From: Arnd Bergmann <arnd@xxxxxxxx>
Subject: mm: memcontrol: avoid unused function warning
A bugfix in v4.8-rc2 introduced a harmless warning when CONFIG_MEMCG_SWAP
is disabled but CONFIG_MEMCG is enabled:
mm/memcontrol.c:4085:27: error: 'mem_cgroup_id_get_online' defined but not used [-Werror=unused-function]
static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
This moves the function inside of the #ifdef block that hides the
calling function, to avoid the warning.
Fixes: 1f47b61fb407 ("mm: memcontrol: fix swap counter leak on swapout from offline cgroup")
Link: http://lkml.kernel.org/r/20160824113733.2776701-1-arnd@xxxxxxxx
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 36 ++++++++++++++++++------------------
1 file changed, 18 insertions(+), 18 deletions(-)
diff -puN mm/memcontrol.c~mm-memcontrol-avoid-unused-function-warning mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcontrol-avoid-unused-function-warning
+++ a/mm/memcontrol.c
@@ -4082,24 +4082,6 @@ static void mem_cgroup_id_get_many(struc
atomic_add(n, &memcg->id.ref);
}
-static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
-{
- while (!atomic_inc_not_zero(&memcg->id.ref)) {
- /*
- * The root cgroup cannot be destroyed, so it's refcount must
- * always be >= 1.
- */
- if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
- VM_BUG_ON(1);
- break;
- }
- memcg = parent_mem_cgroup(memcg);
- if (!memcg)
- memcg = root_mem_cgroup;
- }
- return memcg;
-}
-
static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
{
if (atomic_sub_and_test(n, &memcg->id.ref)) {
@@ -5821,6 +5803,24 @@ static int __init mem_cgroup_init(void)
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)) {
+ /*
+ * The root cgroup cannot be destroyed, so it's refcount must
+ * always be >= 1.
+ */
+ if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
+ VM_BUG_ON(1);
+ break;
+ }
+ memcg = parent_mem_cgroup(memcg);
+ if (!memcg)
+ memcg = root_mem_cgroup;
+ }
+ return memcg;
+}
+
/**
* mem_cgroup_swapout - transfer a memsw charge to swap
* @page: page whose memsw charge to transfer
_
--
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