil in > > its > > > > > pure form. > > > > > > > > As I can see the impact is very limited. > > > > > > It is small impact to DPDK but can be huge to user application: > > > > This is why we traditionally have in the release-notes for each release= a > > section dedicated to calling out changes from one release to another. [= See > > http://dpdk.org/doc/intel/dpdk-release-notes-1.7.0.pdf section 5]. Sinc= e > > from release-to-release there are generally only a couple of changes - > > though our next release may be a little different - the actual changes = are > > clear enough to read about without wading through pages of documentatio= n. > I > > thinking calling out the change in both the release notes and the API d= ocs > > is sufficient even for a change like this. > > > > Basically, I wouldn't let API stability factor in too much in trying to= get > > a proper fix for this issue. > > > > /Bruce > > >=20 > Summarizing all proposed solutions and to be able to produce final patch = - what > Is desired behavior after fix? >=20 > 1. do we leave as is in Patch v2: > 1.1 if canceling from other thread - if one of the alarms is executing, w= ait to > finish its execution and then cancel any rearmed alarms. > 1.2 if canceling from alarm handler and one of the alarms to cancel is th= is > executing callback do no wait for it to finish and cancel anything else= . >=20 > in both cases return number of canceled callbacks. >=20 > 2. Do exactly like in 1. but return -EINPROGRESS instead of canceled alar= ms > if one of the alarms to cancel is currently executing callback from ala= rm thread > (information about number of canceled alarms will be lost). Or instead of returning -EINPROGRESS set errno to EINPROGRESS (replace returning error value by setting errno and function can always return numbe= r of canceled callbacks - in error condition 0)? >=20 > 3. refuse to cancel anything if canceling currently executing alarm from = alarm > callback and return -EINPROGRESS otherwise do like in 1.1. >=20 > 4. Implement behaviour 1/2/3 (which?) and add API call to interrogate lis= t of > alarms and retrun state of given alarms(s). >=20 > 5. other solutions? >=20 > Pawel