On Sat, 16 Feb 2008 11:41:35 +0100 Brice Goglin <[EMAIL PROTECTED]> wrote:
> Andrew Morton wrote: > > What is the status of getting infiniband to use this facility? > > > > How important is this feature to KVM? > > > > To xpmem? > > > > Which other potential clients have been identified and how important it it > > to those? > > > > As I said when Andrea posted the first patch series, I used something > very similar for non-RDMA-based HPC about 4 years ago. I haven't had > time yet to look in depth and try the latest proposed API but my feeling > is that it looks good. > "looks good" maybe. But it's in the details where I fear this will come unstuck. The likelihood that some callbacks really will want to be able to block in places where this interface doesn't permit that - either to wait for IO to complete or to wait for other threads to clear critical regions. >From that POV it doesn't look like a sufficiently general and useful design. Looks like it was grafted onto the current VM implementation in a way which just about suits two particular clients if they try hard enough. Which is all perfectly understandable - it would be hard to rework core MM to be able to make this interface more general. But I do think it's half-baked and there is a decent risk that future (or present) code which _could_ use something like this won't be able to use this one, and will continue to futz with mlock, page-pinning, etc. Not that I know what the fix to that is.. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
