memcg: zap memcg_can_account_kmem
memcg_can_account_kmem() returns true iff
!mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) &&
memcg_kmem_is_active(memcg);
To begin with the !mem_cgroup_is_root(memcg) check is useless, because one
can't enable kmem accounting for the root cgroup (mem_cgroup_write()
returns EINVAL on an attempt to set the limit on the root cgroup).
Furthermore, the !mem_cgroup_disabled() check also seems to be redundant.
The point is memcg_can_account_kmem() is called from three places:
mem_cgroup_salbinfo_read(), __memcg_kmem_get_cache(), and
__memcg_kmem_newpage_charge(). The latter two functions are only invoked
if memcg_kmem_enabled() returns true, which implies that the memory cgroup
subsystem is enabled. And mem_cgroup_slabinfo_read() shows the output of
memory.kmem.slabinfo, which won't exist if the memory cgroup is completely
disabled.
So let's substitute all the calls to memcg_can_account_kmem() with plain
memcg_kmem_is_active(), and kill the former.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c86cc44..23976fd 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2762,12 +2762,6 @@
static DEFINE_MUTEX(activate_kmem_mutex);
-static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg)
-{
- return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) &&
- memcg_kmem_is_active(memcg);
-}
-
/*
* This is a bit cumbersome, but it is rarely used and avoids a backpointer
* in the memcg_cache_params struct.
@@ -2787,7 +2781,7 @@
struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
struct memcg_cache_params *params;
- if (!memcg_can_account_kmem(memcg))
+ if (!memcg_kmem_is_active(memcg))
return -EIO;
print_slabinfo_header(m);
@@ -3164,7 +3158,7 @@
rcu_read_lock();
memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner));
- if (!memcg_can_account_kmem(memcg))
+ if (!memcg_kmem_is_active(memcg))
goto out;
memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg));
@@ -3249,7 +3243,7 @@
memcg = get_mem_cgroup_from_mm(current->mm);
- if (!memcg_can_account_kmem(memcg)) {
+ if (!memcg_kmem_is_active(memcg)) {
css_put(&memcg->css);
return true;
}