Subject: Re: vsdo_datapage.h WTF?

From: Benjamin Herrenschmidt <[email-masked]>
Date: Sun, 08 Oct 2006 07:54:35 +1000

On Sun, 2006-10-08 at 00:58 +1000, Anton Blanchard wrote:
> Hi,
> 
> > No. There -used- to be this systemcfg structure that was exposed to
> > userspace on ppc64. I made it deprecated. However, for the sake of
> > backward compatbility, I kept vdso datapage with the exact same layout
> > for the first part of it (before the syscall maps) and haven't removed
> > the mmap call for it, but it will be gone soon.
> 
> We need a way to export cache size/associativity information (sysfs,
> /proc/device-tree parsing?) and a plan to fix the applications using it
> first.

The application using it can still use its own copy of the old header
tho. And that's why I haven't removed the /proc file and will probably
not do in the near future.

Regarding cache infos, I noticed the lack of anything useful in the
device-tree on Power5 LPAR or did I miss something ? Which means that on
recent machines, the kernel doesn't even know.

Ben.