Re: [patch 02/41] cpu alloc: The allocator

[Eric Dumazet]

Christoph Lameter a écrit :
> On Wed, 4 Jun 2008, Mike Travis wrote:
>
> > I'm a bit confused.  Why is DEFINE_PER_CPU_SHARED_ALIGNED() conditioned on
> > ifdef MODULE?
> >
> >         #ifdef MODULE
> >         #define SHARED_ALIGNED_SECTION ".data.percpu"
> >         #else
> >         #define SHARED_ALIGNED_SECTION ".data.percpu.shared_aligned"
> >         #endif
> >
> >         #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)                       \
> >                 __attribute__((__section__(SHARED_ALIGNED_SECTION)))            \
> >                 PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name             \
> >                 ____cacheline_aligned_in_smp
>
> Looks wrong to me. There can be shared objects even without modules.

Well, MODULE is not CONFIG_MODULES :)

If compiling an object that is going to be statically linked to kernel, 
MODULE is not defined, so we have shared objects.

When compiling a module, we cannot *yet* use .data.percpu.shared_aligned 
section, since module loader wont handle this section.

Alternative is to change modules linking for all arches to merge 
.data.percpu{*} subsections correctly, or tell module loader to take 
into account all .data.percpu sections.

AFAIK no module uses DEFINE_PER_CPU_SHARED_ALIGNED() yet...



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/