I not quit sure whether this is the right place to ask, if is not please tell me which mail list should I send to the mail, thanks.
When run the POSIX test, some cases about pthread rwlock fail. Test steps are as follow:
1. Main thread set its shcedule policy as "SCHED_FIFO", with highest priority: sched_get_priority_min()+2.
2. Main thread read lock 'rwlock'
3. Create a writer thread, with schedule policy as "SCHED_FIFO", and priority using sched_get_priority_min()+1.
4. The thread write lock 'rwlock', should block.
5. Main thread create a reader thread, with schedule policy as "SCHED_FIFO", and priority sched_get_priority_min()
6. Reader thread read lock 'rwlock', should block, since there is a higher priority writer blocked on 'rwlock'
But the reader thread doesn't block. Because in POSIX specification or pthread_rwlock_rdlock() manual page says:
If the Thread Execution Scheduling option is supported, and the threads involved in the lock are executing
with the scheduling policies SCHED_FIFO or SCHED_RR, the calling thread shall not acquire the lock if a
writer holds the lock or if writers of higher or equal priority are blocked on the lock; otherwise, the call‐
ing thread shall acquire the lock.
So it seems the implementation of pthread rwlock doesn't obey the POSIX specification, right? If so, if there is a plan to
make eglibc rwlock obey the POSIX specification?
I notice that there is a flag in pthread_rwlock_t to spec prefer read lock or right lock, but it doesn't care the priorities.
Any reply is appreciate.
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