On Mon, 2007-08-20 at 17:12 +0300, Avi Kivity wrote: > Dor Laor wrote: > > Using Rusty's code there is no waste. > > Each descriptor has a flag (head|next). Next flag stands for pointer to > > the > > next descriptor with u32 next index. So the waste is 4 bytes. > > Sg descriptors are chained on the same descriptor ring. > > > > Block I/O can easily require 256 sglist entries, eating up your ring.
Absolutely; I think we'd want this variable sized, rather than a single page as the current implementation does for no really sound reason. That said, I don't have a problem with Avi's out-of-band mechanism. A "DMA" hypercall can follow that almost as easily, and it does give that nice "fixed number of slots" effect. Cheers, Rusty. _______________________________________________ Virtualization mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/virtualization
