Re: [Qemu-devel] [PATCH 05/16] translate-all: iterate over TBs in a page with PAGE_FOR_EACH_TB

[Emilio G. Cota]

On Wed, Feb 28, 2018 at 13:40:15 -0800, Richard Henderson wrote:
> On 02/26/2018 09:39 PM, Emilio G. Cota wrote:
> > +/* list iterators for lists of tagged pointers in TranslationBlock */
> > +#define TB_FOR_EACH_TAGGED(head, tb, n, field)                  \
> > +    for (n = (head) & 1,                                        \
> > +             tb = (TranslationBlock *)((head) & ~1);            \
> > +         tb;                                                    \
> > +         tb = (TranslationBlock *)tb->field[n],                 \
> > +             n = (uintptr_t)tb & 1,                             \
> > +             tb = (TranslationBlock *)((uintptr_t)tb & ~1))
> > +
> > +#define PAGE_FOR_EACH_TB(pagedesc, tb, n)                       \
> > +    TB_FOR_EACH_TAGGED((pagedesc)->first_tb, tb, n, page_next)
> > +
> 
> I'm not sure I like the generalization of TB_FOR_EACH_TAGGED.  Do you use it
> for anything besides PAGE_FOR_EACH_TB?

Yes, see patch 13. I've added the following comment to the commit log:
 - Introduce the TB_FOR_EACH_TAGGED macro, and use it to define
   PAGE_FOR_EACH_TB, which improves readability. Note that
   TB_FOR_EACH_TAGGED will gain another user in a subsequent patch.

> Weird indentation in the clauses.

Is this any better?

#define TB_FOR_EACH_TAGGED(head, tb, n, field)                          \
    for (n = (head) & 1, tb = (TranslationBlock *)((head) & ~1);        \
         tb; tb = (TranslationBlock *)tb->field[n], n = (uintptr_t)tb & 1, \
             tb = (TranslationBlock *)((uintptr_t)tb & ~1))

> Otherwise,
> Reviewed-by: Richard Henderson <address@hidden>

Thanks,

                Emilio