Re: [PATCH 8/14] i386 / Add a per cpu gdt accessor

From: Chris Wright
Date: Tue Aug 16 2005 - 19:25:10 EST


* Andi Kleen (ak@xxxxxxx) wrote:
> On Tue, Aug 16, 2005 at 05:07:36PM -0700, Chris Wright wrote:
> > * Andi Kleen (ak@xxxxxxx) wrote:
> > > On Wed, Aug 10, 2005 at 09:56:40PM -0700, zach@xxxxxxxxxx wrote:
> > > > Add an accessor function for getting the per-CPU gdt. Callee must already
> > > > have the CPU.
> > >
> > > What is the accessor good for?
> > >
> > > It looks just like code obfuscation to me.
> >
> > Xen handles gdt differently (one page per cpu instead of per_cpu data).
> > So this is for handling that access cleanly.
>
> It would be much cleaner to use a per_cpu pointer then and just allocate
> it differently.

OK, that's easily done, but it will add extra indirection. This currently
changes nothing for common case. The cpu_gdt_descr effectively has that
address cached already (just not as per_cpu).
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