From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 10/11] memcg: allow a memcg with kmem charges to be destructed. Date: Mon, 25 Jun 2012 11:34:42 -0700 Message-ID: <20120625183442.GG3869@google.com> References: <1340633728-12785-1-git-send-email-glommer@parallels.com> <1340633728-12785-11-git-send-email-glommer@parallels.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=U6YEUUKf0tMAcNVWWSQGjd8gPtV1FTmMLT3kuN7SSF4=; b=eozXgkoyL6iA/Jl8jpYTMyWsnb4pufDVnsn8D0lzXrG6otWuJGWlXtgyvq1hFEovFn 3Vxbx+2/w+Si2QoQ1NLQRW+QDTDbM3PXzzbNh4aITlqzJtzB4QQ9VNFW+SyBhOe1DJQz ScaYaAQOZb02A1waS67oLC8GP3LkdaLR4lfy0Ii7HEzUDn0PIYycvfiBEIBmcm8ykBb9 LKIm1tfp8Ncq6P15NcfHCMNPP4pXp5Jtjokss2eQoPNOJrwccwn0VURDzANLFSjIeZm6 CxOCNxNV2CUYPpucSvxZKTHuuxtmwtcli8roX1bAmzRpb0PfAgNGFGQPe4r++jQZwxQV Jiag== Content-Disposition: inline In-Reply-To: <1340633728-12785-11-git-send-email-glommer@parallels.com> Sender: owner-linux-mm@kvack.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Glauber Costa Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org, Frederic Weisbecker , David Rientjes , Pekka Enberg , Michal Hocko , Johannes Weiner , Christoph Lameter , devel@openvz.org, kamezawa.hiroyu@jp.fujitsu.com, Pekka Enberg , Suleiman Souhlal On Mon, Jun 25, 2012 at 06:15:27PM +0400, Glauber Costa wrote: > Because the ultimate goal of the kmem tracking in memcg is to > track slab pages as well, we can't guarantee that we'll always > be able to point a page to a particular process, and migrate > the charges along with it - since in the common case, a page > will contain data belonging to multiple processes. > > Because of that, when we destroy a memcg, we only make sure > the destruction will succeed by discounting the kmem charges > from the user charges when we try to empty the cgroup. > > Signed-off-by: Glauber Costa > CC: Christoph Lameter > CC: Pekka Enberg > CC: Michal Hocko > CC: Kamezawa Hiroyuki > CC: Johannes Weiner > CC: Suleiman Souhlal > --- > mm/memcontrol.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index a6a440b..bb9b6fe 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -598,6 +598,11 @@ static void disarm_kmem_keys(struct mem_cgroup *memcg) > { > if (test_bit(KMEM_ACCOUNTED_THIS, &memcg->kmem_accounted)) > static_key_slow_dec(&mem_cgroup_kmem_enabled_key); > + /* > + * This check can't live in kmem destruction function, > + * since the charges will outlive the cgroup > + */ > + BUG_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0); WARN_ON() please. Misaccounted kernel usually is better than dead kernel. Thanks. -- tejun -- 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