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authorMinchan Kim <minchan.kim@gmail.com>2011-10-31 17:06:55 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-08-01 12:27:16 -0700
commit5e02dde6aee7c4492b3a62ad93e7f1120877a019 (patch)
treeea27226fff5a55ddf9a94d5f7a3d14cc6b87b0dc
parent19faec0520b3b16dfd58cde30938a3c4d3dcdd5b (diff)
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mm: zone_reclaim: make isolate_lru_page() filter-aware
commit f80c0673610e36ae29d63e3297175e22f70dde5f upstream. Stable note: Not tracked in Bugzilla. THP and compaction disrupt the LRU list leading to poor reclaim decisions which has a variable performance impact. 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 <minchan.kim@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--include/linux/mmzone.h2
-rw-r--r--mm/vmscan.c20
2 files changed, 20 insertions, 2 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 0ed9149..80acfbc 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -164,6 +164,8 @@ static inline int is_unevictable_lru(enum lru_list l)
#define ISOLATE_ACTIVE ((__force isolate_mode_t)0x2)
/* Isolate clean file */
#define ISOLATE_CLEAN ((__force isolate_mode_t)0x4)
+/* Isolate unmapped file */
+#define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x8)
/* LRU Isolation modes. */
typedef unsigned __bitwise__ isolate_mode_t;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6835735..0c78bd3 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1048,6 +1048,9 @@ 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
@@ -1471,6 +1474,12 @@ 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)) {
@@ -1588,19 +1597,26 @@ 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