The patch titled
Subject: mm/memcontrol.c: convert mem_cgroup_id::ref to refcount_t type
has been added to the -mm tree. Its filename is
mm-convert-mem_cgroup_id-ref-to-refcount_t-type.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-convert-mem_cgroup_id-ref-to-refcount_t-type.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-convert-mem_cgroup_id-ref-to-refcount_t-type.patch
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------------------------------------------------------
From: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Subject: mm/memcontrol.c: convert mem_cgroup_id::ref to refcount_t type
This will allow to use generic refcount_t interfaces to check counters
overflow instead of currently existing VM_BUG_ON(). The only difference
after the patch is VM_BUG_ON() may cause BUG(), while refcount_t fires
with WARN(). But this seems not to be significant here, since such the
problems are usually caught by syzbot with panic-on-warn enabled.
Link: http://lkml.kernel.org/r/153910718919.7006.13400779039257185427.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 2 +-
mm/memcontrol.c | 10 ++++------
2 files changed, 5 insertions(+), 7 deletions(-)
--- a/include/linux/memcontrol.h~mm-convert-mem_cgroup_id-ref-to-refcount_t-type
+++ a/include/linux/memcontrol.h
@@ -78,7 +78,7 @@ struct mem_cgroup_reclaim_cookie {
struct mem_cgroup_id {
int id;
- atomic_t ref;
+ refcount_t ref;
};
/*
--- a/mm/memcontrol.c~mm-convert-mem_cgroup_id-ref-to-refcount_t-type
+++ a/mm/memcontrol.c
@@ -4299,14 +4299,12 @@ static void mem_cgroup_id_remove(struct
static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
{
- VM_BUG_ON(atomic_read(&memcg->id.ref) <= 0);
- atomic_add(n, &memcg->id.ref);
+ refcount_add(n, &memcg->id.ref);
}
static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
{
- VM_BUG_ON(atomic_read(&memcg->id.ref) < n);
- if (atomic_sub_and_test(n, &memcg->id.ref)) {
+ if (refcount_sub_and_test(n, &memcg->id.ref)) {
mem_cgroup_id_remove(memcg);
/* Memcg ID pins CSS */
@@ -4523,7 +4521,7 @@ static int mem_cgroup_css_online(struct
}
/* Online state pins memcg ID, memcg ID pins CSS */
- atomic_set(&memcg->id.ref, 1);
+ refcount_set(&memcg->id.ref, 1);
css_get(css);
return 0;
}
@@ -6357,7 +6355,7 @@ subsys_initcall(mem_cgroup_init);
#ifdef CONFIG_MEMCG_SWAP
static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
{
- while (!atomic_inc_not_zero(&memcg->id.ref)) {
+ while (!refcount_inc_not_zero(&memcg->id.ref)) {
/*
* The root cgroup cannot be destroyed, so it's refcount must
* always be >= 1.
_
Patches currently in -mm which might be from ktkhai@xxxxxxxxxxxxx are
scripts-tags-add-declare_hashtable.patch
mm-convert-mem_cgroup_id-ref-to-refcount_t-type.patch
