[PATCH] mm: memcontrol: remove the kmem states

From: Muchun Song
Date: Mon Oct 25 2021 - 08:53:38 EST


Now the kmem states is only used to indicate whether the kmem is
offline. However, we can set ->kmemcg_id to -1 to indicate whether
the kmem is offline. Finally, we can remove the kmem states to
simplify the code.

Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 7 -------
mm/memcontrol.c | 7 ++-----
2 files changed, 2 insertions(+), 12 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e34bf0cbdf55..509e1480e3be 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -180,12 +180,6 @@ struct mem_cgroup_thresholds {
struct mem_cgroup_threshold_ary *spare;
};

-enum memcg_kmem_state {
- KMEM_NONE,
- KMEM_ALLOCATED,
- KMEM_ONLINE,
-};
-
#if defined(CONFIG_SMP)
struct memcg_padding {
char x[0];
@@ -318,7 +312,6 @@ struct mem_cgroup {

#ifdef CONFIG_MEMCG_KMEM
int kmemcg_id;
- enum memcg_kmem_state kmem_state;
struct obj_cgroup __rcu *objcg;
struct list_head objcg_list; /* list of inherited objcgs */
#endif
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e26f87cd7e4c..760e3669a7c8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3621,7 +3621,6 @@ static int memcg_online_kmem(struct mem_cgroup *memcg)
return 0;

BUG_ON(memcg->kmemcg_id >= 0);
- BUG_ON(memcg->kmem_state);

memcg_id = memcg_alloc_cache_id();
if (memcg_id < 0)
@@ -3638,7 +3637,6 @@ static int memcg_online_kmem(struct mem_cgroup *memcg)
static_branch_enable(&memcg_kmem_enabled_key);

memcg->kmemcg_id = memcg_id;
- memcg->kmem_state = KMEM_ONLINE;

return 0;
}
@@ -3648,11 +3646,9 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg)
struct mem_cgroup *parent;
int kmemcg_id;

- if (memcg->kmem_state != KMEM_ONLINE)
+ if (memcg->kmemcg_id == -1)
return;

- memcg->kmem_state = KMEM_ALLOCATED;
-
parent = parent_mem_cgroup(memcg);
if (!parent)
parent = root_mem_cgroup;
@@ -3671,6 +3667,7 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg)
memcg_drain_all_list_lrus(kmemcg_id, parent);

memcg_free_cache_id(kmemcg_id);
+ memcg->kmemcg_id = -1;
}
#else
static int memcg_online_kmem(struct mem_cgroup *memcg)
--
2.11.0