mm/memcg: scanning_global_lru means mem_cgroup_disabled

Although one has to admire the skill with which it has been concealed,
scanning_global_lru(mz) is actually just an interesting way to test
mem_cgroup_disabled().  Too many developer hours have been wasted on
confusing it with global_reclaim(): just use mem_cgroup_disabled().

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 68e5819d0f1bc5345ba5488acecd7387b1dda27d..7dcc7dac6e1d4b8a86c32fb719cdf8fa670ced30 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -140,26 +140,16 @@ static bool global_reclaim(struct scan_control *sc)
 {
        return !sc->target_mem_cgroup;
 }
-
-static bool scanning_global_lru(struct mem_cgroup_zone *mz)
-{
-       return !mz->mem_cgroup;
-}
 #else
 static bool global_reclaim(struct scan_control *sc)
 {
        return true;
 }
-
-static bool scanning_global_lru(struct mem_cgroup_zone *mz)
-{
-       return true;
-}
 #endif
 
 static struct zone_reclaim_stat *get_reclaim_stat(struct mem_cgroup_zone *mz)
 {
-       if (!scanning_global_lru(mz))
+       if (!mem_cgroup_disabled())
                return mem_cgroup_get_reclaim_stat(mz->mem_cgroup, mz->zone);
 
        return &mz->zone->reclaim_stat;
@@ -168,7 +158,7 @@ static struct zone_reclaim_stat *get_reclaim_stat(struct mem_cgroup_zone *mz)
 static unsigned long zone_nr_lru_pages(struct mem_cgroup_zone *mz,
                                       enum lru_list lru)
 {
-       if (!scanning_global_lru(mz))
+       if (!mem_cgroup_disabled())
                return mem_cgroup_zone_nr_lru_pages(mz->mem_cgroup,
                                                    zone_to_nid(mz->zone),
                                                    zone_idx(mz->zone),
@@ -1587,7 +1577,7 @@ static int inactive_anon_is_low(struct mem_cgroup_zone *mz)
        if (!total_swap_pages)
                return 0;
 
-       if (!scanning_global_lru(mz))
+       if (!mem_cgroup_disabled())
                return mem_cgroup_inactive_anon_is_low(mz->mem_cgroup,
                                                       mz->zone);
 
@@ -1626,7 +1616,7 @@ static int inactive_file_is_low_global(struct zone *zone)
  */
 static int inactive_file_is_low(struct mem_cgroup_zone *mz)
 {
-       if (!scanning_global_lru(mz))
+       if (!mem_cgroup_disabled())
                return mem_cgroup_inactive_file_is_low(mz->mem_cgroup,
                                                       mz->zone);