Messages in this thread | | | Date | Thu, 07 Sep 2006 18:30:13 +0900 (JST) | Subject | Re: NPTL mutex and the scheduling priority | From | Atsushi Nemoto <> |
| |
On Thu, 7 Sep 2006 04:32:44 -0400, Jakub Jelinek <jakub@redhat.com> wrote: > > But pthread_cond_signal and sem_post still wakeup a thread in FIFO > > order, as you can guess. > > > > With the plist patch (applied by hand), I can get desired behavior. > > Thank you. But It seems the patch lacks reordering on priority > > changes. > > Yes, either something like the plist patch for FUTEX_WAKE etc. or, if that > proves to be too slow for the usual case (non-RT threads), FIFO wakeup > initially and conversion to plist wakeup whenever first waiter with realtime > priority is added, is still needed. That will cure e.g. non-PI > pthread_mutex_unlock and sem_post. For pthread_cond_{signal,broadcast} we > need further kernel changes, so that the condvar's internal lock can be > always a PI lock.
Thank you, I'll stay tuned.
> > <off_topic> > > BTW, If I tried to create a PI mutex on a kernel without PI futex > > support, pthread_mutexattr_setprotocol(PTHREAD_PRIO_INHERIT) returned > > 0 and pthread_mutex_init() returned ENOTSUP. This is not a right > > behavior according to the manual ... > > </off_topic> > > Why? > POSIX doesn't forbid ENOTSUP in pthread_mutex_init to my knowledge.
http://www.opengroup.org/onlinepubs/009695399/functions/pthread_mutexattr_setprotocol.html http://www.opengroup.org/onlinepubs/009695399/functions/pthread_mutex_init.html
From ERRORS section of pthread_mutexattr_setprotocol:
The pthread_mutexattr_setprotocol() function shall fail if: [ENOTSUP] The value specified by protocol is an unsupported value.
And ENOTSUP is not enumerated in ERRORS section of pthread_mutex_init.
--- Atsushi Nemoto - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |