Re: [Xen-ia64-devel] [PATCH 1/7][SMP] add volatile to mpt_table

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

Le Vendredi 16 Juin 2006 16:32, Alex Williamson a Ãcrit :
> On Fri, 2006-06-16 at 10:38 +0900, Isaku Yamahata wrote:
> > The below two lines follows.
> >
> >         map_start = mpt_table + (__pa(start) >> PAGE_SHIFT);
> >         map_end   = mpt_table + (__pa(end) >> PAGE_SHIFT);
> >
> > Gcc produces warnings without volatile.
>
> Isaku,
>
>    I think it would be more clear to cast mpt_table as a non-volatile
> than to introduce new volatile variables to avoid compiler warnings.
> These has me confused as well.  Thanks,
Just my opinion:

I don't see the confusion and I don't like the cast.  I'd prefer to keep the 
qualifier.
If map_start/map_end are not deferred the volatile qualifier has no cost.  If 
they are deferred, the volatile qualifier should be kept.

[Again, this is just my opinion].

Tristan.

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