+ mm-memcontrol-remove-the-kmem-states.patch added to -mm tree

+ mm-memcontrol-remove-the-kmem-states.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm: memcontrol: remove the kmem states
has been added to the -mm tree.  Its filename is
     mm-memcontrol-remove-the-kmem-states.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-remove-the-kmem-states.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-remove-the-kmem-states.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
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;
 }
@@ -3654,11 +3652,9 @@ static void memcg_offline_kmem(struct me
 	struct mem_cgroup *parent, *child;
 	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;
@@ -3687,6 +3683,7 @@ 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)
_

Patches currently in -mm which might be from songmuchun@bytedance.com are

mm-memcontrol-remove-the-kmem-states.patch