On Mon, 2018-03-26 at 10:54 -0600, Jason Gunthorpe wrote: > On Mon, Mar 26, 2018 at 11:08:45AM +0000, David Laight wrote: > > > > This is a super performance critical operation for most drivers and > > > > directly impacts network performance. > > > > Perhaps there ought to be writel_nobarrier() (etc) that never contain > > any barriers at all. > > This might mean that they are always just the memory operation, > > but it would make it more obvious what the driver was doing. > > I think that is what writel_relaxed is supposed to be. > > The only restriction it has is that the writes to a single device > using UC memory must be kept in program order.. Which requires barriers on some architectures :-) Also we don't have a clear definition of what happens on WC memory. Cheers, Ben. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
