revert "memcg, vmscan: do not attempt soft limit reclaim if it would not scan anything"

Revert commit e839b6a1c8d0 ("memcg, vmscan: do not attempt soft limit
reclaim if it would not scan anything")

I merged this prematurely - Michal and Johannes still disagree about the
overall design direction and the future remains unclear.

Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 2 insertions, 8 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5ee0af463f2e..5cf7726764cc 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1872,11 +1872,7 @@ enum mem_cgroup_filter_t
 mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
                 struct mem_cgroup *root)
 {
-        struct mem_cgroup *parent;
-
-        if (!memcg)
-                memcg = root_mem_cgroup;
-        parent = memcg;
+        struct mem_cgroup *parent = memcg;
 
         if (res_counter_soft_limit_excess(&memcg->res))
                 return VISIT;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 97b0ed16749f..cdd300b81485 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -142,9 +142,7 @@ static bool global_reclaim(struct scan_control *sc)
 
 static bool mem_cgroup_should_soft_reclaim(struct scan_control *sc)
 {
-        struct mem_cgroup *root = sc->target_mem_cgroup;
-        return !mem_cgroup_disabled() &&
-                mem_cgroup_soft_reclaim_eligible(root, root) != SKIP_TREE;
+        return !mem_cgroup_disabled();
 }
 #else
 static bool global_reclaim(struct scan_control *sc)