Hi Hannes, On Thu, Apr 28, 2011 at 5:48 PM, Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > On Wed, Apr 27, 2011 at 01:25:19AM +0900, Minchan Kim wrote: >> In async mode, compaction doesn't migrate dirty or writeback pages. >> So, it's meaningless to pick the page and re-add it to lru list. >> >> Of course, when we isolate the page in compaction, the page might >> be dirty or writeback but when we try to migrate the page, the page >> would be not dirty, writeback. So it could be migrated. But it's >> very unlikely as isolate and migration cycle is much faster than >> writeout. >> >> So, this patch helps cpu and prevent unnecessary LRU churning. >> >> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> >> Cc: Mel Gorman <mgorman@xxxxxxx> >> Cc: Rik van Riel <riel@xxxxxxxxxx> >> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> >> Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx> >> --- >> Âmm/compaction.c | Â Â2 +- >> Â1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/mm/compaction.c b/mm/compaction.c >> index dea32e3..9f80b5a 100644 >> --- a/mm/compaction.c >> +++ b/mm/compaction.c >> @@ -335,7 +335,7 @@ static unsigned long isolate_migratepages(struct zone *zone, >> Â Â Â Â Â Â Â } >> >> Â Â Â Â Â Â Â /* Try isolate the page */ >> - Â Â Â Â Â Â if (__isolate_lru_page(page, ISOLATE_BOTH, 0, 0, 0) != 0) >> + Â Â Â Â Â Â if (__isolate_lru_page(page, ISOLATE_BOTH, 0, !cc->sync, 0) != 0) >> Â Â Â Â Â Â Â Â Â Â Â continue; > > With the suggested flags argument from 1/8, this would look like: > > Â Â Â Âflags = ISOLATE_BOTH; > Â Â Â Âif (!cc->sync) > Â Â Â Â Â Â Â Âflags |= ISOLATE_CLEAN; > > ? Yes. I will change it. > > Anyway, nice change indeed! Thanks! -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href