Re: [00/17] Large Blocksize Support V3

Nicholas Miell
2007-04-27T17:32:13Z

On Fri, 2007-04-27 at 12:55 -0400, Theodore Tso wrote:
> On Thu, Apr 26, 2007 at 10:15:28PM -0700, Andrew Morton wrote:
> > And hardware gets better. If Intel & AMD come out with a 16k pagesize
> > option in a couple of years we'll look pretty dumb. If the problems which
> > you're presently having with that controller get sorted out in the next
> > generation of the hardware, we'll also look pretty dumb.
>
> Unfortunately, this isn't a problem with hardware getting better, but
> a willingness to break backwards compatibility.
>
> x86_64 uses a 4k page size to avoid breaking 32-bit applications. And
> unfortunately, iirc, even 64-bit applications are continuing to depend
> on 4k page alignments for things like the text and bss segments. If
> the userspace ELF and other compiler/linker specifications were
> appropriate written so they could handle 16k pagesizes, maybe 5 years
> from now we could move to a 16k pagesize. But this is going to
> require some coordination between the userspace binutils folks and
> AMD/Intel in order to plan such a migration.
>
> - Ted

The AMD64 psABI requires binaries to work with any page size up to 64k.

Whether that's true in practice is another matter entirely, of course.

--
Nicholas Miell <nmiell@comcast.net>