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

From: Minchan Kim <minchan@kernel.org>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Rik van Riel <riel@redhat.com>,
	YiPing Xu <xuyiping@hisilicon.com>,
	aquini@redhat.com, rknize@motorola.com,
	Chan Gyun Jeong <chan.jeong@lge.com>,
	Hugh Dickins <hughd@google.com>,
	linux-kernel@vger.kernel.org, Al Viro <viro@ZenIV.linux.org.uk>,
	virtualization@lists.linux-foundation.org, bfields@fieldses.org,
	linux-mm@kvack.org, Gioh Kim <gi-oh.kim@profitbricks.com>,
	koct9i@gmail.com, Sangseok Lee <sangseok.lee@lge.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	jlayton@poochiereds.net, Vlastimil Babka <vbabka@suse.cz>,
	Mel Gorman <mgorman@suse.de>
Subject: Re: [PATCH v3 06/16] zsmalloc: squeeze inuse into page->mapping
Date: Tue, 19 Apr 2016 16:40:59 +0900	[thread overview]
Message-ID: <20160419074059.GA18448__34952.8184430257$1461051626$gmane$org@bbox> (raw)
In-Reply-To: <20160417150804.GA575@swordfish>

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!