mm: memcontrol: reparent nr_deferred when memcg offline

Now shrinker's nr_deferred is per memcg for memcg aware shrinkers, add
to parent's corresponding nr_deferred when memcg offline.

Link: https://lkml.kernel.org/r/20210311190845.9708-13-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 32bd62047238af6a31876593a3355cbe7d27fd7b..c193be7607090590dc4b5d8c9df5421909ce237f 100644 (file)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1614,6 +1614,7 @@ static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
 int alloc_shrinker_info(struct mem_cgroup *memcg);
 void free_shrinker_info(struct mem_cgroup *memcg);
 void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id);
+void reparent_shrinker_deferred(struct mem_cgroup *memcg);
 #else
 #define mem_cgroup_sockets_enabled 0
 static inline void mem_cgroup_sk_alloc(struct sock *sk) { };

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 36f31d611dea066793aa8dbe168dec7081218ae9..3004afb6d0901e7b51aca95ffdf4f2770e13abd8 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5154,6 +5154,7 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
        page_counter_set_low(&memcg->memory, 0);
 
        memcg_offline_kmem(memcg);
+       reparent_shrinker_deferred(memcg);
        wb_memcg_offline(memcg);
 
        drain_all_stock(memcg);

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9617c5ff3e98b3b7fdb45ea76301da64b352e40a..8c2d2003acbea9afcbdd4118b97955e677ab7c4c 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -397,6 +397,30 @@ static long add_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker,
        return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]);
 }
 
+void reparent_shrinker_deferred(struct mem_cgroup *memcg)
+{
+       int i, nid;
+       long nr;
+       struct mem_cgroup *parent;
+       struct shrinker_info *child_info, *parent_info;
+
+       parent = parent_mem_cgroup(memcg);
+       if (!parent)
+               parent = root_mem_cgroup;
+
+       /* Prevent from concurrent shrinker_info expand */
+       down_read(&shrinker_rwsem);
+       for_each_node(nid) {
+               child_info = shrinker_info_protected(memcg, nid);
+               parent_info = shrinker_info_protected(parent, nid);
+               for (i = 0; i < shrinker_nr_max; i++) {
+                       nr = atomic_long_read(&child_info->nr_deferred[i]);
+                       atomic_long_add(nr, &parent_info->nr_deferred[i]);
+               }
+       }
+       up_read(&shrinker_rwsem);
+}
+
 static bool cgroup_reclaim(struct scan_control *sc)
 {
        return sc->target_mem_cgroup;