Re: [PATCH] Replace zone padding with a definition in cache.h

From: Andrew Morton
Date: Wed Mar 16 2005 - 00:25:35 EST


Christoph Lameter <christoph@xxxxxxxxxxx> wrote:
>
> On Tue, 15 Mar 2005, Andrew Morton wrote:
>
> > Christoph Lameter <christoph@xxxxxxxxxxx> wrote:
> > >
> > > +#ifndef ____cacheline_pad_in_smp
> > > +#if defined(CONFIG_SMP)
> > > +#define ____cacheline_pad_in_smp struct { char x; } ____cacheline_maxaligned_in_smp
> > > +#else
> > > +#define ____cacheline_pad_in_smp
> > > +#endif
> > > +#endif
> >
> > That's going to spit a warning with older gcc's. "warning: unnamed
> > struct/union that defines no instances".
> >
> Is it really that important?

Well, it makes gcc-2.95.x unusable, and a number of people like to use it.

It has not proven too burdensome to support. And we know that if it works
on 2.95.x, it will work on 3.1, 3.2, 3.3, etc.

> If the struct is named then there may be
> conflicts if its used repeatedly.

Hence the "hack" which you just deleted ;)
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