On Wed, Apr 29, 2020 at 06:42:55PM +0200, Markus Elfring wrote:
> > In a couple of places in the slub memory allocator, the code uses
> > "s->offset" as a check to see if the free pointer is put right after the
> > object. That check is no longer true with commit 3202fa62fb43 ("slub:
> > relocate freelist pointer to middle of object").
>
> Will any further collateral evolution become interesting?
What do you mean by this question?
> > +static inline unsigned int get_info_end(struct kmem_cache *s)
> > +{
> > + if (freeptr_outside_object(s))
> > + return s->inuse + sizeof(void *);
> > + else
> > + return s->inuse;
> > +}
>
> How do you think about the following source code variants?
>
> + return freeptr_outside_object(s)
> + ? s->inuse + sizeof(void *)
> + : s->inuse;
That is less clear than the version Wayman posted.
> > static struct track *get_track(struct kmem_cache *s, void *object,
> > enum track_item alloc)
> > {
> > struct track *p;
> >
> > - if (s->offset)
> > - p = object + s->offset + sizeof(void *);
> > - else
> > - p = object + s->inuse;
> > + p = object + get_info_end(s);
> >
> > return p + alloc;
> > }
>
> + struct track *p = object + get_info_end(s);
>
> return p + alloc;
Yes, I think that's an improvement.
