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 <vdavy...@parallels.com>
---
mm/memcontrol.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1ec22bf380d0..63d58d79470d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2786,12 +2786,6 @@ static DEFINE_MUTEX(memcg_slab_mutex);
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.
@@ -2811,7 +2805,7 @@ static int mem_cgroup_slabinfo_read(struct seq_file *m,
void *v)
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);
@@ -3188,7 +3182,7 @@ struct kmem_cache *__memcg_kmem_get_cache(struct
kmem_cache *cachep,
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));
@@ -3273,7 +3267,7 @@ __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup
**_memcg, int order)
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;
}
--
1.7.10.4
--
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