Re: [PATCH][2.5] smp_call_function_mask

From: Alan Cox (alan@lxorguk.ukuu.org.uk)
Date: Tue Jan 21 2003 - 18:14:49 EST


On Tue, 2003-01-21 at 07:13, Manfred Spraul wrote:
> Alan wrote:
>
> >On Fri, 2003-01-17 at 05:18, Zwane Mwaikambo wrote:
> >> + /* Wait for response */
> >> + while (atomic_read(&data.started) != num_cpus)
> >> + barrier();
> >
> >Only old old intel x86 that does -bad- things as it
> >generates a lot of bus locked cycles. Better to do
> >
> > while(atomic_read(&data.started) != num_cpus)

> from 2.5.52, <asm-i386/atomic.h>
> #define atomic_read(v) ((v)->counter)
> AFAIK atomic_read never contained locked bus cycles.

For x86 at least it never did, you are right. Must be time for
a brain transplant

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