memory barrier in UP

[Mulyadi Santosa]

Hi...

On Mon, Dec 12, 2011 at 01:11, subin gangadharan
<subingangadharan at gmail.com> wrote:
> Hi All,
>
> I am reading about the barrier from linux kernel development.In this
> books, he says
> "On SMP kernels they are defined only as usual memory barriers.where
> as on UP kernels they are
> defined only as a compiler barrier"
>
> Does this mean in UP, processor won't reorder the instructions ?

In some arch like Alpha, loosely reordering even in UP could happen at
any time. But in x86 UP, IIRC there's only strict re-ordering, meaning
that every read is always fetching latest write etc.

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
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