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authorKirill Tkhai <ktkhai@virtuozzo.com>2018-10-26 15:09:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-10-26 16:26:35 -0700
commit1c2d479a119b84feacbe4de782016f1bf1ad16dc (patch)
tree75f2e6cd750a91ea76e336aab97fdb50b0cb62c4
parent4a222127f3631e6cdde228e3bb6b599f52b96d14 (diff)
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@virtuozzo.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Andrea Parri <andrea.parri@amarulasolutions.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/memcontrol.h2
-rw-r--r--mm/memcontrol.c10
2 files changed, 5 insertions, 7 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 4399cc3f00e4..7ab2120155a4 100644
--- a/include/linux/memcontrol.h
+++ b/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;
};
/*
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 645ede7ad1b2..92d38c88250f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4299,14 +4299,12 @@ static void mem_cgroup_id_remove(struct mem_cgroup *memcg)
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 cgroup_subsys_state *css)
}
/* 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.