Re: [PATCH 2/7] memcg: remove MEMCG_NR_FILE_MAPPED

[Michal Hocko <mhocko@suse.cz>]

On Wed 04-07-12 14:56:08, Michal Hocko wrote:
> On Thu 28-06-12 18:58:31, Sha Zhengju wrote:
> > From: Sha Zhengju <handai.szj@taobao.com>
> > 
> > While accounting memcg page stat, it's not worth to use MEMCG_NR_FILE_MAPPED
> > as an extra layer of indirection because of the complexity and presumed
> > performance overhead. We can use MEM_CGROUP_STAT_FILE_MAPPED directly.
> > 
> > Signed-off-by: Sha Zhengju <handai.szj@taobao.com>
> 
> Acked-by: Michal Hocko <mhocko@suse.cz>

And forgot to mention that this one can be merged right away.

> 
> > ---
> >  include/linux/memcontrol.h |   25 +++++++++++++++++--------
> >  mm/memcontrol.c            |   24 +-----------------------
> >  mm/rmap.c                  |    4 ++--
> >  3 files changed, 20 insertions(+), 33 deletions(-)
> > 
> > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> > index 83e7ba9..20b0f2d 100644
> > --- a/include/linux/memcontrol.h
> > +++ b/include/linux/memcontrol.h
> > @@ -27,9 +27,18 @@ struct page_cgroup;
> >  struct page;
> >  struct mm_struct;
> >  
> > -/* Stats that can be updated by kernel. */
> > -enum mem_cgroup_page_stat_item {
> > -	MEMCG_NR_FILE_MAPPED, /* # of pages charged as file rss */
> > +/*
> > + * Statistics for memory cgroup.
> > + */
> > +enum mem_cgroup_stat_index {
> > +	/*
> > +	 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
> > +	 */
> > +	MEM_CGROUP_STAT_CACHE, 	   /* # of pages charged as cache */
> > +	MEM_CGROUP_STAT_RSS,	   /* # of pages charged as anon rss */
> > +	MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
> > +	MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */
> > +	MEM_CGROUP_STAT_NSTATS,
> >  };
> >  
> >  struct mem_cgroup_reclaim_cookie {
> > @@ -164,17 +173,17 @@ static inline void mem_cgroup_end_update_page_stat(struct page *page,
> >  }
> >  
> >  void mem_cgroup_update_page_stat(struct page *page,
> > -				 enum mem_cgroup_page_stat_item idx,
> > +				 enum mem_cgroup_stat_index idx,
> >  				 int val);
> >  
> >  static inline void mem_cgroup_inc_page_stat(struct page *page,
> > -					    enum mem_cgroup_page_stat_item idx)
> > +					    enum mem_cgroup_stat_index idx)
> >  {
> >  	mem_cgroup_update_page_stat(page, idx, 1);
> >  }
> >  
> >  static inline void mem_cgroup_dec_page_stat(struct page *page,
> > -					    enum mem_cgroup_page_stat_item idx)
> > +					    enum mem_cgroup_stat_index idx)
> >  {
> >  	mem_cgroup_update_page_stat(page, idx, -1);
> >  }
> > @@ -349,12 +358,12 @@ static inline void mem_cgroup_end_update_page_stat(struct page *page,
> >  }
> >  
> >  static inline void mem_cgroup_inc_page_stat(struct page *page,
> > -					    enum mem_cgroup_page_stat_item idx)
> > +					    enum mem_cgroup_stat_index idx)
> >  {
> >  }
> >  
> >  static inline void mem_cgroup_dec_page_stat(struct page *page,
> > -					    enum mem_cgroup_page_stat_item idx)
> > +					    enum mem_cgroup_stat_index idx)
> >  {
> >  }
> >  
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index a2677e0..ebed1ca 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -77,20 +77,6 @@ static int really_do_swap_account __initdata = 0;
> >  #endif
> >  
> >  
> > -/*
> > - * Statistics for memory cgroup.
> > - */
> > -enum mem_cgroup_stat_index {
> > -	/*
> > -	 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
> > -	 */
> > -	MEM_CGROUP_STAT_CACHE, 	   /* # of pages charged as cache */
> > -	MEM_CGROUP_STAT_RSS,	   /* # of pages charged as anon rss */
> > -	MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
> > -	MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */
> > -	MEM_CGROUP_STAT_NSTATS,
> > -};
> > -
> >  static const char * const mem_cgroup_stat_names[] = {
> >  	"cache",
> >  	"rss",
> > @@ -1926,7 +1912,7 @@ void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
> >  }
> >  
> >  void mem_cgroup_update_page_stat(struct page *page,
> > -				 enum mem_cgroup_page_stat_item idx, int val)
> > +				 enum mem_cgroup_stat_index idx, int val)
> >  {
> >  	struct mem_cgroup *memcg;
> >  	struct page_cgroup *pc = lookup_page_cgroup(page);
> > @@ -1939,14 +1925,6 @@ void mem_cgroup_update_page_stat(struct page *page,
> >  	if (unlikely(!memcg || !PageCgroupUsed(pc)))
> >  		return;
> >  
> > -	switch (idx) {
> > -	case MEMCG_NR_FILE_MAPPED:
> > -		idx = MEM_CGROUP_STAT_FILE_MAPPED;
> > -		break;
> > -	default:
> > -		BUG();
> > -	}
> > -
> >  	this_cpu_add(memcg->stat->count[idx], val);
> >  }
> >  
> > diff --git a/mm/rmap.c b/mm/rmap.c
> > index 2144160..d6b93df 100644
> > --- a/mm/rmap.c
> > +++ b/mm/rmap.c
> > @@ -1148,7 +1148,7 @@ void page_add_file_rmap(struct page *page)
> >  	mem_cgroup_begin_update_page_stat(page, &locked, &flags);
> >  	if (atomic_inc_and_test(&page->_mapcount)) {
> >  		__inc_zone_page_state(page, NR_FILE_MAPPED);
> > -		mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_MAPPED);
> > +		mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
> >  	}
> >  	mem_cgroup_end_update_page_stat(page, &locked, &flags);
> >  }
> > @@ -1202,7 +1202,7 @@ void page_remove_rmap(struct page *page)
> >  					      NR_ANON_TRANSPARENT_HUGEPAGES);
> >  	} else {
> >  		__dec_zone_page_state(page, NR_FILE_MAPPED);
> > -		mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_MAPPED);
> > +		mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
> >  	}
> >  	/*
> >  	 * It would be tidy to reset the PageAnon mapping here,
> > -- 
> > 1.7.1
> > 

-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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