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>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5ee0af4..5cf7726 100644 (file)
--- 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 97b0ed1..cdd300b 100644 (file)
--- 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)