Re: memory barrier in UP

Hi... On Mon, Dec 12, 2011 at 01:11, subin gangadharan <subingangadharan@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 training: mulyaditraining.blogspot.com