From 1f57f7e7b4b0d3e63fdc46f5b902f451ae897989 Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Wed, 3 Aug 2011 10:52:49 +1000 Subject: [PATCH] In __zone_reclaim case, we don't want to shrink mapped page. Nonetheless, we have isolated mapped page and re-add it into LRU's head. It's unnecessary CPU overhead and makes LRU churning. Of course, when we isolate the page, the page might be mapped but when we try to migrate the page, the page would be not mapped. So it could be migrated. But race is rare and although it happens, it's no big deal. Signed-off-by: Minchan Kim Acked-by: Johannes Weiner Reviewed-by: KAMEZAWA Hiroyuki Reviewed-by: KOSAKI Motohiro Reviewed-by: Michal Hocko Cc: Mel Gorman Cc: Rik van Riel Cc: Andrea Arcangeli Signed-off-by: Andrew Morton --- include/linux/mmzone.h | 3 +++ mm/vmscan.c | 20 ++++++++++++++++++-- 2 files changed, 21 insertions(+), 2 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index ad4b490b926c..19fd15d4734c 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -170,6 +170,9 @@ static inline int is_unevictable_lru(enum lru_list l) #define ISOLATE_ACTIVE ((__force fmode_t)0x2) /* Isolate clean file */ #define ISOLATE_CLEAN ((__force fmode_t)0x4) +/* Isolate unmapped file */ +#define ISOLATE_UNMAPPED ((__force fmode_t)0x8) + /* LRU Isolation modes. */ typedef unsigned __bitwise__ isolate_mode_t; diff --git a/mm/vmscan.c b/mm/vmscan.c index e4dd1aee9a8d..73e6d0699ef1 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1049,6 +1049,9 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file) if ((mode & ISOLATE_CLEAN) && (PageDirty(page) || PageWriteback(page))) return ret; + if ((mode & ISOLATE_UNMAPPED) && page_mapped(page)) + return ret; + if (likely(get_page_unless_zero(page))) { /* * Be careful not to clear PageLRU until after we're @@ -1478,6 +1481,12 @@ shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone, reclaim_mode |= ISOLATE_ACTIVE; lru_add_drain(); + + if (!sc->may_unmap) + reclaim_mode |= ISOLATE_UNMAPPED; + if (!sc->may_writepage) + reclaim_mode |= ISOLATE_CLEAN; + spin_lock_irq(&zone->lru_lock); if (scanning_global_lru(sc)) { @@ -1598,19 +1607,26 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, struct page *page; struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); unsigned long nr_rotated = 0; + isolate_mode_t reclaim_mode = ISOLATE_ACTIVE; lru_add_drain(); + + if (!sc->may_unmap) + reclaim_mode |= ISOLATE_UNMAPPED; + if (!sc->may_writepage) + reclaim_mode |= ISOLATE_CLEAN; + spin_lock_irq(&zone->lru_lock); if (scanning_global_lru(sc)) { nr_taken = isolate_pages_global(nr_pages, &l_hold, &pgscanned, sc->order, - ISOLATE_ACTIVE, zone, + reclaim_mode, zone, 1, file); zone->pages_scanned += pgscanned; } else { nr_taken = mem_cgroup_isolate_pages(nr_pages, &l_hold, &pgscanned, sc->order, - ISOLATE_ACTIVE, zone, + reclaim_mode, zone, sc->mem_cgroup, 1, file); /* * mem_cgroup_isolate_pages() keeps track of -- 2.39.5