On Tue, Jun 11, 2013 at 10:17:52AM -0700, Linus Torvalds wrote: > On Tue, Jun 11, 2013 at 9:48 AM, Paul E. McKenney > <paul...@linux.vnet.ibm.com> wrote: > > > > Another approach is to permanently associate queues with each lock, > > but that increases the size of the lock -- something that has raised > > concerns in the past. But if adding 32 bytes to each ticketlock was OK, > > this simplifies things quite a bit. > > Yeah, no. The spinlocks need to be small. We have them in > size-conscious data structures like "struct dentry" and "struct page", > and they really must not be bigger than an "int" in the non-debug > case. > > In fact, I've occasionally thought about combining a spinlock with a > refcounter if that could make things fit in 32 bits on smaller > machines, because we also have ops like "atomic_dec_and_lock()" that > could possibly be optimized if they fit in one word. That is probably > not worth it, but spinlocks do need to remain small.
I was afraid of that. On the other hand, I guess that this means that I sent out the correct patch of the two that I prepared. ;-) Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/