[PATCH 2/2] Filter unevictable page out in deactivate_page

Minchan Kim
2011-05-01T15:04:22Z

It's pointless that deactive_page's pagevec operation about
unevictable page as it's nop.
This patch removes unnecessary overhead which might be a bit problem
in case that there are many unevictable page in system(ex, mprotect workload)

Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
---
mm/swap.c | 9 +++++++++
1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index 2e9656d..b707694 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -511,6 +511,15 @@ static void drain_cpu_pagevecs(int cpu)
*/
void deactivate_page(struct page *page)
{
+
+ /*
+ * In workload which system has many unevictable page(ex, mprotect),
+ * unevictalge page deactivation for accelerating reclaim
+ * is pointless.
+ */
+ if (PageUnevictable(page))
+ return;
+
if (likely(get_page_unless_zero(page))) {
struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs);

--
1.7.1