Hi Mel,
On Thu, Jun 09, 2011 at 02:33:27PM +0100, Mel Gorman wrote:
> 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
I used page_is_file_cache and logical not.
If page_is_file_cache returns zero(ie, anon), logicacl not makes it with 0.
If page_is_file_cache doesn't return zero(ie, file), logical not makes it with 1.
So, anon pages would be put in count[0] and file pages would be in count[1].
Do I miss your point?
> 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
--
Kind regards
Minchan Kim
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