[PATCH] mm, memcg: assign memcg-aware shrinkers bitmap to memcg fix

[Johannes Weiner]

The shrinker bitmap allocation is a bit out of place in the css
onlining path.

Allocate and free those bitmaps as part of the memcg alloc and free
procedures.

Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
 mm/memcontrol.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c9098200326f..82eb40b715da 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4342,6 +4342,7 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
 {
 	int node;
 
+	memcg_free_shrinker_maps(memcg);
 	for_each_node(node)
 		free_mem_cgroup_per_node_info(memcg, node);
 	free_percpu(memcg->stat_cpu);
@@ -4381,6 +4382,9 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
 		if (alloc_mem_cgroup_per_node_info(memcg, node))
 			goto fail;
 
+	if (memcg_alloc_shrinker_maps(memcg))
+		goto fail;
+
 	if (memcg_wb_domain_init(memcg, GFP_KERNEL))
 		goto fail;
 
@@ -4470,11 +4474,6 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
 {
 	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
 
-	if (memcg_alloc_shrinker_maps(memcg)) {
-		mem_cgroup_id_remove(memcg);
-		return -ENOMEM;
-	}
-
 	/* Online state pins memcg ID, memcg ID pins CSS */
 	atomic_set(&memcg->id.ref, 1);
 	css_get(css);
@@ -4527,7 +4526,6 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
 	vmpressure_cleanup(&memcg->vmpressure);
 	cancel_work_sync(&memcg->high_work);
 	mem_cgroup_remove_from_trees(memcg);
-	memcg_free_shrinker_maps(memcg);
 	memcg_free_kmem(memcg);
 	mem_cgroup_free(memcg);
 }
-- 
2.18.0