> >> It gets better, though. The same hook is used in the version of blktap > >> in linux-2.6.18-xen (not, as far as I can see, in the sparse tree for > >> xen-3.1-testing): > > > > Oh, I'm thinking more in the direction of killing blktap altogether in > > favor of a pure userspace implementation on top of gntdev. > > I think this would represent good progress, though I wonder if there > would be a performance penalty due to performing the mapping and > unmapping in user-space (multiple syscalls per mapping versus a single > hypercall). Maybe a change to the gntdev userspace API to allow batching of mapping requests? I'm not aware of a batched mmap interface, which would seem to be the ideal solution; but it should be possible to batch this stuff somehow. Although it seems like some kind of really weird ioctl might be needed :-S to do it *without* such a batched interface... blktap in userspace, if any performance problems can be addressed, would seem to be a far nicer way of doing things. And it's less code to merge upstream ;-) Cheers, Mark -- Dave: Just a question. What use is a unicyle with no seat? And no pedals! Mark: To answer a question with a question: What use is a skateboard? Dave: Skateboards have wheels. Mark: My wheel has a wheel! _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
