Re: What does atomic_read actually do?

[Joseph Seigh]

On Sat, 18 Dec 2004 20:54:40 +0100, Arjan van de Ven <arjan@xxxxxxxxxxxxx>  
wrote:

> On Sat, 2004-12-18 at 14:20 -0500, Joseph Seigh wrote:
> > I mean atomic in the either old or new sense.  I'm wondering what
> > guarantees
> > the atomicity.  Not the C standard.  I can see the gcc compiler uses a  
> > MOV
> > instruction to load the atomic_t from memory which is guaranteed atomic  
> > by
> > the architecture if aligned properly.  But gcc does that for any old int
> > as far as I can see, so why use atomic_read?
>
> it does so on *x86

Is this documented for gcc anywhere?  Just because it does so doesn't
mean it's guaranteed.

Joe Seigh

-
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/