From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Wodkowski, PawelX" Subject: Re: [PATCH v2] Change alarm cancel function to thread-safe: 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> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: quoted-printable Cc: "dev-VfR2kkLFssw@public.gmane.org" To: "Wodkowski, PawelX" , "Richardson, Bruce" Return-path: In-Reply-To: Content-Language: en-US List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" > -----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