From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <18265.47545.897637.377869@domain.hid> Date: Fri, 7 Dec 2007 22:23:05 +0100 In-Reply-To: <475952CD.3020003@domain.hid> References: <4757EBAE.4050608@domain.hid> <2ff1a98a0712060513g3b056866x883691498daf00e1@domain.hid> <4757F811.70905@domain.hid> <2ff1a98a0712060528y13159abdwb83617a8744b3735@domain.hid> <2ff1a98a0712060544x6e1e8c11q52e9417fb096e4b7@domain.hid> <475801AA.3060300@domain.hid> <2ff1a98a0712060621k436f32b7sc1d1cfe53bea8f18@domain.hid> <475952CD.3020003@domain.hid> From: Gilles Chanteperdrix Subject: Re: [Xenomai-core] How to cancel a Xenomai POSIX thread List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wolfgang Grandegger Cc: xenomai-core Wolfgang Grandegger wrote: > Hi Gilles, > > Gilles Chanteperdrix wrote: > > On Dec 6, 2007 3:05 PM, Wolfgang Grandegger wrote: > >> Gilles Chanteperdrix wrote: > >>> On Dec 6, 2007 2:28 PM, Gilles Chanteperdrix > >>> wrote: > >>>> On Dec 6, 2007 2:24 PM, Wolfgang Grandegger wrote: > >>>>> Gilles Chanteperdrix wrote: > >>>>>> On Dec 6, 2007 1:31 PM, Wolfgang Grandegger wrote: > >>>>>>> Hello, > >>>>>>> > >>>>>>> how do I cancel or delete a Xenomai POSIX thread running in primary > >>>>>>> context from a higher priority thread? IIUC, pthread_kill() can only be > >>>>>>> used in secondary context. I tried pthread_cancel(), but it only works > >>>>>>> when hitting a cancelation point, e.g. pthread_testcancel(). Setting > >>>>>>> pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS) did not help. Is > >>>>>>> there a code snippet or even an example program showing how to cancel a > >>>>>>> pthread in primary context? > >>>>>> pthread_kill or pthread_cancel should result in sending a signal to > >>>>>> the target thread, so should cause this thread to switch to secondary > >>>>>> mode to handle it. If you want to wait for the target thread to be > >>>>>> canceled, you should use pthread_cancel and pthread_join. > >>>>> There is no way to cancel a pthread in primary mode from another pthread? > >>>> No. You always need secondary mode to effectively delete a thread. The > >>>> same goes for the native skin. > >>> Ok. I understand what you mean. You want pthread_cancel not to leave > >>> primary mode. This can easily be done by causing pthread_cancel to use > >>> the kernel-space real-time pthread_cancel service. This should work > >>> with no further modification. > >> I want to cancel/delete a task running in primary mode, e.g. > >> > >> void* work_task(void* dummy) > >> { > >> int count = 0; > >> while (1) > >> count++; > >> } > >> > >> from the outside (= another higher priority task). How can I use the > >> kernel-space real-time pthread_cancel service? My POSIX app is runs in > >> user-land. > > > > I was thinking about adding a pthread_cancel syscall that would have > > triggered the kernel-space pthread_cancel. But this will not work: > > user-space cleanup handlers would no longer get executed. However, > > this can work for pthread_kill. Here is a patch which adds the > > pthread_kill syscall. > > Great, thanks a lot. This seems to work but I'm now fiddling with proper > cleanup and exit. I have attached my small test program. It behaves > somehow strange, at least to me: > > - I see task period overruns when the low prio task is started. I > suspect some switch to secondary mode in init_task(). > > - The program/system hangs after the listed messages: > > # ./kill_pthread > Starting high_prio_task > Killed low_prio task: count=3813129, overruns=0 > > Any idea what I'm doing wrong? > > This is with Linux 2.4.25 and Xenomai 2.3.x on a MPC5200 board. Your test runs fine with Xenomai trunk (on ARM). I will now try with current state of the v2.3.x branch. -- Gilles Chanteperdrix.