Re: [Kiobuf-io-devel] RFC: Kernel mechanism: Compound event wait /notify + callback chains

Alan Cox
2001-02-01T18:58:21Z

> It doesn't really matter that much, because we write to the pagecache
> first anyway.

Not for raw I/O. Although for the drivers that can't cope then going via
the page cache is certainly the next best alternative

> The real thing is that we want to have some common data structure for
> describing physical memory used for IO. We could either use special

Yes. You also need a way to describe it in terms of page * in order to do
mm locking for raw I/O (like the video capture stuff wants)

> by Larry McVoy's splice paper) should allow just that, nothing more an
> nothing less. For use in disk-io and networking or v4l there are probably
> other primary data structures needed, and that's ok.

Certainly having the lightweight one a subset of the heavyweight one is a good
target.