> Date: Mon, 11 Jul 2016 16:10:04 +0200 (CEST) > From: Stefan Fritsch <s...@sfritsch.de> > > On Mon, 11 Jul 2016, Reyk Floeter wrote: > > The intentional 4GB limit is for forwarding: what if you forward mbufs > > from a 64bit-capable interface to another one that doesn't support 64bit > > DMA? And even if you would only enable it if all interfaces are > > 64bit-capable, what if you plug in a 32bit USB/hotplug interface? We did > > not want to support bounce buffers in OpenBSD. > > Yes, I have understood that. My mail was more about non-mbuf DMA: Does it > make sense to allow 64bit DMA in other cases while keeping the 4GB > limitation for mbufs?
My guess is: not really. I have a hard time coming up with a driver that will allocate significant amounts of DMA memory that isn't a disk or a network driver.
