[PATCH] mm, vmscan: Give up balancing node for high order allocations earlier

[Hillf Danton]

To avoid excessive reclaim, we give up rebalancing for high order 
allocations right after reclaiming enough pages.

Signed-off-by: Hillf Danton <hillf...@alibaba-inc.com>
---

 mm/vmscan.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index ee7e531..d080fb2 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3159,8 +3159,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int 
classzone_idx)
 
        do {
                bool raise_priority = true;
-
-               sc.nr_reclaimed = 0;
+               unsigned long reclaimed_pages = sc.nr_reclaimed;
 
                /*
                 * If the number of buffer_heads in the machine exceeds the
@@ -3254,7 +3253,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int 
classzone_idx)
                 * Raise priority if scanning rate is too low or there was no
                 * progress in reclaiming pages
                 */
-               if (raise_priority || !sc.nr_reclaimed)
+               if (raise_priority || sc.nr_reclaimed == reclaimed_pages)
                        sc.priority--;
        } while (sc.priority >= 1);
 
--