From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: [PATCH 2/8] mm: memcontrol: remove double kmem page_counter init Date: Thu, 10 Dec 2015 13:40:19 +0100 Message-ID: <20151210124019.GH19496@dhcp22.suse.cz> References: <1449599665-18047-1-git-send-email-hannes@cmpxchg.org> <1449599665-18047-3-git-send-email-hannes@cmpxchg.org> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <1449599665-18047-3-git-send-email-hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Johannes Weiner Cc: Andrew Morton , Vladimir Davydov , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-team-b10kYP2dOMg@public.gmane.org On Tue 08-12-15 13:34:19, Johannes Weiner wrote: > The kmem page_counter's limit is initialized to PAGE_COUNTER_MAX > inside mem_cgroup_css_online(). There is no need to repeat this > from memcg_propagate_kmem(). > > Signed-off-by: Johannes Weiner Acked-by: Michal Hocko > --- > mm/memcontrol.c | 24 ++++++++++-------------- > 1 file changed, 10 insertions(+), 14 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index eda8d43..02167db 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2840,8 +2840,7 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css, > } > > #ifdef CONFIG_MEMCG_KMEM > -static int memcg_activate_kmem(struct mem_cgroup *memcg, > - unsigned long nr_pages) > +static int memcg_activate_kmem(struct mem_cgroup *memcg) > { > int err = 0; > int memcg_id; > @@ -2876,13 +2875,6 @@ static int memcg_activate_kmem(struct mem_cgroup *memcg, > goto out; > } > > - /* > - * We couldn't have accounted to this cgroup, because it hasn't got > - * activated yet, so this should succeed. > - */ > - err = page_counter_limit(&memcg->kmem, nr_pages); > - VM_BUG_ON(err); > - > static_branch_inc(&memcg_kmem_enabled_key); > /* > * A memory cgroup is considered kmem-active as soon as it gets > @@ -2903,10 +2895,14 @@ static int memcg_update_kmem_limit(struct mem_cgroup *memcg, > int ret; > > mutex_lock(&memcg_limit_mutex); > - if (!memcg_kmem_is_active(memcg)) > - ret = memcg_activate_kmem(memcg, limit); > - else > - ret = page_counter_limit(&memcg->kmem, limit); > + /* Top-level cgroup doesn't propagate from root */ > + if (!memcg_kmem_is_active(memcg)) { > + ret = memcg_activate_kmem(memcg); > + if (ret) > + goto out; > + } > + ret = page_counter_limit(&memcg->kmem, limit); > +out: > mutex_unlock(&memcg_limit_mutex); > return ret; > } > @@ -2925,7 +2921,7 @@ static int memcg_propagate_kmem(struct mem_cgroup *memcg) > * after this point, because it has at least one child already. > */ > if (memcg_kmem_is_active(parent)) > - ret = memcg_activate_kmem(memcg, PAGE_COUNTER_MAX); > + ret = memcg_activate_kmem(memcg); > mutex_unlock(&memcg_limit_mutex); > return ret; > } > -- > 2.6.3 -- Michal Hocko SUSE Labs