where is __memory_barrier in kernel ?

[Mulyadi Santosa]

On Thu, Mar 10, 2011 at 22:13, loody <miloody at gmail.com> wrote:
> hi
>
> 2011/3/8 piyush moghe <pmkernel at gmail.com>:
>> Yes what you are saying is also right, since in order to prevent the
>> ordering all the pending memory operations should have completed
>> hence as you mentioned processor stops and make sure all the memory
>> operations are completed.
> I am not sure whether all the memory operations are completed after
> cpu stops running for a while.
> I think there should be a more aggressive and precise instruction  to
> handle this behavior, right?

In x86 which does strict ordering, memory barrier is rarely needed,
unless in case such as synchronization between processors or core. In
loose ordering processor such as Alpha, you really need it.

about your question "i am not sure whether all memory operations are
completion"...well, maybe you got it wrong. It's not forcing them to
complete...it make them to be done right now..... a.k.a no more
ordering..."just execute them" now. Symantically, their meanings are
different, right?

and btw, what do you mean by "aggresive and precise"?
-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
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