From cf2b8fbf1d2f7ba07999e97685563c94483d33d6 Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Thu, 9 Oct 2014 15:28:59 -0700 Subject: [PATCH] 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 Acked-by: Johannes Weiner Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c86cc442ada4..23976fd885fd 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2762,12 +2762,6 @@ 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. @@ -2787,7 +2781,7 @@ 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); @@ -3164,7 +3158,7 @@ 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)); @@ -3249,7 +3243,7 @@ __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; } -- 2.34.1