From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx126.postini.com [74.125.245.126]) by kanga.kvack.org (Postfix) with SMTP id 624636B0031 for ; Thu, 8 Aug 2013 20:50:31 -0400 (EDT) Received: by mail-ve0-f175.google.com with SMTP id oy10so3630033veb.34 for ; Thu, 08 Aug 2013 17:50:30 -0700 (PDT) Date: Thu, 8 Aug 2013 20:50:26 -0400 From: Tejun Heo Subject: Re: [PATCH 1/3] memcg: limit the number of thresholds per-memcg Message-ID: <20130809005026.GE13427@mtj.dyndns.org> References: <1375874907-22013-1-git-send-email-mhocko@suse.cz> <20130807132210.GD27006@htj.dyndns.org> <20130807134654.GJ8184@dhcp22.suse.cz> <20130807135818.GG27006@htj.dyndns.org> <20130807143727.GA13279@dhcp22.suse.cz> <20130807220513.GA8068@shutemov.name> <20130808144351.GD3189@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130808144351.GD3189@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: "Kirill A. Shutemov" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Johannes Weiner , KAMEZAWA Hiroyuki , Andrew Morton , Anton Vorontsov Hello, On Thu, Aug 08, 2013 at 04:43:51PM +0200, Michal Hocko wrote: > > Is it correct that you fix one local DoS by introducing a new one? > > With the page the !priv user can block root from registering a threshold. > > Is it really the way we want to fix it? > > OK, I will think about it some more. The only thing the patch does is replacing implicit global resource limit with an explicit one. Whether that's useful or not, I don't know, but it doesn't really change the nature of the problem or actually fix anything. The only way to fix it is rewriting the whole thing so that allocations are broken up per source, which I don't think is a good idea at this point. I'd just add a comment noting why it's broken. Given that delegating to !priv users is horribly broken anyway, I don't think this worsens the situation by too much anyway. 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