Hi! On Mon, Jul 20, 2009 at 09:52:57AM +0800, Zhang Xiliang wrote: > I tested the unlock order of rwlock in Linux with SCHED_FIFO and SCHED_RR, and found > that when readers blocked has higher priority than writers, writers always shall > take precedence over readers. > > A write process <--unlock the rwlock > ->A higher priority read process <--block > ->A lower priority write process <--acquired rwlock > > In pthread_rwlock_rdlock() manual, it says: If the Thread Execution Scheduling option is > supported, when threads executing with the scheduling policies SCHED_FIFO, SCHED_RR, or > SCHED_SPORADIC are waiting on the lock, they shall acquire the lock in priority order > when the lock becomes available. > > Signed-off-by: Zhang Xiliang <zhangxiliang@xxxxxxxxxxxxxx> I wonder if there is some kind of policy about how to incorporate this information; putting it in the POSIX manpages is probably unfeasible, but maybe a nptl(7) man-page could be created, covering implementation notes, and put in SEE ALSO section of all pthread manpages? -- Petr "Pasky" Baudis A lot of people have my books on their bookshelves. That's the problem, they need to read them. -- Don Knuth -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
