From 4feb21bdac4c00a30f3c0d9361bd3565e6afa72f Mon Sep 17 00:00:00 2001 Message-Id: <4feb21bdac4c00a30f3c0d9361bd3565e6afa72f.1306689214.git.minchan.kim@gmail.com> In-Reply-To: References: From: Minchan Kim Date: Thu, 12 May 2011 02:16:44 +0900 Subject: [PATCH v2 05/10] compaction: make isolate_lru_page with filter aware 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. Reviewed-by: KAMEZAWA Hiroyuki Reviewed-by: KOSAKI Motohiro Acked-by: Johannes Weiner Acked-by: Mel Gorman Cc: Rik van Riel Cc: Andrea Arcangeli Signed-off-by: Minchan Kim --- mm/compaction.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 61eab88..e218562 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -243,6 +243,7 @@ static unsigned long isolate_migratepages(struct zone *zone, unsigned long last_pageblock_nr = 0, pageblock_nr; unsigned long nr_scanned = 0, nr_isolated = 0; struct list_head *migratelist = &cc->migratepages; + enum ISOLATE_PAGE_MODE mode = ISOLATE_BOTH; /* Do not scan outside zone boundaries */ low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn); @@ -327,7 +328,9 @@ static unsigned long isolate_migratepages(struct zone *zone, } /* Try isolate the page */ - if (__isolate_lru_page(page, ISOLATE_BOTH, 0) != 0) + if (!cc->sync) + mode |= ISOLATE_CLEAN; + if (__isolate_lru_page(page, mode, 0) != 0) continue; VM_BUG_ON(PageTransCompound(page)); -- 1.7.0.4