From: KOSAKI Motohiro on
Even if pageout() is called from direct reclaim, we can delegate io to
flusher thread if vm pressure is low.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro(a)jp.fujitsu.com>
---
mm/vmscan.c | 7 +++++++
1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8b78b49..eab6028 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -623,6 +623,13 @@ static enum page_references page_check_references(struct page *page,
if (current_is_kswapd())
return PAGEREF_RECLAIM_CLEAN;

+ /*
+ * Now VM pressure is not so high. then we can delegate
+ * page cleaning to flusher thread safely.
+ */
+ if (!sc->order && sc->priority > DEF_PRIORITY/2)
+ return PAGEREF_RECLAIM_CLEAN;
+
return PAGEREF_RECLAIM;
}

--
1.6.5.2



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