From mboxrd@z Thu Jan  1 00:00:00 1970
From: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH -v2] memcg: don't do cleanup manually if mem_cgroup_css_online()
 fails
Date: Wed, 3 Apr 2013 16:37:53 +0800
Message-ID: <515BEA61.9080100@huawei.com>
References: <515A8A40.6020406@huawei.com> <20130402121600.GK24345@dhcp22.suse.cz> <20130402141646.GQ24345@dhcp22.suse.cz> <515AE948.1000704@parallels.com> <20130402142825.GA32520@dhcp22.suse.cz> <515AEC3A.2030401@parallels.com> <20130402150422.GB32520@dhcp22.suse.cz> <515BA6C9.2000704@huawei.com> <20130403074300.GA14384@dhcp22.suse.cz> <515BDEF2.1080900@huawei.com> <20130403081843.GC14384@dhcp22.suse.cz>
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To: Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>
Cc: Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>, LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Cgroups <cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org

>>> But memcg_update_cache_sizes calls memcg_kmem_clear_activated on the
>>> error path.
>>>
>>
>> But memcg_kmem_mark_dead() checks the ACCOUNT flag not the ACCOUNTED flag.
>> Am I missing something?
>>
> 
> Dang. You are right! Glauber, is there any reason why
> memcg_kmem_mark_dead checks only KMEM_ACCOUNTED_ACTIVE rather than
> KMEM_ACCOUNTED_MASK?
> 
> This all is very confusing to say the least.
> 
> Anyway, this all means that Li's first patch is correct. I am not sure I
> like it though. I think that the refcount cleanup should be done as
> close to where it has been taken as possible otherwise we will end up in
> this "chase the nasty details" again and again. There are definitely two
> bugs here. The one introduced by e4715f01 and the other one introduced
> even earlier (I haven't checked that history yet). I think we should do
> something like the 2 follow up patches but if you guys think that the smaller
> patch from Li is more appropriate then I will not block it.
> 

Or we can queue my patch for 3.9, and then see if we want to change the
tear down process, and if yes we make the change for 3.10.