From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: memcg Can't context between v1 and v2 because css->refcnt not released Date: Thu, 10 Aug 2017 12:34:06 +0200 Message-ID: <20170810103405.GL23863@dhcp22.suse.cz> References: <20170810071059.GC23863@dhcp22.suse.cz> <20170810081920.GG23863@dhcp22.suse.cz> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: wang Yu Cc: Johannes Weiner , Tejun Heo , cgroups@vger.kernel.org, linux-mm@kvack.org [restoring the CC list] On Thu 10-08-17 17:57:38, wang Yu wrote: > 2017-08-10 17:28 GMT+08:00 wang Yu : [...] > > after drop caches, memory.stat shows not pages belong the group, but > > memory.usage_in_bytes not zero, so maybe other pages > > has wrong to belong this group > > after drop cache, there maybe have kmem pages ,e.g. slab > it can't free both drop cache or tasks free, > so back this problem, without mem_cgroup_reparent_charges, > cgroup v1 can't umount , and cgroup v2 can't mount Ohh, right. It is true that there is no explicit control over kmem page life time. I am afraid this is something non-trivial to address though. I am not sure swithing between cgroup versions is a strong enough use case to implement something like that but you can definitely try to do that. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org