Re: thread_info implementation

[David Howells <dhowells@redhat.com>]

"David S. Miller" <davem@redhat.com> wrote:
>    OK, so back to square one: why am I supposed to do all this work for
>    something that will likely slow things slightly down and, at best,
>    doesn't hurt performance?  The old set up works great and as far as
>    I'm concerned, is not broken.
>
> It keeps your platform the same, and it does help other platforms.
> It is the nature of any abstraction change we make in the kernel
> that platforms have to deal with.

It wasn't all that big a change for the i386 arch either. Most of the changes
to assembly actually involved cleaning up and various assembly sources and
sharing constants (something that should probably have been done a lot
earlier).

What might be worth doing is to move the task_struct slab cache and
(de-)allocator out of fork.c and to stick it in the arch somewhere. Then archs
aren't bound to have the two separate. So for a system that can handle lots of
memory, you can allocate the thread_info, task_struct and supervisor stack all
on one very large chunk if you so wish.

David