@@ -3629,7 +3629,8 @@ static int memcg_online_kmem(struct mem_cgroup *memcg)
if (cgroup_memory_nokmem)
return 0;
- BUG_ON(memcg->kmemcg_id >= 0);
+ if (unlikely(mem_cgroup_is_root(memcg)))
+ return 0;
memcg_id = memcg_alloc_cache_id();
if (memcg_id < 0)
@@ -3658,6 +3659,9 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg)
if (cgroup_memory_nokmem)
return;
+ if (unlikely(mem_cgroup_is_root(memcg)))
+ return;
+
parent = parent_mem_cgroup(memcg);
if (!parent)
parent = root_mem_cgroup;
@@ -3665,20 +3669,11 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg)
memcg_reparent_objcgs(memcg, parent);
kmemcg_id = memcg->kmemcg_id;
- BUG_ON(kmemcg_id < 0);
/* memcg_reparent_objcgs() must be called before this. */
memcg_drain_all_list_lrus(kmemcg_id, parent);
memcg_free_cache_id(kmemcg_id);
- memcg->kmemcg_id = -1;
-}
-
-static void memcg_free_kmem(struct mem_cgroup *memcg)
-{
- /* css_alloc() failed, offlining didn't happen */
- if (unlikely(memcg->kmemcg_id != -1))
- memcg_offline_kmem(memcg);
}
#else
static int memcg_online_kmem(struct mem_cgroup *memcg)
@@ -3688,9 +3683,6 @@ static int memcg_online_kmem(struct mem_cgroup *memcg)
static void memcg_offline_kmem(struct mem_cgroup *memcg)
{
}
-static void memcg_free_kmem(struct mem_cgroup *memcg)
-{
-}
#endif /* CONFIG_MEMCG_KMEM */
static int memcg_update_kmem_max(struct mem_cgroup *memcg,
@@ -5219,7 +5211,6 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
{
struct mem_cgroup *parent = mem_cgroup_from_css(parent_css);
struct mem_cgroup *memcg, *old_memcg;
- long error = -ENOMEM;
old_memcg = set_active_memcg(parent);
memcg = mem_cgroup_alloc();
@@ -5249,38 +5240,36 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
}
/* The following stuff does not apply to the root */
- error = memcg_online_kmem(memcg);
- if (error)
- goto fail;
-
if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
static_branch_inc(&memcg_sockets_enabled_key);
return &memcg->css;
-fail:
- mem_cgroup_id_remove(memcg);
- mem_cgroup_free(memcg);
- return ERR_PTR(error);
}
static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+ if (memcg_online_kmem(memcg))
+ goto remove_id;
+
/*
* A memcg must be visible for expand_shrinker_info()
* by the time the maps are allocated. So, we allocate maps
* here, when for_each_mem_cgroup() can't skip it.
*/
- if (alloc_shrinker_info(memcg)) {
- mem_cgroup_id_remove(memcg);
- return -ENOMEM;
- }
+ if (alloc_shrinker_info(memcg))
+ goto offline_kmem;
/* Online state pins memcg ID, memcg ID pins CSS */
refcount_set(&memcg->id.ref, 1);
css_get(css);
return 0;
+offline_kmem:
+ memcg_offline_kmem(memcg);
+remove_id:
+ mem_cgroup_id_remove(memcg);
+ return -ENOMEM;
}
static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
@@ -5338,7 +5327,6 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
cancel_work_sync(&memcg->high_work);
mem_cgroup_remove_from_trees(memcg);
free_shrinker_info(memcg);
- memcg_free_kmem(memcg);
mem_cgroup_free(memcg);
}
If we do it in the mem_cgroup_css_online() to make the kmem online, we do not need to set ->kmemcg_id when the kmem is offline. And we also can remove memcg_free_kmem(). So just do that to simplify the code. Signed-off-by: Muchun Song <songmuchun@bytedance.com> --- mm/memcontrol.c | 42 +++++++++++++++--------------------------- 1 file changed, 15 insertions(+), 27 deletions(-)