Re: Add macros for ReorderBufferTXN toptxn

On Tue, Mar 14, 2023 at 10:43 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Tue, Mar 14, 2023 at 12:37 PM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
> >
> > Thanks for the review!
> >
> > On Mon, Mar 13, 2023 at 6:19 PM vignesh C <vignesh21(at)gmail(dot)com> wrote:
> > ...
> >
> > > 4) We check if txn->toptxn is not null twice here both in if condition
> > > and in the assignment, we could retain the assignment operation as
> > > earlier to remove the 2nd check:
> > > - if (txn->toptxn)
> > > - txn = txn->toptxn;
> > > + if (isa_subtxn(txn))
> > > + txn = get_toptxn(txn);
> > >
> > > We could avoid one check again by:
> > > + if (isa_subtxn(txn))
> > > + txn = txn->toptxn;
> > >
> >
> > Yeah, that is true, but I chose not to keep the original assignment in
> > this case mainly because then it is consistent with the other changed
> > code --- e.g. Every other direct member assignment/access of the
> > 'toptxn' member now hides behind the macros so I did not want this
> > single place to be the odd one out. TBH, I don't think 1 extra check
> > is of any significance, but it is not a problem to change like you
> > suggested if other people also want it done that way.
> >
>
> Can't we directly use rbtxn_get_toptxn() for this case? I think that
> way code will look neat. I see that it is not exactly matching the
> existing check so you might be worried but I feel the new code will
> achieve the same purpose and will be easy to follow.
>

OK. Done as suggested.

PSA v3.

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Kind Regards,
Peter Smith.
Fujitsu Australia