Re: [PATCH 0/9] x86-64 put current in r10

Matti Aarnio
2005-11-30T15:18:49Z

On Tue, Nov 29, 2005 at 11:21:18PM -0500, Benjamin LaHaise wrote:
> Date: Tue, 29 Nov 2005 23:21:18 -0500
> From: Benjamin LaHaise <bcrl@kvack.org>
> To: Andi Kleen <ak@suse.de>
> Cc: linux-kernel@vger.kernel.org
> Subject: [PATCH 0/9] x86-64 put current in r10
>
> Hello Andi,
>
> The following emails contain the patches to convert x86-64 to store current
> in r10 (also at http://www.kvack.org/~bcrl/patches/v2.6.15-rc3/). This
> provides a significant amount of code savings (~43KB) over the current
> use of the per cpu data area. I also tested using r15, but that generated
> code that was larger than that generated with r10. This code seems to be
> working well for me now (it stands up to 32 and 64 bit processes and ptrace
> users) and would be a good candidate for further exposure.

I would rather prefer NOT to introduce this at this time.
My primary concern is that during "even numbered series" there
should not be radical internal ABI/API changes, like this one.

In 2.7 it can be introduced, by all means.

Indeed at the moment my thinking is, that X86-64 is way more UNSTABLE,
than it should be. (And Linux kernel overall, but that is another story.)

> -ben

/Matti Aarnio