Re: [PATCH v3 04/19] mm: slub: implement SLUB version of obj_to_index()

[Christopher Lameter]

On Wed, 22 Apr 2020, Roman Gushchin wrote:

> On Wed, Apr 22, 2020 at 11:52:13PM +0000, Christoph Lameter wrote:
> > On Wed, 22 Apr 2020, Roman Gushchin wrote:
> >
> > >  enum stat_item {
> > >  	ALLOC_FASTPATH,		/* Allocation from cpu slab */
> > > @@ -86,6 +87,7 @@ struct kmem_cache {
> > >  	unsigned long min_partial;
> > >  	unsigned int size;	/* The size of an object including metadata */
> > >  	unsigned int object_size;/* The size of an object without metadata */
> > > +	struct reciprocal_value reciprocal_size;
> >
> >
> > This needs to be moved further back since it is not an item that needs to
> > be cache hot for the hotpaths.
>
> It could be relatively hot, because it's accessed for reading on every
> accounted allocation.

The patch seems to only use it for setup and debugging? It is used for
every "accounted" allocation???? Where? And what is an "accounted"
allocation?