[PATCH v1] mm:memcg: skip memcg of current in mem_cgroup_soft_limit_reclaim

[Zhaoyang Huang]

for the soft_limit reclaim has more directivity than global reclaim, we
have current memcg be skipped to avoid potential page thrashing.

Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxxxxxx>
---
 mm/memcontrol.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 8c0280b..9d09e95 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2537,12 +2537,21 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
 			mz = mem_cgroup_largest_soft_limit_node(mctz);
 		if (!mz)
 			break;
-
+		/*
+		 * skip current memcg to avoid page thrashing, for the
+		 * mem_cgroup_soft_reclaim has more directivity than
+		 * global reclaim.
+		 */
+		if (get_mem_cgroup_from_mm(current->mm) == mz->memcg) {
+			reclaimed = 0;
+			goto next;
+		}
 		nr_scanned = 0;
 		reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat,
 						    gfp_mask, &nr_scanned);
 		nr_reclaimed += reclaimed;
 		*total_scanned += nr_scanned;
+next:
 		spin_lock_irq(&mctz->lock);
 		__mem_cgroup_remove_exceeded(mz, mctz);
 
-- 
1.9.1