Re: [PATCH v3 06/16] zsmalloc: squeeze inuse into page->mapping

[Minchan Kim <minchan@kernel.org>]

On Mon, Apr 18, 2016 at 12:08:04AM +0900, Sergey Senozhatsky wrote:
> Hello,
> 
> On (03/30/16 16:12), Minchan Kim wrote:
> [..]
> > +static int get_zspage_inuse(struct page *first_page)
> > +{
> > +	struct zs_meta *m;
> > +
> > +	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
> > +
> > +	m = (struct zs_meta *)&first_page->mapping;
> ..
> > +static void set_zspage_inuse(struct page *first_page, int val)
> > +{
> > +	struct zs_meta *m;
> > +
> > +	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
> > +
> > +	m = (struct zs_meta *)&first_page->mapping;
> ..
> > +static void mod_zspage_inuse(struct page *first_page, int val)
> > +{
> > +	struct zs_meta *m;
> > +
> > +	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
> > +
> > +	m = (struct zs_meta *)&first_page->mapping;
> ..
> >  static void get_zspage_mapping(struct page *first_page,
> >  				unsigned int *class_idx,
> >  				enum fullness_group *fullness)
> >  {
> > -	unsigned long m;
> > +	struct zs_meta *m;
> > +
> >  	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
> > +	m = (struct zs_meta *)&first_page->mapping;
> ..
> >  static void set_zspage_mapping(struct page *first_page,
> >  				unsigned int class_idx,
> >  				enum fullness_group fullness)
> >  {
> > +	struct zs_meta *m;
> > +
> >  	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
> >  
> > +	m = (struct zs_meta *)&first_page->mapping;
> > +	m->fullness = fullness;
> > +	m->class = class_idx;
> >  }
> 
> 
> a nitpick: this
> 
> 	struct zs_meta *m;
> 	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
> 	m = (struct zs_meta *)&first_page->mapping;
> 
> 
> seems to be common in several places, may be it makes sense to
> factor it out and turn into a macro or a static inline helper?
> 
> other than that, looks good to me

Yeb.

> 
> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>

Thanks for the review!