On Tue, Jun 07, 2011 at 11:38:14PM +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.
> In addtion, cc->nr_[anon|file] is used in only acct_isolated so it doesn't have
> fields in conpact_control.
> This patch removes fields from compact_control and makes clear function of
> acct_issolated which counts the number of anon|file pages isolated.
>
> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> Cc: Mel Gorman <mgorman@xxxxxxx>
> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
> Acked-by: Rik van Riel <riel@xxxxxxxxxx>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>
> ---
> mm/compaction.c | 18 +++++-------------
> 1 files changed, 5 insertions(+), 13 deletions(-)
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 021a296..61eab88 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -35,10 +35,6 @@ struct compact_control {
> unsigned long migrate_pfn; /* isolate_migratepages search base */
> bool sync; /* Synchronous migration */
>
> - /* Account for isolated anon and file pages */
> - unsigned long nr_anon;
> - unsigned long nr_file;
> -
> unsigned int order; /* order a direct compactor needs */
> int migratetype; /* MOVABLE, RECLAIMABLE etc */
> struct zone *zone;
> @@ -212,17 +208,13 @@ static void isolate_freepages(struct zone *zone,
> static void acct_isolated(struct zone *zone, struct compact_control *cc)
> {
> struct page *page;
> - unsigned int count[NR_LRU_LISTS] = { 0, };
> + unsigned int count[2] = { 0, };
>
> - list_for_each_entry(page, &cc->migratepages, lru) {
> - int lru = page_lru_base_type(page);
> - count[lru]++;
> - }
> + list_for_each_entry(page, &cc->migratepages, lru)
> + count[!!page_is_file_cache(page)]++;
>
> - cc->nr_anon = count[LRU_ACTIVE_ANON] + count[LRU_INACTIVE_ANON];
> - cc->nr_file = count[LRU_ACTIVE_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);
> + __mod_zone_page_state(zone, NR_ISOLATED_ANON, count[0]);
> + __mod_zone_page_state(zone, NR_ISOLATED_FILE, count[1]);
You are hard-coding assumptions about the value of LRU_INACTIVE_ANON
and LRU_INACTIVE_FILE here. I have no expectation that these will
change but who knows for sure? To be robust against unexpected
changes, count should still be NR_LRU_LISTS and you should use the
LRU_INACTIVE_ANON and LRU_INACTIVE_FILE values.
I agree that summing LRU_ACTIVE_* is silly.
--
Mel Gorman
SUSE Labs
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