Re: [PATCH -mm 3/3] page-cgroup: fix flags definition

[Johannes Weiner <hannes@cmpxchg.org>]

On Tue, Jun 24, 2014 at 04:20:52PM -0700, Andrew Morton wrote:
> On Tue, 24 Jun 2014 20:33:06 +0400 Vladimir Davydov <vdavydov@parallels.com> wrote:
> 
> > Since commit a9ce315aaec1f ("mm: memcontrol: rewrite uncharge API"),
> > PCG_* flags are used as bit masks, but they are still defined in a enum
> > as bit numbers. Fix it.
> > 
> > ...
> >
> > --- a/include/linux/page_cgroup.h
> > +++ b/include/linux/page_cgroup.h
> > @@ -1,12 +1,10 @@
> >  #ifndef __LINUX_PAGE_CGROUP_H
> >  #define __LINUX_PAGE_CGROUP_H
> >  
> > -enum {
> > -	/* flags for mem_cgroup */
> > -	PCG_USED,	/* This page is charged to a memcg */
> > -	PCG_MEM,	/* This page holds a memory charge */
> > -	PCG_MEMSW,	/* This page holds a memory+swap charge */
> > -};
> > +/* flags for mem_cgroup */
> > +#define PCG_USED	0x01	/* This page is charged to a memcg */
> > +#define PCG_MEM		0x02	/* This page holds a memory charge */
> > +#define PCG_MEMSW	0x04	/* This page holds a memory+swap charge */
> >  
> >  struct pglist_data;
> >  
> > @@ -44,7 +42,7 @@ struct page *lookup_cgroup_page(struct page_cgroup *pc);
> >  
> >  static inline int PageCgroupUsed(struct page_cgroup *pc)
> >  {
> > -	return test_bit(PCG_USED, &pc->flags);
> > +	return !!(pc->flags & PCG_USED);
> >  }
> >  #else /* !CONFIG_MEMCG */
> >  struct page_cgroup;
> 
> hm, yes, whoops.  I think I'll redo this as a fix against
> mm-memcontrol-rewrite-uncharge-api.patch:

Ouch, yes please.  Thanks for catching this, Vladimir.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

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