[patch 063/262] mm: memcontrol: remove the kmem states

Andrew Morton
2021-11-05T20:37:59Z

From: Muchun Song <songmuchun@bytedance.com>
Subject: mm: memcontrol: remove the kmem states

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.

Link: https://lkml.kernel.org/r/20211025125259.56624-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

include/linux/memcontrol.h | 7 -------
mm/memcontrol.c | 7 ++-----
2 files changed, 2 insertions(+), 12 deletions(-)

--- a/include/linux/memcontrol.h~mm-memcontrol-remove-the-kmem-states
+++ a/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
--- a/mm/memcontrol.c~mm-memcontrol-remove-the-kmem-states
+++ a/mm/memcontrol.c
@@ -3626,7 +3626,6 @@ static int memcg_online_kmem(struct mem_
return 0;

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

memcg_id = memcg_alloc_cache_id();
if (memcg_id < 0)
@@ -3643,7 +3642,6 @@ static int memcg_online_kmem(struct mem_
static_branch_enable(&memcg_kmem_enabled_key);

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

return 0;
}
@@ -3653,11 +3651,9 @@ static void memcg_offline_kmem(struct me
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;
@@ -3676,6 +3672,7 @@ static void memcg_offline_kmem(struct me
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)
_