On Fri, Mar 09, 2007 at 12:02:31AM +0100, Thomas Gleixner wrote: > On Thu, 2007-03-08 at 18:29 +0100, Ingo Molnar wrote: > > * Nick Piggin <[EMAIL PROTECTED]> wrote: > > > > > Hi Ingo, > > > > > > I'm seeing an LTP test fail for ltp test sigaction_16_24. Basically, > > > it tests whether the SA_RESTART flag works for the sem_wait operation. > > Not sure, whether the testcase is correct or not. See below > > > > I see sem_wait is implemented with futex_wait, so I wonder whether we > > > can make it restartable? Am I going about it the right way? (Seems to > > > fix the testcase here). > > > > i think that's quite right. I'm wondering why this never came up before? > > But your fix is not complete i think: > > > > > + restart->arg2 = time; > > > + return -ERESTART_RESTARTBLOCK; > > > + } > > > > 'time' here is relative, so the restarted syscall will do a /full/ wait > > again. > > > > maybe we should rather convert futex timed-waits to hrtimers? Thomas? > > The problem is that the original API is based on relative time and > therefor can not be changed. > > sem_wait returns -EINTR to the application when it is interrupted, while > pthread_mutex_lock does not.
But this still means sem_wait should restart if SA_RESTART is set, right? And pthread_mutex_lock could be implemented to not return -EINTR, even if futex_wait does, couldn't it? (I guess it probably already is, considering that futex_wait alsready returns -EINTR). > > http://www.opengroup.org/onlinepubs/009695399/functions/sem_wait.html > > http://www.opengroup.org/onlinepubs/009695399/functions/pthread_mutex_lock.html > > We need to create a seperate op for the futex - just like the pi_futex > and use absolute time there too. > > tglx > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
