revert "vmscan, memcg: do softlimit reclaim also for targeted reclaim"

Revert commit a5b7c87f9207 ("vmscan, memcg: do softlimit reclaim also
for targeted reclaim")

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>

3 files changed, 9 insertions, 15 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index ef2b9bd7fafa..6054c9f3a5e8 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -234,8 +234,7 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
         mem_cgroup_update_page_stat(page, idx, -1);
 }
 
-bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
-                struct mem_cgroup *root);
+bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg);
 
 void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx);
 static inline void mem_cgroup_count_vm_event(struct mm_struct *mm,
@@ -435,8 +434,7 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
 }
 
 static inline
-bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
-                struct mem_cgroup *root)
+bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg)
 {
         return false;
 }
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 65e7bec4b0f0..47cdc7eb1a6b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1760,13 +1760,11 @@ int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
 #endif
 
 /*
- * A group is eligible for the soft limit reclaim under the given root
- * hierarchy if
- *      a) it is over its soft limit
+ * A group is eligible for the soft limit reclaim if
+ *      a) it is over its soft limit
  *      b) any parent up the hierarchy is over its soft limit
  */
-bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
-                struct mem_cgroup *root)
+bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg)
 {
         struct mem_cgroup *parent = memcg;
 
@@ -1774,14 +1772,12 @@ bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
                 return true;
 
         /*
-         * If any parent up to the root in the hierarchy is over its soft limit
-         * then we have to obey and reclaim from this group as well.
+         * If any parent up the hierarchy is over its soft limit then we
+         * have to obey and reclaim from this group as well.
          */
         while ((parent = parent_mem_cgroup(parent))) {
                 if (res_counter_soft_limit_excess(&parent->res))
                         return true;
-                if (parent == root)
-                        break;
         }
 
         return false;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 17a7134de4d7..0e081cada4ba 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -142,7 +142,7 @@ static bool global_reclaim(struct scan_control *sc)
 
 static bool mem_cgroup_should_soft_reclaim(struct scan_control *sc)
 {
-        return !mem_cgroup_disabled();
+        return !mem_cgroup_disabled() && global_reclaim(sc);
 }
 #else
 static bool global_reclaim(struct scan_control *sc)
@@ -2195,7 +2195,7 @@ __shrink_zone(struct zone *zone, struct scan_control *sc, bool soft_reclaim)
                         struct lruvec *lruvec;
 
                         if (soft_reclaim &&
-                            !mem_cgroup_soft_reclaim_eligible(memcg, root)) {
+                            !mem_cgroup_soft_reclaim_eligible(memcg)) {
                                 memcg = mem_cgroup_iter(root, memcg, &reclaim);
                                 continue;
                         }