Re: [RFC 5/8] compaction: remove active list counting

[Johannes Weiner <hannes@cmpxchg.org>]

On Wed, Apr 27, 2011 at 01:25:22AM +0900, Minchan Kim wrote:
> acct_isolated of compaction uses page_lru_base_type which returns only
> base type of LRU list so it never returns LRU_ACTIVE_ANON or LRU_ACTIVE_FILE.
> So it's pointless to add lru[LRU_ACTIVE_[ANON|FILE]] to get sum.
> 
> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Andrea Arcangeli <aarcange@redhat.com>
> Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
> ---
>  mm/compaction.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 9f80b5a..653b02b 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -219,8 +219,8 @@ static void acct_isolated(struct zone *zone, struct compact_control *cc)
>  		count[lru]++;
>  	}
>  
> -	cc->nr_anon = count[LRU_ACTIVE_ANON] + count[LRU_INACTIVE_ANON];
> -	cc->nr_file = count[LRU_ACTIVE_FILE] + count[LRU_INACTIVE_FILE];
> +	cc->nr_anon = count[LRU_INACTIVE_ANON];
> +	cc->nr_file = count[LRU_INACTIVE_FILE];
>  	__mod_zone_page_state(zone, NR_ISOLATED_ANON, cc->nr_anon);
>  	__mod_zone_page_state(zone, NR_ISOLATED_FILE, cc->nr_file);
>  }

I don't see anything using cc->nr_anon and cc->nr_file outside this
code.  Would it make sense to remove them completely?