Re: [Tarantool-patches] [PATCH v2 06/16] port: increase padding of struct port

[Nikita Pettik <korablev@tarantool.org>]

On 04 Dec 14:42, Konstantin Osipov wrote:
> * Nikita Pettik <korablev@tarantool.org> [19/11/21 10:00]:
> > We are going to extend context of struct port_sql. One already inherits
> > struct port_tuple, which makes it size barely fits into 48 bytes of
> > padding of basic structure (struct port). Hence, let's increase padding
> > a bit to be able to add at least one more member to struct port_sql.
> 
> This is very verbose but still unclear :) What makes you certain 4
> bytes is enough?  Be it a pointer or integer, it may be 4 or 8
> bytes depending on the platform.
> Please explain.

Because I'm adding two 1-byte members (uint8_t). Two additional
bytes just to avoid another one size patching in case smb needs
more space.

> Otherwise lgtm.
> 
> > ---
> >  src/lib/core/port.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/src/lib/core/port.h b/src/lib/core/port.h
> > index d61342287..bfdfa4656 100644
> > --- a/src/lib/core/port.h
> > +++ b/src/lib/core/port.h
> > @@ -122,7 +122,7 @@ struct port {
> >  	 * Implementation dependent content. Needed to declare
> >  	 * an abstract port instance on stack.
> >  	 */
> > -	char pad[48];
> > +	char pad[52];
> >  };
> >  
> >  /** Is not inlined just to be exported. */
> > -- 
> > 2.15.1
> > 
> 
> -- 
> Konstantin Osipov, Moscow, Russia